Dr. Martin Tobin testifies on Thursday, April 8. 
Dr. Martin Tobin testifies on Thursday, April 8.  Pool

A renowned pulmonary critical care doctor testified last week that George Floyd died from a “low level of oxygen” when former police officer Derek Chauvin pinned him to the street and restricted his ability to breathe.

“This caused damage to his brain that we see, and it also caused a PEA arrhythmia that caused his heart to stop,” Dr. Martin Tobin of Chicago testified, referring to pulseless electrical activity, a type of cardiac arrest.

“The cause of the low level of oxygen was shallow breathing,” he added. “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 identified four main reasons why Floyd died:

  • The handcuffs and the street acting as a “vise”
  • Chauvin’s left knee on his neck
  • Floyd’s prone position
  • Chauvin’s right knee on Floyd’s back, arm and side

Combined, these limited Floyd’s ability to expand his lungs and narrowed his hypopharynx, a part of the throat that air passes through.

Floyd’s preexisting health conditions and drug use were not relevant to his death, Tobin said.

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