Derek Chauvin trial, day 10: George Floyd died from low oxygen due to officers' restraint, forensic pathologist says
MINNEAPOLIS — The chief medical examiner for Hennepin County who conducted the autopsy on George Floyd testified Friday in the murder trial of Derek Chauvin, telling jurors that Floyd's breathing did not appear to be impaired by the placement of Chauvin's knee on Floyd's neck.
Dr. Andrew Baker testified that Floyd's existing and underlying heart disease was a contributing cause of his death; it was evidenced by a heart that "weighed more than it should" and coronary arteries that were significantly narrowed.
"The law enforcement subdual and neck compression is just more than Mr. Floyd could take by virtue of his heart conditions," Baker said.
In his autopsy report last year, Baker said Floyd's heart and lungs stopped amid "law enforcement subdual, restraint and neck compression," but he did not use the word "asphyxia," or oxygen loss. He ruled the death a homicide.
Friday morning, the former Hennepin County medical examiner told the jury that Floyd died from asphyxia due to officers' restraint – going a step further than the autopsy.
"This is a death where both heart and lungs stop working,"said Dr. Lindsey Thomas, a former forensic pathologist for the county who trained Baker. "The point is it’s due to law enforcement subdual, restraint and compression."
A family-commissioned autopsy released around the same time found Floyd's death was a homicide caused by "asphyxiation from sustained pressure."
Chauvin is charged with second-degree murder, third-degree murder and second-degree manslaughter in Floyd's death.
Where things stand: This week, the prosecution has called experts and police officials to testify about proper use of force and medical professionals to testify about how Floyd died. Prosecutors have also asked experts to testify about the role of drugs found in Floyd's system, trying to head off the defense's argument that drugs played a key role in his death. The defense has highlighted the effect meth and fentanyl may have on the heart and lungs. The defense has also argued the crowd of bystanders gathered near the scene distracted and threatened the officers, preventing them from giving care to Floyd and meriting additional force.
- Court is adjourned for the day. Jurors will return Monday at 9:30 a.m. CDT.
- Andrew Baker, the chief medical examiner for Hennepin County who conducted the autopsy on George Floyd, took the stand Friday afternoon.
- Jurors have heard from 35 witnesses so far – all called by the prosecution.
- A medical expert in the physiology of breathing said Thursday the way Floyd was restrained prevented him from breathing properly and caused his death.
- Another, a police surgeon, said Floyd didn't overdose or have a heart attack.
- A forensic toxicologist who analyzed George Floyd's blood and urine told jurors Thursday the amount of meth in Floyd's system was consistent with a prescribed dose – a "very low" amount.
Dr. Andrew Baker, the chief medical examiner for Hennepin County, told jurors that the "top-line" direct cause of Floyd's death remained unchanged today: Floyd's heart and lungs stopped beating as a result of being subdued, restrained and having his neck compressed by police officers during their encounter.
During the autopsy, Baker said he did not find any injuries to Floyd’s back, nor any bruises or scrapes. But he found “several injuries” to Floyd’s face that would match Floyd’s face pinned to the asphalt in the prone position the night before, Baker said.
He also noted handcuff marks on his hands and blunt-force injuries on Floyd's right pointed and middle fingers.
“These are entirely consistent with him being in an altercation with someone,” Baker said.
During the examination of Floyd's body and organs during autopsy, Baker's initial look found no real damage to the brain, lungs or heart – although he said there was evidence of severe narrowing of coronary arteries, significant enough to cause sudden death in a person.
Still, Baker said, "To the best of my knowledge, he was generally healthy on May 25 before the events of that evening."
He also noted he waited to watch video of Floyd's struggle with police until after his exam: “I didn’t want to bias my exam with any preconceived notions,” Baker said.
Baker also testified he did not note deprivation of blood or oxygen to the brain, but noted that "the person has to survive the anoxic brain injury for a considerable period of time before we can see" any brain cell damage.
Baker said Floyd's heart was outside the upper limit of normal for a man of his size, contradicting Thomas' earlier testimony.
"His heart already needed more oxygen by its size," but that was limited because of narrowed coronary arteries, he said.
Baker said the altercation and pain of being pressed against asphalt would've caused an increase in stress hormones like adrenaline that would "ask your heart to beat faster. He added: "It's going to ask your body for more oxygen so that you can get through that altercation."
Baker also said he found no evidence of a pill or pill fragments in Floyd's stomach.
The defense has argued that Floyd's underlying heart issues and drug use contributed to his death.
During questioning from defense attorney Eric Nelson, Baker said he included heart disease, the history of hypertension and the drugs in his system on the death certificate because they played a contributory role in Floyd's death.
"He experienced a cardiopulmonary arrest in the context of law enforcement, subdual, restraint, compression," Baker said. "It was the stress of that interaction that tipped him over the edge, given his underlying heart disease and its toxicology status."
Baker noted neck compression is on the "top line" of his cause-of-death statement and said he thought Chauvin’s knee was primarily on Floyd’s back, side or the area in between Floyd’s neck. Baker said he didn't believe Chauvin's knee placement would anatomically cut off Floyd's breathing, but also acknowledged he was no expert in assessing and reading video footage.
Prior experts have testified that Chauvin's knee was primarily on Floyd's neck through the 9 minutes and 29 seconds that Floyd was prone and handcuffed on the ground last May.
Baker said he did not find anatomical evidence to support the conclusion of death by asphyxiation, adding that he recalled informing Hennepin County attorneys of that fact.
But he also said that he could not detail the impact of the encounter with Chauvin on Floyd's breathing because he is not a pulmonologist. He repeatedly referred Nelson to ask such questions to such an expert of the respiratory system.
Also, Baker told jurors that if Floyd had been found dead in his locked residence with no evidence of trauma, he would've concluded Floyd died of an overdose.
Nelson's questioning appeared "to be annoying" to one juror, a Black man, who was seen squinting his eyes toward the attorney and shaking his head slightly.
Upon re-direct questioning by state's attorney Jerry Blackwell,Baker emphasized that the top-line direct cause of death remain unchanged today – it's still "cardiopulmonary arrest" as a result of Floyd being subdued, restrained and his neck compressed by law enforcement. Baker noted again that details like Floyd's drug intake or underlying heart issues are "contributing causes."
"It was my top line then. It would stay my top line now," Baker said of the law enforcement restraint. "I would still classify it as a homicide today."
Friday morning, the prosecution called forensic pathologist Dr. Lindsey Thomas as an expert witness who has reviewed documents and videos in the case. She also trained Dr. Andrew Baker, the Hennepin County chief medical examiner who ruled Floyd's death a homicide, and who was expected to testify later on Friday.
Thomas said she agreed with Baker's autopsy findings. "In this case, I believe the primary mechanism of death is asphyxia, or low oxygen," she said. "This is not a sudden cardiac death."
Thomas entered semi-retirement in 2017 but still does consulting and works in the medical examiner’s offices in Reno and Las Vegas. Previously, she was the medical examiner for several Minnesota counties. She said she's performed about 5,000 autopsies and has consulted with other medical examiners on roughly 1,000 more autopsies.
Thomas said Floyd's autopsy was "really great for ruling things out." She said there was no evidence from the autopsy that Floyd had sufficient lung disease to impair his breathing. He didn't have a heart attack or a stroke, she said. And the slow nature of Floyd's death shows he did not die of a methamphetamine or fentanyl overdose, she said.
"Basically, Mr. Floyd was in a position ... where he was unable to get enough oxygen," Thomas said, echoing prior testimony by Dr. Martin Tobin and Dr. Bill Smock, other medical expert witnesses called by the prosecution on Thursday. Answering prosecutor Jerry Blackwell, she later emphasized: "There's no evidence to suggest he would have died that night except for the interactions with law enforcement."
The long struggle with police produced chemical reactions in Floyd's body that caused physiological stress, Thomas said: "This goes on for minute, after minute, for nine minutes,” she said. The physiological stress that results from that situation doesn't show up in an autopsy, but could be considered a contributing cause of death,” Thomas testified.
On cross examination, lead defense attorney Eric Nelson suggested Floyd's underlying heart issues and drug use contributed to his death.
Prompted by Nelson, Thomas said the autopsy showed Floyd's heart was enlarged and that Floyd had narrowing of coronary arteries. If Floyd had died at home, with no confrontation with police, Thomas said she would probably have concluded that Floyd died of heart disease.
Asked if, in another hypothetical scenario where Floyd was found dead at home, she would conclude Floyd died of an overdose, Thomas said she "could consider" it.
Nelson also referenced studies in Canada that found people arrested in the prone position did not die. Thomas appeared skeptical of the study. She said the prone position is not inherently dangerous "unless there are other factors."
"I could be laying by the pool in Florida, on my stomach in the prone position, not inherently dangerous?" Nelson said. "Right," said Thomas.
When prosecutor Jerry Black re-questioned Thomas, he challenged the hypothetical scenarios Nelson had . "Aren't those questions a lot like asking, Mrs. Lincoln, if we take John Wilkes Booth out of this,” Blackwell began, only to be stopped by Judge Peter Cahill for posing an argumentative question. Thomas agreed, as a forensic pathologist, she would not pursue a hypothetical situation by removing factors that she concluded had caused death.
Blackwell also followed up on Nelson's pool scenario. "George Floyd was not laying by the pool on his stomach in Florida, was he?" Blackwell asked. "No," Thomas said.
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.
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. Read more about his testimony here.