The Big Sleep

Trials have begun using suspended animation to help critically ill patients

Read my latest piece for The Economist in full below or by following this link.

THE picture that is immediately brought to mind by talk of suspended animation is usually one of the crew of Nostromo waking up from their deep sleep after a long journey through space in the 1979 movie “Alien”. Yet this gives a somewhat misleading impression of Samuel Tisherman’s new trauma technique, which uses an innovative rapid-cooling procedure to suspend life. Dr Tisherman and his colleagues prefer to call it emergency preservation and resuscitation (EPR). The first trials using EPR on people are now being held at the University of Pittsburgh Medical Centre Presbyterian Hospital. Early next year more trials are planned at the Shock Trauma Centre, part of the University of Maryland Medical System.

Dr Tisherman’s EPR process, developed with the help of $800,000 from the Department of Defence, is mostly about resurrection. The idea at this stage is to use equipment like the catheters and pumps that can be found in any trauma centre to suspend the life of critically injured people in order to buy more time for surgeons to try to save them.

EPR works by lowering the patient’s body temperature and replacing their blood with a cold saline solution. Hypothermia is already induced in patients to help reduce bleeding during some surgical procedures. But cooling the body down so that it goes into a suspended state has not been tried before. The idea came from observations that people have been resuscitated having stopped breathing for half an hour or more after falling into icy water.

Research on EPR was begun in Pittsburgh by the late Peter Safar and Dr Tisherman. Dr Safar, who died in 2003, was a pioneer of cardiopulmonary resuscitation, known as CPR. Dr Tisherman carried on with the work and, after successful experiments on animals, got approval for human trials. The Food and Drug Administration decided the procedure was exempt from informed consent, as patients would be too ill to give it themselves and might benefit because they were likely to die as no other treatment was available. For now, the patient has to be between 18 and 65 years old, have a penetrating wound, such as a knife, gunshot or similar injury, suffer a cardiac arrest within five minutes of arrival in the hospital and fail to respond to usual resuscitation efforts.

It is one thing to carry out EPR in an ordered laboratory but quite another to do it in a busy emergency centre. The first challenge is for medical staff to insert a catheter into arteries to flush all the blood out of the patient. The blood is replaced by giving the patient 2-3 litres a minute of saline solution at a chilly 10°C. The procedure has to be completed within 20-30 minutes to have a chance of working.

Once the patient is in a suspended state, a surgeon will try to repair the wound within an hour to prevent any bleeding when blood circulates again. Finally, a heart-lung bypass machine is used to restart the blood flow and warm the patient up. The medical team will try to keep the patient slightly cooler than normal, at around 34°C, for 12 hours. Then an attempt will be made to bring the patient round. In animal experiments the heart did not always start by itself.

If the human trials are successful, the aim is to take the technique out into the field. For example, a paramedic might be able to use EPR to put a dangerously ill patient into a suspended state until they can be rushed to a specialist hospital. Such a system could also be used on the battlefield to evacuate injured soldiers. Portable EPR systems will depend on the development of new technology to miniaturise and automate equipment. That might be possible with, for instance, smart catheters that use ultrasound to help non-specialists guide them correctly into blood vessels. It is another example of science fiction becoming science fact.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s