Chauvin Trial: Medical Expert Says George Floyd Died From A Lack Of Oxygen

Dr. Martin Tobin, a pulmonary specialist who works in critical care, testified Thursday that George Floyd died from a lack of oxygen, bolstering the prosecution's argument that former Minneapolis police officer Derek Chauvin caused Floyd's death last May.

Tobin is appearing as an expert witness for the prosecution. He said the state asked him to review documents and videos depicting the circumstances of Floyd's death. Tobin watched some of those videos hundreds of times, he said.

"Have you formed an opinion to a reasonable degree of medical certainty on the cause of Mr. Floyd's death?" prosecutor Jerry Blackwell asked.

"Yes, I have," the doctor replied. "Mr. Floyd died from a low level of oxygen, and this caused damage to his brain that we see. And it also caused a PEA [pulseless electrical activity] arrhythmia that caused his heart to stop."

Prosecutors say Chauvin killed Floyd by pressing his knee on Floyd's neck for about nine minutes. But Chauvin's attorney says that Floyd was experiencing a drug overdose and had an underlying heart condition.

Last year, the Hennepin County medical examiner's office ruled Floyd's death a homicide, saying his heart and lungs stopped functioning "while being restrained" by police. But it also noted "other significant conditions," including fentanyl intoxication and recent methamphetamine use as well as heart disease.