MINNEAPOLIS – A doctor with 40 years of experience in the physiology of breathing presented critical testimony in Derek Chauvin’s murder trial on Thursday, describing why George Floyd couldn’t breathe as Chauvin and other agents held him face to face on the ground and handcuffed in the street on the last Memorial Day.
Dr. Martin Tobin taught jurors the repercussions of the officers’ use of force which he said slowly suffocated him. After Floyd was pulled from a police car, he was placed face down on hard asphalt. Her hands were handcuffed behind her back, and officers pressed her arms to her body, pressing against her chest. And Chauvin’s left knee was on Floyd’s neck while his right was on Floyd’s back and side, Tobin said, compressing Floyd’s lungs even more.
“It’s like the left side (of Floyd’s body) is in a vise. It’s totally sunk, squeezed through the street below,” Tobin said. “And then, the way the handcuffs are handled, it totally interferes with the central features of how we breathe.”
Tobin told jurors that “a healthy person subjected to what Mr. Floyd was subjected to would have died as a result,” which could contradict the defense argument that Floyd died of a combination of his struggle with officers, health issues and drugs.
Tobin has been an expert witness in numerous court cases, most involving allegations of medical malpractice. But this was his first criminal case, which he says is one of the reasons he did not ask for payment when the prosecution contacted him.
His testimony took place on the ninth day of the trial, after prosecutors presented video evidence captured by body-worn cameras and bystanders, as well as eyewitness testimony, Minneapolis police officers, paramedics, d ” an emergency room doctor and a use of force expert.
The testimony of medical experts like Tobin is expected to play a key role in the trial of Chauvin, who is charged with second and third degree murder and second degree manslaughter.
Floyd was trying to breathe with his fingers and knuckles
Tobin said the actions of Chauvin and two other officers, J. Alexander Kueng and Thomas Lane, compressed Floyd’s airways and forced him to take shallow breaths. It prevented his lungs from getting rid of carbon dioxide andreplenish oxygen.
Over time, Tobin said, Floyd’s oxygen level dropped to the point that he led to a seizure. He said the cause of Floyd’s death was lack of oxygen, which also caused brain damage and abnormal heart rhythms.
Tobin said he had watched videos of Floyd’s arrests “hundreds of times” and calculated that Chauvin’s left knee was on Floyd’s neck for the majority of the 9 minutes and 29 seconds he was immobilized in the ground.
The effect of the officers’ actions and Floyd’s position was almost “as if a surgeon had come in and removed the lung,” Tobin said, referring to Floyd’s left lung.
Tobin said the footage from the videos shows Floyd trying to use his right fingers and knuckles to lift the right side of his chest to force air into his lungs. “This tells you he’s exhausted his resources and he’s literally trying to breathe with his fingers and knuckles,” Tobin said.
Some jurors sat down and took notes when Tobin said a healthy person would have died had they been held up like Floyd. Many jurors took notes when he described when Floyd stopped breathing and how long he said Chauvin’s knee stayed on Floyd’s neck afterward: 3 minutes and 2 seconds.
90 pounds of pressure on Floyd’s neck, doctor testifies
Floyd’s position restricted a part of the airway called the hypopharynx, which is vulnerable because it is so narrow, Tobin said.
As Chauvin pressed his knee into Floyd’s hypopharyngeal area, Tobin said it became more difficult for Floyd to breathe than it would have been if he had inhaled through a straw.
At one point, Tobin asked jurors to feel their own necks to locate the hypopharynx, which caused a brief interruption as lawyers spoke with Hennepin County Judge Peter Cahill. The judge told jurors they didn’t have to follow his instructions, but almost all did anyway.
Tobin testified about an image from a video showing Chauvin’s left boot toe lifted off the ground as he knelt on top of Floyd. At that time, Tobin testified, 91.5 pounds was pressed directly onto Floyd’s neck. Even 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 almost a quarter when he was placed in the supine position. Once Chauvin pressed his knee to Floyd’s neck, his lung capacity plummeted again, for a total reduction of 43%, Tobin calculated.
“Now the work Mr. Floyd has to do is enormous,” said Tobin. “With every breath he has to fight the street, fight with the small volumes he has and try to lift the officer’s knee with every breath, and also has to increase the effect of the officer inflating his arm. – the handcuffed arm. ”
Defense attorney Eric Nelson attempted to discredit Tobin’s calculations by questioning assumptions about Floyd’s health and Chauvin’s weight. Tobin said he made “very few assumptions.”
Nelson noted that an autopsy showed Floyd’s hypopharynx was not damaged and his neck was not bruised. Tobin said he “wouldn’t expect anything to be found” because oxygen deprivation doesn’t leave fingerprints.
Doctors’ addresses claim Floyd could breathe because he spoke
Floyd yelled “I can’t breathe” more than 20 times. Officers can be heard saying on the body camera video that if he could speak he could breathe.
Tobin said it was a “dangerous” assumption because that doesn’t mean someone will still be breathing in the next moment. Being able to speak meant Floyd’s brain was working, Tobin said, and that meant he was breathing the moment before.
“It gives you a huge, false sense of security because very soon after we are going to see that he has a significant loss of oxygen in the sense that he is moving his leg,” Tobin said. “So that tells you how much this concept of… ‘If you can talk, you can breathe.’ Yes. That is true. On the surface, but very deceptive, very, very dangerous. “
A normal trachea is between the size of a quarter and a penny in diameter, Tobin said. When the windpipe is limited to 15% of that, he said, “you are still able to speak.”
Drug use, medical problems not a factor, says Tobin
Tobin said he reviewed Floyd’s medical records, was aware of his past illnesses, and found that a toxicology report found fentanyl and methamphetamine in his system. He said Floyd’s medical conditions and drug ingestion were irrelevant to his death.
Floyd’s average breathing rate would have been faster if he was suffering from the symptoms of heart disease, Tobin said. He calculated that Floyd’s breathing rate was the same as that of a healthy person, even though fentanyl usually suppresses breathing.
The significant increase in Floyd’s carbon dioxide levels as measured by paramedics and hospital emergency physicians is “completely explained” by the lack of oxygen Floyd suffered from the restraint, Tobin said.
“ This is the moment when life comes out of his body ”
Tobin calculated that Floyd was able to speak for the first 4 minutes and 51 seconds he was on the ground under the officers. This meant that the oxygen was still reaching his brain.
Tobin testified that the video then showed Floyd struggling to create an area for oxygen to enter his lungs, lifting his right shoulder up and down to widen the lung space, and swaying his hips and spine.
At 5 minutes and 3 seconds, Floyd kicked out a leg, Tobin testified. This indicated that he had suffered a hypoxic crisis – a seizure due to lack of oxygen – resulting in fatal brain damage.
After that, said Tobin, Chauvin’s knee placement was no longer relevant as he had already suffered a serious brain injury.
Tobin testified that Floyd passed out at 8:24 pm As an intensive care physician, Tobin said he could tell when a patient was unconscious “by wiggling your eyes or squeezing the muscles in your face.”
“You can see with his eyes, he’s conscious. Then he’s not,” Tobin said. “This is the moment when life comes out of his body.”
By the time Floyd passed out, Tobin said, his blood oxygen level would have been 36mm Hg, well below the normal level of 89mm Hg for a man his age. Less than a minute later, Floyd would have no more oxygen in his blood, he said.
“The knee stayed on the neck for another 3 minutes and 2 seconds,” said Tobin, “after reaching the point where there is not an ounce of oxygen left in the body.” For the last 2 minutes and 44 seconds, said Tobin, officers held the position even though they knew Floyd had no pulse.