Intensive care specialist David Galler remembers the time he tried and failed to save a New Zealander restrained in the same way that caused the death of American man George Floyd.

Content warning: This article contains distressing descriptions of police violence and death.

Thirty years ago, soon after I started my intensive care career, I was urgently called to the emergency department to help a young man brought in by police. At the time the story was sketchy but later more details emerged. The young man in question had recently been under the care of mental health services. Over the days prior to this incident, he had become more agitated and on that day was seen on the rooftop of his house in a distressed state. People who knew the man, including mental health care workers, came to assist, tried to talk him down, but they were unsuccessful. In the end police were called. They too tried their best to coax him down but to no avail.

Several hours later police did get the man off the roof. I never found out exactly how. But I do know that the man remained agitated and anxious and was restrained. The police cuffed his hands behind his back and laid him down on his front in the back of a police car to take him to an acute psychiatric facility. During that journey, one officer pinned him down with a knee in the small of his back.

It became clear that the young man had stopped breathing so the police diverted to our emergency department.

On arrival, he was in cardiac arrest, deeply unconscious, not breathing and with no pulse. He received immediate resuscitation: chest compressions were begun, he was intubated and ventilated and he was given several rounds of intravenous adrenaline.

After 10 or so minutes his heart started and with some help from an ongoing drug infusion, it rapidly returned to a normal rhythm and rate with a good blood pressure.

We were pleased, but of course anxious about the consequences of such a prolonged period of no blood flow and no oxygen being delivered to the tissues, especially to the brain. The heart behaves quite differently: it takes a lot to stop it and not much to start it. We know that if has stopped as a result of asphyxia the lack of oxygen was prolonged and severe – and that the brain will certainly be badly damaged.

Over the next few days we supported this young man with all our means but in the end, as we suspected, he showed no sign of recovering and he subsequently died.

An inquest followed and attention turned to an already well described situation called positional asphyxia or postural asphyxia, also the most likely cause of George Floyd’s death in the US. In that case, the results of two postmortems have now been released. Both of them describe a similar scenario to the one I recall: a man with his wrists handcuffed behind him, lying prone, a knee on his neck – but also a knee in the small of his back pinning him to the ground, a position which we know causes fatigue of the most important of our respiratory muscles, the diaphragm.

As that situation persisted, Floyd’s breathing would have become increasingly inadequate, carbon dioxide levels would have risen sharply in his blood and eventually he would have stopped breathing. According to one of the postmortems, both the compression of Floyd’s neck and the pressure on his back caused his death.

The postmortem conducted by the county’s medical examiner found that Floyd had pre-existing cardiac disease – a common finding in many postmortem examinations – implying that this also contributed to his death.

The medical and police literature has reported cases like this on many occasions since the tragedy I witnessed 30 years ago. We absolutely know what can happen when people are restrained in the way George Floyd was, and so should police forces everywhere. It is inconceivable to me that police could be ignorant of the consequences of using this method of restraint and absurd to think that could form part of any credible defence for those accused of causing harm by it.

The Spinoff approached NZ Police with questions about their current restraint policies but they declined to comment.