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Summer can be a good time to catch up on tv shows we missed the first time around (e.g., Dead to Me, Luther series 5, and Catch-22). It can also be a good time to catch up on cases we somehow failed to flag when they came out earlier in the year. We won’t beat ourselves up too much for missing the excellent result in the soon-to-be-frozen north in In re Bair Hugger Forced Air Warming Devices Prods. Liab. Litig., 2019 WL 4394812 (D. Minn. July 31, 2019). After all, the opinion was filed under seal and became available only recently. We have, of course, covered many interesting developments in the Bair Hugger saga. (Bexis visited Iceland this Summer, so we are quick to spot the opportunity for sagas.) See Bair Hugger blogposts here and here, for example. This latest decision should sound the death knell for the Bair Hugger multi-district litigation.

About six weeks ago (before Bexis circumnavigated the land of geysers, trolls, and the famous 1972 Fischer-Spassky chess championship match), the defendants won summary judgment on all the claims in the Bair Hugger MDL in the District of Minnesota. The plaintiffs claimed that the Bair Hugger, a device for keeping surgical patients warm, had caused joint infections. This claim rested on the opinions of certain plaintiff experts, including at least one repeat player many of you will know. Those plaintiff experts, as per the usual terpsichore, offered general and specific causation opinions. Key to the victory this Summer was the defendants’ successful effort to convince Judge Ericksen to revisit her previous decision in December 2017 to admit plaintiffs’ general causation expert testimony. Those experts had offered “airflow disruption” and “dirty machine” theories, and the court’s Christmas gift to the plaintiffs last December was to hold that those theories passed muster.

Getting courts to reconsider opinions is not easy. How did it happen here? An intervening bellwether trial, with effective cross-examination of the plaintiff experts, showed the flaws in the experts’ opinions. The trial judge ended up quoting one of our favorite Posner lines (“the courtroom is not the place for scientific guesswork, even of the inspired sort. Law lags science; it does not lead it.”), and excluded the plaintiffs’ medical causation experts and fluid dynamics expert. Judge Eriksen also relied on, inter alia, the Mirena decision. She engaged in an insightful discussion of the difference between reconstructions of actual events and illustrations of general principles. The air flow modeling was rudimentary and failed to replicate relevant conditions accurately. Opinions based on unproven and untested computer modeling amounted to ipse dixit leaps over yawning analytical gaps. The plaintiff experts failed to account for the movement of people in operating rooms. The plaintiff expert opinions were also suspect because they were developed for use in litigation. It was improper for the plaintiffs’ experts to cite literature for conclusions that the articles’ authors did not reach. Moreover, the plaintiff experts failed to investigate and rule out obvious alternative causes. Nor was there general acceptance of plaintiffs’ expert’s causation theories.

Adios to both the “airflow disruption” and “dirty machine” theories of defect.

These, er, problems with the plaintiff expert opinions managed simultaneously to shock and bore us. This sort of biased, result-driven sloppiness is all too familiar to any defendant stuck in an MDL. Kudos to the Judge in the Bair Hugger MDL for ultimately doing the right thing.

The Daubert rulings meant that the plaintiffs could not raise a genuine material issue of fact regarding causation. That outcome, by itself, spelled doom for almost all of the plaintiffs’ claims. The plaintiffs tried to save their claims for unjust enrichment and consumer protection, arguing that those claims do not require proof of causation. But the court held that causation is implicitly required for unjust enrichment, otherwise how could the defendants have received a benefit under inequitable circumstances? Similarly, the consumer protection claims depend on a showing by the plaintiffs that they were injured by the defendants’ actions. “Because Plaintiffs lack reliable evidence that the Bair Hugger causes infection, Plaintiffs cannot establish that they suffered an injury as a result of Defendants’ actions.”

Keeping score – the defendants have now won summary judgment in both the federal MDL and the Minnesota state court “mini-MDL,” about which we have already blogged. Naturally, the Bair Hugger plaintiffs have appealed to the Eighth Circuit. On this record, with a district court judge who afforded the plaintiffs every opportunity to take their best shot, we expect and hope for a resounding affirmance.