The medical examiner who conducted George Floyd’s autopsy went to testify in Derek Chauvin’s trial

The official autopsy of the Hennepin County Medical Examiner made no mention of asphyxiation as the cause of death, which was a major pillar in the prosecution’s case. In contrast, an independent autopsy ordered by Floyd’s family said he died of “persistent pressure suffocation” when his neck and back were compressed by agents, cutting off blood supply to his brain.

A pulmonary intensive care physician testified Thursday that Floyd died of “low oxygen levels” when Chauvin pressed him on the street with his knee, limiting Floyd’s ability to breathe. Chauvin has pleaded not guilty to charges of second-degree murder, third-degree murder, and third-degree manslaughter.

Dr. Chicago’s Martin Tobin identified four main reasons why Floyd died: the handcuffs and the street acting as a “vice”; Chauvin’s left knee on his neck; Floyd’s prone position; and Chauvin’s right knee on Floyds 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.

“The cause of the low oxygen level was shallow breathing,” said Tobin. Small breaths. Small tidal volumes. Shallow breaths that couldn’t carry the air through his lungs to the essential parts of the lungs that get oxygen into the blood and remove the carbon dioxide. ‘

Floyd’s pre-existing health problems and drug use were irrelevant to his death, Tobin said.

“A sane person who had been subjected to what Mr. Floyd was subjected to would have died,” he said.

The medical analysis is important to the prosecution’s case that Chauvin was a substantial cause of Floyd’s death when he placed his body weight on Floyd’s neck and back for more than nine minutes – causing death from “positional asphyxiation.” Chauvin’s attorney Eric Nelson has argued that Floyd died of a drug overdose and pre-existing health problems.

Tobin rejected the theory that fentanyl played a role in Floyd’s death, along with Dr. Bill Smock, an emergency care physician and police surgeon for the Louisville Metro Police, who also testified Thursday.

People who overdose on fentanyl become lethargic and stop breathing, while Floyd tried desperately to breathe, Smock said.

“That’s not a fentanyl overdose,” he said. “That’s someone begging to breathe.”