Suspended animation trialled in emergency medicine

surgery

A ground-breaking new trial held at the New York Academy of Sciences is testing the viability of putting people into a state of suspended animation to improve their chances of survival after sustaining catastrophic injuries

The procedure, emergency preservation and resuscitation (EPR), involves rapidly cooling the brain to around 10°C to 15°C by replacing a patient’s blood with ice-cold saline solution. Though the outcomes of the trial are yet to be revealed, the process is believed to be especially useful for improving the survival rates of victims of stabbings or shootings.

So, let’s take a look at the science behind the procedure: when an individual loses a significant amount of blood through an injury, the heart can become compromised and stop pumping blood and oxygen around the body. A lack of oxygen travelling to the brain can result in severe brain damage, and due to these factors, victims of stabbings or shootings typically have less than a five-per-cent chance of survival. Using the EPR method all but stops patient brain activity and dramatically lowers the temperature of the body. This, in turn, slows the chemical reactions in a patient’s cells, meaning that they require less oxygen – and so a patient’s risk of irreversible brain damage significantly decreases.

With this objective in mind, the University of Maryland School of Medicine team, led by Samuel Tisherman, have begun trialling the EPR procedure – a move that was approved by the US Food and Drug Administration, which also ruled that patient consent was not necessary, as there are currently no alternative treatments available and patients’ injuries are otherwise likely to be fatal.

Tisherman’s goal is to demonstrate that EPR can drastically improve the patient’s chances of survival by giving the surgical team a milestone two hours to treat the patient, compared to the usual five minutes a team has before irreversible brain damage occurs. The trial will compare the outcomes of 20 patients who receive either standard emergency care or EPR.

Studies in EPR have previously been carried out on pigs with acute trauma, who, it transpired, could be cooled for three hours, stitched up and resuscitated. “We felt it was time to take it to our patients,” said Tisherman in an interview with New Scientist. “Now we are doing it and we are learning a lot as we move forward with the trial. Once we can prove it works here, we can expand the utility of this technique to help patients survive that otherwise would not.”

However, there are still complications that need to be carefully addressed – namely, within the resuscitation process. Upon warming a patient back to 37°C, chemical reactions can damage a patient’s cells, an effect known as reperfusion injuries. Still, the benefits of completing the trial will be astronomical for the medical world, and we look forward to reporting on the findings.

“I want to make clear that we’re not trying to send people off to Saturn, we’re trying to buy ourselves more time to save lives,” said Tisherman.