Although questions about what happens to us when we (or, more precisely, our physical bodies) die are mostly metaphysical, rather than scientific, a new study, published in The Canadian Journal of Neurological Sciences, had recently fanned the flames by showing that brain activity may persist for up to 10 minutes after death.
In clinical terms, as soon as the heart stops beating, as measured by an electrocardiograph (ECG), and there is no detectable breathing, a patient is pronounced dead.
The study, led by the University of Western Ontario, Canada, had measured the cardio-circulatory, arterial blood pressure (ABP) and oxygen saturation outputs of four patients in a Canadian intensive care unit before, during and after the withdrawal of life-support.
As predicted, electroencephalographic (EEG) activity had ceased well before both the ECG and ABP flatlined in three of the subjects, meaning there was no detectable brain activity even before the threshold of clinical death.
In one patient, however, there was a burst of delta brain waves, commonly associated with deep sleep, as many as 10 minutes after cardiac arrest had occurred. This could mean that people’s final moments on this side of “the divide” are highly individual experiences.
Past research, conducted on rats, had suggested that brain function in terminal subjects goes out with a bang in a single surge that happens shortly before clinical death – an interesting finding that sparked a lot of speculation regarding the nature of consciousness, although it was later found to have no parallel in humans.
One way of making sense of the new data would be to assume a technical malfunction, although none was detected by the researchers themselves:
“It is difficult to posit a physiological basis for this EEG activity given that it occurs after a prolonged loss of circulation. These waveform bursts could, therefore, be artefactual in nature, although an artefactual source could not be identified.”
The small sample size and the fact that all of the subjects were gravely ill and heavily medicated at the time of the study are more reasons for scepticism.
However, as the research team noted in their paper, their findings are, if nothing else, intriguing and could potentially have serious “medical, ethical, and legal concerns” as they pertain to the practice of organ donation.