When is dead actually dead? New research suggests death might not be an instantaneous "lights off" moment, but a comparatively slow and wandering process.
A new study, published in the New England Journal of Medicine this week, has set out to answer the age-old question of when death occurs by studying the final moments of hundreds of dying patients in intensive care units. Just as previous research has suggested, they found that the act of dying is somewhat of a process. Even once the cogs have started turning and death is certain, the heart can continue to spark with activity several times.
For the study, an international team of scientists closely monitored the vital signs of over 600 seriously ill patients while they were being taken off life support with the permission of their family. The key finding was that the heart can often stop and restart several times during the dying process before it totally stops for good.
Out of 480 patients, 67 people (14 percent) underwent periods of pulselessness followed by the resumption of cardiac activity - the heart was effectively stopping and restarting in flutters. With most patients, the heart activity stopped and restarted within a matter of seconds. However, one person experienced zero pulses for 4 minutes 20 seconds before heartbeats returned, before they eventually died.
"To do this, we had to go into ICUs and monitor people as they were dying. This is a very personal experience. And here we were collecting data, sending it to a server, downloading it, and having people review the vital signs... how things stopped and if they restarted. People were worried. Some physicians didn't want to do it. Some researchers felt uncomfortable," Dr Sonny Dhanani, lead study author, Chief Critical Care at the Children's Hospital of Eastern Ontario, and Associate Professor at the University of Ottawa, said in a statement.
The study is part of Death Prediction and Physiology after Removal of Therapy Study (DePPICt) research program led by Dr Dhanani, which aims to gain a deeper understanding of peoples’ final moments and present new opportunities for organ and tissue donation.
The question of when death occurs is not just an interesting thought experiment, but it also has some very important implications in the real world, most notably in the field of transplants and organ donation. After all, doctors don’t want to remove a heart if the process of dying is still unfolding. The findings of this new study affirm the current standard to wait for at least 5 minutes after the heart stops before determining death and proceeding to organ donation.
However, make no mistake, the researchers were keen to point out that their study does not hint that it may be possible to bring someone back to life once the “dying process” has begun.
“The term 'autoresuscitation' used in this context may be a misnomer if it is interpreted as a return to viable life. In the current study, no patients who had a resumption of cardiac activity regained consciousness or survived,” the study concludes
“These transient resumptions of cardiac activity after withdrawal of life-sustaining measures are not equivalent to autoresuscitation as observed after terminated CPR [Cardiopulmonary resuscitation], in which returns of circulation have rarely resulted in return of consciousness and survival."