George Floyd died from a lack of oxygen during his arrest on May 25, according to a medical witness in the trial of former Minneapolis Police Department officer Derek Chauvin.
Chauvin, who kneeled on Floyd’s neck for more than nine minutes during the arrest, is charged with second- and third- degree murder and second-degree manslaughter. Floyd was handcuffed and face down while in the restraint.
Floyd's cause of death is expected to play a key role in the outcome of the trial.
Pulmonology expert Dr. Martin Tobin, a witness called by the prosecution Thursday, said he believes Floyd died from a lack of oxygen caused by an inability to breathe properly while in the restraint.
“Mr. Floyd died from a low level of oxygen. This caused the damage to his brain that we see, and it also caused a [pulseless electrical activity] arrhythmia that caused his heart to stop,” Tobin said. “The cause of the low level of oxygen was shallow breathing.”
Tobin said the forces that caused Floyd’s shallow breathing were the officers’ knees on his body, including Chauvin’s knee on his neck, being handcuffed against the street and being in the prone position.
Tobin also pointed out that Chauvin’s knee remained on Floyd’s neck for more than three minutes after he had stopped breathing.
Tobin’s testimony was in line with the broader case laid out by the prosecution, who have alleged Floyd died due to Chauvin’s actions during the arrest. The defense has alleged Floyd died due to heart issues and drugs in his system.
Chauvin’s defense attorney Eric Nelson questioned Tobin about whether a fentanyl overdose can also cause a lack of oxygen, which Tobin acknowledged.
But Tobin also told the prosecution that people dying from a fentanyl overdose will go into a coma, which was not the case in Floyd’s death.
Two autopsy reports previously found that Floyd had methamphetamine and fentanyl in his system at the time of his death, though neither were identified as contributing factors in his death.
Forensic toxicology expert Dr. Daniel Isenschmid also testified Thursday. Isenschmid stated that the levels of methamphetamine found in Floyd’s system after he died were “very low” compared to the typical level found during DUI cases.
While Floyd did have fentanyl in his blood, he also had the fentanyl metabolite norfentanyl in his blood, which is rare in the case of overdoses, Isenschmid stated.
“We frequently see fentanyl with no norfentanyl whatsoever because after a very acute fentanyl intoxication, the body doesn’t have time to break it down,” Isenschmid said, noting that it's common for DWI suspects with fentanyl in their system to have higher levels of the drug in their blood that Floyd did on the day of his death.
Police surgeon Dr. Bill Smock, another witness brought out by the prosecution, echoed the opinion that Floyd did not die from a drug overdose. Smock also cited the lack of a coma that would result from a fentanyl overdose.
“Mr. Floyd died from positional asphyxia, which is a fancy way of saying he died because he had no oxygen in his body,” Smock said. “That is not a fentanyl overdose, that is someone begging to breathe.”
Nelson questioned Smock about the effect of the additional stress Floyd experienced during the arrest could have had on him. Smock acknowledged that the struggle between Floyd and the officers could have elevated Floyd’s heart rate.