Medical Experts Disagree on Possible Causes of Floyd's Death, Point Finger at Chauvin

On 9 April, Hennepin County's chief medical examiner appeared before the jury to shed further light on the causes of George Floyd's death. The prosecution is arguing that Floyd died from a lack of oxygen, or asphyxia, caused by police holding the African American prone and handcuffed on the pavement. For its part, Chauvin's legal team is placing the emphasis on Floyd's underlying health conditions and recent use of drugs, suggesting that they could have led to breathing problems and cardiac arrest.

It was Baker who performed the initial autopsy on George Floyd's body on 26 May 2020. The autopsy found zero physical signs of "traumatic asphyxia or strangulation" and suggested that the "combined effects of Mr. Floyd being restrained by the police, his underlying health conditions and any potential intoxicants in his system likely contributed to his death."  

Still, the African American's death certificate, signed by Baker, says that Floyd's immediate cause of death was "cardiopulmonary arrest complicating law enforcement subdual restraint and neck compression," listing "arteriosclerotic and hypertensive heart disease, fentanyl intoxication, and recent methamphetamine use" as secondary factors. It also cites the manner of death as "homicide." 

​During his Friday testimony Baker clarified his point by saying that "the law enforcement subdual restraint and the neck compression was more than Mr. Floyd could take by virtue of [his] heart conditions." He noted, however, that Chauvin's knee did not cut off Floyd's airway, adding that no damage to the brain from loss of blood or oxygen was observed in this case.

​While agreeing with Chauvin's defence attorney Eric Nelson that "both the heart disease as well as the history of hypertension and the drugs that were in his system played a role in Mr. Floyd's death," the medical examiner highlighted that they weren't the "direct causes."

Baker specified that the term "homicide" used in Floyd's death certificate is not an equivalent to the similar sounding legal term and does not determine "culpability or intent." According to the US National Association of Medical Examiners (NAME), "[h]omicide occurs when death results from a volitional act committed by another person to cause fear, harm, or death."

Baker's Testimony Seemingly at Odds With Those of Other Medical Experts

Although Baker's testimony appears to be playing into the hands of the prosecution, it in some sense contradicts the opinions of the other medical experts who earlier outlined their assessments in the court.

Thus, Dr. Martin Tobin, a lung specialist at the Edward Hines Jr. VA Hospital and Loyola University’s medical school in Chicago, told the jury on 8 April that Floyd died "from a low level of oxygen" and ruled out the black man's underlying health condition and drug use as factors contributing to his death.

"Mr. Floyd died from a low level of oxygen, and 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," Tobin said, adding that "a healthy person subjected to what Mr. Floyd was subjected to would have died as a result of what he was subjected to."

Dr. Bill Smock, the police surgeon of the Louisville Police Department who testified before the court on the same day, appeared to share Tobin's stance: "Mr Floyd died of positional asphyxia, which is a fancy way of saying he died because he had no oxygen in his body," Smock said. "When the body is deprived of oxygen, in this case from pressure on his chest and back, he gradually succumbed to lower and lower levels of oxygen until it was gone and he died."

For her part, Dr. Lindsey Thomas, a medical examiner who worked on Baker's staff from 2013 to 2017, suggested on Friday that "the primary mechanism of death is asphyxia, or low oxygen."

Tobin, Smock, Thomas and forensic toxicologist David Isenschmid ruled out the assumption that Floyd could have died of a drug overdose.

What About Almost Lethal Dose of Drugs in Floyd's System?

However, Chauvin's defence continues to push ahead with the potentially lethal effect of drug use in Floyd's case. The autopsy found psychoactive substances in the 46-year-old's system, including fentanyl and methamphetamine.

​During the cross examination Dr. Lindsey Thomas admitted that there are no "safe" levels of meth contamination. Medical experts also largely agree that methamphetamine would increase a person’s heart rate as well as their heart's oxygen needs.

"Meth is not good for damaged hearts from pathologists' viewpoint," admitted Dr. Baker, adding that Floyd's heart was 540 grammes, i.e. outside the upper limit of normal for someone his size. The state's chief medical examiner also acknowledged that he had certified deaths from overdose in cases when fentanyl level in individuals' systems was at levels even lower than that of Floyd, i.e. 11 nanogrammes.

While not listing drug intoxication as a direct cause of Floyd's death, the chief medical examiner reiterated his earlier notion that "had Mr. Floyd been home alone in his locked residence with no evidence of trauma, and the only autopsy finding was that fentanyl level, then yes, I would certify his death as due to fentanyl toxicity."

Earlier, on 7 April, Chauvin's defence attorney Eric Nelson almost caught the prosecution by surprise by asking Agent James Reyerson of the Minnesota Bureau of Criminal Apprehension whether he could hear George Floyd saying on a record "I ate too many drugs." While initially Reyerson agreed that this is what he had said, he later back-pedalled on his statement claiming that Floyd actually said, "I ain’t do no drugs."

​The defence also referred to the fact that pills containing a mixture of fentanyl and meth were recovered in the car Floyd had been in at the moment of the arrest and in the squad vehicle in which the law enforcement agents had tried to detain him. Floyd's saliva was found on the pills.

A man who was in Floyd's car at the time of the latter's arrest and who is suspected to be a drug dealer has signalled that he would invoke his Fifth Amendment privilege against self-incrimination.

It was suggested by the defence that the 46-year-old could have quickly ingested opiates in his possession when confronted by the police. However, Dr. Baker stated on 9 April that neither pills nor their particles had been found in Floyd's stomach during the autopsy.

Prosecutors are 'Back on Track'

This week was marked with ups and downs for the defence team of Chauvin who is charged with second-degree murder, third-degree murder and manslaughter charges. It found, in particular, that for at least some time Chauvin had not knelt on Floyd's back but on his shoulder blade. Nelson also demonstrated that the Minneapolis police officer had neither used a "choke hold" nor "unconscious neck restraint" in this case, while interviewing MPD Lieutenant Johnny Mercil, the state’s expert on MPD use-of-force policy and training.

​Furthermore, Mercil appeared to agree that under the circumstances of Floyd's arrest it had been appropriate for an officer to maintain a neck restraint for a substantial period of time.

​It appears that the medical experts' testimonies have boosted the prosecution's standing, as suggested in the op-ed of Andrew McCarthy, a senior fellow at National Review Institute and former assistant United States attorney for the Southern District of New York. Still, for fairness' sake, "the cause of death testimony does not settle the matters of Chauvin’s knowledge and intent," he writes.

"Moreover, proof that he caused Floyd’s death is not proof that Chauvin intended to cause Floyd’s death, intended to cause him real injury, or acted in a manner that was criminally irresponsible. That will have to be established to the jury’s satisfaction," the lawyer underscores.