NEJM: How long will the real “death” come after the heartbeat stops?

For most of history, stopping the heart has been synonymous with death. The difference between a living person and a dead person declared dead boils down to nothing more than the ability to beat the pulse.

This is a heavy topic, but it is a choice that everyone should face: when the last breath of the loved one is swallowed, how long will the real death come?

For the medical community, the minimum pulseless duration required before organ donation after the circulatory system is determined to be dead has not been fully studied. Therefore, there is no clear boundary for the criteria for determining death.

Recently, this study published in the New England Journal of Medicine (NEJM) may not alleviate our pain when making this decision, but it may allow us to relax a little while experiencing it, and at the same time nurture us Trust in doctors who give hospice care can also help ease the tension between doctors and patients.

In this study, a research team led by the Canadian Intensive Care Trial Group and the Canadian Organ Donation and Transplantation Research Project conducted a survey of adults who died after planning to stop life-sustaining measures in 20 intensive care units in Canada, the Czech Republic, and the Netherlands. A prospective observational study to investigate the incidence and time of their recovery of ECG and pulse activity.

During the 30-minute monitoring of the patient after the death is determined, the clinician observes continuous blood pressure and electrocardiogram (ECG) waveforms to determine whether it is possible to restore heart activity.

They screened a total of 1999 patients, of which 631 patients were included in the study. The purpose of the study was to count cases of dying patients’ hearts returning to activity after the last beating was considered.

With the advancement of science and technology, we now clearly know that not only the heartbeat, but also the various physical signs related to living people, from brain activity to cell metabolism, in fact, they all have their own stopping time, and the length varies. Choosing any one of them to represent the end of life is obviously beyond the work of scientists.

Moreover, reaching agreement on a series of standards representing death goes far beyond academic scope. In the process of organ donation, time is very precious, because tissues are constantly facing the problem of hypoxia.

It is difficult for the families of the deceased who have just fallen into grief to stare at the clock after the death of their loved ones; for the doctors who count the time, this is a test of trust.

Based on the fusion of ruthless facts and culturally sensitive values, people always try to reach a consensus on the definition of “death” that “everyone is happy”.

However, the examination of vital signs and brainstem activity has become very complicated, not to mention clinical examinations. This has led some medical systems to rely on the circulatory system as an indicator of life under certain circumstances.

The exact time for breathing and pulse to disappear is different, but 5 minutes is a widely accepted number. After that, we had to say goodbye to our loved ones, and then the doctor started the organ transplant procedure.

In this study, 480 patients were eligible and had sufficient data, of which 67 (14%) resumed heart activity after a period of pulselessness, and 5 of them were reported by clinicians. The maximum duration of recovery is 4 minutes and 20 seconds.

Among those who experienced a brief recovery of their heartbeat, only five had their heartbeats that the clinician could clearly feel; for the rest, their heart activity must be demonstrated by electrocardiogram (ECG) data.

55 patients recovered their heartbeat activity without a pulse within one to two minutes. The longest time without heartbeat among all patients was 4 minutes and 20 seconds, followed by a brief pulse recovery. On average, this kind of rebirth only lasted a few seconds, and in the end, none of them were able to recover.

Of the 32 patients who agreed to donate their organs, only two recovered their heart activity, once at the 64th second and the other at the 151st second.

Coupled with the measurement of arterial pressure drop and the details of the electrical activity of the heart, these data strongly support the “5-minute rule” of cardiac arrest, at least for those patients who have been dependent on life support systems. For others, more complex measures may be necessary.

In a race against time, predicting the final moments of human life is very important. But knowing expectations can also help family and friends dispel doubts about medical decisions and ease the doctor-patient relationship. After all, this is a matter of life and death.

Paper link:

https://www.nejm.org/doi/full/10.1056/NEJMoa2022713

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