In a significant legal victory for 3M Co., federal jurors in Minneapolis decided Wednesday that a South Carolina man did not convincingly show that a defective patient-warming device caused a surgical infection he suffered about eight years ago.

After more than two weeks of testimony before U.S. District Judge Joan Ericksen, the jury took less than two hours to decide Wednesday that 3M's Bair Hugger patient-warming system likely did not contain design defects that led to Louis Gareis' infection after his 2010 hip replacement surgery.

The verdict may hold wider implications for thousands of plaintiffs who have filed similar cases against 3M after seeing ads for the litigation on television. Maplewood-based 3M cheered the decision, while Gareis' attorneys vowed an appeal.

3M says the Minnesota-invented Bair Hugger is used in more than 80 percent of U.S. hospitals, including places like the Mayo Clinic, to fight surgical infections by preventing hypothermia during surgery. The system includes a disposable "blanket" that fills up with warm air that is pumped through a hose from a warming unit that sits on the floor of the operating room.

Gareis, 76, was the first person to go to a trial against 3M and its subsidiary Arizant, claiming that the Bair Hugger actually causes orthopedic joint infections by lifting particles from the operating room floor and placing them just above a surgical site. Although the particles are not infectious themselves, they often carry bacteria that are infectious.

The burden of proof in the federal civil trial didn't require Gareis to prove the Bair Hugger caused his infection. Rather, he had to show that the device's defective design was "more likely than not" the cause of his infection.

No study has ever shown that a Bair Hugger device moved a particle into a wound that led to an infection, nor has any bacterium gathered from an infected patient ever been definitively linked to a Bair Hugger. The safety of forced-air warming devices was studied extensively by the Food and Drug Administration last year and by 300 doctors who took part in an international conference in 2013.

In closing arguments Wednesday, 3M attorney Jerry Blackwell of Blackwell Burke in Minneapolis questioned how the plaintiffs' attorneys representing Gareis could divine scientific insight that had eluded the nation's top medical experts: "The top hospitals in the United States of America don't know something that these lawyers know? It doesn't make any sense," Blackwell said.

In his own closing arguments, Gareis' attorney Kyle Farrar of Farrar & Ball in Houston said the jurors had seen more evidence about the Bair Hugger's infection-spreading potential during the two-week trial than virtually any doctor. He said other hospitals like the Cleveland Clinic are ending their use of the Bair Hugger, based on studies showing how heat from the device can move particles in an operating room.

"3M is asking you to ignore science. The scientific evidence is there. You have it," Farrar said. "The hospitals that Mr. Blackwell mentioned don't have this evidence."

Both sides offered a compendium of studies that they said supported their side and refuted the other. At times, the two sides looked at the same evidence and perceived different things. Blackwell said a November 2011 article in the Journal of Bone and Joint Surgery that favored the plaintiffs included just one "patient," which was actually a mannequin. Farrar disagreed, saying the same study actually examined 1,400 real-world patients. The jury was left to decide.

The attorneys also sparred over an advanced supercomputer simulation the plaintiffs created that mapped the movements of 3 million particles when the Bair Hugger was on.

An animation depicted how particles were quickly swept up from the floor and deposited in the air just above the patient because heat created by the Bair Hugger disrupted the normal ceiling-to-floor airflow in an operating room.

3M's attorneys cast doubt on the simulation, noting that it failed to account for other sources of heat, turbulence and particles in the operating room where Gareis was treated in Columbia, S.C.

Gareis and his wife had been seeking more than $200,000 for his medical expenses, among other claims.

"Mr. and Mrs. Gareis are very disappointed with the verdict," Gareis attorney Genevieve Zimmerman said in an e-mail.

Zimmerman noted that Ericksen excluded virtually every internal 3M document supporting Gareis' allegations that were offered before trial.

The trial may hold wider implications beyond just Gareis' situation. Several thousand people have sued 3M claiming the Bair Hugger caused their joint-replacement infections using scientific evidence similar to what was presented in the Gareis case.

"Bellwether" trials like Gareis' are used in federal court to test arguments in a small number of cases to help the two sides determine whether to litigate, settle or drop other lawsuits with similar allegations. There was no word of movement in any other case on Wednesday.

"3M is grateful that the jury put science first," the company said in a statement about the Gareis case. "This verdict affirms the science behind the 3M Bair Hugger system, which has been proven to be a safe and effective way to warm patients during surgery."

Joe Carlson • 612-673-4377