Study Tracks How Heart Can Struggle To Restart As Death Unfolds

When life-sustaining treatments are withdrawn in a critically ill patient and the heart has stopped pumping blood, the heart can appear to briefly restart itself in 14% of patients, according to a new study that was undertaken to confirm when a patient can safely be declared dead and organs can be harvested for donation.

The analysis, reported in The New England Journal of Medicine, used electrocardiograms and blood pressure measurements to assess the current practice of typically waiting 5 minutes after the last heartbeat before declaring death.

Of the 631 patients who were tested, the longest it took for any patient's stopped heart to briefly show signs of life again was 4 minutes and 20 seconds. And after a few beats, that heart stopped for good.

"There were a lot of stories about people coming back to life after being declared dead, and we were worried that that impacted people consenting to organ donation and prevented medical centers from offering donations," chief author Dr. Sonny Dhanani of Children's Hospital of Eastern Ontario told Reuters Health in a telephone interview. "We thought we should confirm this window of 5 minutes of flatlining before recovery of organs."

​

Their evidence suggests that sporadic electrical activity is not uncommon in a heart after it stops, doctors monitoring dying patients should look for it, and if they see it, the 5-minute death clock should be restarted.

Dr. Dhanani said the results were both surprising and reassuring.

"The surprising part was that the transient resumption of cardiac activity occurred. When we looked at waveforms beat by beat, we found this happened in 14% of our cases. That's higher than I thought. But the reassuring part was that the longest resumption happened at 4 minutes 20 seconds, which is below our standard," he said.

The important part is that "these events were very short lived and I was reassured that nobody actually came back to life," said Dr. Dhanani. "Everybody in the study died and there was no evidence of regaining consciousness. That's really important when it comes to donations and someone being a donor. That's what worries some people a lot."

There's been no universally-acknowledged time for determining circulatory death. The waiting periods for harvesting after the heartbeat has ceased have ranged from 2 to 10 minutes. Five minutes is the usual standard. In no case involving a would-be organ donor where the monitors are watch carefully has the patient regained consciousness or survived to leave the hospital.

The new study, known as DePPaRT for Death Prediction and Physiology after Removal of Therapy, was done at 16 sites in Canada, three in the Czech Republic and one in the Netherlands.

The doctors who were attending the patients noticed a resumption of heart activity in only 1% of the cases. When the research team went back and scrutinized the data, they saw a resumption of electrical activity in the heart in 14% of the cases.

In a few cases, after the initial burst of activity, the heart went quiet a second time and then showed another short burst before finally falling still.

In all, there were 55 resumptions in 45 patients. The pauses ranged from 64 seconds to nearly 3 minutes.

"The median duration of resumed cardiac activity was 3.9 seconds," the team reported, although the range was broad: 1 second to 13 minutes and 14 seconds.

The findings mean that when life support is withdrawn, "all these patients should have all the monitors on and they should be watched continuously for those full 5 minutes before the determination of death," said Dr. Dhanani. "And if there is a resumption of circulation or blood pressure, they should restart the clock and wait another 5 minutes. Then we can be reassured that death is permanent."

He said stories about patients coming back to life are probably due to physicians not monitoring the heart carefully and being caught by surprise by final bursts of activity.

"I think there's going to be zero controversy about this," said Dr. Dhanani, chief of critical care at Children's. "I think doctors are going to be reassured by this. This is the information people have been hoping for to add comfort to the donation process."

—Gene Emery

Source