Determining When An Expert Witness Is “Expert Enough”

In medical malpractice case, trial court’s exclusion of defense expert as unqualified was not harmless error; the defense expert’s opinion that the plaintiff’s expert’s conclusion was not supported by the medical literature plaintiff cited did not require the defense expert to have as much specialized “training and experience” as the opposing expert whom he critiqued, in Huss v. Gayden, 571 F.3d 442 (5th Cir. June 10, 2009) (No. 04-60962), petition for rehearing denied, 585 F.3d 823 (5th Cir. Oct. 15, 2009)

The lack of precision in the Daubert test for the admission of expert witness testimony serves as a source of its remarkable flexibility and also as a source of frustration to practitioners. It is clear that under Daubert, an expert witness need not be a star in his or her field to qualify. On the other hand, minimal preparation or training frequently is insufficient for expert qualification. The Fifth Circuit recently probed the question of just when an expert is “expert enough” in a medical malpractice case. The result reached by the circuit demonstrates that expertise is a matter that must be assessed within the context of the evidence presented and arguments that will be made at trial.

In the case, plaintiff Huss brought a medical malpractice suit against their family physician Gayden alleging that he “negligently administered the drug Terbutaline Sulfate to Barbara during her pregnancy” in order to slow or halt premature labor contractions. The plaintiff alleged negligence because the plaintiff “was not actually in labor” nor had there been any “indication” that she was in labor. As a result, the complaint alleged that she developed “cardiomyopathy,” a condition in which the heart muscle becomes inflamed and fails to function as well as it should. Huss, __ at __ (footnote omitted).

During a jury trial before a magistrate judge, whether Terbutaline [structural formula of Terbutaline Sulfate is pictured above] could cause cardiomyopathy “was heavily disputed.” The plaintiff’s “primary causation expert,” Dr. Carlton, testified that “Terbutaline is known in the medical community to cause cardiomyopathy. Dr. Carlton opined that if Barbara [Huss] had experienced shortness of breath out of proportion to what a physician would expect in a late-term pregnancy” that this indicated “Terbutaline caused or contributed to Barbara's heart and lung conditions.”

In response to this evidence:

“[The] Defendants sought to elicit testimony from their expert, Dr. Reddix, that medical literature relied upon by Dr. Carlton in forming his opinion does not show a causative relationship between Terbutaline and cardiomyopathy. The magistrate judge did not permit Dr. Reddix to state this opinion, as this was ‘outside the area of his expertise.’”
Huss, 571 F.3d at 449. The jury verdict was for the plaintiff and the defendant appealed contending that exclusion of its expert was erroneous.

The circuit agreed and reversed and remanded, finding that the exclusion of the defense expert was erroneous under Daubert and FRE 702 and that this error was not harmless. The circuit noted that the court excluded the defense expert because he had “less training and experience with Terbutaline than Dr. Carlton,” the plaintiff’s expert. This exclusion was erroneous for at least two grounds.

First, the judge’s comparative assessment of contending experts misapplied Daubert. As the circuit noted, “the Daubert standards are flexible, and the most important question is not whether one party's expert is more qualified than the other's, but rather, whether an expert's testimony is reliable.” Because the “main purpose” of the defense expert’s opinion was “to rebut an untenable conclusion” by the plaintiff’s expert, all he needed to have was sufficient knowledge which would “qualif[y] him to tell the jury that Dr. Carlton's inferential leap was unsupported by medical literature.” This general application of the scientific method and interpretation of medical studies did not require that the defense expert “be specialized in cardiology or toxicology to act as a counterpoint to the Husses' experts.” Huss, 571 F.3d at 455.

Therefore, even though the defense expert was not board-certified in cardiology or toxicology he was qualified to opine on the thrust of the scientific literature about the effect of the drug. This background included that the defense expert was a board-certified internist, that he had practiced internal medicine for fifteen years, had treated patients with heart conditions, was familiar with the condition of cardiomyopathy, had treated patients with cardiomyopathy, and had prescribed drugs for that condition. His testimony regarding the implications of the medical literature regarding Terbutaline was a “natural extension of his medical and public health training and his experience.” Huss, 571 F.3d at 454.

Second, the trial judge’s focus on the relative levels of expertise between the two experts entirely “missed the purpose for which defendants sought to elicit Dr. Reddix's opinion.” The magistrate judge failed to note that the defense expert was presented “primarily to discredit the contention that Terbutaline is a known cause of cardiomyopathy” as the plaintiff’s expert opined. In presenting this view, the defense expert “did not need to be board-certified in cardiology or toxicology to explain that the studies relied on by the Husses.” Rather, the defense expert only needed sufficient “training and experience as a medical professional [as to] qualify him to tell the jury why the literature does not establish a causal link.” The circuit concluded that the defense expert’s education and knowledge “allowed him to form a reliable opinion as to whether, as a general matter, Terbutaline causes cardiomyopathy.” Huss, 571 F.3d at 455.

The circuit reversed and remanded the case because it concluded that the error prejudiced the defendants. “The crux of this case was whether Terbutaline causes cardiomyopathy,” explained the circuit. The exclusion of the defense expert testimony “prevented the defendants from demonstrating that the Husses relied on medical literature which was unreliable, anecdotal, and contradicted by other studies,” and because the case was close, the defense expert testimony would “have added information that, if the jurors found it credible, might have been determinative” of the difficult causation questions.”Huss, 571 F.3d at 456 (quoting Battle v. Mem'l Hosp. at Gulfport, 228 F.3d 544, 553 (5th Cir. 2000) (microbiomedical researcher testimony was not cumulative and its exclusion was not harmless because it added information on a topic addressed generally by other experts and it might have affected the jury’s assessment of thee evidence in the case)).

Federal Rules of Evidence