Court Admits Pediatrics Expert Witness’ Specific Causation Opinion Based on Differential Diagnosis
Posted on January 3, 2025 by Expert Witness Profiler
For over 10 years, Fisher-Price sold a product called the Rock ‘n Play Sleeper (RnP). The Plaintiff, Ameena Brown, argued that the defective design of the RnP was to blame because her infant son, A.B., had died from sleeping in it. The dangers of this inclined sleeper product were widely debated in this case.
It all started when A.B.’s mother, Plaintiff Ameena Brown, was gifted a secondhand Rock ‘n Play for A.B. During naptime and overnight sleep, Ameena would place A.B. supine in the RnP, which she kept in the living room.
On January 15, 2018, the day before A.B.’s death, there was nothing out of the ordinary about A.B.’s health or demeanor. At approximately 6:00 AM the next morning, Ameena awoke and went to check on A.B. A.B. was found dead in the Rock ‘n Play.
Plaintiffs sought to introduce Darlene Calhoun‘s testimony to show: (1) the design of the RnP increased the risk of harm; (2) A.B. died from suffocation after rolling onto his side and pressing his face against the side of the RnP; (3) A.B. could have expected a normal life expectancy despite his premature birth; and (4) A.B. experienced conscious pain and suffering before death. Calhoun’s report also touches on the topic of rebreathing.
Defendants contended Calhoun: (1) lacked the requisite qualifications to opine on cause of death; (2) had no basis to conclude the RnP’s design is defective aside from the opinion of other experts in this case; (3) bases her conclusions on “mere association” as opposed to “reliable scientific opinions;” and (4) relied on a theory of increased risk causation which is impermissible under Pennsylvania law.
Pediatrics Expert Witness
Darlene A. Vasbinder-Calhoun, D.O. is a retired Neonatalist-Perinatalist. She received her D.O. degree in 1991 from the Ohio University College of Osteopathic Medicine. She is board certified in pediatrics. Calhoun describes her experience as “clinical practice in Neonatal-Perinatal Medicine,” working in Neonatal intensive care units, and conducting academic research.
Discussion by the Court
During her deposition, Calhoun stated “[m]y opinion is that [A.B.] died from suffocation related to the compression of his mouth and nose against the fabric of the Rock ‘n Play Sleeper.”
Calhoun formed that opinion based on her review of A.B.’s medical records, the witness statements of A.B.’s mother, various studies Calhoun cited in her report, and her own training and experience.
Calhoun May Not Offer General Causation Testimony
Defendants asserted that Calhoun does not qualify as a biomechanical engineer, or a forensic pathologist, and so cannot opine as to design flaws or cause of death. Further, Defendants contended that Calhoun relies upon “mere association”—the fact A.B. was found deceased in the device—rather than reliable scientific opinions, testing, or data demonstrating causation.
Calhoun’s general causation opinion “is simply saying that here the Rock ‘n Play can cause death.” The Court held that a review of Calhoun’s report as it pertains to general causation shows little analysis based upon her own expertise. Although she bases her general causation opinion on the type of “information reasonably relied upon by experts in the particular field,” she does not add any of her own context as to how the design of the RnP can cause death.
Defendants further contended Calhoun “does not have any experience related to product safety testing” which would render her discussion of Fisher-Price’s testing procedures and recall decisions admissible. The Court held that Calhoun has never conducted tests on infant sleep products, and her discussion about whether Fisher-Price knew the RnP posed a threat to infants amounts to a recounting of alleged facts generated without her particularized skills and education. Admitting this testimony may also mislead the jury and would permit Calhoun to testify about recalls and test procedures of which she has no expertise to testify.
Calhoun’s Specific Causation Testimony Is Admissible
Though Calhoun did not formally label her opinion as the result of a differential diagnosis, Plaintiffs contended that is precisely the methodology Calhoun utilizes in her report. A differential diagnosis involves the doctor creating a list of possible causes of death, and then working through the medical records to exclude each of those potential causes until only one reasonable explanation remains.
In her report, Calhoun considers as possible causes of death, and then excludes: Sudden Infant Death Syndrome; Gastroesophageal Reflux Disease; complications from A.B.’s Atrial Septal Defect; complications from A.B.’s Nasogastric Feeding Tube; and A.B.’s respiratory conditions. She also considered A.B.’s developmental age, his preference to turn to his right side, and the way he was found in the RnP the morning of his death.
Calhoun provides her reasoning, based on her training and experience, for concluding that she can rule out the alternative causes of death she considered. She then concludes, based on those exclusions and the information available to her, that A.B. died of asphyxiation. Further, she concludes due to A.B.’s developmental delays that he would have been unable to roll onto his side, absent the design of the RnP facilitating his roll. Calhoun created a list of possible causes of A.B.’s death, and her report explains why she excluded each alternative.
Defendants raise several specific issues with Calhoun’s methodology, but these issues, according to the Court, relate to the credibility of her opinion, not its admissibility.
For instance, Defendants’ argument based on Calhoun’s inability to know exactly what transpired during the time between Brown placing A.B. in the RnP and his death amounts to an argument against the credibility of Calhoun’s diagnosis, but not its admissibility.
Calhoun Cannot Rely On Increased Risk Of Harm To Establish Causation
Defendants contended Calhoun impermissibly relied on an “increased risk” standard, which Pennsylvania law prohibits in product liability cases. Calhoun’s ultimate conclusion stated, “[i]t is my opinion that the design of the Rock ‘n Play Sleeper increased the risk of harm for and was the direct cause of [A.B.’s] asphyxiation, physical pain and suffering, and death.”
After extensive argument, Defendants conceded their position with Plaintiffs as they “understood counsel to be acknowledging that they were not trying to substitute increased risk for proof of causation.” Here, Calhoun offered a basis for specific causation which goes beyond her reliance on increased risk. Moreover, Defendants have conceded that Plaintiffs are not attempting to substitute increased risk for causation. Accordingly, the Court held that Calhoun may not testify that increased risk establishes causation.
Held
The Court held that Calhoun’s training and expertise qualifies her to opine on the specific cause of death in this case. She may not provide an opinion on general causation based on the design of the RnP. She may not opine that increased risk establishes causation.
Key Takeaway:
The Court concluded that Calhoun’s general causation opinion, which primarily restates the opinions of other experts, lacked analysis rooted in her own expertise and risked misleading the jury; therefore, it must be excluded. However, her specific causation opinion was deemed admissible, as it relied on a reliable differential diagnosis methodology, which considered and ruled out alternative potential causes of death based on her training and experience. The Court also added that while Calhoun may testify that the RnP’s design increased the risk of harm, she cannot assert that increased risk alone establishes causation for A.B.’s death under Pennsylvania law.
Please refer to the blog previously published about this case:
Case Details:
| Case Caption: | Ameena Brown V. Fisher-Price, Inc. |
| Docket Number: | N20C-01-067 |
| Court: | Superior Court of Delaware, New Castle |
| Order Date: | December 20, 2024 |
