Smoke rose in curls of green laser light, quickly filling the mock operating room and fogging the air around a mannequin patient.

Dr. Scott Augustine, a controversial medical entrepreneur and anesthesiologist, demonstrated what he says are inherent dangers in the design of a standard piece of hospital equipment that he invented — 3M's Bair Hugger machine, which keeps patients' bodies warm during surgery to promote healing.

The machines have become nearly as common in orthopedic surgery suites as 3M's Post-it Notes are in office cubicles. If you've had joint surgery in the past decade, chances are good that one of 3M's disposable Bair Hugger "blankets" was draped over you before and during the procedure, connected to a warm-air blower on or near the floor.

But over the years, Augustine has become convinced that the device's use can lead to excruciating infections around implants. He says the curls of smoke, revealed in laser light, prove the device can lift air from the floor and propel microscopic bacteria up to the patient.

The result is an increased risk for deep-joint infections: "In an operating room," he said, "air should never go upwards."

This theory of infection risk is at the center of a massive legal fight in which Maplewood-based 3M Co. is defending itself against thousands of medical injury and product-defect lawsuits. Augustine has become a persistent critic of the warming system he designed, even though it has become standard equipment at most hospitals across the United States.

Tens of millions of dollars are at stake. 3M says the device is used in more than 80 percent of all U.S. hospitals, including nine of the top 10 orthopedic centers. The device generates hundreds of millions in annual revenue for 3M on the promise that it prevents — not causes — an untold number of surgical infections.

"3M is committed to fighting this litigation because we believe in the science of our patient warming device," the company said in a statement to the Star Tribune.

The company says Augustine is pushing junk science and bad-mouthing the Bair Hugger because he has a newer, competing product to sell. In legal filings, 3M has made reference to Augustine's checkered legal history — he was once banned from doing business with Medicare for five years — and his repeated attempts to sell the Bair Hugger's owners new technology that is supposedly safer.

The company says Augustine's unproven theory has led to thousands of copycat lawsuits after more than 18,000 TV ads appeared seeking clients.

"If not for Scott Augustine, there would be no litigation against the Bair Hugger system," Jerry Blackwell, 3M's lead outside attorney in the Bair Hugger litigation, told the Star Tribune. "The record shows that he and his associates created and touted phony science targeting the Bair Hugger system to try to manufacture a public health scare, then he fed that same made-up science to plaintiffs' lawyers hoping they would sue the Bair Hugger out of existence."

Studies in the medical literature reach contradictory conclusions, and both sides attack unfavorable research as either flawed or biased. Augustine says 3M has cheated on internal studies to cover up what he sees as obvious risks with the device, while 3M says the critical studies were done with unsound methods or biased researchers.

The company prevailed in the first courtroom test last May, when jurors in Minneapolis rejected Augustine's theory after a couple hours of deliberation in an initial "bellwether" case.

But another 5,000 surgical-infection plaintiffs are still waiting for their day in court. Augustine is steadfast in his belief that the lawsuits will inevitably eliminate the Bair Hugger from the market. He says 10 different studies have confirmed that the Bair Hugger's waste heat interferes with the carefully orchestrated downward flow of air in operating rooms, including studies conducted by 3M.

"3M has known from the beginning that they've got a problem, and they've done nothing about it," he said in an interview. "… I think 3M [decided], if you can't debate an issue on science, you have to make a smoke screen of some sort. And the smoke screen they chose corporately to make … was to vilify me."

Doctor, inventor

Augustine practiced medicine after receiving a medical degree from the University of Minnesota in 1979. But he has long considered himself an inventor, with more than 100 patents to his name.

A two-story wall of his medical-device patent plaques is one of the first things visitors see at his company headquarters in Eden Prairie. His inventions have earned him millions of dollars over the years.

The idea for the Bair Hugger came about, he said, in response to the fact that patients used to emerge from surgery with uncontrollable shivers and chattering teeth from cold operating rooms. Postoperative hypothermia puts stress on the heart and the immune system, but existing patient-warming systems used ineffective means like warm-water mattresses or "infrared French fry lights."

Augustine had an idea to use warmed air. "I came up with what I thought was the solution, and built the prototypes in my garage," he said. "That was back in the '80s, when Steve Jobs and Bill Gates … were doing their thing. Starting a company was just sort of the thing to do back then."

Augustine Medical Inc. secured funding to move out of the garage and shipped its first Bair Hugger unit in 1988, less than two years after becoming a company.

Early legal battles

The early years were not entirely smooth ones.

Augustine got into a legal fight in the early '90s with a competitor, Cincinnati Sub-Zero (CSZ), which alleged that Augustine Medical misled people by claiming that the Bair Hugger could rewarm patients in less than five minutes and by publishing misleading thermal images of the system.

A judge ultimately ruled that neither CSZ nor Augustine Medical was likely to prove its device was better than the other because their dueling product tests were "unscientific, results-oriented" experiments. But the judge also ordered Augustine Medical to retract a false statement and ordered both companies to stop making unsupported claims.

Then in the early 2000s, conflicts emerged on the board and Augustine ultimately stepped aside. CEO J. Randall Benham, general counsel for Augustine Medical at the time, said in an e-mail that some of the original shareholders were getting anxious for an exit when a new board member broached the idea of a sale for about $29 per share.

Augustine thought that was much too low. He also suspected the board member was in league with the prospective buyers.

"Scott challenged the new director," Benham wrote. "A majority of the board did not believe Scott's claims, and generally thought that he was simply trying to avoid selling the company.

"In the end, the new director left, and so did Scott. The company sold within a year or so thereafter."

The price, Augustine said, was $76 a share. Since he owned a 21 percent stake in the privately held company, he said he came out "pretty well" in the deal.

The buyers ultimately paid $225 million for Augustine's company, court records show.

Barred from Medicare

He was not, however, free of entanglements from his time as CEO.

The company, which took on the name Arizant in the sale, had started getting inquiries from the U.S. Justice Department. While Augustine acknowledges that some board members might have been getting "nervous" about the inquiries, he said this had nothing to do with his departure.

Then in 2003, Augustine, Augustine Medical and others were indicted for felonies alleging health care fraud involving a different product, as a result of an undercover FBI sting operation targeting health care supply companies. Augustine Medical pleaded guilty and paid more than $12 million in civil and criminal penalties.

Augustine himself fought the case in court and got all the felony charges against him dropped in exchange for pleading guilty to a misdemeanor that related to withholding information from an FBI front company. He was barred from working for any company that did business with Medicare for five years and had to pay a $2 million fine.

"What I pled guilty to was not giving a nonsense letter to the pretend distributor who wasn't either buying product or selling product or billing Medicare, and not a single dollar transacted anywhere," he said. "Now 3M characterizes that as me being some kind of heinous Medicare fraud guy."

A better solution?

It was sometime in late 2007 or early 2008, Augustine said, that he "stumbled" upon the risk of infections linked to the Bair Hugger, during research for a different device. He also happened upon a solution — a high-tech electric blanket product he calls the HotDog patient warming system.

"When we stumbled on the idea that the infections were happening, I felt I had to do something about it. That also led me to say, 'Hey, we've got to [use] this material we found,' " he said. "We stumbled onto this stuff. We were able to make heaters out of it. Forced air has a problem. Let's make this be the solution."

Then he set about trying to promote his solution, which doesn't involve forced air, while raising the alarm about the Bair Hugger.

In 2010, as Arizant's owners were negotiating a sale of the company to 3M, court records show that Augustine warned decisionmakers about the flaws he saw in the Bair Hugger and then offered to sell them the HotDog system as a solution. The alleged flaws included a risk that the Bair Hugger's blower unit could become contaminated with germs that would blow into the operating room and the potential for the device's "waste heat" to disrupt the downward "laminar" airflow that normally protects patients.

Augustine wrote then-Arizant CEO Gary Maharaj in April 2010 saying Arizant was not dealing with critical safety problems: "You have two critical problems to deal with, but the good news is that if you don't panic, they are both solvable. I'm offering to sell you the solution to the contamination problem, and there are several possible solutions to the laminar flow disruption problem," Augustine wrote.

He wrote to Arizant's private-equity owner at the time saying the Bair Hugger was probably going to be recalled soon, and that the equity firm's $500 million stake in Arizant was one "stroke of a regulator's pen from vaporizing." He ended that July 2010 letter by saying "word has gotten out to the plaintiff's attorneys," and "you should be motivated to fix your product problems for reasons other than just the FDA."

Despite Augustine's warnings, 3M acquired Arizant for $810 million in October 2010.

He didn't let up.

First, he took his concerns public in a Dec. 25, 2010, story in the New York Times. Two years later Augustine wrote directly to 3M, saying 3M was facing a "very high probability" of having to write down its whole investment in Arizant. "Now the good news — HotDog warming is for sale," Augustine wrote to 3M's president of infection prevention in January 2012.

He floated the idea of 3M spending "another half billion dollars to own the patient warming franchise," which he said would give 3M the ability to handle its problem quietly.

3M, like Arizant, turned him down.

'Non-testifying expert'

Unbeknownst to 3M, Augustine had been working another track.

In a sworn 2015 affidavit, Augustine disclosed that he'd had an attorney-client relationship with the Texas plaintiff's firm Kennedy Hodges since around July 2009. Kennedy Hodges "fairly quickly" expressed interest in suing companies that made forced-air warming devices, Augustine said, and his role with the firm morphed into "non-testifying expert."

Kennedy Hodges went on to file the first Bair Hugger case.

Augustine didn't ask for any money for his efforts, he said in the affidavit, "because they were consistent with my two goals: to stop Bair Hugger (which I invented) from injuring more patients and to promote the use of HotDog patient warming, the air-free patient-warming device that I invented as an alternative to Bair Hugger."

Asked about his profit motives and his dealings with plaintiff's lawyers, Augustine said it would be dishonest to deny that he intends to benefit financially from the Bair Hugger's demise. But he downplays his role in launching the 5,000-odd lawsuits against 3M.

"To say that I'm the architect of this litigation is not totally false. We put together the information that the lawyers needed to do what they do," Augustine said. "Now, they just go off and do it. You don't tell a bunch of lawyers to do anything."

One document that Kennedy Hodges provided to other lawyers who might want to pursue Bair Hugger cases cites Augustine's work in discovering and warning about the system's flaws and notes the size of the opportunity.

"There are 12,000 to 20,000 orthopedic implant infections in the United States each year. Bair Hugger warming was used on almost every one," law firm partner David Hodges wrote. "We are taking a leadership role … by sharing our 'road map' of the evidence for these cases with you. We hope this encourages you and other lawyers to pursue similar actions."

Fighting the establishment

As the litigation unfolds, most surgeons are sticking with the Bair Hugger.

The U.S. Food and Drug Administration actively recommends that hospitals continue to use thermoregulating devices, including forced-air systems like Bair Hugger.

The International Consensus Meeting on Periprosthetic Joint Infection, a group that weighs in on approaches to preventing infections, has twice polled its members about the issue. By consensus vote, the group said members are aware of the theoretical risks but do not plan to change their practices.

Dr. Javad Parvizi, the consensus co-chair, noted that with 200 million patients treated with the Bair Hugger over the past decades, even a low rate of increased infections should have become clear.

"If something is really strongly associated with infection, you would see it," Parvizi said, describing his own observations. "I am compelled to do what I feel is right for my patients, and that is to continue to use forced-air warming."

Augustine continues to press his case. He dismisses his skeptics, pointing out, for example, that Parvizi has received money from 3M in the past, with federal records showing $6,500 in payments in 2017.

When Augustine learned his product was doing harm, he said, it conflicted with his Hippocratic oath.

"I'm on a mission to get forced-air warming out of implant surgery," Augustine said. "3M has chosen to characterize that as, you know, Augustine's greedy or Augustine's crazy or Augustine is vindictive. From my point of view, I'm on a safety crusade."