Breathing expert testifies George Floyd died from lack of oxygen while handcuffed, prone, and kneeled on

• An expert pulmonologist told jurors in Derek Chauvin's trial that George Floyd died of low oxygen.
• Being handcuffed, prone, and kneeled on made Floyd unable to expand his chest to breathe, he said.
• He said the effect would've been largely the same whether Chauvin kneeled on Floyd's neck or back.

An expert pulmonologist told jurors Thursday in the trial of former Minneapolis Police officer Derek Chauvin that George Floyd died from a loss of oxygen.

Dr. Martin Tobin's career has been centered on the science of breathing, and he's authored several books and been featured in the world's most prominent medical journals. He testified that what Floyd experienced before his death was like breathing through a straw, "but it's much worse than that."

Tobin's testimony came on the ninth day of the Chauvin's trial. The fired officer is charged with murder and manslaughter; Floyd died after Chauvin kneeled on his back and neck for more than nine minutes in May 2020.

Tobin told the jury Floyd was squished between the street and body weight of officers, interfering with how he was able to breathe.

While being handcuffed alone might not have impaired Floyd's breathing, Tobin said having handcuffs pressed high into his back while he experienced pressure from the street and officers prevented Floyd from expanding his chest.

Tobin avoided medical jargon in his testimony and worked through what he meant using commonplace terms and graphics. At one point, he asked jurors to press on their own throat to explain a medical concept.

A nurse on the jury seemed particularly interested in the testimony, according to pool notes from journalists inside the courtroom.

When cross-examining witnesses throughout the trial, Chauvin's attorney, Eric Nelson, has focused on whether Chauvin's knee was on Floyd's neck the whole time or whether his knee was in between Floyd's shoulder blades at different points.

Tobin told the jury that the effects on breathing are similar regardless.

The doctor also said he was aware that Floyd had health complications before his death.

"A healthy person subjected to what Mr. Floyd was subjected to would have died," he said.