Floyd died from lack of oxygen while Chauvin’s knee was on his neck, says witness

A pulmonary expert testifying in the trial of Derek Chauvin on Thursday said Chauvin kept his knee on George Floyd’s neck for more than three minutes after there was not “one ounce of oxygen left in the body.”

Prosecutor Jerry Blackwell presented a graphic illustrating the moment Floyd’s oxygen level reached zero. When Blackwell asked if Chauvin had lifted his knee from Floyd’s neck at that point, pulmonologist Martin Tobin said he did not.

“The knee remained on the neck for another three minutes and two seconds after we reach the point where there is not one ounce of oxygen left in the body,” Tobin told Blackwell.

Tobin said he determined the moment there was no oxygen left in Floyd’s body by using “very precise science.”

“You can figure this out with very precise science, looking at once somebody stops breathing, what will be the rate of decline in the level of oxygen, how long it will take to reach zero … so we see here that he reaches a level of zero of oxygen,” Tobin said, when explaining how the moment was determined.

Later in his testimony, Tobin, after recognizing the pre-existing health conditions Floyd had, said that a “healthy person” subjected to the same circumstances as Floyd would have died as well.

“Now Dr. Tobin, are you aware that Mr. Floyd had some pre-existing health conditions?” Blackwell asked.

“Yes, I am,” Tobin responded, adding, when prompted by Blackwell, that he read them in the records from Hennepin County and saw them mentioned in the autopsy report.

“Do you have an opinion to a reasonable degree of medical certainty as to whether a person who had none of those pre-existing health conditions, a healthy person, would have died of the same circumstances as Mr. Floyd?” Blackwell asked.

“Yes, a healthy person subjected to what Mr. Floyd was subjected to would have died as a result of what he was subjected to,” Tobin answered.

Virtually all of the jurors took notes after Tobin said Chauvin kept his knee on Floyd’s neck after he determined there was no more oxygen in Floyd’s body, according to a pool report.

Tobin is the first witness to take the stand on day eight in the trial of Chauvin, the former Minneapolis police officer who was charged with three criminal counts in connection to Floyd’s death.

Chauvin was caught on video footage in May with his knee on Floyd’s neck for approximately nine minutes during an arrest.