Pulmonologist says George Floyd died from a 'low level of oxygen'

A pulmonologist who reviewed George Floyd's medical records said Thursday he died "from a low level of oxygen."

Dr. Martin Tobin, a physician specializing in critical care of the lungs, posited that Floyd's prone position in the street and pressure on his neck and back led to a pulseless electrical activity arrhythmia "that caused his heart to stop." Floyd died May 25, 2020, in Minneapolis police custody, and his death sparked nationwide protests against police brutality.

"Mr. Floyd died from a low level of oxygen," he said.

"The cause of the low level of oxygen was shallow breathing," Tobin said, "small breaths, small, tidal volumes, shallow breaths that weren't able to carry the air through his lungs down to the essential areas of the lungs that get oxygen into the blood and get rid of the carbon dioxide."

He continued: "So, there are a number of forces that led to — that is the size of his breath became so small, and so, [a] series of forces higher up that are leading to that, and the main forces that are going to lead to the shallow breath are going to be that he's turned prone on the street, that he has the handcuffs in place combined with the street, and then that he has a knee on his neck, and then that he has a knee on his back and down his side. All of these four forces are ultimately going to result in the low tidal volume, which gives you the shallow breaths that we saw here."

Derek Chauvin's knee remained on Floyd's neck for three minutes after he ran out of oxygen, and his total lung volume decreased by 43%, Tobin added. He also posited that a "healthy person" likely would have died under the same conditions.

"There is not an ounce of oxygen left in his body. And again ... you can figure this out with very precise science, looking at once somebody stops breathing, what will be the rate of decline in oxygen, how long it will take to reach zero," Tobin said.