An emergency room doctor who tried to avoid wasting George Floyd’s life for 30 minutes earlier than announcing him dead testified on Monday that he believed Mr. Floyd had most likely died of a lack of oxygen, bolstering a central argument of the prosecution.

Dr. Bradford T. Wankhede Langenfeld, who was a senior resident at the Hennepin County Medical Center, testified in court docket that Mr. Floyd’s coronary heart was not beating by the time he arrived at the hospital on that day in May. His testimony adopted these of two paramedics who stated final week that Mr. Floyd’s heart had stopped by the time they arrived to the scene of his arrest. The doctor’s testimony got here on the sixth day of the trial of Derek Chauvin, the former police officer charged with murdering Mr. Floyd.

The doctor stated that, based mostly on the data he had at the time, he thought that oxygen deficiency, generally known as asphyxia, was “one of the more likely” causes of Mr. Floyd’s demise.

Prosecutors had stated Mr. Floyd died of asphyxia, showing to divert from the ruling of the county medical expert who carried out an post-mortem on Mr. Floyd and stated that he had died of “cardiopulmonary arrest.” That time period, prosecutors have stated, is relevant to any demise as a result of it merely implies that a particular person’s coronary heart and lungs have stopped.

Eric J. Nelson, Mr. Chauvin’s lawyer, had recommended that Mr. Floyd’s demise was prompted partially by his underlying coronary heart illness and the fentanyl and methamphetamine that have been present in his system. In response to questions from Mr. Nelson, Dr. Wankhede Langenfeld agreed that many alternative issues — together with taking fentanyl and methamphetamine — might trigger a demise that may nonetheless be thought of asphyxiation.

Mr. Nelson used his questioning to press Dr. Wankhede Langenfeld on the proven fact that naloxone, the overdose-reversing remedy typically generally known as Narcan, was by no means administered to Mr. Floyd. Dr. Wankhede Langenfeld stated that even when Mr. Floyd had suffered an overdose, giving him naloxone would have had “no benefit” as a result of his coronary heart had already stopped.

Dr. Wankhede Langenfeld stated he had considered an overdose as a much less likely trigger of Mr. Floyd’s demise, partially as a result of the paramedics who introduced Mr. Floyd to the hospital had given no indication that he had overdosed.

Dr. Wankhede Langenfeld stated that he had pronounced Mr. Floyd dead after about 30 minutes in the emergency division. Mr. Floyd’s official time of demise is 9:25 p.m.

Jerry W. Blackwell, the prosecutor questioning Dr. Wankhede Langenfeld, used some of his questions to emphasise that Mr. Chauvin and different cops at the scene had not given medical care to Mr. Floyd.

In response to the questions, Dr. Wankhede Langenfeld famous that starting C.P.R. as quickly as attainable was vital for sufferers who have been in cardiac arrest, as Mr. Floyd was. He stated that there’s about a 10 to 15 p.c lower in a affected person’s probability of survival for each minute that C.P.R. shouldn’t be administered.

“It’s well-known that any amount of time that a patient spends in cardiac arrest without immediate C.P.R. markedly decreases the chance of a good outcome,” Dr. Wankhede Langenfeld stated. He famous that the time period “cardiac arrest” means solely that a affected person’s coronary heart had stopped, not that the affected person essentially had a coronary heart assault.

The doctor, who is in his early 30s, earned his medical diploma from the University of Minnesota Medical School in 2016 and had acquired his doctor and surgeon license simply 18 days earlier than May 25, when Mr. Floyd was rushed to the hospital, in keeping with state records.