Ruminations: Delineating Death

"However, transient resumption of cardiac activity did occur, which suggests that the physiologic processes of somatic [bodily] death after removal of life-sustaining measures occasionally include periods of cessation and resumption of cardiac electrical and pulsatile arterial activity."
"With the heart being an organ that is strong and robust, the idea that it pauses before finally stopping is actually quite reasonable, physiologically, and probably not unreasonable for us to expect it does so."
DePPaRT Study, New England Journal of Medicine

Dr. Sonny Dhanani Photo: Jean Levac/Postmedia

"People don't die right away."
"One of the fundamental principles of organ donation is that you must be dead to donate. We wanted to provide scientific evidence ... that one is dead before donation."
"I think if doctors and nurses are aware that this [cardiac activity restarts] can happen, that they'll expect it, they'll counsel families."
Dr.Sonny Dhanani, critical care physician, chief, critical care, Children's Hospital of Eastern Ontario, Ottawa

"It's not unusual to see a flatline on the electrical tracing of the heart, followed by electrical beats, or a minute or so where there was no heartbeat, and then a heartbeat, again."
"But this is why this research was important. It helped confirm that this event can occur, but it also provides reassurance [under the current five-minute rule that] the duration of time is satisfactory."
"That somebody, when they have their organs recovered, is truly dead."
Dr.Christopher Doig, head, critical care medicine, University of Calgary

"With the heart being an organ that is strong and robust, the idea that it pauses before finally stopping is actually quite reasonable, physiologically." Photo by Getty Images

When life support is withdrawn, the process commences with the heart contracting with vigor as it is gradually starved of blood and oxygen while muscle cells begin to die off, and blood pressure drops; all of which contribute to the heart going into cardiac arrest. No longer does the brain receive blood and oxygen, nor do other organs. All the while monitors inform doctors in attendance; the catheter in the radial artery to measure blood pressure, and five sticky pads with electrocardiogram leads on chest and abdomen as second-by-second monitors record signals of a pulse, blood pressure or electrical heart activity. These monitors measure death.

Dr.Dhanani and co-authors of the study they have named DePPaRT -- Death Prediction and Physiology after Removal of Therapy study -- as morbidly serendipitously contrived a naming as can be imagined -- monitored heart rate, blood pressure and oxygen saturation levels in over 600 people who had undergone the withdrawal of life support. From the very time that breathing tubes and heart-supporting medications were withdrawn to a full thirty minutes following death-declaration, they were fixated on their goal; to define when death occurs.

In 14 percent of instances the researchers discovered the heart stopped and then spontaneously restarted in brief bursts of cardiac activity to evince a heart beat, a pulse. This phenomenon occurred between 6.4 seconds and four minutes and 20 seconds, intervals identifying the variance in presentations following 'pulselessness' in various dying patients. From among the entire group of some 600 subjects, none among them regained consciousness or survived beyond this end-of-life event, though the rare occasion when some do is well known.

Among all those studied no circulation restarted, and when the heart did finally stop, it was forever. None among them experienced their heart spontaneously begin beating again and continue to beat as has occurred rarely in those who have been pronounced dead once CPR ceased. What the study succeeded in doing was to validate the "no touch" rule currently in use in Canada; the obligatory five-minute wait once the heart stops, prior to definitively declaring death leading to the harvesting of the heart for an organ donation. Elsewhere, such protocols of wait-times vary from two to ten minutes.

There are over four thousand people awaiting a heart transplant to save their futures, in Canada. Dr.Dhanani's concern revolved around an lack of accepted uniformly of organ donations linked to fears of "stories, unrelated to organ donation, about people coming back to life following a determination of death." And that determination can be decided as brain death when medical and legal death is accepted while the heart still beats, or circulatory death; the irreversible loss of heart function. Some 30 percent of organs derive from circulatory death donors, the remainder from brain death.

A precise choreography of response-and-action takes place in sequence with organ donation where doctors wait the minimal time for certainty that circulation loss is permanent before declaring death, bearing in mind that time is of the essence and not a moment longer must lapse before that declaration to ensure that the organ does not deteriorate from blood flow stoppage.

Sixteen adult ICUs in Canada, three in the Czech Republic and one in the Netherlands represented sites of study involving 631 patients whom a catastrophic illness or accident had stricken and where grieving families had agreed to their loved ones' vital signs being recorded for study purposes after removal from life support. In the study, death following cardiac arrest was declared from one minute following withdrawal of life support to as long as 11 days, five hours and 54 minutes with the median time being 60 minutes.

Unassisted resumption of heart activity was detected in 13 people by doctors and staff in the ICU. The researchers studying the data provided by the monitors identified a stop, and then a restart in 67 of 480 people using complete waveform data. A total of 30 people showed a return of cardiac activity in zero to three percent after life support withdrawal, with the longest duration of no pulse before heart activity resumed at one minute and 42 seconds. Another surprise for the researchers was the realization that electrical activity of the heart can continue for minutes once blood pressure ends.