Who is Derek Chauvin Trial Expert Witness Dr. Martin Tobin?
Dr. Martin Tobin, an Irish pulmonologist and physician, was recalled today to the Derek Chauvin trial by prosecutor Jerry Blackwell to rebut the testimony of Dr. David Fowler, a defense medical expert witness.
Dr. Martin Tobin, a native of Co Kilkenny now based in the Chicago area, was briefly recalled by the prosecution today, April 15, to “knock down” defense witness Dr. David Fowler’s theory that carbon monoxide poisoning from a squad car’s exhaust might have contributed to George Floyd’s death, the Associated Press reports.
On Wednesday, Dr. Fowler testified that the fentanyl and methamphetamine in Floyd’s system, and possibly carbon monoxide poisoning, were contributing factors in Floyd’s death.
Prosecutor Jerry Blackwell briefly recalled Dr. Martin Tobin, who previously gave testimony that George Floyd died due to low levels of oxygen causing brain damage and heart arrhythmia, to the stand on Thursday.
Noting that Floyd was found to have an oxygen saturation of 98 percent, Blackwell asked Dr. Tobin if that tells us anything about what the carbon monoxide content could have been.
Dr. Tobin said: “If hemoglobin is saturated at 98 percent, it tells you all there was for everything else is two percent, so the maximum amount of carbon monoxide would be two percent.”
Blackwell said: “So in other words, as to the statement that his [Floyd’s] carboxyhemoglobin could have increased by 10 to 18 percent, in your view, that’s not possible?”
“It’s simply wrong,” Dr. Tobin said, adding that Floyd’s level was at most 2 percent, which is “normal.”
Education and Career
Dr. Tobin, who is a pulmonary and critical care medicine physician and professor based at Loyola University Medical Center in Illinois, was educated at University College Dublin and did his residency through Trinity College Hospitals in Ireland.
Prior to Dr. Tobin being recalled, the defense rested its case on Thursday. Derek Chauvin invoked his fifth amendment right to not testify,
Closing arguments in the Derek Chauvin trial are set to begin Monday, April 19. Afterward, the jury will begin its deliberations.
Dr. Martin Tobin Background
Dr. Tobin was born in rural Ireland, went to medical school in Dublin. He is a physician in pulmonary and critical care medicine at Edward Hines Jr. V.A. Hospital and Loyola University Medical Center in the Chicago area and has been practicing for more than 40 years, but this was his first time testifying in a criminal case.
Dr. Martin Tobin Chauvin Trial
Dr. Tobin said that Mr. Chauvin and other police officers had restricted Mr. Floyd’s breathing by flattening his rib cage against the pavement and pushing his cuffed hands into his torso, and by the placement of Mr. Chauvin’s knees on his neck and back.
The doctor pinpointed the moment he said Mr. Floyd had shown signs of a brain injury, four minutes before Mr. Chauvin lifted his knee from his body.
“The main forces that are going to lead to the shallow breath are going to be that he’s turned prone on the street, that he has the handcuffs in place combined with the street, and then that he has a knee on his neck and then that he has a knee on his back and on his side,” Hines said. “All of these four forces are ultimately going to result in the low tidal volume, which gives you the shallow breaths that we saw here.”
The prosecution has argued that George Floyd died from Derek Chauvin kneeling on his neck for more than 9 minutes. Tobin said he was asked to review medical records and watch videos related to the case. He said he believed Floyd died of a “low level of oxygen” that caused damage to his brain and also led his heart to stop beating.
Dr. Tobin disputed a defense assertion that an elevated level of carbon dioxide found in Mr. Floyd’s blood was the result of fentanyl use, attributing it instead to the length of time he was not breathing before he was given artificial breaths in an ambulance.