Physicians began to notice a strange phenomenon at the start of the pandemic in March 2020: Some COVID-19 patients who required ventilation took weeks to fully regain consciousness after being taken off the machines and anesthesia, with no signs of brain damage when they recovered.
"We started to get all these weird consults," Nicholas Schiff, MD, a neurologist at New York City-based Weill Cornell Medicine, told The New York Times. "People have been liberated from anesthesia after surviving COVID-19, and they're not waking up."
Since then, Dr. Schiff and his colleagues have been trying to explain this phenomenon. In a paper published Nov. 11 in PNAS, Dr. Schiff and Emery Brown, MD, PhD, a computational neuroscientist at the Massachusetts Institute of Technology in Cambridge, Mass., suggest an answer: The combination of the virus and anesthesia sends the brain into a prolonged state of quiet, similar to how freshwater turtles survive the winter in ice.
"If it's right, it can teach us how to protect and preserve the brain better," Dr. Schiff said.
In their quest to find an answer, researchers learned that turtles prepare their brains for cold winters by flooding them with a chemical called GABA, which quiets the activity of neurons so they don't waste energy-producing electrical pulses as the turtles spend winter months barely breathing in frozen mud. Dr. Schiff and Dr. Brown proposed that in response to GABA-like sedatives that patients on ventilators receive and the stress of the SARS-CoV-2 virus, human neurons similarly move into a quiet mode that doesn't require much oxygen to survive.
If correct, researchers hope the hypothesis could lead to new ways to prevent brain tissue damage after strokes, heart attacks or traumatic brain injuries.