alza-corporation-v-doris-thompson-individually-and-townsi-foulkrod-as ( 2010 )


Menu:
  •                                     NUMBER 13-07-00090-CV
    COURT OF APPEALS
    THIRTEENTH DISTRICT OF TEXAS
    CORPUS CHRISTI - EDINBURG
    ALZA CORPORATION,                                                                                   Appellant,
    v.
    DORIS THOMPSON, INDIVIDUALLY,
    AND TOWNSI FOULKROD
    AS LEGAL REPRESENTATIVE OF
    KENZEY THOMPSON, MINOR,
    INDIVIDUALLY AND ON BEHALF
    OF THE ESTATE OF MICHAELYNN THOMPSON,                                                              Appellees.
    On appeal from the 113th District Court
    of Harris County, Texas.1
    MEMORANDUM OPINION
    Before Justices Yañez, Benavides, and Vela
    Memorandum Opinion by Justice Yañez
    1
    This appeal was transferred to this Court from the First Court of Appeals by order of the Texas
    Suprem e Court. See T EX . G O V ’T C OD E A N N . § 22.220 (Vernon 2004) (delineating the jurisdiction of appellate
    courts); T EX . G O V ’T C OD E A N N . § 73.001 (Vernon 2005) (granting the suprem e court the authority to transfer
    cases from one court of appeals to another at any tim e that there is “good cause” for the transfer).
    Alza Corp. (“Alza”) appeals a judgment on a jury verdict rendered against it in a
    wrongful death case involving allegations of negligence, strict products liability
    manufacturing defects,2 and gross negligence regarding its manufacture of the Duragesic
    patch. The manufacturing defect asserted is a flaw in the seal of the Duragesic patch
    which allowed decedent, Michaelynn Thompson, to receive a fatal overdose of fentanyl,
    a potent narcotic.3 The negligence and gross negligence claims include complaints that
    Alza continued to employ a visual inspection process, intended to spot manufacturing
    defects in the Duragesic patches as they passed on a conveyor belt, even after Alza knew
    that such a process was inadequate to detect the flawed patches in order to remove them
    from distribution to patients.4
    The plaintiffs-appellees (“the Thompson family”)5 tried their claims arising from the
    death of Michaelynn Thompson against Alza before a jury in the 113th Judicial District
    Court in Harris County, Texas, with the Honorable Patricia Hancock presiding. The jury
    found that there was a manufacturing defect in the Duragesic patch worn by Thompson
    which was a cause of her death, and further found that Alza was negligent, but declined
    to find Alza grossly negligent. The trial court rendered judgment on the jury’s verdict. Alza
    2
    “W hile strict liability focuses on the condition of the product, ‘[n]egligence looks at the acts of the
    m anufacturer and determ ines if it exercised ordinary care in design and production.’” Am. Tobacco Co., Inc.
    v. Grinnell, 951 S.W .2d 420, 437 (Tex. 1997) (quoting Caterpillar, Inc. v. Shears, 911 S.W .2d 379, 384 (Tex.
    1995)).
    3
    Alza’s brief describes fentanyl as “a powerful narcotic painkiller” adm inistered by a “Duragesic patch
    that releases doses of the m edicine into the patient’s bloodstream via the skin.”
    4
    W e note that the trial court was not the first court to address punitive dam age claim s against Alza
    based on allegedly defective Duragesic fentanyl patches. See, e.g., Lake-Allen v. Johnson & Johnson, L.P.,
    No. 2:08CV00930DAK, 
    2009 U.S. Dist. LEXIS 64860
    , at *9-10 (D. Utah July 27, 2009) (denying defendants’
    m otion for sum m ary judgm ent on punitive dam age claim s).
    5
    Plaintiffs below and appellees herein include Doris Thom pson, individually, and Townsi Foulkrod as
    legal representative of Kenzey Thom pson, m inor, individually and on behalf of the estate of Michaelynn
    Thom pson.
    2
    appeals by five issues and multiple sub-issues, generally challenging the sufficiency of the
    evidence and two evidentiary rulings. We affirm.
    I. BACKGROUND
    The Duragesic patch is a prescription pain patch utilized to treat moderate to severe
    chronic pain. It is a transdermal system that adheres to a patient’s skin and is designed
    to provide the patient with a continuous, systematic delivery of fentanyl, a potent opioid
    analgesic, for a period of seventy-two hours. This patch is comprised of four layers: an
    external backing of polyester film, a drug reservoir containing fentanyl and alcohol in a gel
    solution, a membrane that controls the rate of fentanyl delivery to the skin surface, and an
    adhesive worn next to the skin. The Duragesic patches come in several strengths.
    The Duragesic 75 mcg/hr patch worn by Thompson at the time of her death6 was
    manufactured on Alza’s Bodolay machine. The patches at issue were made at a rate of
    about four per second, and the quality control process for the patches entailed a visual
    assessment by two inspectors as the patches went by on a high-speed conveyor belt.
    From 2001 through 2004, Alza documented many instances where patients had received
    Duragesic patches manufactured on its Bodolay machine with flawed seals7 that were not
    detected by Alza’s visual inspection process. The number of patient complaints regarding
    defective 75 mcg/hr patches escalated sharply in 2003 and early 2004, ultimately involving
    an inspection by the United States Food and Drug Administration (“FDA”) and the recalls
    of four lots of 75 mcg/hr Duragesic patches.
    Rudolph Holland, a senior technician on the Bodolay running the Duragesic line for
    6
    The evidence showing that Thom pson was wearing this patch will be discussed later in this opinion.
    7
    The FDA ultim ately identified eight different kinds of defects, which ranged in severity from , e.g.,
    “stringer leakers,” where a strand of gel kept the seal on the patch from com plete closure, to the defect at
    issue herein, a “fold-over” defect, which left an entire side of the Duragesic patch unsealed.
    3
    Alza, testified about the specific manufacturing process and product components that
    constitute the Duragesic patch. At trial, Holland testified that he was not mechanically
    inclined, and that no one ever asked him what could have contributed to the number of
    leaking patches.
    Holland testified that he was aware that Alza had been notified of a fold-over defect
    in a Duragesic patch in 2001. Holland’s sworn testimony established that in 2001, after
    learning that a fold-over occurred, and after realizing how the defect occurred during its
    manufacturing process, the company made no changes to its quality control procedures;
    however, Alza did instruct its employees to look for fold-over defects during the visual
    inspection process.    Holland testified that Alza’s visual inspection process entailed
    watching 120 lines of product go by per minute. Holland testified that he has never seen
    a fold-over defect. Alza’s visual inspections detected no problems with the two-and-a-half
    million Duragesic patches that were ultimately recalled by Alza in 2004 because of the
    prevalence of fold-over defects.
    In 2003, Holland “thought everything was fine” regarding the company’s
    manufacturing process, and thought that the visual inspection process was sufficient, but
    conceded in retrospect that “we could have made some changes,” and concluded in his
    testimony before the jury that asking the employees to look harder for defects was not
    sufficient to prevent product defects. Holland testified that Alza improved and modified
    some of its inspection procedures after the Duragesic recall in 2004, so that the Duragesic
    patches now go through a weight check, a pressure check, a visual inspection, and quali-
    pack testing with a vacuum. He further testified that quality assurance employees also
    hold “line audits” every eight hours.
    Holland did not know how many leaking patches Alza produced; however, based on
    4
    patient complaints to the company, 35 out of 40 lots of 75 mcg patches manufactured
    between January 1, 2003 and June 8, 2004 contained leaking patches. According to
    documents he reviewed at trial, Holland testified before the jury that reports of leaking
    patches were lower in two of the five recalled batches than in other batches that Alza
    chose not to recall. Holland expressly admitted in testimony to the jury that he would have
    notified the FDA of the escalating number of fold-over defects earlier than Alza did.
    As mentioned above, when complaints from the public about the Duragesic patch
    escalated sharply in late 2003 and 2004, the FDA investigated this problem. According to
    the FDA’s inspection report,8 Alza characterized the initial problem as an isolated incident,
    and Alza’s approach to the problem was to re-train the operators:
    The firm first came across a fold over defect from a field sample return back
    in 10/01 . . . and assigned a probable cause as the polyester/EVA film being
    folded over during a roll change or start up. The firm’s corrective action was
    to train operators to “heightened awareness” and that the fold over was an
    “isolated incident.” This corrective action did not prevent the fold over defect
    from reoccurring . . . .
    The FDA’s inspection report found Alza’s remedial actions inadequate:
    •       Corrective actions implemented on 10/01 for Pouched Lot #0101663
    were inadequate to prevent the fold over defect from reoccurring as
    demonstrated in Pouched Lot #’s 0327192 and 0327294 on 02/04.
    •       Lack of increased acceptance criteria should an inspection fail a level
    one inspection.
    •       Firm did not follow SOP 05-020-045 to discard product after a defect
    was found.
    •       After awareness of fold over defect and Voluntary Class 1 Recall, firm
    released Pouched Lot # 0330362 into commercial distribution without
    further inspection.
    •       Pouched Lot # 0327711 was released into commercial distribution
    8
    For another court’s discussion of the FDA’s Establishm ent Inspection Report and its Inspectional
    Observations, please see Miller v. Janssen Pharmaceutical Products, L.P., No. 05-CV-4076-DRH , 2007 U.S.
    Dist. LEXIS 31863, at *8-9 (S.D. Ill. May 1, 2007) (not designated for publication).
    5
    even though it failed release specifications.
    •      In-process and QC checks were inadequate to prevent the release of
    the fold over defect as demonstrated in Pouched Lot #’s 0327192 and
    0327294.
    •      Firm did not follow Sop 0-109 to justify continuation of production.
    The FDA’s inspection report also specifically addressed Alza’s training of the operators:
    [T]his approach of reactionary training of operators from field complaints did
    not appear to alleviate these types of product defects due to this corrective
    action being seen in one Exception Report after another. I expressed the
    possibility of the firm to institute a preventative training program for the
    operators in addition to their routine GMP training on a regular basis through
    the year. All parties agreed that this was a positive approach and provided
    a memo reflecting this preventative training program . . . .
    The FDA inspection report also noted that the “defect would be incorporated into the patch
    and could go undetected with current QA checks in place.” Similarly, the FDA proposed
    ways “to prevent this defect from reoccurring,” and Alza agreed that “equipment changes
    and controls are the best remedies for preventing this defect in the future.” In this context,
    the FDA report documented numerous changes in Alza’s Bodolay machine, which was at
    the end of its usefulness and scheduled for replacement, in order to reduce the incidence
    of manufacturing defects. The report includes an evaluation of this process with Alza’s
    management:
    On 6/08/04, [the FDA representative] held a discussion with [Alza
    representatives] regarding the Bodolay I FFS and [its] ability to produce
    quality product or should the machine be retired. All three expressed their
    desire to improve operations and that the implementation of the HH FFS is
    on top priority to be validated and put into production to be the main
    manufacturing line for Duragesic and therefore reserve the Bodolay I FFS as
    a backup machine. They continued to express that the changes made to the
    Bodolay I FFS and the implementation of the vision system on the Bodolay
    I should and will improve the quality of product produced.
    6
    As a result of this defect, Alza recalled about 2,500,000 of its Duragesic patches in 2004.9
    Also during 2004, Dr. Elias Benhamou, a pain management specialist who is board-
    certified in anesthesiology, prescribed Duragesic patches for Michaelynn Thompson, who
    was suffering chronic back pain after a car crash.10 Dr. Benhamou prescribed these
    Duragesic patches during the time period after Alza began its defect investigation but
    before Alza initiated the recall.11 At trial, Dr. Benhamou testified that an overdose of
    fentanyl results in symptoms including discomfort, difficulty breathing, sweating, dizziness,
    9
    The FDA has stated that:
    Recall is an effective m ethod of rem oving or correcting consum er products that are in
    violation of laws adm inistered by the Food and Drug Adm inistration. Recall is a voluntary
    action that takes place because m anufacturers and distributors carry out their responsibility
    to protect the public health and well-being from products that present a risk of injury or gross
    deception or are otherwise defective.
    21 C.F.R.§ 7.40(a) (2009). A recall is an “alternative” to a FDA-initiated court action, and the agency, by
    setting forth specific procedures, can “m onitor recalls and assess the adequacy of a firm ’s efforts in recall.”
    
    Id. The FDA
    evaluates the health hazard presented by a product being recalled or considered for recall and
    assigns the recall a classification, i.e., Class I, Class II, or Class III, to indicate the relative degree of health
    hazard of the product being recalled or considered for recall:
    (1) Class I is a situation in which there is a reasonable probability that the use of, or exposure
    to, a violative product will cause serious adverse health consequences or death.
    (2) Class II is a situation in which use of, or exposure to, a violative product m ay cause
    tem porary or m edically reversible adverse health consequences or where the probability of
    serious adverse health consequences is rem ote.
    (3) Class III is a situation in which use of, or exposure to, a violative product is not likely to
    cause adverse health consequences.
    21 C.F.R. § 7.41 (2009); 21 C .F.R.§ 7.3(m )(1)-(3) (2009). The recall of Alza’s Duragesic patches was
    originally classified as a Class I recall and ultim ately reclassified as a Class II recall.
    10
    W e note that som e of the cases involving claim s against Alza based on flaws in its Duragesic
    fentanyl patches have also included claim s against the prescribing doctor. See, e.g., Borowicz v. Alza Corp.,
    No. 1:09-CV-00785, 
    2009 U.S. Dist. LEXIS 53589
    , at *1-3 (N.D. Ohio June 24, 2009); Browning v. Alza Corp.,
    No. 1:09-04402009, 
    2009 U.S. Dist. LEXIS 42755
    , at *2 (S.D. W . Va. May 20, 2009). But see Middlebrooks
    v. Johnson & Johnson Co., No. 4:08-CV-54 (CDL), 
    2008 U.S. Dist. LEXIS 75420
    , at *1-2 M.D. Ga. Aug. 26,
    2008) (not designated for publication)(no claim s raised against prescribing physician in context of suit against
    Alza and other m akers of allegedly defective Duragesic fentanyl patches); W orkman v. Johnson & Johnson,,
    No. 06-2523 (DMC), 
    2007 U.S. Dist. LEXIS 46214
    , at * 1-2 (D. N.J. June 26, 2007) (not designated for
    publication) (sam e). In this case, neither party raised any allegation against the prescribing physician.
    11
    Less than a m onth passed from Dr. Benham ou’s prescription of the Duragesic patches and
    Thom pson’s death. During that sam e general tim e period, Alza logged 21 com plaints about leaking Duragesic
    patches from one particular lot in circulation within the health care supply system .
    7
    and nausea, and that a Duragesic patch leaking an uncontrolled amount of fentanyl could
    result in the death of the patient.
    During the early morning hours of February 13, 2004, Thompson began vomiting
    and complaining of dizziness and back pain. The vomiting continued on an hourly basis
    until morning. Thompson’s thirteen-year old daughter, Kenzey Marie Thompson, ultimately
    called an ambulance for her at approximately 9:00 a.m. While transporting Thompson to
    the emergency room, the emergency technicians performed an electrocardiogram
    (“EKG”)12 on Thompson showing normal results.
    Thompson’s medical records from Fort Bend Methodist Hospital state that
    Thompson was wearing a “Duragesic patch” upon admission to the emergency room.
    These records indicate that Thompson’s complaints included dizziness, nausea, vomiting,
    abdominal pain, and left flank pain.              Nurse Camille Green testified that Thompson
    complained of abdominal pain and dizziness. Kenzey testified that her mother was acting
    “weird” at the hospital.
    Dr. Donnie Evans, the emergency room physician, treated Thompson. He ordered
    numerous tests, including a chest pain evaluation, an electrocardiogram, and cardiac
    enzyme tests. The tests showed no arrhythmia or heart damage. After Thompson’s
    complaints of pain subsided, Fort Bend began preparations to release her. Kenzey
    telephoned members of their church to come pick them up from the hospital, and
    Thompson and Kenzey waited to be released. Kenzey testified that her mother told her
    that she was really tired and that she was going to take a nap. Kenzey slept also. Upon
    12
    An electrocardiogram , or EKG, graphically records the electrical activity of the heart. See Columbia
    Med. Ctr. of Las Colinas, Inc. v. Hogue, 271 S.W .3d 238, 244 (Tex. 2008) (citing C E C IL E S S E N T IA L S OF
    M EDICINE 47, 55 (Thom as E. Andreoli, M.D. et al. eds., 6th ed. 2004)).
    8
    waking, Kenzey attempted to wake her mother but was unable to do so. She informed a
    nurse, who told her that her mother would have to be awake to be discharged. Kenzey
    saw her mother, apparently asleep, lying on her stomach. Kenzey noted that her mother’s
    legs were bluish-purple with goose bumps, and she was lying face-down in her pillow with
    her hands up by her face, and her fingernails were purple. Kenzey attempted to rouse her
    mother because the nurse had said they could leave if she could wake her, but Kenzey
    was unable to do so.
    Kenzey testified that she had seen a patch on her mother’s abdomen the night
    before, and she said her mother was really good about going to her doctor and changing
    out her patches.
    During this period, Nurse Karen Marie Cothran testified that Kenzey approached her
    sometime before 3:50 p.m., and told her that her mother was sleeping a lot. Cothran told
    Kenzey that her mother would have to wake up before she could be discharged. Cothran
    entered the room at 3:50 p.m. and found Thompson, who was not breathing, laying on her
    stomach with her face in the pillow. She moved Thompson and sounded an emergency
    code.
    Dr. Evans testified that when he entered the room, Thompson’s back was noticeably
    blue. He and a team began resuscitation efforts to no avail. He saw the patch on
    Thompson’s back and ripped it off because it was “an unknown,” and threw it away. On
    the same day that Thompson died, Alza initiated the initial phase of the recall, and several
    days later, Dr. Evans received notice of the recall. He promptly contacted Thompson’s
    family so that they could look into whether the patch had any causal relationship to her
    death. Dr. Evans testified that he had no concerns about drug toxicity, nor did he see signs
    thereof when he was treating her, but at the same time, he did not realize she had the
    9
    patch on. In this regard, we note that testimony at trial established that symptoms of an
    overdose of fentanyl include, inter alia, nausea, vomiting, sleepiness, dizziness, and
    respiratory depression.
    As a result of the contact between Dr. Evans and the Thompson family, the family
    repeatedly requested the medical examiner to test the level of fentanyl in Michaelynn’s
    blood. Despite these requests, the medical examiner performed a routine medical drug
    screen, with negative results, but did not test Thompson’s blood for fentanyl. Evidence at
    trial confirmed that it is not possible to determine whether someone has a toxic level of
    fentanyl in their blood without testing for it.          The medical examiner did save a femoral
    blood sample and sent it to an outside laboratory, Accu-Chem, for testing at the Thompson
    family’s request. This test showed that Thompson had a blood fentanyl quantitation of 11.4
    ng/ml. A therapeutic range for fentanyl is 1.0 to 2.0 ng/ml, and a toxic range is 3.0 to 5.0
    ng/ml. Stated otherwise, the test confirmed that Thompson’s blood showed a toxic level
    of fentanyl that was over ten times the low end of the expected range based on her
    fentanyl prescription, and over five times the uppermost end of that range.13
    Having not performed a test for fentanyl, the Harris County Medical Examiner’s
    report showed Thompson’s cause of death as “cardiomegaly with biventricular hypertrophy
    associated with obesity,” which, according to the testimony at trial, simply means that
    Thompson had an enlarged heart. According to the autopsy report, Thompson was forty-
    two years old, six feet tall, and weighed 367 pounds.
    At the trial arising from Thompson’s death, Mika Greenfield, Alza’s corporate
    representative and quality assurance manager, testified regarding Alza’s knowledge of
    product defects and its manufacturing process. She conceded that fold-over defects exist
    13
    The expected range of fentanyl in Thom pson’s blood, based on the strength of her Duragesic patch
    prescription, was between 1.0 to 2.0 ng/m l, but the actual level in her blood was 11.4 ng/m l.
    10
    where an entire side of the patch is leaking, and she agreed that fold-over defects and
    stringer leakers tend to release fentanyl in an uncontrolled way. Despite the fact that she
    was Alza’s corporate representative, her testimony was conflicting regarding her knowledge
    of whether fentanyl was a dangerous drug, and she was unaware whether morphine was
    more potent than fentanyl.
    Greenfield testified Alza began receiving increasing numbers of public reports of
    leaking patches as early as January 7, 2004. She testified that, for instance, Alza
    confirmed forty-two fold-over defects in one of its lots of Duragesic patches. She admitted
    that these defects were originally found by the public, and not by Alza or its employees.
    She was unable to describe the safety process utilized by Alza to find product defects in
    2003, and conceded that Alza’s technicians found no fold-over defects in any of the
    Duragesic patches produced during the last six months of 2003.
    Greenfield confirmed that Alza was notified of more than one fold-over defect in
    Duragesic patches in 2001. At that time, the company’s response was to heighten visual
    inspection of the patches in a two-foot space on a conveyer belt as the product was
    traveling through the Bodolay system.
    Greenfield testified that she did not know what changes were made on the Bodolay
    after the product recall to ensure that it was not producing defective products even though,
    as part of the company’s quality assurance team, her responsibility was to ensure that the
    manufacturing process is completed without defects. She did offer sworn testimony,
    however, admitting that all changes that were put in place after the product recall, including
    a mechanical visual system, different evaluating methods, equipment modifications, and
    equipment cleaning, would have been available for use in 2001.
    Greenfield testified that Alza did not examine the recalled patches to determine how
    11
    many of the recalled patches actually had defective seals or fold-over defects. She
    conceded that after determining that there was a fold-over defect problem, Alza released
    additional patches for public distribution without any additional inspection of the patches.
    Greenfield further testified that internal correspondence at Alza acknowledged the fact that
    it was keeping the Duragesic patches on the market, despite the defects, because of
    product shortages. Finally, she admitted that the FDA’s inspection processes resulted in
    Alza’s making changes to improve its processes and equipment.
    Juanita Hawkins, the worldwide vice president of Quality Assurance and Technical
    Operations for Cordis Corporation, which is a subsidiary of Johnson & Johnson,14 also
    provided testimony on behalf of Alza. In 1995, Hawkins worked for Janssen as the vice
    president of quality assurance. Hawkins testified that Alza would not and should not
    knowingly release a lot that contained defective products; nevertheless, she admitted that
    the FDA concluded that, and internal documents confirmed that, the company continued
    to release products for commercial distribution despite knowing of product defects therein.
    Dr. David Upmalis also testified on behalf of Alza. He is a general practice
    physician who joined the pharmaceutical industry, and now works with Pharmaceutical
    Research and Development (“PRD”), a research group that “supports Alza, among other
    companies.” He does clinical research in painkillers, “providing medical support for
    Duragesic and a couple of other pain killers that are in the marketplace.” He handles
    correspondence with regulatory agencies, including the FDA, regarding product issues and
    works to obtain approval for drugs. He worked with pediatric clinical trials for the Duragesic
    patch and helped derive labeling for the patch.
    14
    Evidence at trial, including testim ony from W illiam Parks, the director of trade relations for Janssen,
    established that Alza m anufactures the Duragesic patch and Janssen sells and m arkets the Duragesic patch.
    Alza and Janssen are both subsidiaries of Johnson & Johnson.
    12
    Dr. Upmalis testified about two general types of leaks that a Duragesic patch could
    exhibit. A stringer leaker is a patch that has a piece of gel stuck in the seal. According to
    Dr. Upmalis, Alza’s assessments concluded that there was no significant health risk posed
    by stringer leakers. Dr. Upmalis also testified about fold-over defects, where the seal
    breach covers an entire side of the patch.
    Dr. Upmalis testified that, in response to the escalating number of public complaints
    about product defects, Alza formed a health hazard assessment committee which was
    asked to look at fold-over defects on President’s Day weekend, February 14-15, 2004.
    According to Dr. Upmalis, the health risk involved in fold-over defects was higher than for
    stringer leakers because more fentanyl gel could leak from a fold-over defect. Dr. Upmalis
    testified that each lot of Duragesic patches contained around 400,000 units, and Alza
    ultimately estimated that approximately 3,600 patches would be affected by fold-over
    defects in each lot. Dr. Upmalis testified that Alza utilized Medline searches and three
    studies, which were not peer reviewed, in its determination regarding the health risks
    incident to leaking Duragesic patches. In its research, Alza found many incidents of
    adverse events related to the rapid release of fentanyl.
    Dr. Upmalis was involved in writing the Physician’s Desk Reference (“PDR”)
    materials on the Duragesic patch. The warning in the PDR states: “Duragesic patches are
    intended for transdermal use on intact skin only. Using damaged or cut Duragesic patches
    can lead to the rapid release of the contents of the Duragesic patch and absorption of a
    potentially fatal dose of Fentanyl.” Dr. Upmalis testified that this warning resulted from
    people’s “abuse” of, or damage to, the patches. Despite the explicit text of the PDR
    warning, Dr. Upmalis testified that the warning of adverse health consequences therein
    concerns the absorption of fentanyl through mucous membranes rather than skin.
    13
    Dr. Upmalis explained that the adverse drug reporting system requires doctors to
    report to the company and to the FDA if there is an adverse drug event. He admitted that
    under-reporting is a known problem, and he has heard that only one to ten percent of
    adverse reactions are reported. He agreed that the FDA thought that under-reporting is
    particularly high with the Duragesic patch because of the nature of the patient population
    utilizing the patch.       Dr. Upmalis examined Duragesic adverse event reports, which
    included, in 2002, for instance, 53 cases of hypoventilation, 270 cases of dyspnea
    (shortness of breath), 15 cases of respiratory arrest, 33 cases of respiratory depression,
    8 cases of respiratory disorder not otherwise specified, 8 case of respiratory distress, and
    14 cases of respiratory failure.           The 2003 adverse event report numbers were similar.
    According to Dr. Upmalis, given the incidence of under-reporting, these adverse reactions
    were just “the tip of the iceberg.”15
    Dr. Leslie Benet, a pharmacologist who is a professor at the University of California,
    provided further testimony on Alza’s behalf. Dr. Benet testified that he works for almost
    all drug companies. While Alza does not pay him directly for his work, Alza pays the
    university for which he works, which in turn funds his laboratory. Dr. Benet conceded that
    the FDA did not concur with the pharmaceutical-industry funded tests which downplayed
    the health risks from Duragesic patch defects, and that the FDA had determined that the
    justification presented to support the safety of leaking patches was inadequate.16
    Dr. Benet admitted that Alza’s Duragesic labels do not corroborate his trial testimony
    15
    W e note that the jury was instructed that evidence regarding adverse events was relevant on the
    issue of notice to Alza, but not on causation or for any other purpose.
    16
    Testim ony at trial indicated that the absorption of fentanyl from a dam aged patch m ay be increased,
    even without the patch system in place, where, for exam ple, clothes cover the patch and act as an occlusive
    layer, or the patient is laying on the patch, thus causing less evaporation of the vehicle m edium and a greater
    absorption of fentanyl. Dr. Benet further testified that tem perature increases the rate of fentanyl absorption.
    14
    regarding adverse health risks associated with damaged patches. He attempted to explain
    this discrepancy as a result of the fact that all labeling is supposed to include all potential
    toxic eventualities whether they occur or not: “And today, because of litigation such as this,
    every company lists everything that could potentially lead to a litigious situation.” Dr. Benet
    conceded that Alza knew about a number of leaking patches before 2005, and at that time,
    Alza did not place a warning on the Duragesic packaging. According to Dr. Benet, the
    warning that Alza ultimately included on the Duragesic labels is directed to patient
    caregivers, and not to the patch-users themselves, because the caregivers are more likely
    to have a toxic reaction to exposure. Upon cross-examination, Dr. Benet admitted that the
    Duragesic label states that it is for use only in opioid tolerant patients, and that because
    serious or life-threatening hypoventilation could occur, the Duragesic transdermal system
    is contraindicated in patients who are not opioid-tolerant. The label further states that
    damaged or cut patches can lead to rapid release of the contents and absorption of a fatal
    dose.
    Dr. Benet ultimately concluded that Alza and Janssen both knew that fentanyl was
    a toxic substance and the exposure of fentanyl at an uncontrolled rate might be dangerous;
    however, Dr. Benet testified that in this case, given that Thompson had been on pain
    medication for a number of years and had been wearing a patch for more than a month,
    he did not believe that fentanyl gel leaking out on her skin would pose a health risk to a
    reasonable degree of scientific certainty.
    As mentioned above, the Thompson family’s case was tried before Judge Hancock
    in Harris County, Texas, and the jury returned affirmative findings concerning the
    manufacturing defect and Alza’s negligence, but did not find Alza grossly negligent. Alza
    challenges Judge Hancock’s judgment on the verdict by five issues. Alza’s first three
    15
    issues concern the sufficiency of the evidence supporting the verdict.
    II. SUFFICIENCY OF THE EVIDENCE
    A. STANDARD OF REVIEW
    In reviewing the legal sufficiency of the evidence, we view the evidence in the light
    most favorable to the jury’s findings, giving full credit to all favorable evidence if any
    reasonable person could, and disregarding contrary evidence unless reasonable persons
    could not. City of Keller v. Wilson, 
    168 S.W.3d 802
    , 807 (Tex. 2005). In Texas, the jury
    is the sole judge of the witnesses’ credibility, and that time-honored principle is a part of
    our standard of review:
    Jurors are the sole judges of the credibility of the witnesses and the weight
    to give their testimony. They may choose to believe one witness and
    disbelieve another. Reviewing courts cannot impose their own opinions to
    the contrary. Most credibility questions are implicit rather than explicit in a
    jury’s verdict. Thus, reviewing courts must assume jurors decided all of them
    in favor of the verdict if reasonable human beings could do so. Courts
    reviewing all the evidence in a light favorable to the verdict thus assume that
    jurors credited testimony favorable to the verdict and disbelieved testimony
    contrary to it.
    
    Id. at 819
    (footnotes and paragraph break omitted). Accordingly, we must deny a legal
    sufficiency challenge unless: (1) there is a complete absence of evidence of a vital fact;
    (2) all the evidence offered to prove a vital fact amounts to only a mere scintilla and no
    more; (3) the rules of law or evidence completely forbid any consideration of the only
    evidence offered to prove a vital fact; or (4) the evidence which the jury was compelled to
    consider and believe conclusively establishes the opposite of the vital fact. See 
    id. at 810
    & n.15-16. These vital facts may be proved by direct or circumstantial evidence. See Ford
    Motor Co. v. Ridgway, 
    135 S.W.3d 598
    , 601 (Tex. 2004); Russell v. Russell, 
    865 S.W.2d 929
    , 933 (Tex. 1993).
    In reviewing the factual sufficiency of the evidence, we must consider and weigh all
    16
    the evidence, and we should set aside the judgment only if it is so contrary to the
    overwhelming weight of the evidence as to be clearly wrong and manifestly unjust. Pool
    v. Ford Motor Co., 
    715 S.W.2d 629
    , 635 (Tex. 1986); Cain v. Bain, 
    709 S.W.2d 175
    , 176
    (Tex. 1986).
    B. EVIDENCE OF A MANUFACTURING DEFECT AND CAUSATION
    By its first and third issues, Alza challenges the legal and factual sufficiency of the
    evidence supporting the jury’s finding of a manufacturing defect which was a producing
    cause of Thompson’s death. In the instant case, the jury found that “there was a
    manufacturing defect in a Duragesic patch worn by Michaelynn Thompson at the time the
    patch left the possession of Alza that was a producing cause of Michaelynn Thompson’s
    death.”
    In its first issue, Alza contends that there is legally and factually insufficient evidence
    to support the jury finding that a manufacturing defect, existing at the time of manufacture,
    caused Thompson’s death. In connection with this issue, Alza argues: (1) there was no
    proof of proper use of any Duragesic patch in question, and specifically, no proof regarding
    a 75 mcg/h patch; (2) there was no evidence to support a finding of malfunction; and (3)
    the evidence conclusively established that Thompson could not have been wearing a 75
    mcg/h patch from a recalled lot when she died.
    1. Manufacturing Defect
    “A manufacturing defect exists when a product deviates, in its construction or
    quality, from the specifications or planned output in a manner that renders it unreasonably
    dangerous.” Cooper Tire & Rubber Co. v. Mendez, 
    204 S.W.3d 797
    , 800 (Tex. 2006); see
    Bic Pen Corp. v. Carter, 
    251 S.W.3d 500
    , 509 (Tex. 2008). A plaintiff must prove that the
    product was defective when it left the hands of the manufacturer and that the defect was
    17
    a producing cause of the plaintiff’s injuries. 
    Ridgway, 135 S.W.3d at 600
    ; Torrington Co.
    v. Stutzman, 
    46 S.W.3d 829
    , 844 (Tex. 2000). A specific defect “must be identified by
    competent evidence and other possible causes must be ruled out.” Ford Motor Co. v.
    Ledesma, 
    242 S.W.3d 32
    , 42 (Tex. 2007) (quoting Nissan Motor Co. v. Armstrong, 
    145 S.W.3d 131
    , 137 (Tex. 2004)).
    Both direct and circumstantial evidence may be used to establish any material fact.
    Lozano v. Lozano, 
    52 S.W.3d 141
    , 149 (Tex. 2001); Browning-Ferris, Inc. v. Reyna, 
    865 S.W.2d 925
    , 928 (Tex. 1993). To raise a genuine issue of material fact, however, the
    evidence must transcend mere suspicion. 
    Ridgway, 135 S.W.3d at 601
    . Evidence that
    is so slight as to make any inference a guess is in legal effect no evidence. Id.; 
    Lozano, 52 S.W.3d at 148
    .
    2. Proper Use
    Alza contends that appellees’ claims are dependent on “proof of proper use of the
    patch,” citing Parsons v. Ford Motor Co., 
    85 S.W.3d 323
    , 329-30 (Tex. App.–Austin 2003,
    pet. denied) (citing Plas-Tex, Inc. v. U.S. Steel Corp., 
    772 S.W.2d 442
    , 444-45 (Tex.
    1989)). Alza contends that appellees presented no evidence of how any Duragesic patch
    was handled by Thompson on the occasion in question. According to Alza, “[t]he patch
    that was removed by Dr. Evans from [Thompson’s] back was reportedly unremarkable.
    The strength of the patch found on her body at the time of her death was never
    established. The decedent’s daughter claimed that Thompson had a patch on her
    stomach on the day she died.”
    Manufacturers face liability only for products which are defective when used in the
    intended manner or when used in a reasonably foreseeable way. See Houston Lighting
    & Power v. Reynolds, 
    765 S.W.2d 784
    , 786-87 (Tex. 1998) (liability is “limited to uses that
    18
    are objectively reasonable to expect . . . it does not encompass uses . . . which represent
    wholly unexpected product misuse.”) (citations omitted).17 In this regard, a manufacturing
    defect exists if a product does not conform to the design standards and blueprints of the
    manufacturer, and the flaw makes the product more dangerous and therefore unfit for its
    intended or reasonably foreseeable uses. See Benavides v. Cushman, Inc., 
    189 S.W.3d 875
    , 881 (Tex. App.–Houston [1st Dist.] 2006, no pet.).
    Dr. Benhamou, the physician who treated Thompson for pain management and who
    prescribed Duragesic for her, reviewed Thompson’s medical records and testified
    regarding her usage of the Duragesic patches. Thompson had worn Duragesic patches
    ten separate times, from January 13 until February 11, without incident or adverse effect.18
    The timing of her prescription refills for Duragesic patches fit with the prescribed usage of
    the product, and the timing would also illustrate that Thompson was wearing one of the
    newly prescribed 75 mcg patches at the time of her death.
    Thompson’s medical records from the emergency room state that she was admitted
    with a “Duragesic Patch.” Dr. Evans, the emergency room physician, testified that
    Thompson told him she sometimes used the Duragesic patch. He further testified that he
    saw the patch on Thompson’s back and removed it when attempting to resuscitate her
    when she coded because he “thought it may have inhibited our resuscitation [efforts] only
    17
    W e note that the foreseeable risk of harm due to a m isuse of the product, rather than an intended
    use, is not an absolute bar to liability for that portion of an injury caused by a product’s defective design;
    instead, m isuse of a product is a factor that m ust be considered in allocating responsibility for the injury.
    Hernandez v. Tokai Corp., 2 S.W .3d 251, 258 (Tex. 1999).
    18
    Dr. Benham ou testified that the Duragesic prescriptions cam e with five patches in each box with
    directions to change the patches every 72 hours. Dr. Benhamou testified that he prescribed a box of five
    Duragesic 50 m cg patches to Thom pson on January 13. On January 26, Dr. Benham ou increased the dosage
    and prescribed a box of five Duragesic 50 m cg patches and a box of five 25 m cg patches. On February 11,
    Thom pson was given a prescription for a box of five 75 m cg patches. Utilizing a calendar and m edical
    records, Dr. Benham ou testified that the prescription dates indicated proper usage of the product and the
    tim ing indicated usage of the 75 m cg patch at the tim e of Thom pson’s death.
    19
    because it was an unknown factor.” In short, the evidence indicates that Thompson was
    wearing a 75 mcg Duragesic patch at the time of her death.19
    Dr. Benhamou testified that he never had any indication that Thompson was
    abusing Duragesic during his course of treating her. He further testified that he never had
    any indication that she was not following his instructions with regard to the medication.
    Further, Dr. Benhamou testified that he had required Thompson to enter a “medication
    contract” with him, entered into evidence at trial, which spelled out Thompson’s obligations
    with regard to the proper usage of Duragesic. Dr. Robert C. Bux, a physician and board-
    certified forensic pathologist and medical examiner, who was testifying on behalf of the
    Thompson family, concurred that there was “no evidence” that Thompson had misused her
    medication. Dr. Vincent DiMaio, a medical examiner testifying on behalf of Alza, conceded
    that there was “no physical evidence” that Thompson abused the patches.
    Based upon the foregoing, we conclude that the jury had before it legally and
    factually sufficient evidence from which it may have concluded that Thompson was wearing
    and properly using a Duragesic 75 mcg at the time of her death.
    3. Malfunction
    Alza next contends that there is no evidence to support the jury’s finding that the
    Duragesic patch malfunctioned. In connection with this issue, Alza argues that the Accu-
    Chem blood test is unreliable because it was not performed properly, and the 11.4 blood
    level reading does not establish a malfunction because of postmortem redistribution.20
    19
    W hile Thom pson's daughter testified that she was wearing the patch on her stom ach, and m edical
    records and testim ony indicate that she was wearing the patch on her back, this discrepancy is not m aterial
    to the issue of whether or not Thom pson properly used the product.
    20
    As explained at trial, the concept of postm ortem drug redistribution is based on data suggesting that
    there is a post-m ortem diffusion of drugs along a concentration gradient, from sites of high concentration in
    solid organs and central blood vessels, to sites of the lowest concentration in peripheral vessels such as the
    subclavian and fem oral veins. Postm ortem redistribution of a drug m ay be the basis for elevated or toxic drug
    concentrations after death, and accordingly, in certain cases, postm ortem drug concentrations m ay not
    20
    Alza asserts that Accu-Chem deviated from its protocol in performing its testing and further
    failed to perform the testing correctly. Alza also attacks the blood test in its third issue,
    contending that: (1) the Accu-Chem test was not performed properly; (2) Accu-Chem did
    not validate its methodology; (3) Accu-Chem’s methodology of relying on “only one”
    calibrator was not shown to be reliable; (4) Accu-Chem’s test on Thompson’s blood had
    technical break-downs; (5) Accu-Chem had insufficient experience testing for fentanyl in
    human blood for the results to be considered accurate; and (6) the Accu-Chem test is
    based on an inference not supported by the evidence.
    As stated previously, following Thompson’s death, the coroner took blood samples
    from Thompson’s femoral artery and sent the samples to Accu-Chem for testing.
    According to expert testimony at trial, blood from the femoral artery area is not subject to
    contamination from gastric contents or trauma and will represent the levels and
    concentration of substances in the blood at the time of death. Accu-Chem, an independent
    testing agency, analyzed the blood and determined that Thompson had 11.4 ng/ml of
    fentanyl in her body. This amount is toxic and is well over three times the therapeutic level
    of fentanyl.
    Accu-Chem utilized gas chromatography/mass spectrometry (GC/MS) technology
    to test Thompson’s blood. We may consider prior judicial opinions allowing the admission
    of evidence in determining whether the underlying theory of scientific evidence is valid.
    See Emerson v. State, 
    880 S.W.2d 759
    , 767-68 (Tex. Crim. App. 1994); Combs v. State,
    
    6 S.W.3d 319
    , 322 (Tex. App.–Houston [14th Dist.] 1999, no pet.); Jones v. State, 
    716 S.W.2d 142
    , 147 (Tex. App.–Austin 1986, pet. ref’d). Such evidence may be considered
    for the first time on appeal. 
    Emerson, 880 S.W.2d at 765
    . Texas and federal courts have
    accurately reflect antem ortem drug levels.
    21
    found the gas chromatography test to be a reliable method for identifying compounds, and
    it has been generally accepted in the scientific community. See 
    Combs, 6 S.W.3d at 322
    ;
    Wright v. State, 
    853 S.W.2d 154
    , 155 (Tex. App.–Corpus Christi 1993, pet. ref’d); 
    Jones, 716 S.W.2d at 145-52
    ; see also United States v. Bynum, 
    3 F.3d 769
    , 772 (4th Cir. 1993);
    Bolieu v. State, 
    779 S.W.2d 489
    , 490 (Tex. App.–Austin 1989, no pet.) (discussing the
    GC/MS testing as “the Golden Rule” in the field of toxicology). The scientific theory and
    principles underlying GC/MS testing have been proven to be reliable. The experts in the
    instant case appeared to agree that the GC/MS procedure has been properly validated and
    is considered the most accurate method of identifying and quantifying drug levels.
    We next turn our attention to whether the methodology of GC/MS was reliably
    applied in this specific case. Guadalupe-Blanco River Auth. v. Kraft, 
    77 S.W.3d 805
    , 808
    (Tex. 2002); Merrell Dow Pharms. v. Havner, 
    953 S.W.2d 706
    , 712 (Tex. 1997); In re
    S.E.W., 
    168 S.W.3d 875
    , 884 (Tex. App.–Dallas 2005, no pet.). In this regard, we note
    that the law does not require a “court to admit opinion evidence which is connected to
    existing data only by the ipse dixit of the expert.” Kerr-McGee Corp. v. Helton, 
    133 S.W.3d 245
    , 258 (Tex. 2004) (quoting Gen. Elec. Co. v. Joiner, 
    522 U.S. 136
    , 146 (1997)).
    Dr. Gary Harold Wimbish, a board-certified forensic toxicologist, testified on behalf
    of the Thompson family.     He has performed more than a thousand GC/MS tests. He
    testified that the GC/MS test can be used to determine the level of fentanyl in someone’s
    body, and it is an “excellent instrument” that is “commonly used” to determine the level of
    fentanyl in a sample of human blood. He has used GC/MS on several occasions for that
    purpose. He testified that whether a drug level in a person’s body is at a fatal level is part
    of his field of study.
    Dr. Wimbish testified that he is familiar with Accu-Chem and its operations. He
    22
    testified that Accu-Chem is certified by the American Society of Laboratory Chiefs of
    Police, the College of American Pathology, and the Clinical Society for Drug Testing.
    Analytical laboratories such as Accu-Chem are accredited by various organizations and,
    as part of their accreditation, are regularly inspected and participate in “proficiency studies,”
    in which identical portions of the same sample are analyzed by many labs at the same time
    in order to check the accuracy of each procedure as it is performed in the individual
    participating labs.   Accu-Chem participates in proficiency testing by the College of
    American Pathology and it is certified by organizations for performing drug testing on
    parolees and probationers. Dr. Wimbish testified that he is personally experienced with
    Accu-Chem and that it is his “laboratory of choice” for a forensic laboratory.
    Accu-Chem had specifically passed the College of American Pathology’s proficiency
    test for fentanyl, although Dr. John Arthur Tarver, the director of Accu-Chem, testified that
    Accu-Chem does not frequently perform tests for fentanyl. Dr. Tarver further testified that
    an outside organization, the American Society of Crime Laboratory Directors, reviewed and
    approved Accu-Chem’s testing procedures. Further, the particular procedure used to test
    fentanyl was validated externally with a proficiency sample from the College of American
    Pathologists. Accu-Chem sent the College a proficiency sample, and with those standards
    and control standards, Accu-Chem was within five-tenths standard deviations of the mean
    of all the laboratories that performed the test.
    Dr. Graham Richard Jones, a forensic toxicologist, testifying on behalf of Alza,
    acknowledged that Accu-Chem had passed the proficiency test administered by the
    College of American Pathologists in March 2004, before Accu-Chem did the test at issue
    in this case, and had done “well” on the proficiency test.
    Accu-Chem’s report of October 18, 2004 shows a concentration of fentanyl in
    23
    Thompson’s blood of 11.4 nanograms per milliliter.21 The therapeutic range for fentanyl,
    that is, the amount found in the blood related to the relief of pain, is from one to two
    nanograms per milliliter. The toxic range for fentanyl, that is, the range that would have
    toxicity or adverse and deleterious effects, is three to five nanograms per milliliter. Dr.
    Wimbish testified that 11.4 nanograms was a little more than two times the upper limit of
    the toxic range for fentanyl, and was toxic enough to be lethal. Specifically, Dr. Wimbish
    testified that while Thompson may have developed some tolerance to fentanyl, the tested
    level of fentanyl found in her blood was nevertheless three to four times larger than an
    amount which she could have tolerated.
    Based on testimony at trial, the GC/MS test is performed by analyzing and
    comparing the unknown blood sample, in this case, Thompson’s femoral blood specimen
    drawn by the Harris County coroner, with other blood samples where the amount of the
    target substance is known. The results for the unknown sample are then compared to the
    results for the known samples in order to calculate the amount of the target substance
    present in the blood sample. The testimony in this case is complicated by the various
    names and descriptions the experts used with regard to these “known samples,” of which
    we have been able to delineate three basic categories.
    The first category of known samples discussed by the experts is a set of
    “calibrators,” which are samples prepared in a matrix of blood, ethanol, or some other
    21
    Accu-Chem initially tested a sam ple of Thom pson’s blood for fentanyl in April; however, that test
    failed. Dr. Tarver and Dr. W im bish, both testified that this initial test was not valid and the results were not
    reliable because the sam ple of blood provided for testing was insufficient and Accu-Chem did not have the
    “am ount of specim en that our protocol requires.” Accu-Chem received six-tenths of a m illiliter of blood,
    whereas the standard operating procedure called for four m illiliters, and the resulting analytical data did not
    allow for forensic results. Dr. Jones, testifying on behalf of Alza, stated that Accu-Chem ’s first test failed
    because the entire calibration failed “m iserably” and the failure had “absolutely nothing” to do with the am ount
    of the sam ple. W e need not further consider this issue because the results of this initial test are not at issue
    in this case. W e do note that Dr. Tarver stated that the testing m ethodology utilized by Accu-Chem did not
    change between the two tests.
    24
    solvent, each of which contains a known amount of the target compound, in this case,
    fentanyl. A set of calibration standards includes several samples that contain various
    known amounts of the target compound within a specific and broad range. The second set
    of known samples involves “ion ratios.” The ion ratio is the ratio between the abundance
    of two different ions within the same chemical, or two ions representing different chemicals,
    such as fentanyl, and the internal standard form of fentanyl. Ion ratios can be used either
    qualitatively or quantitatively; in other words, they are employed in either identifying the
    substance or in measuring the amount of the substance. The third category of known
    samples are quality control samples, which are used to check the reproducibility of results.
    A quality control sample is a sample which is prepared in the same type of matrix as the
    unknown sample, but which has a known concentration of the target compound that is near
    the expected concentration of the unknown sample. Samples from proficiency studies, if
    they are sufficiently stable, may be used as external quality controls.
    In the instant case, Accu-Chem utilized four calibrators and ion ratio tests in its
    analysis of the fentanyl quantitation in Thompson’s blood. The .5 calibrator failed both the
    quantitative error test and the ion ratio test. The 2.0 calibrator passed the quantitative error
    test and failed the ion ratio test. The 5.0 calibrator failed the quantitative error test and
    passed the ion ratio test. The 20.0 calibrator passed both tests. Utilizing this data, Accu-
    Chem calculated that Thompson’s blood contained 11.4 ng/ml of fentanyl. The result of
    these calculations was validated by comparison to the quality control samples, which had
    been validated by separate protocols before Thompson’s test. Using the quality control
    samples, Accu-Chem’s analysis of Thompson’s blood showed a quantitation of 10.48
    ng/ml.
    Dr. Tarver, the director of Accu-Chem, testified by deposition regarding the test
    25
    protocols and results. Dr. Tarver has degrees in biology and chemistry and a master’s
    degree in biomedical science. He is a diplomat of the American Board of Forensic
    Toxicology and a toxicological chemist for the National Registry of Certified Chemists. Dr.
    Tarver testified that there are no methodology standards that require a certain number of
    calibrators to work to produce a valid test result. While Accu-Chem’s standard procedure
    required the use of four calibrators, Dr. Tarver rejected two of those calibrators. Dr. Tarver
    testified that the rejected controls had no effect on his ultimate conclusions because Accu-
    Chem validated, through external sources, the actual lot number of the standard calibration
    material and the quality control material.
    Dr. Wimbish reviewed and explained Accu-Chem’s written protocols for postmortem
    testing for controlled substances. Accu-Chem’s standard operating procedures allow Dr.
    Tarver, the lab director, to review the analytical protocol and provide that Dr. Tarver has
    the final authority on any analytical protocol in the laboratory, particularly with regard to
    forensic specimens because of their limited and unique quality. With limited samples, the
    laboratory director has to make a decision about reporting results, and often, as per his
    instructions in the standard operating procedures, he can modify those within scientific
    limits as to the acceptability or reportability of a result under unique circumstances. In
    other words, Accu-Chem’s standard operating procedures allow Dr. Tarver to deviate from
    those procedures. Dr. Wimbish testified that it is not unusual for a laboratory director to
    have that kind of discretion with regard to forensic samples.
    Dr. Wimbish testified that Accu-Chem’s test rendered a reliable quantitation within
    reasonable scientific certainty. He explained that Accu-Chem derived its results by utilizing
    and comparing two separate sample sets, then explained his own calculations verifying
    Accu-Chem’s results. Accu-Chem used two of the four calibrators to derive its results. Dr.
    26
    Wimbish verified Accu-Chem’s mathematical analysis utilizing those two calibrators, then
    re-examined the veracity of Accu-Chem’s results utilizing zero as an additional calibration
    point. Dr. Wimbish testified that ideally, all four of the calibrators in Accu-Chem’s test
    would have been functional; however, changing the number of calibrators affects the test’s
    precision, but not its accuracy. In contrast, if all four calibrators fail, then the result is not
    valid because there is no data with which to undertake any quantitative analysis. In short,
    Dr. Wimbish testified that Accu-Chem’s test rendered test results with reasonable scientific
    certainty.
    Dr. Graham Richard Jones, a forensic toxicologist, testified on behalf of Alza.
    According to Dr. Jones, the GC/MS is very powerful, but “it is basically a dumb instrument
    unless you . . . calibrate it.” Calibrators are blood samples containing known amounts of
    fentanyl so that the machine can relate a signal to a concentration of fentanyl. According
    to Dr. Jones, it is “critical” that the calibrators are working. Dr. Jones testified that multiple
    calibrators are utilized in order to obtain multiple data points because the response across
    a concentration range is not always consistent, and different calibrators are used to
    establish the reliability of the test. According to Dr. Jones, the GC/MS machine may
    “behave” differently at higher or lower concentrations; therefore, the calibrators should be
    run at a range of concentrations within which the blood samples are expected to fall. In
    his lab, Dr. Jones requires five out of six calibrators to be working to produce a quantitative
    result for fentanyl. In other testimony, Dr. Jones stated that he might allow one or two
    calibrators to fail; however, the calibrators must be dropped at the “extreme,” or at a place
    distant from where the actual quantitation was. In Dr. Jones’s opinion, the Accu-Chem test
    failed.
    Dr. Jones conceded that Dr. Wimbish disagreed with this analysis, and
    27
    acknowledged that Dr. Wimbish is a reputable forensic toxicologist and that Dr. Jones had
    invited Wimbish to speak at a seminar on the subject of postmortem redistribution. Dr.
    Jones further agreed that, in the instant case, the 10 quality control sample read close to
    the target value, and further conceded that a limited sample of blood affects whether it is
    appropriate to drop a calibrator. As lab director, he acknowledged that he has approved
    a test where a distant calibrator was dropped because of a limited quantity of blood.
    Alza further contends that Accu-Chem’s test was not properly performed because
    Accu-Chem obtained its quality control material from the same source that it obtained its
    calibrators. Dr. Wimbish addressed the “same source issue” with regard to Accu-Chem’s
    testing. Dr. Wimbish testified that it is generally recommended that a laboratory obtain its
    quality control material from a source separate from the source used to obtain the
    calibrators, but it is not required. Alza does not further explain or show how this adversely
    affected the quality of the test or the test results itself.
    Finally, we note that Dr. Wimbish testified that Accu-Chem also tested Thompson’s
    blood for the metabolite of fentanyl and found less than 2 nanograms per milliliter. Based
    on the amount of fentanyl in Thompson’s system, Dr. Wimbish would have expected 8 or
    10 nanograms per milliliter, and the discrepancy means that the fentanyl in Thompson’s
    system came in acutely, or over a short period of time. According to Dr. Wimbish, the “only
    way” to explain the discrepancy between the amount of fentanyl and the amount of fentanyl
    metabolites is that within a day’s period, fentanyl came into Thompson’s system in a “fairly
    rapid” fashion in a “bolus amount,” which is a “large amount . . . flooding into something at
    the same — at the same time.”
    The trial court’s gatekeeping function under Rule 702 does not supplant
    cross-examination as “the traditional and appropriate means of attacking shaky but
    28
    admissible evidence.” Gammill v. Jack Williams Chevrolet, 
    972 S.W.2d 713
    , 728 (Tex.
    1998) (citing Daubert v. Merrell Dow Pharms., 
    509 U.S. 579
    , 596 (1993)); see TEX . R. EVID .
    702. The reasons given by Alza as to why it thought the Accu-Chem test was unreliable
    affect the weight and credibility of the test, but not its admissibility. See Mo.-Kan.Tex. R.R.
    Co. v. May, 
    600 S.W.2d 755
    , 756 (Tex. 1980). Alza and its expert witnesses had the
    opportunity to explore the consequences of these alleged defects in the testing procedures
    and did so at great length.
    Once the trial court found that the scientific principles and procedures underlying the
    test were generally accepted in the relevant scientific community, and the application of
    this theory was reliable, the threshold determination of admissibility of the test was met,
    and the judge was allowed, if not required, to allow the experts to render opinions on the
    presence of fentanyl in Thompson’s blood, leaving for the jury to determine the credibility
    of those expert opinions. See 
    Ledesma, 242 S.W.3d at 42
    . The issue of whether the
    particular analysis of Thompson’s blood by Accu-Chem was performed in the proper
    manner, including whether sufficient quality control procedures were used to ensure the
    accuracy of the test results, was a question of credibility and probative value for the jury
    to determine, after hearing the testimony of all the experts.
    4. Postmortem Redistribution
    Alza contends that even if Accu-Chem’s blood test was accurate, the level of
    fentanyl in Thompson’s blood was the result of postmortem redistribution rather than an
    overdose. Dr. Wimbish testified that postmortem redistribution occurs after death when
    body tissue and organs break down and drug concentrations in one organ may leak into,
    or contaminate, other organs.       In other words, for instance, if a drug is known to
    concentrate in certain tissues, such as the lung, after death, the drug concentration may
    29
    migrate or leak from the lung tissue into the heart and cause an artificially elevated level
    of the drug to be found in a blood sample taken from the heart. Dr. Wimbish testified that
    all pathologists have been trained that the best place to collect a blood specimen to
    prevent contamination is the femoral specimen, and it is scientifically reliable to form an
    opinion about levels of fentanyl in someone’s blood at the time of death based on levels
    taken postmortem from a femoral draw. According to Dr. Wimbish, “[t]hat’s been studied
    on many occasions, and the femoral specimen is by far the best.” Dr. Wimbish testified
    that drugs that are highly protein bound and drugs that have high volumes of distribution
    are those that are most susceptible to postmortem redistribution.               If postmortem
    redistribution were to occur, it would be significantly reduced by the refrigeration prior to
    autopsy.
    Dr. Wimbish testified regarding an article entitled “Postmortem Redistribution of
    Morphine and its Metabolites,” published in the Journal of Forensic Sciences. Dr. Wimbish
    testified that fentanyl and morphine are very similar compounds and are both considered
    to be drugs that have reasonably high volumes of distribution, and accordingly, a study
    regarding the postmortem redistribution of morphine would render results that could be
    used to analyze whether fentanyl was susceptible to postmortem redistribution. According
    to Dr. Wimbish, the morphine study analyzed blood samples taken from the femoral artery
    and from heart blood to determine whether morphine is susceptible to postmortem
    redistribution and determined that there was no significant difference in the results; thus,
    postmortem redistribution of morphine from a human femoral draw was unlikely. This
    study, like all others published in the Journal of Forensic Sciences, was subjected to peer
    review, a critique by other scientists to evaluate and determine if the scientific integrity and
    the protocol as designed in the study would allow a conclusion on a scientific basis.
    30
    Dr. Wimbish testified that there are no peer reviewed, published articles concerning
    postmortem redistribution of fentanyl from a human femoral draw; accordingly, theories
    that postmortem fentanyl redistribution in humans regarding femoral and heart blood
    specimens are speculation.
    Dr. Wimbish also testified about a study performed by Janssen Research
    Foundation, which involved the application of Duragesic patches to six rabbits. This study
    was not published or subject to peer review and was instead a “confidential” study by
    Janssen, a private company and a subsidiary of the manufacturer of the Duragesic patch.
    Janssen administered fentanyl to these rabbits through Duragesic transdermal patches and
    collected blood specimens from the rabbits at different time intervals, both prior to and after
    the death of the rabbits, to try to determine if postmortem redistribution occurred in the
    rabbits. Although Janssen concluded that the study indicated that some postmortem
    redistribution occurred with fentanyl, Dr. Wimbish disagreed.
    Dr. Wimbish testified that it was not scientifically reliable to derive an opinion about
    the postmortem redistribution of fentanyl in human femoral blood from a test involving the
    postmortem distribution of fentanyl in six four-and-a-half-pound rabbits and there was not
    “any equivalence” to allow that correlation.       Dr. Wimbish offered some scathing and
    detailed criticisms of Janssen’s study, which may be summarized as follows. This study
    utilized a human patch on the body of a 4.5 pound rabbit. The “rabbit” sample was too
    limited, and the concentrations in the blood and plasma ranged from therapeutic to toxic
    in three of the six rabbits. The dosages of fentanyl were not administered on a milligram
    per killigram basis, whereby the amount of drug administered to the rabbits could be
    compared to the amount of drug typically prescribed to a human. The surface area of the
    patch proportionally covered a much larger portion of the rabbits than it does humans.
    31
    Utilizing the study data, Dr. Wimbish testified that it shows no real difference in the initial
    blood concentrations and the allegedly increased blood concentrations. While there are
    some increases in concentrations, the Duragesic patches were left on the rabbits after their
    deaths and the continued infusion of fentanyl could cause a rise in fentanyl levels
    throughout the body after death. Dr. Wimbish stated that this process could not be
    differentiated from what Alza’s experts identified as postmortem redistribution. In short,
    Dr. Wimbish testified that this study gives no support to the theory that postmortem
    redistribution of fentanyl occurs in human femoral blood.
    Dr. Wimbish further testified about an article entitled “Duragesic Transdermal Patch:
    Postmortem Tissue Distribution of Fentanyl in 25 Cases,” published in the Journal of
    Analytical Toxicology by Anderson and Muto. This peer-reviewed study analyzed twenty-
    five cases involving humans wearing fentanyl patches where death occurred. According
    to Dr. Wimbish, this study did not show that there was any postmortem redistribution. The
    authors referenced five cases indicating that the postmortem level of fentanyl in the
    femoral blood was higher than in the central blood. However, according to Dr. Wimbish,
    the paper was not designed to test whether postmortem redistribution occurred, and it does
    not support a scientifically reliable theory that it occurs. On cross-examination, Dr.
    Wimbish agreed that the study states that:          “As with other drugs, the amount of
    postmortem redistribution appears to increase as the Fentanyl concentration increases.”
    Dr. Jones testified that in his opinion, the Accu-Chem test was not valid, and even
    if the 11.4 level was accurate, that the blood level shown 18 hours after death did not
    accurately reflect the level of fentanyl in Thompson’s system at the time of death. Dr.
    Jones testified that fentanyl is susceptible to postmortem redistribution, and the Anderson
    and Muto study stands for the proposition that the amount of postmortem redistribution
    32
    appears to increase as the fentanyl concentration increases. According to Dr. Jones,
    postmortem redistribution occurs most strongly around the lungs and heart and less so
    peripherally in locations like the femoral artery. However, draws from the femoral artery
    can still be affected unless it is a “closed” draw. According to Dr. Jones, the Anderson and
    Muto study shows that postmortem redistribution occurs with fentanyl but “maybe in not
    every case.” He agreed that the scientific community had not reached a conclusion as to
    whether postmortem redistribution artificially elevates fentanyl concentrations in human
    femoral blood. Dr. Jones further testified that resuscitation efforts can increase the degree
    of postmortem redistribution, and noted that testimony from nurse Kathryn Nu Bourn
    indicated that CPR was performed on Thompson for approximately twenty minutes prior
    to death.
    Dr. Jones testified that the “rabbit” study performed by Janssen indicates that
    fentanyl concentrations increase after death, and “the most likely cause or contributor
    would be postmortem redistribution.” Dr. Jones first became aware of the Janssen rabbit
    study when he was provided that study by Janssen’s counsel. He conceded that it was
    unpublished and was not peer-reviewed, and that it was performed “confidentially” by the
    defendant that has been sued in this case. He acknowledged that the four-to-five pound
    rabbits were subjected to more than twenty-two times the level of fentanyl that is used in
    humans, and that the Duragesic patches remained on the rabbits after death and
    continued to distribute fentanyl into the rabbits.
    Dr. Jones was retained by Janssen as an expert in at least sixteen cases. He
    expects that in “certainly most cases” he will testify that the fentanyl levels are too high
    because postmortem redistribution “could have occurred.” He cannot say how much
    Thompson’s fentanyl blood level would have been affected by postmortem redistribution
    33
    to calculate what the fentanyl level would have been at the time of death.
    Based on the foregoing testimony, we cannot conclude that Alza’s evidence
    conclusively established that the level of fentanyl in Thompson’s blood was the result of
    postmortem redistribution. At most, the evidence presented in support of this theory was
    speculative in nature. Alza’s own expert, Dr. Jones, stated that postmortem redistribution
    of fentanyl in humans “could have occurred,” but “maybe in not every case,” and he
    conceded that the scientific community had not yet determined if postmortem redistribution
    artificially elevates fentanyl concentrations in human femoral blood. The studies utilized
    by Alza to support its theory were either not directed at determining whether postmortem
    redistribution occurs with fentanyl, such as the Anderson and Muto study, or were
    “confidential” studies, which were not peer reviewed, which were performed by Alza or its
    own subsidiaries or employees. The study that Alza primarily relies on to support its theory
    of postmortem redistribution relied solely on fentanyl testing on six rabbits. Animal studies,
    standing alone, are generally held to be inadequate to prove causation in humans absent
    other confirming epidemiological data. See, e.g., 
    Havner, 953 S.W.2d at 729
    (collecting
    authorities). Accordingly, we reject Alza’s contention that Thompson’s fentanyl blood level
    of 11.4 ng/ml was conclusively caused by postmortem redistribution.
    5. Use of a Recalled Patch
    Alza contends that the evidence conclusively establishes that Thompson could not
    have been wearing a 75 mcg/h patch from a recalled lot when she died.22 First, Alza
    argues that the Thompson family cannot prove that Michaelynn Thompson’s Duragesic
    patch was among the 2,500,000 patches recalled either during the initial recall or the
    22
    W illiam Parks, the director of trade relations for Janssen and the liaison between retail and
    wholesale custom ers and the com pany, was unable to determ ine which lot that the patch Thom pson was
    wearing cam e from .
    34
    subsequent expanded recalls that Alza had to perform when it became apparent that its
    initial recall was not nearly broad enough. However, proof that Thompson’s Duragesic
    patch was itself recalled is not an element of the Thompson family’s claims and is,
    therefore, immaterial.
    Under the Texas Rules of Evidence, “written notification by a manufacturer of any
    defect in a product produced by such manufacturer to purchasers thereof is admissible
    against the manufacturer on the issue of existence of the defect to the extent that it is
    relevant.” TEX . R. EVID . 407(b); 
    Parsons, 85 S.W.3d at 331
    n.2; Wright v. General Motors
    Corp., 
    717 S.W.2d 153
    , 155 (Tex. App. Houston 1st Dist. 1986, no writ). While evidence
    that a product fell within a recall is evidence of a defect, the converse is not true: evidence
    that a manufacturer did not recall a product or evidence that the product at issue fell
    outside the recall is no evidence that the product is not defective. If the Thompson family
    had brought claims that focused on an allegation that Alza had negligently executed a
    recall which it undertook to perform,23 evidence that Michaelynn Thompson’s Duragesic
    patch was among the 2,500,000 patches recalled might possibly be of some relevance, but
    Alza’s argument is wholly irrelevant to the Thompson family’s strict product liability
    manufacturing defect claims (and also irrelevant to the family’s general negligence claims,
    which focused on Alza’s careless quality assurance processes).
    Although the emergency room doctor removed and discarded Thompson’s
    23
    See Torrington Co. v. Stutzman, 46 S.W .3d 829, 838-39 (Tex.2000) (discussing circum stances
    when a defendant’s post-sale defect investigation gives rise to a duty to perform that undertaking with ordinary
    care). As we recognized years ago, Texas law is generally not the source of any duty to warn of product
    defects uncovered after sale, but there is such a duty when the m anufacturer has regained control of a
    product after the defect was learned and the m anufacturer failed to rem edy a defect before reselling the
    product. See Bell Helicopter Co. v. Bradshaw, 594 S.W .2d 519, 531-32 (Tex. Civ. App.–Corpus Christi 1979,
    writ ref’d n.r.e.). Although Texas law is not the source of a m ore general post-sale duty, there are other
    potential sources of such a duty which m ight be enforced under Texas law. See, e.g., Lowe v. Gen. Motors
    Corp., 
    624 F.2d 1373
    , 1379-1380 (5th Cir. 1980) (violation of Federal Motor Vehicle Safety Standards can
    serve as basis for negligence per se claim ).
    35
    Duragesic patch before it could be analyzed, it has been a well accepted principle of Texas
    law for at least forty years that, in products liability cases, the claimant need not offer direct
    evidence to prove a defect because such proof “usually can only be made by circumstantial
    evidence.” Turner v. Gen. Motors Corp., 
    584 S.W.2d 844
    , 848 (Tex. 1979) (citing Darryl
    v. Ford Motor Co., 
    440 S.W.2d 630
    , 632 (Tex. 1969)); see 
    Ridgway, 135 S.W.3d at 602
    (Hecht, J., concurring) (stating that Texas law allows proof of product liability by
    circumstantial evidence in certain cases); see also Shaun T. Mian Corp. v.
    Hewlett-Packard Co., 
    237 S.W.3d 851
    , 858 (Tex. App.–Dallas 2007, pet. denied)
    (providing a thorough examination of the principles underlying the use of circumstantial
    evidence in product liability cases). Accordingly, when “the plaintiff has no evidence of a
    specific design defect or manufacturing defect, he may offer evidence of the product’s
    malfunction as circumstantial proof of the defect.” Sipes v. Gen. Motors Corp., 
    946 S.W.2d 143
    , 155 (Tex. App.–Texarkana 1997, writ denied).
    In this case, it is undisputed that Alza’s Bodolay machine was the machine which
    would have made Thompson’s Duragesic patch as well as the many patches which had
    documented defects in their seals.24 This Bodolay machine was already scheduled for
    replacement, but before it could be replaced, it had to undergo several modifications to try
    to reduce the number of manufacturing defects it was producing. It is undisputed that
    these modifications were not implemented until after the time period when Thompson’s
    Duragesic patch would have been manufactured on Alza’s Bodolay machine. Moreover,
    the documentary evidence and Alza’s own witnesses confirmed that public reports of
    leaking patches were higher in some lots of Duragesic patches that were not recalled than
    24
    Likewise, Thom pson’s D uragesic patch was m ade according to the sam e control processes as
    those defective patches which escaped detection and were shipped to the public with flawed seals despite
    Alza’s visual inspection of the patches as they passed along a conveyor belt.
    36
    in some of the lots that Alza recalled. Finally, Duragesic patches with defective seals are
    a known cause of patients receiving an overdose of fentanyl, and as stated in Alza’s own
    second recall notice, it is undisputed that such fentanyl exposure can be fatal:
    Exposure to the leaked medication could result in . . . an increased
    transdermal absorption of the opiate component fentanyl, leading to
    potentially life-threatening complications.
    Based on the foregoing, and other evidence discussed herein, the jury had before it legally
    and factually sufficient evidence from which it may have concluded that a manufacturing
    defect in the Duragesic patch worn by Thompson caused her death. Accordingly, we
    overrule Alza’s first issue and those subissues therein.
    C. CAUSATION
    In its third issue, Alza contends that there was legally and factually insufficient
    evidence to support the jury’s causation findings. Alza also challenges the reliability of the
    expert testimony supporting the causation finding. See Volkswagen of Am., Inc. v.
    Ramirez, 
    159 S.W.3d 897
    , 903 (Tex. 2004)(“A party may raise a properly preserved
    complaint on appeal that scientific evidence is unreliable and thus no evidence to support
    a judgment.”). First, we address the reliability of the expert testimony, and then we will
    separately address the sufficiency of the evidence. See Whirlpool Corp. v. Camacho, 
    298 S.W.3d 631
    , 639 (Tex. 2009); Volkswagen of Am., 
    Inc., 159 S.W.3d at 904
    .
    1. The Reliability of Thompson’s Expert Testimony
    on Causation
    Alza argues that the testimony offered by Thompson’s experts, Dr. Robert C. Bux
    and Dr. Sayed Feghali, was legally and factually insufficient and it varied materially from
    the actual “undisputed” facts.     Alza contends that, because of these deficiencies,
    Thompson failed to produce expert testimony that any defect in a Duragesic patch worn
    by Thompson was a producing or proximate cause of her death. Alza further argues that
    37
    the causation opinions of Thompson’s experts are no evidence because they are based
    solely on the Accu-Chem test. In this context, Alza argues that Thompson’s expert opinion
    testimony fails the Robinson test and is unreliable. See E.I. du Pont de Nemours & Co.
    v. Robinson, 
    923 S.W.2d 549
    , 557 (Tex. 1995).
    A two-part test governs whether expert testimony is admissible: (1) the expert must
    be qualified; and (2) the testimony must be relevant and based on a reliable foundation.
    Helena Chem. Co. v. Wilkins, 
    47 S.W.3d 486
    , 499 (Tex. 2001). Whether the trial court
    properly admitted expert testimony is subject to an abuse of discretion standard of review.
    Id.; 
    Robinson, 923 S.W.2d at 549
    , 558. The test for abuse of discretion is whether the trial
    court acted without reference to any guiding rules or principles. Id.; Downer v. Aquamarine
    Op., Inc., 
    701 S.W.2d 238
    , 241-42 (Tex. 1985). The test is not whether “in the opinion of
    the reviewing court, the facts present an appropriate case for the trial court’s action.”
    
    Robinson, 932 S.W.2d at 558
    . A reviewing court cannot conclude that a trial court abused
    its discretion merely because it would have ruled differently. 
    Id. The trial
    court has “broad”
    discretion to determine the admissibility of expert evidence. Exxon Pipeline Co. v. Zwahr,
    
    88 S.W.3d 623
    , 629 (Tex. 2002); 
    Sanchez, 997 S.W.2d at 590
    ; 
    Robinson, 923 S.W.2d at 558
    . We must uphold the trial court’s evidentiary ruling if there is any legitimate basis for
    it. Owens-Corning Fiberglas Corp. v. Malone, 
    972 S.W.2d 35
    , 43 (Tex. 1998); Norstrud
    v. Trinity Universal Ins. Co., 
    97 S.W.3d 749
    , 752 (Tex. App.–Fort Worth 2003, no pet.).
    For an expert’s testimony to be admissible, it must possess a reliable foundation.
    Cooper Tire & Rubber 
    Co., 204 S.W.3d at 800
    . “Admission of expert testimony that does
    not meet the reliability requirement is an abuse of discretion.” 
    Id. Expert testimony
    is
    unreliable if it is based on unreliable data, or if the expert draws conclusions from his
    underlying data “based on flawed methodology.” 
    Havner, 953 S.W.2d at 714
    . Expert
    38
    testimony is also unreliable if “there is simply too great an analytical gap between the data
    and the opinion proffered.” 
    Gammill, 972 S.W.2d at 726
    (quoting Gen. Elec. Co. v. Joiner,
    
    522 U.S. 136
    , 146 (1997)).
    In E.I. du Pont de Nemours & Co. v. Robinson, the supreme court set out six factors
    courts may consider in deciding whether expert testimony is reliable:
    1.     the extent to which the theory has been or can be tested;
    2.     the extent to which the technique relies on the subjective
    interpretation of the expert;
    3.     whether the theory has been subjected to peer review and/or
    publication;
    4.     the technique’s potential rate of error;
    5.     whether the underlying theory or technique generally has been
    accepted as valid by the relevant scientific community; and
    6.     the nonjudicial uses which have been made of the theory or
    
    technique. 923 S.W.2d at 557
    . These Robinson factors are nonexclusive, Cooper Tire & Rubber 
    Co., 204 S.W.3d at 801
    , and “are not always useful in evaluating expert testimony.” 
    Id. at 802.
    When the Robinson factors do not readily lend themselves to a review of the expert
    testimony, “there must be some basis for the opinion offered to show its reliability.”
    
    Gammill, 972 S.W.2d at 726
    . An expert’s “bare opinion” will not suffice and is unreliable
    if “based solely upon his subjective interpretation of the facts.” Volkswagen of Am., 
    Inc., 159 S.W.3d at 906
    .
    Dr. Bux, a physician and board certified forensic pathologist who practices as a
    medical examiner and the coroner for El Paso County, Colorado, provided testimony for
    the Thompson family. Based on his review and analysis of Thompson’s medical records
    from the day of her death, her autopsy report and microscopic pathology slides, and the
    39
    Accu-Chem data, Dr. Bux testified that Thompson died from a fentanyl overdose and not
    heart disease. Thompson presented to the emergency room with symptoms of nausea,
    vomiting, and back pain, and later complained of dizziness, but she was alert and oriented.
    She was on an EKG monitor during her transportation to the hospital by the emergency
    medical personnel, and also while she was in the emergency room, and “those monitors
    do not reveal any kind of cardiac abnormality or rhythm disturbance” but instead show “her
    regular normal heartbeat.” Thompson’s medical records from the day of her death do not
    show that she reported any symptoms that would suggest that she was experiencing a
    cardiology-related problem, such as chest pain or shortness of breath.
    Dr. Bux further testified that a “cardiac panel” test was performed on Thompson’s
    blood. This panel included an array of tests, which, inter alia, checked for high levels of
    certain enzymes indicating damage to muscles, including cardiac muscle, and troponin,
    which is specific for cardiac muscle. The results of the cardiac panel were “all either
    negative or within normal limits, which tells me that at the time she came in, it did not
    appear from an enzyme standpoint that she had anything going on with her heart.” Finally,
    examining the autopsy data, Dr. Bux testified that, microscopically, Thompson’s heart
    muscle looked normal except for the hypertrophy. He concluded there was no forensic
    evidence in the records on the day that Thompson died that supports a determination that
    Thompson died from sudden cardiac arrest and that sudden cardiac arrest was not a
    plausible cause of Thompson’s death. According to Dr. Bux, a large heart is not an actual
    cause of death.
    Dr. Bux considered the other drugs that were administered to Thompson at the
    hospital, including Antivert, Zofran, and Dilaudid, and excluded them as factors in
    Thompson’s demise based on the dosages given, the methods of infusion, and the timing
    40
    of their administration. He found it significant that the emergency room physician removed
    the Duragesic patch from Thompson during his efforts to resuscitate her and also
    administered Narcan, which is an antidote for a narcotic overdose.
    Dr. Bux testified that Accu-Chem’s toxicological report showed a quantitation of
    fentanyl at 11.4 ng/ml, which is a “lethal” level. He further testified that respiratory
    depression due to a drug overdose occurs in the last minutes or hour before death, that
    it is very difficult to “pick up,” and that it is completely foreseeable for Thompson to not
    show signs of respiratory depression at 3:15 p.m., but die from it thirty-five minutes later.
    Dr. Sayed Feghali, a cardiologist who works at the Texas Heart Institute and
    teaches at Baylor School of Medicine, also testified on behalf of the Thompsons regarding
    whether or not Thompson could have died from cardiac problems.25 He is board certified
    in cardiology and interventional cardiology. This was his first time to provide expert
    testimony in a lawsuit.
    According to Dr. Feghali, fentanyl has a narrow therapeutic margin. He has used
    it intravenously in thousands of patients. After reviewing all of Thompson’s medical
    records, including EKGs from a sleep study that Thompson had participated in, the EKG
    taken by emergency workers on the day Thompson died, and the EKGs taken during
    attempts to resuscitate her, Dr. Feghali testified that Thompson died from an overdose of
    fentanyl, and Thompson’s morbid obesity and sleep apnea played a minor part, if any, in
    her death. Dr. Feghali testified that other medications that she was given could not have
    caused respiratory depression because she was given appropriate doses.
    Dr. Feghali concluded that Thompson could not have died from a cardiac event
    25
    As part of the Thom pson fam ily’s burden on specific causation, they were required to offer evidence
    excluding other causes of Michaelynn’s death with reasonable certainty. Merrell Dow Pharms. v. Havner, 953
    S.W .2d 706, 720 (Tex. 1997).
    41
    because her autopsy showed no damaged heart tissue and the pathology report
    referenced no damage to Thompson’s heart muscle or any blockage of her arteries.
    According to Dr. Feghali, a sudden malignant arrhythmia does not come from nowhere and
    there should be a cause for it somewhere in the heart, like heart damage, heart scarring,
    a blockage, or a viral infection. In other words, the heart muscle will show prior damage
    of some kind. Dr. Feghali further based his conclusion that Thompson did not die from a
    sudden cardiac event because electric discrepancies did not appear on the EKGs
    performed either while en route to the emergency room, or saliently, while the emergency
    team was trying to resuscitate her. Dr. Feghali testified that while Thompson’s heart was
    large, it was normally sized for her body.
    On appeal, Alza does not challenge Dr. Bux or Dr. Feghali’s credentials. Their
    testimony analytically linked the data they observed to their theory of how Thompson died.
    They based their testimony on witness testimony, medical records, autopsy records, blood
    samples taken at the autopsy, the blood testing, and Alza’s own literature and drug
    warnings. The testing was based on generally acceptable scientific principles. The jury
    was free to examine this evidence. The experts’ testimony does not present a case where
    “there is simply too great an analytical gap between the data and the opinion proffered,”
    
    Gammill, 972 S.W.2d at 726
    , or where the expert’s testimony amounted to nothing more
    than a recitation of his credentials and a subjective opinion. See Cooper 
    Tire, 204 S.W.3d at 801
    . The Thompson family met its burden to prove Dr. Bux and Dr. Feghali’s testimony
    was relevant and reliable. See Whirlpool 
    Corp., 298 S.W.3d at 638
    . We conclude that
    Alza’s complaints about the experts’ testimony go to its weight, not its admissibility. The
    trial court therefore did not abuse its discretion in admitting the testimony of either Dr. Bux
    or Dr. Feghali.
    42
    2. Sufficiency of the Causation Evidence
    We next examine the legal and factual sufficiency of the evidence of causation
    supporting the jury’s finding. See 
    id. In addition
    to the evidence and testimony previously
    recounted herein, we will examine the testimony of Alza’s retained expert witnesses: Dr.
    Vincent DiMaio, the medical examiner in Bexar County; Dr. Joseph Varon, who specializes
    in internal medicine, intensive care, pulmonary and chest diseases, sleep disorders,
    geriatrics, and emergency medicine; and Dr. Aaron Kenneth Calodney, a medical doctor
    and pain management specialist.
    Dr. DiMaio testified that Thompson died from a fatal cardiac arrhythmia, an irregular
    beating of the heart, produced by the massive enlargement of her heart. According to Dr.
    DiMaio, it was essentially a “coincidence” that Thompson went to the hospital and died of
    an arrhythmia. Dr. DiMaio testified that thirteen percent of people who die suddenly and
    unexpectedly have a large heart as the cause of death. Yet he conceded before the jury
    that one cannot perform a test for cardiomyopathy and he is not a cardiologist. While Dr.
    DiMaio agreed that Thompson’s medical records and testimony evidence sleepiness, and
    sleepiness is a sign of fentanyl toxicity, he stated that if Thompson had received a fatal
    dose of fentanyl, she would have become sleepy and then gone into a coma for two to
    three hours prior to death, in contrast to the evidence herein which indicates that
    Thompson was found dead thirty to thirty-five minutes after being seen by a nurse. Dr.
    DiMaio testified that the only way a fentanyl overdose kills immediately is if it is infused
    intravenously. Finally, Dr. DiMaio testified that, in retrospect, the medical examiner for
    Harris County should have tested Thompson for fentanyl.
    Dr. Varon testified in counterpoint to Dr. Feghali. While Dr. Varon conceded that
    he is not board-certified in cardiology, he claimed that he is the “number one guy” on
    43
    sudden cardiac death. He works at the medical center in Houston and teaches at the
    University of Texas Health Science Center and other places. According to Dr. Varon, signs
    to look for in diagnosing a fentanyl or narcotic overdose include: constricted pupils,
    sweating, drowsiness or lethargy, and the cessation of breathing. Dr. Varon testified that
    these symptoms appear fast with intravenous transfusions of fentanyl or more slowly when
    the drug is introduced orally or through a skin patch. With a fentanyl overdose, he would
    have expected Thompson to be lethargic, sleepy, drowsy, and have depressed
    respirations, yet he did gave sworn testimony that he did not recall any of these symptoms
    in her medical records which expressly document some of these symptoms.
    According to Dr. Varon, it takes sixteen hours to achieve the full blood level effects
    of a fentanyl patch. However, when questioned about proper fentanyl dosages, he testified
    that he does not follow the therapeutic ranges on narcotics in the PDR, and in response
    to a question regarding whether his dosages regarding fentanyl were “catch as catch can,”
    replied, “exactly right.”
    Dr. Varon testified that he is familiar with sudden cardiac arrest, and that 500 to
    1,000 cases of sudden cardiac arrest occur every day in the United States and that one
    episode of cardiac arrhythmia can cause death. The underlying arrhythmia can be caused
    by the heart not getting enough oxygen or potassium. According to Dr. Varon, there are
    several risk factors for a sudden cardiac arrhythmia, including blockages in the heart, sleep
    apnea, medications, problems with electrolytes, trauma, or an enlarged heart.
    Dr. Varon examined the autopsy report, which stated that Thompson was six feet
    tall and weighed 367 pounds, and testified that obesity also carries a higher risk for health
    problems like apnea and sudden cardiac death. Thompson’s heart weighed 600 grams
    and had enlarged chambers, whereas a normal heart weighs between 350 to 500 grams.
    44
    According to Dr. Varon, the more dilated the heart is, the higher the chances of cardiac
    arrhythmia. Dr. Varon testified that in his opinion, Thompson did not have a healthy heart,
    and he opined that she expired from a sudden cardiac death, which was the result of
    arrhythmia or a defibrillate. He also testified that it was just a coincidence that Thompson
    was in the hospital when she died of arrhythmia. In this regard, he stated that Thompson
    had participated in a sleep study which showed she had sleep apnea, although he
    conceded that the records from that study showed that she had 144 instances of apnea
    without any corresponding arrhythmia. Dr. Varon testified that Thompson’s medical
    records from 2001 and 2002 show potential heart problems in two instances where she
    complained of chest pains and tightness, difficulty breathing, nausea, and general
    weakness, although the records fail to show any such diagnosis.
    According to Dr. Varon, an individual can experience a regular heart rate which
    progresses to full arrhythmia in minutes. However, Dr. Varon admitted that the EKGs
    which were performed on Thompson on the date of her death showed no abnormalities
    with regard to Thompson’s heart valves, and her autopsy showed no atherosclerosis or
    other heart damage. He further agreed that big people can have big, healthy hearts.
    Dr. Aaron Kenneth Calodney, a medical doctor and pain management specialist,
    provided further testimony on behalf of Alza. Dr. Calodney has written thousands of
    prescriptions for Duragesic patches. He testified that Duragesic patches fall within a “class
    II” system of narcotics, and a class II narcotic is something that is “[d]efinitely” dangerous
    if misused. Dr. Calodney testified that he would not start an opioid naive patient on a 50
    milligram patch because it could potentially be fatal. He testified that fentanyl is an opioid
    like morphine, but is approximately 100 times more potent than morphine.
    Dr. Calodney testified that the PDR is a common reference for professionals to use
    45
    to ascertain the particular qualities and properties of drugs, and further testified regarding
    the PDR’s section on the Duragesic patch. The PDR states that “since the peak fentanyl
    levels occur between 24 and 72 hours of treatment, prescribers should be aware that
    serious or life-threatening hypoventilation may occur, even in opiate tolerant patients during
    the initial application period.” It further states that “[o]verestimating the Duragesic dose
    when converting patients from another opiate medication can result in fatal overdose with
    the first dose.” The 2005 PDR states that using damaged or cut patches can lead to the
    rapid release of the contents of the patch and absorption of a potentially fatal dose of
    fentanyl.
    Dr. Calodney has never seen a damaged patch, but he agreed that if the patch was
    damaged and the drug were to escape, then that could lead to a rapid release of fentanyl.
    He refused to testify regarding whether a rapid release could lead to a fatal overdose, “not
    knowing whether the stuff inside the patch can actually be absorbed through the skin”
    without the patch system itself.
    According to Dr. Calodney, Thompson was an appropriate candidate for use of a
    Duragesic patch. Dr. Calodney stated that complications from an overdose of fentanyl
    include itching, nausea and vomiting, difficulty urinating, and respiratory depression; he
    reviewed Thompson’s medical records and nevertheless stated that he saw no signs in her
    medical records that indicated the appearance of fentanyl toxicity. He further testified that
    if someone is receiving too much fentanyl, a change in their level of consciousness is
    observable over a period of time; the patient will begin to get drowsy and develop changes
    in respiration after that. According to Dr. Calodney, these changes happen slowly and
    gradually as the medication is infused, presumably through a rate-controlled membrane.
    We note at this juncture that, in contrast, Dr. Wimbish testified that the respiratory center
    46
    adapts to drug tolerance and a patient may not experience respiratory depression until the
    threshold for tolerance is exceeded, and it may be close to the fatal event in a tolerant
    individual. In other words, respiratory depression is not necessarily observable in a tolerant
    individual. According to Dr. Wimbish, it could be “part of the terminal event rather than a
    harbinger of something to come.”
    To a significant extent, deciding whether Thompson died from an enlarged heart or
    a sudden arrhythmia, as alleged by Alza, or an overdose of fentanyl, as alleged by the
    Thompson family, turned on the jury’s examination of the evidence and its assessment of
    the credibility of the various witnesses. We note that the jury was, of course, entitled to
    weigh the credibility of these witnesses. 
    Ledesma, 242 S.W.3d at 41
    (holding that the jury
    was entitled to take into account that an expert had worked for the manufacturer and had
    never found a defect in a product).26
    Causation may be established by circumstantial evidence. 
    Ridgway, 135 S.W.3d at 601
    ; Ford Motor Co. v. Cammack, 
    999 S.W.2d 1
    , 7 (Tex. App.–Houston [14th Dist.]
    1998, pet. denied); J.K. and Susie L. Wadley Research Inst. & Blood Bank v. Beeson, 
    835 S.W.2d 689
    , 698 (Tex. App.–Dallas 1992, writ denied). This principle of Texas law has
    been well recognized for decades. Gladewater v. Pike, 
    727 S.W.2d 514
    , 518 (Tex. 1987)
    (“Circumstantial evidence and inferences therefrom are a sufficient basis for a finding of
    causation.”); Farley v. M M Cattle Co., 
    529 S.W.2d 751
    , 755 (Tex. 1975) (“Proximate
    cause, like any other ultimate fact, may be established by circumstantial evidence.”); Lynch
    v. Ricketts, 
    158 Tex. 487
    , 
    314 S.W.2d 273
    , 275-76 (Tex. 1958) (“It is well settled . . . that
    26
    W e note that we are not the first court to review Alza’s claim that its own experts’ dism issive
    testim ony about the flaws in its Duragesic fentanyl patches is authoritative or Alza’s argum ents that the
    claim ant’s experts’ contrary opinions should be wholly disregarded. See, e.g., Kunnemann v. Janssen
    Pharmaceutica Products, L.P., No. 05 C 3211, 
    2008 U.S. Dist. LEXIS 101724
    , at *8-32 (N.D. Ill. Dec. 2, 2008)
    (not designated for publication). Likewise, we are not the first court to conclude “[t]hese issues m ust be
    resolved by a jury.” See 
    id. at *32.
    47
    negligence and causation, like any other ultimate fact, may be established by
    circumstantial as well as direct evidence.”); Peveto v. Smith, 
    134 Tex. 308
    , 
    133 S.W.2d 572
    , 576 (1939) (relying on circumstantial evidence to prove negligence and causation);
    see also Tex. Elec. Coop. v. Dillard, 
    171 S.W.3d 201
    , 206 (Tex. App.–Tyler 2005, no pet.)
    (“Cause in fact . . . may be proven by circumstantial evidence . . . .”). The question of
    causation is a fact question for the jury, and the jury has broad latitude to infer causation
    from the circumstances surrounding an accident, especially when it is not possible to
    produce direct proof of causation. J.K. and Susie L. 
    Wadley, 835 S.W.2d at 698
    ; 
    Farley, 529 S.W.2d at 756
    . The plaintiff need not exclude all possibility that the accident occurred
    other than as he alleges. 
    Farley, 529 S.W.2d at 756
    . Rather, the plaintiff is only required
    to convince the jury by a preponderance of the evidence that the accident occurred as
    alleged. Renfro Drug Co. v. Lewis, 
    235 S.W.2d 609
    , 621 (1950); Gulf States Util. Co. v.
    Dryden, 
    735 S.W.2d 263
    , 267 (Tex. App.- Beaumont 1987, no writ). In the specific context
    of a strict product liability case, the claimants can support their theory of how the incident
    occurred with circumstantial evidence. See, e.g., 
    Ridgway, 135 S.W.3d at 601
    ; Gen.
    Motors Corp. v. Sanchez, 
    997 S.W.2d 584
    , 587 (Tex. 1999); Kindred v. Con/Chem, Inc.,
    
    650 S.W.2d 61
    , 63 (Tex.1983).
    As stated previously, under the Texas Supreme Court’s articulation of the standard
    of review in City of Keller, in reviewing the legal sufficiency of the evidence, we view the
    evidence in the light most favorable to the jury’s findings, giving full credit to all favorable
    evidence if any reasonable person could, and disregarding contrary evidence unless all
    reasonable persons could not. City of 
    Keller, 168 S.W.3d at 807
    . The evidence supporting
    the jury’s finding on causation was not completely lacking, nor was it beyond the court’s
    authority to admit it, nor was it a mere scintilla, nor was it conclusively disproved by
    48
    contrary evidence. See Uniroyal Goodrich Tire Co. v. Martinez, 
    977 S.W.2d 328
    , 334 (Tex.
    1998); see also Whirlpool 
    Corp., 298 S.W.3d at 638
    . Moreover, considering and weighing
    all of the evidence in the case, the verdict was not so against the great weight and
    preponderance of the evidence as to be manifestly unjust, shock the conscience, or clearly
    demonstrate bias. See Golden Eagle Archery, Inc. v. Jackson, 
    116 S.W.3d 757
    , 761-62
    (Tex. 2003).
    Based on the foregoing, we overrule Alza’s third issue.
    III. EVIDENCE OF NEGLIGENCE
    In its second issue, Alza contends that there is legally insufficient evidence to
    support the submission or jury finding that Alza was negligent because there was no expert
    evidence on the standard of care.
    As an initial matter, we note that a party may pursue claims and seek damages on
    alternative theories of liability.   TEX . R. CIV. P. 48; Waite Hill Servs., Inc. v. World Class
    Metal Works, Inc., 
    959 S.W.2d 182
    , 184 (Tex. 1998). When we have held that the
    evidence is legally and factually sufficient to support the trial court’s judgment on one of
    multiple alternative causes of action, “it is unnecessary to address” the issues that concern
    alternative theories that might have also served as a basis to affirm the judgment. Adams
    v. H & H Meat Prods., Inc., 
    41 S.W.3d 762
    , 771 (Tex. App.–Corpus Christi 2001, no pet.)
    (citing TEX . R. APP. P. 47.1); see Nw. Mortgage, Inc. v. Salinas, 
    999 S.W.2d 846
    , 865 (Tex.
    App.–Corpus Christi 1999, pet. denied) (stating that when “the trial court’s judgment can
    be supported on the basis of” one of multiple theories of recovery, “we need not address
    these remaining points” which address alternative theories of recovery). Accordingly, we
    need not address Alza’s second issue, which challenges the legal sufficiency of the
    evidence supporting the jury’s finding of negligence as an alternative basis for affirming the
    49
    judgment. See TEX . R. APP. P. 47.1.
    Nevertheless, even if we were to find it necessary to address this issue, we note that
    the jury was instructed that:
    “Negligence” means failure to use ordinary care, that is, failing to do that
    which a pharmaceutical manufacturer of ordinary prudence would have done
    under the same or similar circumstances or doing that which a
    pharmaceutical manufacturer of ordinary prudence would not have done
    under the same or similar circumstances.
    Where an issue involves only general knowledge and experience rather than expertise, it
    is a matter entrusted to the jury to decide. See GTE Sw., Inc. v. Bruce, 
    998 S.W.2d 605
    ,
    620 (Tex. 1999). In contrast, “[e]xpert testimony is necessary when the alleged negligence
    is of such a nature as not to be within the experience of the layman.” FFE Transp. Servs.
    v. Fulgham, 
    154 S.W.3d 84
    , 91 (Tex. 2004) (quoting Roark v. Allen, 
    633 S.W.2d 804
    , 809
    (Tex. 1982) (holding that diagnosis of skull fractures is not within the experience of the
    layman)); see also Turbines, Inc. v. Dardis, 
    1 S.W.3d 726
    , 738 (Tex. App.–Amarillo 1999,
    pet. denied) (holding that inspection and repair of an aircraft engine are not within the
    experience of the layman); Hager v. Romines, 
    913 S.W.2d 733
    , 734-35 (Tex. App.–Fort
    Worth 1995, no writ) (holding that operation of an aircraft and aerial application of herbicide
    are not within the experience of the layman). In determining whether expert testimony is
    necessary to establish negligence, Texas courts have considered whether the conduct at
    issue involves the use of specialized equipment and techniques unfamiliar to the ordinary
    person. 
    Fulgham, 154 S.W.3d at 91
    .
    In light of the testimony and admissions by Alza’s employees and representatives
    regarding its manufacturing and quality inspection process for the Duragesic patch, the
    determination regarding whether Alza breached the standard of care applicable to a
    reasonable pharmaceutical manufacturer does not entail specialized knowledge or skill
    50
    unique to a scientific discipline and beyond the knowledge and experience of the average
    jury. See, e.g, Worsham v. A.H. Robins Co., 
    734 F.2d 676
    , 685 (11th Cir. Fla. 1984)
    (affirming a judgment against the manufacturer of the Dalkon Shield IUD on claims of
    negligence despite the absence of expert testimony on the duty of care); Palmer v. A.H.
    Robins Co., 
    684 P.2d 187
    , 209-10 (Colo. 1984) (same); cf. McNeil Pharm. v. Hawkins, 
    686 A.2d 567
    , 585 (D.C. 1996) (requiring competent expert testimony regarding the violation
    of the statutes and regulations submitted to the jury in warnings case). On the contrary,
    resolution of the negligence issue turns on an assessment of evidence relating to Alza’s
    decision to manufacture the Duragesic patch on a machine known to produce defective
    patches and to test its products with a method known to be insufficient to ascertain the
    absence of defect. The ultimate determination of whether Alza’s conduct comported with
    that degree of care which a reasonably prudent drug manufacturer would use under the
    same or similar circumstances was well within the experience of persons of ordinary
    intelligence. Thus, expert opinion evidence was not essential to the Thompson family’s
    claim in negligence.27
    However, even if we were to determine otherwise, and conclude that expert
    testimony was necessary, this requirement would have been met by the testimony
    proffered by Alza’s own representatives and employees. While the Thompson family might
    not have presented a retained expert on pharmaceutical manufacturing to establish their
    claim that Alza was negligent in its manufacturing process, Alza’s own representatives and
    employees, including a senior technician, the company representative, and its quality
    assurance specialist, offered expert opinion testimony regarding Alza’s acts and omissions
    27
    In this context, the determ ination whether expert testim ony is necessary is reviewed under a de
    novo standard of review. See FFE Transp. Servs. v. Fulgham, 154 S.W .3d 84, 90 (Tex. 2004).
    51
    with regard to the Duragesic patch, from which credible and expert evidence the jury may
    have concluded that Alza was negligent. These witnesses testified that Alza released
    leaking patches to the public and only learned that its patches were defective because of
    consumer complaints; that Alza wrongly determined that the 2001 fold-over incidents were
    isolated events and accordingly, did not take corrective action that would have prevented
    distribution of the 2004 recalled lots; that Alza’s inspection plan for the product lots was
    deficient; that Alza did not follow its own deficient plan and allowed distribution of trays of
    patches that it knew contained defects; that Alza continued to release patches after both
    learning of the leaks and determining the manufacturing flaw that resulted in the leaks; and
    that Alza continued to implement a visual inspection process despite knowing that it was
    ineffective to discover product defects.
    Ultimately, in the instant case, the primary facts were accurately presented to the
    jury, and the jurors were as capable of understanding and drawing correct conclusions
    from the facts as an expert witness. While there are cases that would fail without expert
    testimony because the technical and scientific aspects of the case would result in a jury’s
    inability to comprehend the issues, Alza has not shown that the standard of care issue is,
    by definition, a matter beyond the jurors or that this is “one of the rare causes of action in
    which the law predicates recovery upon expert testimony.” Salem v. U.S. Lines Co., 
    370 U.S. 31
    , 35 (1962).
    For the foregoing reasons, we overrule Alza’s second issue.
    IV. EVIDENTIARY RULINGS
    Alza’s fourth and fifth issues attack the trial court’s admission of evidence regarding
    Accu-Chem’s test and its recall of the Duragesic 75 mcg patch.
    A. STANDARD OF REVIEW
    52
    We review the admission or exclusion of evidence under an abuse of discretion
    standard. See In re J.P.B., 
    180 S.W.3d 570
    , 575 (Tex. 2005). Thus, evidentiary rulings
    admitting or excluding evidence are committed to the trial court’s “sound” discretion. See
    Tex. Dep’t of Transp. v. Able, 
    35 S.W.3d 608
    , 617 (Tex. 2000); City of Brownsville v.
    Alvarado, 
    897 S.W.2d 750
    , 753 (Tex. 1995); Gee v. Liberty Mut. Fire Ins. Co., 
    765 S.W.2d 394
    , 396 (Tex. 1989). A trial court abuses its discretion if it acts without reference to any
    guiding rules and principles or if the act complained of is arbitrary and unreasonable. City
    of 
    Brownsville, 897 S.W.2d at 754
    ; see also Carpenter v. Cimarron Hydrocarbons Corp.,
    
    98 S.W.3d 682
    , 687 (Tex. 2002). We must uphold a trial court’s evidentiary ruling if there
    is any legitimate basis in the record to support it. Owens-Corning Fiberglas 
    Corp., 972 S.W.2d at 43
    .
    For the exclusion of evidence to constitute reversible error, the complaining party
    must show that (1) the trial court committed error, and (2) the error probably caused the
    rendition of an improper judgment. State v. Cent. Expressway Sign Assocs., No. 08-061,
    
    53 Tex. Sup. Ct. J. 134
    , 2009 Tex. LEXIS 967, at **5-6 (Tex. Nov. 30, 2009); McCraw v.
    Maris, 
    828 S.W.2d 756
    , 757 (Tex. 1992); see TEX . R. APP. P. 44.1; Nissan Motor Co. v.
    Armstrong, 
    145 S.W.3d 131
    , 144 (Tex. 2004). A person seeking to reverse a judgment
    based on evidentiary error need not prove that “but for” the error a different judgment would
    necessarily have been rendered, but only that the error probably resulted in an improper
    judgment. State, 2009 Tex. LEXIS 967, at *6; City of 
    Brownsville, 897 S.W.2d at 754
    ;
    
    McCraw, 828 S.W.2d at 758
    . A successful challenge to evidentiary rulings usually requires
    the complaining party to show that the judgment turns on the particular evidence excluded
    or admitted. Bay Area Healthcare Group, Ltd. v. McShane, 
    239 S.W.3d 231
    , 234 (Tex.
    2007); Nissan Motor 
    Co., 145 S.W.3d at 144
    . In making this determination, we review the
    53
    entire record. Reliance Steel & Aluminum Co. v. Sevcik, 
    267 S.W.3d 867
    , 871 (Tex. 2008);
    Nissan Motor 
    Co., 145 S.W.3d at 144
    .
    The supreme court has recognized the impossibility of prescribing a specific test
    for harmless error review and has characterized the standard as “more a matter of
    judgment than precise measurement.” Reliance 
    Steel, 267 S.W.3d at 871
    (quoting Nissan
    Motor 
    Co., 145 S.W.3d at 144
    ).           Accordingly, as stated by Justice O’Neill, that
    determination is entrusted “to the sound discretion of the reviewing court.” State, 2009 Tex.
    LEXIS 967, at *5 (citing 
    McCraw, 828 S.W.2d at 757-58
    ; Lorusso v. Members Mut. Ins.
    Co., 
    603 S.W.2d 818
    , 821 (Tex. 1980)).
    We consider several factors in conducting a harmless error review for the erroneous
    admission of evidence: the state of the evidence, the strength and weakness of the case,
    and the verdict. Reliance 
    Steel, 267 S.W.3d at 871
    . Stated otherwise, we consider the
    effect of the admission of the evidence; the role the evidence played in the context of trial;
    efforts by counsel to emphasize the erroneous evidence; and whether the admission of the
    improper evidence was calculated or inadvertent. See 
    id. at 871-75.
    Thus, “the exclusion
    or admission is likely harmless if the evidence was cumulative, or the rest of the evidence
    was so one-sided that the error likely made no difference in the judgment.” State, 2009
    Tex. LEXIS 967, at *6; see Reliance 
    Steel, 267 S.W.3d at 873
    . But if erroneously admitted
    or excluded evidence was “crucial” to a “key issue,” the error is likely to be found harmful.
    State, 2009 Tex. LEXIS 967, at *6. We further consider whether there was contrary
    evidence that the improperly admitted evidence was calculated to overcome.                  Id;
    
    Armstrong, 145 S.W.3d at 144
    .
    B. ADMISSION OF EVIDENCE REGARDING FENTANYL LEVELS IN THOMPSON ’S BLOOD
    In its fourth issue, Alza contends that the trial court committed harmful error resulting
    54
    in an improper judgment by admitting the results of the Accu-Chem postmortem blood test
    that was improperly performed and by permitting Thompson’s experts to opine on the
    cause of death based solely on unreliable test results. We have previously addressed this
    matter with regard to Alza’s other issues and need not further address it herein. See TEX .
    R. APP. P. 47.1. This issue is overruled.
    C. ADMISSION OF EVIDENCE REGARDING ALZA’S RECALL OF FENTANYL PATCHES
    In its fifth issue, Alza contends that the trial court’s admission of evidence that Alza
    recalled several lots of Duragesic patches constituted an abuse of discretion that was
    reasonably calculated to and probably caused the rendition of an improper judgment. In
    several sub-issues, Alza argues that: (1) there is no evidence independent of the recall
    that Thompson was wearing a patch with the same defect; (2) the evidence of recall does
    not tend to make a fact that is of consequence to the suit any more or less probable; (3)
    the evidence of recall was outweighed by prejudice and caused a confusion of the issues;
    and (4) the admission of the recall evidence was reasonably calculated to and probably
    caused the rendition of an improper judgment. Thompson counters that this evidence was
    both admissible and relevant.
    On February 17, 2004, Alza recalled one lot of 75 mcg Duragesic patches through
    an “Urgent Class 1 Drug Recall Notification.” This recall notice stated that a “potential seal
    breach on one edge may allow drug to leak from the patch.” The notice further stated that:
    Exposure to the Duragesic hydrogel contents could result in an increased
    absorption of the opioid component, fentanyl, leading to increased drug
    effect, including nausea, sedation, drowsiness, or potentially life threatening
    complications.
    On April 7, 2004, Alza recalled four additional lots of 75 mcg Duragesic patches in an
    “Urgent Expanded Drug Recall Notification.” This recall warned that:
    Exposure to the leaked medication could result in inadvertent ingestion or an
    55
    increased transdermal absorption of the opiate component, fentanyl, leading
    to potentially life-threatening complications.
    Texas Rule of Evidence 407 provides:
    A written notification by a manufacturer of any defect in a product produced
    by such manufacturer to purchasers thereof is admissible against the
    manufacturer on the issue of existence of the defect to the extent it is
    relevant.
    TEX . R. EVID . 407(b). This Court addressed the admissibility of recall evidence in Ford
    Motor Co. v. Durrill, 
    714 S.W.2d 329
    (Tex. App.–Corpus Christi 1986), judgm’t vacated by
    agreement, 
    754 S.W.2d 646
    (Tex. 1988):
    In appellant’s twentieth point of error, Ford urges that the trial court erred in
    admitting the Pinto recall letter and testimony relating to the Pinto recall. The
    Durrills argue that the evidence was relevant to show Ford’s conscious
    disregard for the public safety. Rule 407(b) allows a written ratification by a
    manufacturer of a product defect to be admitted against the manufacturer on
    the issue of existence of the defect to the extent that it is relevant. The fact
    that recall letters are admissible is settled by the existence of TEX . R. EVID .
    407(b). The circumstances for admission in this case are somewhat unusual
    in that the letter was admitted to show both Ford’s failure to warn of an
    alleged similar defect in the Mustang II and to show that a defect existed in
    the Mustang II by showing its similarities to the recalled Pinto.
    Dr. Robert Brenner testified that the Ford Motor Company should have sent
    a recall letter like the “Pinto” letter to Mustang owners as well. He testified
    that the safety related defect which precipitated the Pinto -Bobcat recall was
    very similar, if not identical to the safety related defect that Ford knew existed
    in the Pinto-Bobcat and Mustang.
    The evidence of the Pinto recall was relevant both to the defect issue and
    the failure to warn. It was incumbent upon the Durrills to show by
    independent evidence that the Mustang II was defective at the time of injury
    in order for the letter to be admissible to show the existence of a defect. See
    Blakely, Article IV: Relevancy and Its Limits, 20 HOUS. L. REV. 151, 220
    (1983). The Durrills established, by independent evidence, that the Mustang
    II was defective in the same manner as the Pinto. Additionally, we find that
    the evidence was admissible to illustrate Ford’s failure to warn.
    See 
    id. at 340.
    Rule 407(b) clearly states that the evidence of the recalls is admissible in evidence
    on the issue of the existence of the defect to the extent that it is relevant. Specifically, the
    56
    issue of recall is, in the words of Texas Rule of Evidence 407, “admissible against [Alza]
    on the issue of existence of the defect to the extent it is relevant.” The defect referenced
    in the recall is the same defect as alleged in the instant case, that is, an alleged breach in
    the seal of the patch causing an uncontrolled release of fentanyl, and thus, the recall is
    relevant.
    Alza contends that there is no evidence independent of the recall that Thompson
    was wearing a patch with the same defect as referenced in the recall. Assuming without
    deciding that Thompson was required to show some independent proof that the particular
    product in question suffered from the same defect, the record contained such evidence.
    Thompson was prescribed the same patch that was the subject of Alza’s recall, and her
    patch was manufactured during the same period of time and on the same machine as the
    recalled patches. Prior to and upon admission to the hospital, she displayed symptoms
    of overdose including nausea, vomiting, sleepiness, and dizziness. Thompson’s blood test
    showed an overdose of fentanyl. Accordingly, there is independent evidence of the alleged
    defect in the involved product.
    Alza contends that the evidence of recall does not tend to make a fact that is of
    consequence to the suit any more or less probable. However, recall letters are admissible
    as some evidence that the defect existed when the product left the manufacturer. This is
    an element that Thompson was required to prove. 
    Ridgeway, 135 S.W.3d at 600
    (holding
    that the plaintiff must prove that the product was defective when it left the hands of the
    manufacturer and that the defect was a producing cause of the plaintiff’s injuries).
    Finally, Alza contends that the evidence of recall was outweighed by prejudice and
    caused a confusion of the issues, and the admission of the recall evidence was reasonably
    calculated to and probably caused the rendition of an improper judgment. Because
    57
    Thompson was required to prove that the defect existed not only at the time of her death
    but also at the time when the Duragesic patch left Alza’s hands, the relevancy of the recall
    letters outweighs any possible prejudice in their admission into evidence. In this regard,
    we note that “testimony is not inadmissible on the sole ground that it is ‘prejudicial’ because
    in our adversarial system, much of a proponent’s evidence is legitimately intended to
    wound the opponent.” Bay Area Healthcare 
    Group, 239 S.W.3d at 234
    . A jury is entitled
    to know that the existence of the defect in a particular kind of Duragesic patch was likely
    and that such likelihood was greater as to the 75 mcg patches as to other patches
    manufactured by Alza.       Accordingly, the prejudicial impact of the recall letters is
    outweighed by its relevance on the issue whether the product was defective when it left the
    hands of the manufacturer. We note that the recall does not by itself make a prima facie
    case, shift the burden of proof, or prove that the defect existed at the time of the incident.
    See, e.g., Fields v. Volkswagen of Am., Inc., 
    555 P.2d 48
    , 58 (Okla. 1976),
    We conclude that, under the circumstances of this case, the recalls were properly
    admissible in evidence for the purpose of determining whether the defect identified by
    Thompson’s expert witnesses existed when Alza put the patch into Thompson’s hands.
    We note that to sustain a verdict for a plaintiff based upon an existing defect, such recall
    evidence, standing alone, would be insufficient. Here, however, we have the credible
    testimony of Thompson’s experts, albeit contradicted by that of Alza’s expert witnesses,
    which justified the jury’s conclusion that the Duragesic patch worn by Thompson was
    defective and the defect caused her death. Accordingly, we hold that, in the circumstances
    of this case, the recall evidence was properly admissible in evidence for the limited
    purpose of determining whether the defect identified by plaintiff’s expert witnesses arose
    while the product was in Alza’s control. We overrule Alza’s fifth issue.
    58
    V. CONCLUSION
    Having overruled each of Alza’s issues, we affirm the judgment of the trial court.
    _____________________
    Linda R. Yañez
    Justice
    Delivered and filed
    the 1st day of April, 2010.
    59