Medical experts in Derek Chauvin trial testify that George Floyd died from lack of oxygen, restraint A renowned expert on breathing and a doctor who trains police officers both testified that Floyd died from lack of oxygen, brought on by the officers' restraint. Author: Emily Haavik, Lou Raguse, Diane Sandberg (KARE11) Published: 6:07 AM EDT April 8, 2021 Updated: 7:23 PM EDT April 8, 2021 MINNEAPOLIS — Editor's note: Some of the images depicted in the video and testimony are graphic. Have a question you'd like to hear our trial experts answer? Send it to lraguse@kare11.com or text it to 763-797-7215. Renowned breathing expert testified that George Floyd died from 'low level of oxygen' caused by 'shallow breaths.'