MINNEAPOLIS — A medical expert in the physiology of breathing testified in the murder trial of Derek Chauvin that the way George Floyd was restrained — handcuffed behind his back, face-down on the ground, with a knee on his neck — prevented him from breathing properly.
Dr. Martin Tobin, called as an expert witness by the prosecution, said the cause of Floyd’s death was hypoxia, or a low level of oxygen that led to asphyxia, or suffocation. The overall effect of the restraint was almost “as if a surgeon had gone in and removed the lung,” he said, referring to Floyd’s left lung.
“A healthy person subjected to what Mr. Floyd was subjected to would have died as a result of what he was subjected to,” Tobin said.
Chauvin is charged with second-degree murder, third-degree murder and second-degree manslaughter in Floyd’s death. The defense argues Floyd died as a result of the drugs in his system and underlying medical issues, but prosecutors say Floyd was killed by Chauvin’s knee on his neck for more than nine minutes.
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Latest updates:
- Daniel Isenschmid, a forensic toxicologist who analyzed George Floyd’s blood and urine, took the witness stand Thursday afternoon.
- Jurors have heard from 31 witnesses so far – all called by the prosecution.
- Attorney questioning returned to the topic of Floyd’s drug use on Wednesday. Nelson suggested Floyd said the words, “I ate too many drugs” during his struggle with police last Memorial Day and played several seconds of unintelligible police body-camera audio for witnesses.
- Wednesday afternoon, two forensic scientists said pills found in the SUV and police squad car Floyd had been in that day contained methamphetamine, a stimulant, and fentanyl, a synthetic opioid. A toxicology report found both drugs in Floyd’s system after his death.
Forensic toxicologist: George Floyd had ‘very low’ amount of meth in blood
Daniel Isenschmid, a forensic toxicologist who analyzed George Floyd’s hospital blood and urine collected from the Hennepin County Medical Examiner’s autopsy, took the witness stand Thursay afternoon. Isenschmid works at NMS Laboratory in Horsham, Pennsylvania and previously worked at various medical examiner’s offices.
He told jurors he found fentanyl and methamphetamine in Floyd’s blood. The amount of meth was consistent with a prescribed dose – a “very low” amount, he said.
Isenschmid said he also found evidence of caffeine, smoking and THC in Floyd’s body. Morphine was not found in the blood, but rather in the urine sample, which could indicate that the drug was taken prior to the day Floyd died, he said.
Also found in Floyd’s system was narcan, which Isenschmid testified can be indicative of someone undergoing treatment.
Doctor who researches breathing says Floyd was in a ‘vise’ between officers and street
Dr. Martin Tobin, a physician who has been working in respiratory physiology for 40 years, testified Thursday that Floyd died from a “low level of oxygen,” which caused damage to his brain and an abnormal heartbeat. Tobin was called as an expert witness by prosecutors and examined records and video in the Floyd case, but he did not conduct an examination of Floyd’s body.
Tobin said he watched videos of Floyd’s arrests “hundreds of times” and found Chauvin’s left knee was on Floyd’s neck for the majority of the time. The combination of Floyd being handcuffed behind his back, the officers’ manipulation of the cuffs, and the pavement beneath Floyd combined to interfere with Floyd’s ability to breathe, Tobin testified.
“It’s like the left side is in a vise. It’s totally pushed in, squeezed in from the street at the bottom, and then from the way the handcuffs are manipulated,” he said. “That totally interferes with central features of how we breathe.â€
Tobin said images from the videos show Floyd trying to use his right fingers and knuckles to push the right side of his lungs up to get air into them. “This tells you he has used up his resources and he’s literally trying to breathe with his fingers and knuckles,” Tobin said. Tobin looked at the jurors as he testified, and every juror took notes.Â
Tobin said when the toe of Chauvin’s boot was off the ground and his knee was on Floyd’s neck, 91.5 pounds of weight were coming down directly on theneck. When Chauvin’s toes were on the ground, he said Floyd had 86.9 pounds on his neck.
Tobin said Floyd’s lung capacity dropped by nearly a quarter when he was in the prone position. Once Chauvin added his knee onto Floyd’s neck, his lung capacity dropped by 43%, Tobin calculated.
“Now the work Mr. Floyd has to perform is huge,” Tobin said. “With each breath he has to fight against the street, fight with the small volumes he has, and try to lift up the officer’s knee with each breath, and has to also lift up the effect of the officer pumping up his arm – the handcuffed arm.”
During the first four minutes and 51 seconds of the subduing, Floyd was able to speak, which meant oxygen was reaching his brain, Tobin said. After five minutes and three seconds, Floyd kicked out one leg in an extended position – signaling he had suffered brain damage. After that point, the movement of Chauvin’s knee was no longer relevant because the damage was done.
“You’re seeing here fatal injury to the brain from a lack of oxygen,” Tobin said.
Tobin testified that Floyd lost consciousness at 8:24 p.m. As an intensive care unit doctor, Tobin said he could tell a patient lost consciousness “by how you flick your eyes, or how you constrict the muscles in your face.”
“You can see from his eyes, he’s conscious. Then, he isn’t,” Tobin said. “That’s the moment the life goes out of his body.” Floyd took his last breath at 8:25 p.m., Tobin said, but “the knee remained on the neck for another 3 minutes and 2 seconds, after we reached the point where there’s not an ounce of oxygen left in the body.”
On cross examination by lead defense attorney Eric Nelson, Tobin addressed the argument Floyd died due to his poor health and drug use, saying Floyd’s breathing wasn’t impacted by fentanyl in his system, or underlying health issues.
Tobin also said, after questioning, he is aware Floyd’s autopsy showed no evidence of any bruising or damage to the hypopharynx – part of the throat that Tobin earlier said was restricted by the officers’ restraint.
Tobin said he “wouldn’t expect there to be anything found” on the hypopharynx upon autopsy, “because the effects on the hypopharynx are not going to remain at the time of autopsy.” He noted that sleep apnea evidence isn’t present the following morning, adding, “when I go to the church, I sit on a hard bench, I don’t get bruising of my buttocks when I leave.”
Unlike some previous witnesses, Tobin pushed back against Nelson’s attempts to get short yes or no answers. He also corrected the defense lawyer at times. When Nelson tried to discredit Tobin’s testimony by questioning the assumptions underlying his calculations, Tobin said he made “very few assumptions, “adding “they’re not theoretical.”
When questioning returned to the prosecution, attorney Jerry Blackwell said: “If you consider all the nanosecond and milliseconds in the 5 minutes and 3 seconds, where was Mr. Chuavin the vast majority of the time?”
“On Mr. Floyd’s neck, back and his arm,” Tobin said.
“Not constantly changing?” Blackwell said.
“No,” Tobin said, adding, “The cause of death is the low level of oxygen that caused the brain damage, and caused the heart to stop.”
‘Duty of care’: Prosecutors say Chauvin betrayed policy by not giving Floyd aid
The prosecution has said Chauvin is not only culpable in Floyd’s death but that he also failed to carry out his duty to provide basic care when Floyd was in medical distress and then became unresponsive.
Several Minneapolis police department officials testified Chauvin violated department policy by failing to move Floyd on his side to ease his breathing once he had been restrained face-down on the ground.
“When someone is in our custody, we have an obligation to provide for their care,” Minneapolis Police Chief Medaria Arradondo told jurors. That’s true even if an officer is applying defense tactics, the chief said. “They’re still in our custody,” he said. “They have rights.”
The defense has argued Chauvin and the other officers were unable to care for Floyd because they were distracted and threatened by a crowd of vocal, upset bystanders. “As the crowd grew in size, seemingly so too did their anger,” lead defense attorney, Eric Nelson, told jurors. Read more.
Expert witness Sgt. Jody Stiger says Chauvin used ‘deadly’ force
Sgt. Jody Stiger, a Los Angeles Police Department officer who has conducted about 2,500 use-of-force reviews in his career, told jurors Wednesday that Chauvin used “deadly” force on George Floyd and kept his knee on Floyd’s neck for more than nine minutes.
Stiger said the initial force used on Floyd was appropriate because Floyd was resisting arrest as officers tried to get him into their patrol car. However, after officers forced Floyd to the ground, “they should have de-escalated the situation,” Stiger said. Instead, the officers continued to intensify the situation, he said.
Stiger said the number of officers on the scene outweighed any threat posed by Floyd, who was not actively resisting while he was in the prone position. He said “no force should have been used after he was in that position.” But the pressure continually exerted by Chauvin “raised the possibility of death,” he said. More here.
