George Floyd died because of lack of oxygen, expert tells court

George Floyd died of a lack of oxygen from being pinned face down on the pavement with his hands cuffed behind him, a medical expert testified at former officer Derek Chauvin's murder trial. Mr Floyd's breathing while he was being held down by Chauvin and other officers was too shallow to take in enough oxygen, which in turn damaged his brain and caused an abnormal heart rhythm that made his heart stop, said Dr Martin Tobin, a lung and critical care specialist at the Edward Hines, Jr VA Hospital and Loyola University's medical school in Chicago.

Video Transcript

JERRY BLACKWELL: Have you formed an opinion to a reasonable degree of medical certainty as to what the cause is or was for the low level of oxygen in Mr. Floyd?

MARTIN TOBIN: Yes, I have.

JERRY BLACKWELL: Would you tell us what that is?

MARTIN TOBIN: The cause of the low level of oxygen was shallow breathing. Forces that are going to lead to the shallow breath are going to be that he's turned prone on the street, that he has the handcuffs in place combined with the street, and then that he has a knee on his neck, and then that he has a knee on his back and on his side. All of these four forces are ultimately going to result in the low tidal volume, which gives you the shallow breaths that we saw here.

So the way they're pushing down on his handcuffs combined with the street, his left side-- and it's particularly the left side. We see that. It's like the left side is in a vice. It's totally being pushed in, squeezed in from each side from the street, at the bottom, and then from the way that the handcuffs are manipulated. It's not just the handcuffs. It's how the handcuffs are being held, how they're being pushed, where they're being pushed that totally interfere with central features of how we breathe.