The medical examiner who performed the autopsy of George Floyd testified at the trial of Derek Chauvin

The official autopsy of the Hennepin County medical examiner made no mention of suffocation as a cause of death, which was a major pillar in the case of prosecutors. In contrast, an independent autopsy commissioned by Floyd’s family said he died of ‘suffocation due to sustained pressure’ when his neck and back were compressed by officers, which cut off the blood flow to his brain.

A doctor with lung-critical care testified Thursday that Floyd died of a ‘low level of oxygen’ when Chauvin pinned him with his knee in the street, limiting Floyd’s breathing ability. Chauvin pleaded not guilty to charges of second-degree murder, third-degree murder and third-degree manslaughter.

Dr. Martin Tobin of Chicago identified four main reasons why Floyd died: the handcuffs and the street as a ‘vice’; Chauvin’s left knee on his neck; Floyd’s inclined position; and Chauvin’s right knee on Floyd’s back, arm and side. Together, it limits Floyd’s ability to expand his lungs and narrow his hypopharynx, a part of the throat that moves through the air.

“The cause of the low level of oxygen was shallow breathing,” Tobin said. “Small breaths. Small tidal volumes. Shallow breaths that could not carry the air through his lungs, to the essential parts of the lungs that get oxygen in the blood and get rid of the carbon dioxide.”

Tobin says Floyd’s pre-existing health conditions and drug use were not relevant to his death.

” A healthy person who is subject to what Mr. Floyd is subject, would die, ‘he said.

The medical analysis is important to the prosecutor’s case that Chauvin was a material cause of Floyd’s death when he placed his body mass on Floyd’s neck and back for more than nine minutes, causing the death by ‘positional asphyxia’. Chauvin’s defense attorney Eric Nelson argued that Floyd died of a drug overdose and pre-existing health conditions.

Tobin rejects the theory that fentanyl played a role in Floyd’s death, along with dr. Bill Smock, an emergency physician and a Louisville metro police surgeon, also testified Thursday.

People who overdo fentanyl become listless and stop breathing while Floyd desperately tries to breathe, Smock said.

“It’s not an overdose of fentanyl,” he said. “This is someone begging to breathe.”