This case is must reading for any trial lawyer (plaintiff or defense) who litigates product liability cases that rely on sophisticated expert testimony. In a workmanlike 35-page opinion (I did say the case was complex), the Eighth Circuit reversed the trial court’s exclusion of the plaintiffs’ medical and engineering experts and its resulting grant of summary judgment to the defendant. In re: Bair Hugger Forced Air Warming Devices Products Liability Litigation – Amador v. 3M Company, https://ecf.ca8.uscourts.gov/opndir/21/08/192899P.pdf (8th Cir., No. 19-2899, 8/16/21). This was the first bellwether trial in a multidistrict litigation involving more than 6000 consolidated lawsuits, so the Eighth Circuit’s ruling enables a very significant MDL to move forward.
Devices to keep patients warm during surgery have been developed to prevent surgical hypothermia, which can lead to complications and poor outcomes. Convective systems blow hot air through a hose into a perforated blanket draped over the patient; conductive systems transfer heat by direct contact with the patient’s skin. The system at issue in this case, the Bair Hugger, is the forced hot air type. The 6000-plus MDL plaintiffs claim that they contracted periprosthetic joint infections due to the use of the Bair Hugger during joint replacement (knee or hip) surgery. “Periprosthetic joint infection (PJI) is one of the most devastating and costly complications following total joint arthroplasty (TJA)….[PJI is] one of the major [causes] of implant failure after TJA….The annual cost of infected revisions to U.S. hospitals increased from $320 million in 2001 to $566 million by 2009, and it is estimated that the cost will exceed $1.62 billion by 2020.” V. Aggarwal et al., “Periprosthetic joint infection: Current concept,” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3601222/ (2013).
As the Eighth Circuit explained,
Plaintiffs advance two theories for how the Bair Hugger caused their PJIs during their orthopedic-implant surgeries. According to the “airflow disruption” theory, waste heat from the Bair Hugger creates convection currents that carry ambient bacteria from nonsterile areas of the operating room to the surgical site…resulting in PJIs. According to the “dirty machine” theory, the Bair Hugger is internally contaminated with bacteria, which are blown through the blanket into the operating room, where they become ambient and eventually reach the surgical site, resulting in PJIs.
In support of these theories, the plaintiffs relied on three general-causation medical experts – an epidemiologist, an infectious diseases specialist and an orthopedic surgeon – and two engineers. As noted above, the Eighth Circuit reversed the trial court’s exclusion of the experts (all of the them) and its resulting grant of summary judgment. The detailed analysis through which the court of appeals reached that conclusion is elegant, instructive, and well worth reading by any litigator who handles these types of cases. But what caught my eye about this case was the court’s discussion of the conflicting standards of review that come into play when reviewing a trial court’s exclusion of expert testimony, as well as the multitude of factors (none of which is conclusive by itself) that an appellate court must consider in this situation. Key excerpts follow; citations and internal quotation marks are omitted, except for certain references to Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993):
Federal Rule of Evidence 702 governs the admissibility of expert testimony, and under this rule the district court is vested with a gatekeeping function, ensuring that “any and all scientific testimony or evidence admitted is not only relevant, but reliable” (quoting Daubert). In exercising this gatekeeping function, the district court has broad discretion, and on appeal we will not disturb a decision concerning the exclusion of expert testimony absent an abuse of that discretion.
That said, we have recognized that the liberal thrust of Rule 702 regarding the admissibility of expert testimony creates an intriguing juxtaposition with our oft-repeated abuse-of-discretion standard of review. While we adhere to this discretionary standard for review of the district court’s Rule 702 gatekeeping decision, cases are legion that, correctly, under Daubert, call for the liberal admission of expert testimony.
Rule 702’s screening requirement has been boiled down to a three-part test. [First, the testimony must be relevant; second, the expert must be qualified.] Third, the testimony must be reliable or trustworthy in an evidentiary sense. At issue here is the third part of this test – whether Plaintiffs’ experts’ proposed testimony meets Rule 702’s reliability requirement….
The reliability inquiry is a “flexible” one, with “[m]any factors” bearing on it (quoting Daubert). In Daubert, the Court articulated four non-exclusive factors relevant to this inquiry. These factors are (1) whether the expert’s theory or technique can be or has been tested, (2) whether the theory or technique has been subjected to peer review or publication, (3) the known or potential rate of error of the theory or technique, and (4) whether the technique or theory is generally accepted. Factors recognized since Daubert include whether the experts are proposing to testify about matters growing naturally and directly out of research they have conducted independent of the litigation, or whether they have developed their opinions expressly for purposes of testifying.
Additionally, while Daubert instructed that the focus of the reliability inquiry “must be solely on principles and methodology, not on the conclusions that they generate,” the Supreme Court later clarified that “conclusions and methodology are not entirely distinct from one another. Thus,…a district court may exclude expert testimony if it finds that there is simply too great an analytical gap between the data and the opinion proffered. Or, to put it in the language we have frequently used both before and after Daubert, a district court may exclude an expert’s opinion if it is so fundamentally unsupported by its factual basis that it can offer no assistance to the jury.
When a district court excludes an expert’s opinion for being fundamentally unsupported, yet another intriguing juxtaposition is evident in our case law. On the one hand, we have recognized that we owe significant deference to the district court’s determination that expert testimony is excessively speculative, and we can reverse only if we are convinced that the district court made a clear error of judgment on the basis of the record before it. On the other hand, we have stated numerous times that, as a general rule, the factual basis of an expert opinion goes to the credibility of the testimony, not the admissibility….
Thus, excluding an expert’s opinion for being fundamentally unsupported is an exception to the general rule that gaps in an expert witness’s knowledge go to weight, not admissibility. (Emphasis added.) Doubts regarding whether an expert’s testimony will be useful should generally be resolved in favor of admissibility. “Vigorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means” of addressing “shaky but admissible evidence” (quoting Daubert).
