Day 9 of Chauvin trial: Floyd died of a ‘low level of oxygen’ not drugs, says expert

Washington Post / YouTube Dr. Martin Tobin on the witness stand at the Derek Chauvin murder trial

Day nine of the Derek Chauvin murder trial was a pivotal one for the prosecution. After a series of testimonies from law enforcement throughout the week, the prosecution changed gears on Thursday and called medical experts to make the state’s case for the cause of George Floyd’s death.

Chief among today’s witnesses was pulmonologist Dr. Martin Tobin. The Chicago-based lung and critical care specialist took the witness stand first. His testimony took up the greater part of the morning, and by all accounts, he was the most compelling witness for the prosecution since MPD Chief Medaria Arradondo on Monday.

Special prosecutor Jerry Blackwell asked the pulmonology expert about his extensive background and established the fact that the renowned doctor was not being paid for his testimony.

He then asked Dr. Tobin what he determined was the cause of Floyd’s death. Tobin replied, “Mr. Floyd died of a low level of oxygen. This caused damage to his brain that we see and it also caused a PEA [pulseless electrical activity] arrhythmia that caused his heart to stop.”

“Have you formed an opinion to a reasonable degree of medical certainty as to what the cause was for the low level of oxygen in Mr. Floyd?” Blackwell asked.

Tobin said, “The cause of the low level of oxygen was shallow breathing. Small breaths … Shallow breaths that wasn’t able to carry the air through his lungs down to the essential areas of the lungs that get oxygen into the blood and get rid of the carbon dioxide.”

Tobin told the jurors he’d viewed all of the videos of the May 25, 2020, fatal arrest, and certain segments of the videos hundreds of times. He had an artist compile the videos to create a reenactment. His findings were that Floyd’s shallow breaths were caused by four contributing factors: the handcuffs; the knee on the neck; the prone position on the street; and the knee on the back, arms, and sides.

Blackwell had Dr. Tobin talk through each factor for the jurors. Tobin explained how the police officers’ weight on the left side of Floyd’s body shut down his left lung “almost to the effect as if a surgeon went in and removed the lung,” Dr. Tobin testified.

Looking directly at the jurors and with his Irish accent, Dr. Tobin broke down complex medical terms in easy-to-understand language. With calm and matter-of-fact authority, the doctor described a torturous death for Floyd.

Tobin showed a still of Floyd’s knuckle on a car tire next to where he was pinned to the street. He explained that Floyd was attempting to use his fingers and knuckle to lift himself up so his chest could expand, and he could breathe. His presentation also showed where Chauvin’s feet were completely off the ground at one point, meaning his full weight was on Floyd.

“A healthy person subjected to what Mr. Floyd was subjected to would have died as a result,” Tobin said.

Dr. Tobin also pointed out a part of the video that shows Floyd’s leg kicking upward in the video as he lay face down on the asphalt—the result of a myoclonic seizure. “Something we clinicians see in patients when they suffer a brain injury due to lower-level oxygen,” Dr. Tobin said.

The most ghastly moment came when Dr. Tobin showed the jurors the exact moment he thought Floyd’s life left his body. “You can see his eyes, he’s conscious, and then you see that he isn’t. That’s the moment the life goes out of his body,” he said.

After Floyd’s life left his body, Tobin said it took Chauvin three minutes and 27 seconds to finally remove his knee.

Chauvin is charged with third-degree murder, second-degree murder, and second-degree manslaughter for the killing of Floyd. Per Minnesota guidelines, prosecutors only have to prove that Chauvin’s actions were a “substantial causal factor” in Floyd’s death, not the sole reason.

By the number of objections from the defense, Dr. Tobin’s testimony appeared to have been striking a chord with the jurors. Pool reports indicate the jurors were taking lots of notes throughout his testimony.

At one point, Tobin told the jurors to touch their necks as he explained an idea. Many of the jurors did as instructed, according to pool reports—much to the chagrin of defense attorney Eric Nelson who called a sidebar. After the sidebar, Judge Peter Cahill then instructed the jurors that they didn’t have to do as Dr. Tobin instructed, but they could if they wanted to.

During cross-examination, Nelson sought to undermine Tobin’s testimony by noting that he hadn’t actually examined Floyd. The defense contends that Floyd died of a drug overdose and underlying health conditions. Nelson’s cross-examination did not seem to go as well as it has the last few days with some of the police officers.

Also appearing on the witness stand on Thursday was Dr. Daniel Isenschmid of NMS Labs, who examined Floyd’s urine and blood. He testified that some of the fentanyl in Floyd’s system had metabolized to norfentanyl, which counters the defense’s claim that Floyd died of a fentanyl overdose.  

Isenschmid explained that usually when someone overdoses on fentanyl, “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.”

Emergency medicine physician Dr. Bill Smock, who specializes in forensic medicine, closed out the day of testimony. He also testified that Floyd died of “positional asphyxia,” which he explained was a fancy way of saying he died “because he had no oxygen left in his body.”

He also explained away the idea that Floyd died of excited delirium or a heart attack. “There’s no evidence of a blood clot in any of the arteries, there’s no evidence of hemorrhage from a ruptured plaque, and there’s no evidence that Mr. Floyd had a heart attack,” Smock said.

Smock rejected the defense’s claim that Floyd died of an overdose, stating that he didn’t show the signs. “He’s breathing; he’s talking. He’s not snoring,” Smock said of Floyd’s last moments. “He is saying, ‘please, please get off of me. I want to breathe; I can’t breathe!’ That is not a fentanyl overdose, that is somebody begging to breathe.”

More medical testimony is expected on Friday, as Hennepin County Chief Medical Examiner Andrew Baker, who performed the official autopsy on Floyd, is set to take the witness stand. Baker ruled Floyd’s death a homicide last year.