Respiratory Expert: George Floyd Died Of Asphyxia As A Result Of Chauvin's Actions

A doctor specializing in respiratory medicine testified in court Thursday that George Floyd died of asphyxia as a result of being handcuffed facedown on the street with former Minneapolis police officer Derek Chauvin kneeling on him.

Dr. Martin Tobin, who works in the intensive care unit at Hines VA Hospital in Illinois and has studied respiratory physiology for 40 years, said Floyd died of a low level of oxygen, also known as asphyxia or hypoxia.

This caused damage to his brain, Tobin testified, and it also caused a [pulseless electrical activity] arrhythmia that caused his heart to stop.

Floyds low oxygen level was caused by shallow breathing due to his being handcuffed in the prone position against the pavement as Chauvin knelt on Floyds neck as well as his back and side, according to Tobin.

Dr. Tobin, a physician who is a renowned expert on pulmonology testifies that George Floyd died of a low level of oxygen.

The shallow breathing resulted from Floyd being prone on the street and handcuffed, with a knee on his neck and back and an arm at his side, he says pic.twitter.com/3EbiCXXFyV

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Dr. Tobin, a physician who is a renowned expert on pulmonology testifies that George Floyd died of a low level of oxygen.

The shallow breathing resulted from Floyd being prone on the street and handcuffed, with a knee on his neck and back and an arm at his side, he says pic.twitter.com/3EbiCXXFyV
CBS News (@CBSNews) April 8, 2021

Floyd was being squashed between the hard ground and the officers as they pushed his handcuffs high into his back, Tobin says. Such actions would totally interfere with central features of how we breathe, he added.

Its like the left side is in a vise, Tobin testified. Its totally been pushed in, squeezed in from each side, from the street at the bottom and from the way that the handcuffs are manipulated.

Its as if a surgeon has gone in and removed the lung not quite, but along those lines, Tobin added. Very little opportunity for him to be able to get any air to move into the left side of his chest.

Tobin gave his assessment to the court on the ninth day of witness testimony in Chauvins trial. Chauvin has been charged with second- and third-degree murder as well as manslaughter in Floyds death. He has pleaded not guilty to all charges.

Tobin testified Thursday that Chauvin kneeling on Floyds neck prevented air from getting through the hypopharynx, a hollow tube that passes food, water and air through the bottom of the throat. Floyds placement in the prone position also narrowed the hypopharynx, Tobin said.

When you have to breathe through a narrow passageway, its like breathing through a drinking straw, but its much worse than that, Tobin said.

Tobins testimony undercut the defenses argument that drug use not Chauvins actions played a major role in Floyds death.

The Hennepin County Medical Examiners Offices autopsy report , released in June last year, classified Floyds death as a homicide and said it was caused by cardiopulmonary arrest complicating law enforcement subdual, restraint and neck compression.

The report also stated that Floyd tested positive for COVID-19 in April 2020 and that he had fentanyl and methamphetamine in his system when he died but didnt draw a causal link between the drugs and his death.

Fentanyl typically causes a persons respiratory rate to slow, Tobin testified Thursday. Floyds respiratory rate was a normal 22 breaths per minute just before he lost consciousness. If fentanyl were impacting Floyds breathing, his respiratory rate likely would have been about 10 breaths per minute at that point, according to Tobin.

The defense has argued that Floyds high carbon dioxide level recorded at the hospital the night of his death was caused by fentanyl use. But Tobin said that phenomenon is solely explained by Floyds lack of breathing.

Any healthy person subjected to what Floyd was subjected to during his arrest would have died, Tobin said.

Later Thursday, Dr. Bill Smock, the police surgeon for the Louisville Metro Police Department, testified that he believed Floyd died of positional asphyxia, which Smock described as a fancy way of saying he died because he had no oxygen left in his body.

Mr. Floyd died from positional asphyxia, which is a fancy way of saying he died because he had no oxygen left in his body, says Dr. Bill Smock, a police surgeon and emergency medicine physician with specialized training in forensic medicine pic.twitter.com/0gkbq3YBeN

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Mr. Floyd died from positional asphyxia, which is a fancy way of saying he died because he had no oxygen left in his body, says Dr. Bill Smock, a police surgeon and emergency medicine physician with specialized training in forensic medicine pic.twitter.com/0gkbq3YBeN
CBS News (@CBSNews) April 8, 2021

Like Tobin, Smock said Floyd could be seen during his arrest suffering an anoxic seizure, which occurs when theres a fatal injury to the brain from a lack of oxygen.

You can hear the handcuffs shake, and youll see the body camera shake when he has an anoxic seizure, Smock testified.

Smock also dismissed suggestions that Floyd might have died of a drug overdose, noting that his methamphetamine level was very low and he didnt exhibit certain symptoms of fentanyl overdose, such as constricted pupils. He also said there was absolutely no evidence that Floyd died of a heart attack.

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The doctor who treated Floyd the night he died in May 2020 testified on Monday. He said that, given the information he had at the time of Floyds death, he believed Floyd likely died of asphyxia.

Videos recorded by bystanders and the officers body-worn cameras showed Chauvin kneeling on Floyds neck for 9 minutes and 29 seconds as Floyd stated multiple times that he couldnt breathe. Chauvin remained in this position for several minutes even after Floyd ceased moving and breathing.