Emery Brown, anesthesiologist, Professor of Computational Neuroscience at MIT, and Co-Director of the Harvard-MIT Division of Health Sciences and Technology, unveiled the surprising truth about exactly what happens to your brain under anesthesia and what it suggests for understanding the brain and improving treatment.
What motivated you to speak at TEDMED?
When I had the honor to be invited, I realized that it would be a great opportunity to educate the public on general anesthesia and other practices in anesthesiology. The state of general anesthesia is viewed as a blackbox process by the field of anesthesiology, other fields of medicine and the general public. I was motivated by the importance of bringing an informed, modern perspective on general anesthesia to the lay public, the medical field, neuroscientists and anesthesiologists.
Why does this talk matter now? What impact do you hope the talk will have?
General anesthesia is viewed as a mystery both within as well as outside of medicine. After nearly 170 years of administering anesthesia in the United States, how anesthesia works is still considered as unknown and by some as unknowable. My research can change this because we can teach medical and lay communities that anesthesia works primarily through the production of oscillations that disrupt the way regions in the brain communicate. This disruption of communication is how the drugs make patients unconscious. These oscillations are readily visible in the EEG patterns of patients under general anesthesia. Different anesthetic drugs produce different patterns. The EEG patterns differ because different anesthetics bind to different targets in the brain and therefore produce oscillations in different circuits. All of these patterns are much larger and highly organized than the awake EEG or the EEG of people who are asleep. Therefore, anesthesia caregivers can learn to read these patterns and know whether a patient is appropriately unconscious to undergo surgery. Reading the EEG to monitor the brain states of patients under general anesthesia can be used to eliminate the frightening problem of awareness (waking up paralyzed). Dosing of anesthetic drugs can be more carefully titrated and the incidence of postoperative cognitive dysfunction and delirium will likely be reduced.
General anesthesia is a profound drug-induced reversible coma. A patient has to be in a state of coma, i.e. being completely insensate and unaware, in order to tolerate the traumatic insults required to execute most surgical procedures. Sleep is a natural state of reduced brain inactivation that is necessary for maintaining normal health. Sleep is defined by two primary states; non-rapid eye movement (non-REM) and rapid-eye movement (REM) sleep. The brain switches approximately every 90 minutes between the non-REM and REM states during natural sleep. The EEG under sleep and a person’s behavioral state (being readily arousable) show that general anesthesia is not sleep.
I hope my talk can provide an accessible forum for the lay public to understand, 1) how general anesthesia works, and 2) that this process which is used every day in millions of people around the world should no longer be viewed as a mystery.
Beyond the need to have general anesthesia for surgery and certain diagnostic procedures, the study of general anesthesia from a neuroscience perspective provides an essentially unexplored way to learn about the brain. This study may also lead to new therapies for treating depression, sleep disorders, pain and facilitating the recovery of patients from coma.
What is the legacy you want to leave?
I hope to have taught the public how general anesthesia works and made it possible for the public to understand that anesthesia is not a mystery. I used this knowledge to improve anesthesia care for the thousands of people in the US and the millions of people worldwide who daily receive general anesthesia and sedation to safely and humanely undergo invasive diagnostic and therapeutic procedures.
What’s next for you?
My next step is to change practice and research in anesthesiology. I will be setting up my Center for the Neuroscience Study of Anesthesia at Massachusetts General Hospital, where we’ll work to gain deeper insights into the altered states of arousal created by anesthetics; develop new neurophysiologically based EEG strategies for monitoring the state of the brain under general anesthesia and sedation; teach anesthesiologists and other anesthesia caregivers how to read the EEG in order to understand the brain states of patients receiving general anesthesia and sedation; develop new ways to precisely control the state of general anesthesia and sedation; study ways to rapidly bring patients out of the state of general anesthesia; create all new approaches to producing general anesthesia and sedation that are side effect free, particularly for children and the elderly; educate the medical professional and the public about how general anesthesia works; show that general anesthesia, when viewed from a neuroscience perspective, offers a new and virtually untapped way to learn about the brain; use knowledge gained from studying the brain under general anesthesia to devise new strategies to treating depression, new approaches to producing sleep, treating pain, epilepsy, autism and facilitating recovery from coma.
Any action items you want the viewer of your video to take?
I would appreciate knowing what viewers think about the work. It’s important for everyone to encourage greater funding for study of the neuroscience of anesthesia by federal and private funding agencies. The benefits will go well beyond simply anesthesia care. I also think that it is important that the public encourage the anesthesiology community to put in place guidelines and strategies to use the EEG to monitor the brain states of patients receiving anesthesia care.