According to a doctor called by prosecutors to testify in the trial of former Minneapolis Police officer Derek Chauvin, the potentially fatal levels of fentanyl and methamphetamine in George Floyd’s body at the time of his arrest were not the cause of his death.
Dr. Martin Tobin of Chicago said a “low-level of oxygen” caused by Chauvin pinning Floyd to the ground during his arrest “caused damage to his brain that we see, and it also caused a PEA arrhythmia that caused his heart to stop.”
“The cause of the low level of oxygen was shallow breathing,” Tobin said. “Small breaths. Small tidal volumes. Shallow breaths that weren’t able to carry the air through his lungs down to the essential areas of the lungs that get oxygen into the blood and get rid of the carbon dioxide.”
Attorneys for the state and Chauvin’s lawyer, Eric Nelson, have dueled about whether the drugs in his system or Chauvin’s actions caused Floyd’s death.
Much of Tobin’s testimony relied on the physics of Chauvin placing his knee on Floyd’s neck or back area. The placement of the knee itself has been a topic of contention.
Tobin testified that by using physics and mathematical equations, largely centered around the relative weight of both Chauvin and Floyd, the street acted as a “vice” grip, and that Chauvin’s left knee on Floyd’s neck area, combined with his right knee on Floyd’s back and Floyd’s prone position during his arrest, caused Floyd’s lungs to stop expanding and retracting. He also said that Floyd’s hypopharynx – the part of the throat where air passes through – was narrowed during the arrest.
Nelson countered by noting, among other things, that Floyd’s hypopharynx was found to be undamaged during his autopsy.
The Minnesota Sun spoke with Josh Foxworth, an aerospace engineer and physics expert, about Tobin’s testimony. Foxworth is also a former Republican congressional candidate from Texas.
“The doctor’s basic premise was that applying weight to the back of a prone person on concrete lowers their oxygen levels to the point of losing consciousness and then death,” Foxworth said. “He claimed to be able to calculate the weight Chauvin was applying to Floyd as well as Floyd’s oxygen levels. There are multiple problems with this.”
He continued:
First, there are simply too many factors involved in a human being’s body to calculate the weight he is applying from a picture. To assume that it is half just because you see one foot off the ground is a horrendous simplification.
Second, the prosecutor asked the expert about studies which disagreed with the expert’s belief that weight on someone in the prone position lowers their oxygen levels. The expert then stated that these studies were invalid because it is pressure and not force (weight) that matters and that measuring oxygen levels is not the key indicator.
From an engineering standpoint, hearing someone never mention pressure and then jump to it as the primary issue is bizarre. Hearing him talk about oxygen levels for an hour and then dismiss them in tests was also weird.
If pressure was the key metric, then the location of that pressure on the lungs would be even more key and it simply would not be possible for one knee to cut off air to both lungs.
Friday is day 10 of the high profile trial.
Earlier this week, a prominent Black Lives Matter activist promised riots if Chauvin is non convicted of Floyd’s murder.
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Pete D’Abrosca is a contributor at The Minnesota Sun and The Star News Network. Follow Pete on Twitter. Email tips to [email protected].
