The Brain Can Survive Longer After Heart Stops Than Previously Thought

Researchers from the Grossman School of Medicine at New York University have discovered that the brain begins to incur irreversible damage over a longer period than previously believed after the heart stops supplying oxygen. Currently, doctors believe this occurs after 10 minutes following cardiac arrest. However, new research sheds more light on the events unfolding during these critical moments, as reported by ScienceAlert.

"While doctors have long believed that the brain incurs irreversible damage roughly 10 minutes after the heart stops supplying it with oxygen, our work has shown that the brain can exhibit signs of electrical activity recovery for a much longer duration during ongoing cardiopulmonary resuscitation," said pulmonologist Sam Parnia.

Researchers utilized an electroencephalogram (EEG) – a device for measuring brain activity – and monitored oxygen levels in the brain during the administration of cardiopulmonary resuscitation. This allowed them to gain insight into what happens in the brain of a person teetering on the edge of life and death.

Out of the 567 patients who participated in the study, 213 had their heart function restored. Of those, only 53 survived to be discharged, and just 28 were healthy enough to partake in further interviews.

The numbers themselves underscore how critical cardiac arrest can be for the human body. At the moment when the heart ceases to maintain its stable rhythm, blood pressure drops sharply, allowing carbon dioxide and other metabolic byproducts to accumulate to toxic levels, preventing precious oxygen from reaching energy-demanding tissues.

Interestingly, despite their hearts not functioning properly, 40% of the surviving patients exhibited normal or near-normal brain activity even an hour after undergoing cardiopulmonary resuscitation. This suggests that the brain may continue to function in a certain mode for much longer than previously believed. However, it's an individualized indicator influenced by various factors.

While this is far from a conclusive finding, hints that the brain still processes signals from the surrounding environment, memories, and emotions during cardiopulmonary resuscitation could provide more insights into how our nervous system prioritizes cognitive functions or copes with the risk of complete shutdown.