Dr. Martin Tobin, a renowned pulmonary expert tasked by the state of Minnesota to assess George Floyd’s death, testified on Thursday at Derek Chauvin’s trial that Floyd died of oxygen deprivation caused by the former officer’s restraint of him in a crucial piece of testimony for the prosecution.
Tobin, a physician at Hines VA Medical Center in Chicago who has worked in respiratory physiology for 40 years and lectured around the world, said he came to that determination after reviewing the medical records related to the case, in addition to bystander testimony and video footage of the arrest.
Tobin said he was able to conclude to a reasonable degree of medical certainty that Floyd died from a low level of oxygen, with the cause being a “series of force” related to Chauvin’s restraint.
“That he’s turned prone on the street, that he has the handcuffs in place combined with the street, and that he has a knee on his neck and that he has a knee on his back and side” are the forces that resulted in shallow breaths.
“This caused damage to his brain,” which then caused his heart to stop, Tobin explained.
“Shallow breaths that weren’t able to carry the air through his lungs down to the essential areas of the lungs and get oxygen to the blood,” the expert explained.
Tobin said that based on a digital model of the arrest, Chauvin had his knee on Floyd’s neck for “more than 90% of the time.”
Tobin is the second witness to testify that Floyd died of oxygen deficiency (otherwise known as “asphyxia”). Dr. Bradford Langenfeld, an emergency care doctor who treated Floyd when he was brought to the Hennepin County Medical after his May 25 arrest, said he determined asphyxia to be the most likely cause of death for Floyd. Langenfeld said he saw no signs of a heart attack or drug overdose, as Chauvin’s defense team is arguing.
Thursday was the ninth day of the trial of Chauvin, a 19-year veteran of the Minneapolis Police Department facing murder and manslaughter charges for Floyd’s death. Chauvin, and three other officers, pinned Floyd to the ground for over nine minutes as they arrested him for trying to buy a pack of cigarettes with a counterfeit $20 bill. A video of the incident went viral on the internet and sparked months of racial justice and policing reform protests. The defense is arguing that the use of force from police was justified given Floyd’s behavior during the arrest, and is seeking to persuade jurors that Floyd instead died of a drug overdose and underlying health conditions.