Automated Anesthesia Promises to Reduce Cost and Save Lives

Not only would it reduce cost, it would also minimize errors thus saving lives!

That's what Massachusetts General Hospital (MGH) has done by creating a computer-controlled general anesthesia delivery system designed specifically for putting patients with severe head injuries or persistent seizures into medically-induced coma. It does the traditional adjusting of drug infusion to maintain a deep and safe state of unconsciousness, without utilizing nurses and other health professionals to constantly monitor the patient's brain activity. And since it uses computers, the monitoring and delivery is more precise and efficient. So that means fewer mishaps for less cost!

The MGH researchers, together with colleagues from Massachusetts Institute of Technology (MIT), have reported successfully testing their approach on animals. "People have been interested for years in finding a way to control anesthesia automatically," says Emery Brown, MD, PhD, of the MGH Department of Anesthesia, Critical Care and Pain Medicine; the Warren M. Zapol Professor of Anesthesia at Harvard Medical School; the Edward Hood Taplin Professor of Medical Engineering and Computational Neuroscience at MIT; and senior author of the report. "To use an analogy that compares giving anesthesia to flying a plane, the way it's been done is like flying a direct course for hours or even days without using an autopilot. This is really something that we should have a computer doing."

Anesthesiologists have had computer-assisted technologies for many years, but no FDA-approved system exists that completely controls anesthesia administration based on realtime monitoring of a patient's brain activity. Brown notes that until this study no one had demonstrated the level of control required for a completely automated system. Medically-induced coma requires keeping patients at a precise level of brain activity for several days -- and this new system, called a brain-machine interface, appears to offer exactly that.

This research is part of a long-term project investigating the physiological basis of general anesthesia. Brown's team at MGH and MIT has identified and studied patterns of brain activity reflecting various states of anesthesia. One of the deepest states called burst suppression is characterized by an electroencephalogram (EEG) pattern in which brief periods of brain activity – the bursts – are interrupted by stretches of greatly reduced activity that can last for seconds or longer. When patients with serious head injuries that cause a buildup of pressure within the skull, or those with persistent seizures, are put into a medically-induced coma to protect against additional damage, the goal is to maintain brain activity in a state of burst suppression.

Brown's team adapted programs that they had previously developed to analyze the activity of neurons. These were algorithms designed to read and analyze an EEG pattern in real time and determine a target level of brain activity -- in this case the stage of burst suppression. Based on that target, a computer-controlled device adjusts the flow of an anesthetic drug to achieve the desired brain state, and real-time analysis of the continuous EEG readings is fed back to the system to insure that the actual readings stay on target -- this is what's known in the world of Computer Numeric Control (CNC) as a closed-loop system.

"As far as we know, these are the best results for automated control of anesthesia that have ever been published," says Brown. "We're now in discussions with the FDA for approval to start testing this in patients." And the MGH has also applied for a patent for the technology.

Reducing costs and saving lives! Thanks to technology! Thanks to human innovation!