Recent Massachusetts General Hospital investigations into the neurobiology underlying the effects of general anesthesia have begun to reveal the ways different anesthetic agents alter specific aspects of the brain’s electrical signals, reflected by EEG (electroencephalogram) signatures.
While those studies have provided information that may lead to improved techniques for monitoring the consciousness of patients receiving general anesthesia, until now they have been conducted in relatively young adult patients.
Now a series of papers from Mass General researchers is detailing the differences in the way common anesthetics affect the brains of older patients and children, findings that could lead to ways of improving monitoring technology and the safety of general anesthesia for such patients.
“Anesthesiologists know well that the management of patients age 60 or older requires different approaches than for younger patients,” says Emery Brown, MD, PhD, of the MGH Department of Anesthesia, Critical Care and Pain Medicine.
“The doses required to achieve the same anesthetic state in older patients can be as little as half what is needed for younger patients. Explanations for that difference have focused on age-related declines in cardiovascular, respiratory, liver and kidney function, but the primary sites of anesthetic effects are the brain and central nervous system.”
Patrick Purdon, PhD, also of the Mass General Department of Anesthesia, Critical Care and Pain Medicine, adds, “We know even less about how anesthetic drugs influence brain activity in children, and the current standard of care for assessing the brain state of children under anesthesia calls only for monitoring vital signs like heart rate and blood pressure.
This lack of knowledge is especially troubling, given recent studies suggesting an association between early childhood surgery requiring general anesthesia and later cognitive problems.”