Dr. Andrew Baker is arguably one of the most important witnesses to be called in the murder trial of Derek Chauvin. It was his duty to determine why George Floyd died.
Dr. Baker, the Hennepin County medical examiner, performed the first autopsy on Mr. Floyd, eventually determined that his heart and lungs stopped functioning while being subdued, restrained and compressed by police officers.
The way Mr. Floyd died, Dr. Baker concluded, was murder. And in the months since, almost everything he said in the autopsy report has been dissected and examined by experts and laymen alike.
In opening statements last week, the prosecution indicated that they would follow an unusual strategy: some aspects of Dr. Baker & # 39; s findings and introducing one reason he did not mention – insufficient oxygen – as the cause of death for Mr. Floyd.
For their part, Mr. Chauvin's jurors that pre-existing heart disease, high blood pressure and recent drug use, as documented by Dr. Baker, led to the death of Mr. Floyd because of what they thought was a cardiac arrhythmia.
As the trial approaches a stage where Mr Floyd's cause of death will take center stage, we spoke with several forensic pathologists not involved in the case to explain some of the terms used in the proceedings, how they identified the cause and determine the manner of death and how this concerns the case. Here's what we learned.
What is a medical examiner?
In the United States, some jurisdictions use coroners and others use medical investigators to determine the cause of certain deaths, including those that occur while in police custody. Unlike coroners, medical examiners must be doctors. Dr. Baker is certified in forensic pathology and is Hennepin County's chief medical examiner. The medical examiner's office is an independent office. It is not part of law enforcement.
Is there always one cause of death?
In the event of death, a death certificate is completed, both for public health and legal reasons. The form includes cause of death in the first part and contributing factors in the second part. "Usually we have to come up with one cause," said Dr. Judy Melinek, a board-certified forensic pathologist. Anything else that might be wrong with a person is "contributing." & # 39; & # 39;
Pathologists describe the cause of death as the immediate injury or illness that leads to death. It is the "disease or injury that causes the deadly sequence of events without intervention," said Dr. Melinek.
What is the mode of death?
The manner of death refers to the circumstances surrounding the death. There are usually five choices (a few jurisdictions include more): natural, accident, suicide, murder, or indeterminate.
Homicide is often described as "death at the hands of another or others". A murder is not necessarily criminal – murder cases, for example, can be a matter of self-defense. The courts, not the medical investigators, find the criminal guilt.
Is more than one autopsy being considered?
In addition to examining the body, which is usually done quickly, pathologists consider other materials, such as the police report, videos, medical records and toxicology reports, said Dr. Priya Banerjee, a board-certified forensic pathologist. “We don't practice in a black box,” she said. Until all the results of the investigation are in, she says, she usually says the case is pending further investigation.
Are the cause and manner of death always clear?
In the vast majority of cases, the cause and manner of death are clear, say forensic pathologists. But in some situations, the professional opinions of trained and experienced experts may differ.
"Some cases are much more complicated than others," said Dr. Banerjee. When an "autopsy wasn't a slam dunk," said Dr. Banerjee, the written cause of death may be "more comprehensive because many things are being considered".
This can happen when an autopsy does not reveal a fatal injury, such as a gunshot wound to the brain. "Autopsies are good at showing detectable changes in the tissues of the body," said Dr. Christopher Happy, a certified forensic pathologist, "but they are not good at showing functional things, such as a seizure or respiratory depression or arrhythmia unless it has a lesion associated with it. "
What did Dr. Baker ultimately determine?
Dr. Baker described Mr. Floyd's cause of death as "cardiopulmonary arrest complicating subduality, restraint and neck compression." The way of dying, he wrote, was murder.
The use of the term cardiopulmonary arrest caused public confusion as some people mistakenly assumed it meant Mr. Floyd had had a heart attack. Cardiopulmonary arrest means "the heart stops beating and the lungs stop moving," said Dr. Cyril Wecht.
Some pathologists say they don't include it as a cause of death because it describes all deaths.
Dr. Baker also described "other important conditions," including pre-existing conditions such as severe disease of the blood vessels of Mr. Floyd's heart. He also described laboratory findings of the opiate drug fentanyl and methamphetamine in Mr. Floyd's blood. If these are not listed as causes of death, it means that he concluded that "there were before, but the deadly sequence of events did not begin," said Dr. Melinek. Listing them "is to clarify" what made Mr. Floyd more vulnerable to the cause of death, she said, "no excuse."
Here the context is important. Dr. Baker told prosecutors that if Mr. Floyd had "been found dead alone at home" with no "other identifiable causes," they wrote, it might have been acceptable to determine that Mr. Floyd died of an overdose due to relatively high levels of fentanyl. found in his blood collected at the hospital.
Instead, recordings revealed both Mr. Floyd's long-standing reluctance just before his death and that he seemed agitated rather than lethargic, suggesting tolerance to higher doses of fentanyl. The drug "usually causes you to relax," said Dr. Wecht.
Dr. In contrast, Melinek said Mr. Chauvin's attorneys appear to be trying to use the medical findings to convince the jury that Mr. Floyd “was essentially a ticking time bomb, had pre-existing conditions that made this endpoint possible, not because there was excessive violence was used. "
Just claiming that he was at higher risk of death from police reluctance due to underlying health problems or drug use would likely be legally insufficient, some experts said.
What did his preliminary findings say?
The medical examiner's office had not yet completed its investigation when prosecutors filed a complaint stating that preliminary findings had provided no physical evidence to support a diagnosis of "traumatic asphyxiation or strangulation". to support. It said the combined effects of police reluctance, underlying health problems, including heart disease, and "potential intoxicants in his system, likely contributed to his death."
Forensic pathologists said it can be problematic in high-profile cases to release findings early because they may be misinterpreted or incomplete. "I never actually disclose the provisional cause of death," said Dr. Banerjee.
What did a second autopsy think of Mr. Floyd?
After the initial autopsy, forensic pathologists no longer have access to an intact body, and sometimes organs or tissues are unavailable because they have been removed for further examination. Still, doctors sometimes document findings that an examiner missed at the initial autopsy or that were unclear.
"There are several reasons why you might see something on the second autopsy that wasn't seen on the first autopsy and vice versa," said Dr. Melinek.
Mr. Floyd's family hired Dr. Michael Baden and Dr. Allecia Wilson to perform a second autopsy. Both experts said the pressure on Mr. Floyd's neck and back during his coercion by the police led to him dying of asphyxiation, a term Dr. Baker did not use it in his official report.
The word choking is derived from an ancient Greek term meaning "without pulse." Doctors now use it to indicate lack of oxygen, which can occur for many reasons. The heart of the matter is whether Mr. Chauvin's actions led to any of these, such as inhibiting the movement of the diaphragm that allows the lungs to expand, or reducing the flow of blood that carries oxygen to vital tissues. Oxygen deficiency can occur not only from neck compression, experts said, but also from pressure on the back when someone is lying face down, and it may not leave any major physical marks.
The cause of death described by both Dr. Baker as the pathologists who performed the second autopsy came down to essentially the same thing, some experts said, namely "that external pressure in a predisposed position to Mr. Floyd caused his death," said Dr. Banerjee said.
Shaila Dewan contributed reporting.