George Floyd died from a lack of oxygen as he was pinned “in a vice” against the street during his arrest, a doctor at the trial of ex-police officer Derek Chauvin in Minneapolis has said.
Dr Martin Tobin said Mr Floyd did not die from fentanyl found in his system, contradicting the defence’s argument.
Mr Chauvin, 45, was filmed kneeling on Mr Floyd’s neck for more than nine minutes during his arrest last May.
The ex-officer is on trial for murder and has denied the charges against him.
A toxicology report released last June said that Mr Floyd had the painkiller fentanyl in his system.
However Dr Tobin, an intensive care doctor, said that Mr Floyd’s breathing did not slow down enough for the drug to have been a factor in his total loss of oxygen.
The footage of Mr Chauvin, who is white, with his knee on African-American Mr Floyd’s neck sparked global protests against racism.
The trial is in its second week and is expected to last for at least one month. The defence is due to begin arguing its case next week.
Asked about the positioning of the handcuffs behind Mr Floyd’s back, coupled with the downward pressure of Mr Chauvin’s weight against him, Dr Tobin – an expert in pulmonary medicine – said that Mr Floyd’s ability to expand his chest was severely impaired.
He said it was his medical opinion that Mr Floyd died after a low level of oxygen stopped his heart.
“[George Floyd] is jammed down against the street, so the street is playing a major role in preventing him from expanding his chest.
“He’s against a hard asphalt street, so the way they’re pushing down on his handcuffs combined with the street… it’s like the left side is in a vice.”
Dr Tobin said the positioning of the handcuffs was also significant.
“It’s how they’re being pushed, where they are being pushed, that totally interfere with central features of how we breathe.”
Dr Tobin said that the position of Mr Chauvin’s knee, pushing down against the left side of Mr Floyd’s chest, meant that it was “almost… as if a surgeon had gone in and removed the [left] lung”.
“Not quite, but along those lines.
Dr Tobin said that Mr Floyd had already shown signs of brain injury about four minutes before Mr Chauvin took his knee off his neck, and that a healthy person who was put through this “would have died” too.
About three minutes before Mr Chauvin removed his knee, Dr Tobin said, there was “not an ounce of oxygen left in his body”.
“The knee remains on the neck for another three minutes and 27 seconds after he takes his last breath,” Dr Tobin said. “After the officers have found themselves that there’s no pulse, the knee remains on the neck for another two minutes and 44 seconds”.
Dr Tobin used footage captured during Mr Floyd’s arrest to provide his medical opinion on the ninth day of Mr Chauvin’s trial in Minneapolis, Minnesota.