Healthy Discoveries: Going under: anesthesia closer to coma than sleep

Healthy discoveries

U.S. researchers said, in results that could lead to better therapies for coma and better anesthesia that instead of a deep sleep, general anesthesia is more like a reversible drug-induced coma.

Dr. Nicholas Schiff of Weill Cornell Medical College in New York, who worked on the study with Dr. Emery Brown of Massachusetts General Hospital and Dr. Ralph Lydic of the University of Michigan said that General anesthesia is pharmacological coma, not sleep.


Their results, published in the New England Journal of Medicine, represent a three-year research of the similarities and dissimilarities of sleep, coma and anesthesia.


They said while doctors and patients usually describe general anesthesia as going to sleep, there are significant differences between the states, with only slightly of overlap between the deepest states of sleep and the very lightest phases of anesthesia.


While sleeping commonly involves moving through a series of phases, in general anesthesia, patients are typically taken to a specific phase or state and kept there during the surgery. This phase most nearly looks like a coma.


"The brain is becoming very, very quiet. The activity of the neurons is being dampened dramatically," Schiff said in a telephone interview. "That is also true in coma."


Schiff, an expert in coma recovery, said while no two brain harms are similar, studying the way people come out of anesthesia could be used as a model for predicting the stages of emerging from a coma.


"Although recovery from anesthesia is much quicker, there are cues that some of the circuit mechanisms have some overlap," he said.


That could lead to monitoring tools and diagnostics to appraise what stage of recovery a person with a coma is in, and it could be used to develop new strategies to help doctors bring patients back to consciousness.


Schiff said that Knowing more about the brain circuit mechanisms may also help researchers develop drugs to tweak specific brain circuits.


Brown, an expert in general anesthesia, said in a statement that and the study should lend new insight into understanding general anesthesia.


"Anesthesiologists know how to maintain their patients in the states of general anesthesia securely, but most aren't familiar with the neural circuit mechanisms that permit them to carry out their life-sustaining work," he said. 

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