Lung doc: Floyd died due to lack of oxygen

A veteran lung doctor testified Thursday that George Floyd’s death was caused in part by Derek Chauvin’s knees pressing against his neck and back, making it impossible for him to breathe, and that Floyd showed signs of a brain injury about four minutes before Chauvin lifted his knee from his neck.

Martin Tobin, a pulmonologist and critical care doctor in Chicago, said in court that the combination of Chauvin’s pressure, the handcuffs pulling Floyd’s hands behind his back and Floyd’s body being pressed against the street had caused him to die “from a low level of oxygen.”

The testimony from Tobin on the ninth day of the trial of Chauvin, the former Minneapolis police officer who has been charged in Floyd’s death, signaled a shift into a new phase in which medical testimony will be crucial. Chauvin’s lawyer has suggested Floyd died from the fentanyl and methamphetamine that were found in his system, but prosecutors argue that Chauvin had killed him by kneeling on him for more than nine minutes and cutting off his air supply.

Tobin was adamant that Chauvin’s actions had caused Floyd’s death May 25. He pinpointed the exact moment, in the graphic bystander video of the arrest, in which he said Floyd had died, noting that his eyes had opened wide and then closed again. At that point, Chauvin’s knee remained on his neck.

“You can see his eyes — he’s conscious — and then you see that he isn’t,” Tobin said. “That’s the moment the life goes out of his body.”

The doctor also rejected the defense’s arguments about drugs, saying videos show Floyd breathing at a normal rate before he went unconscious.

“A healthy person subjected to what Mr. Floyd was subjected to would have died,” Tobin said.

Tobin, who works in pulmonology and critical care at Edward Hines Jr. Veterans Affairs Hospital and at Loyola University’s medical school, spoke for more than two hours to jurors. He said he had asked not to be paid when prosecutors asked if he would testify in the case.

At several points, he encouraged jurors to feel parts of their own necks to demonstrate what he was saying; most of them followed along.

Tobin said the factors that cut off Floyd’s air supply had led to what could be called “asphyxia,” which he said was just another word for oxygen deprivation.