An Epic Discovery
General anesthesia is among the most important advances in medicinal pharmacology. Prior to the discovery of general anesthesia, surgery was always a last-resort therapy and patients suffered incredible pain. Various drugs, including alcohol and opium, were used to reduce this suffering, but these were mostly inadequate or contributed to morbidity and mortality. In the early 19th century, a number of surgeons and dentists, including Crawford Long and Horace Wells began using nitrous oxide and diethyl ether during painful procedures. W.T.G. Morton, a dentist, successfully demonstrated the use of ether to block surgical pain and awareness at the Massachusetts General Hospital on October 16, 1846 (Figure 1). Word of his achievement spread rapidly around the civilized world and the use of ether, nitrous oxide, and later chloroform for inducing "anesthesia" became common during surgery, dental procedures, and childbirth. Modern anesthetic drugs are used with increasing frequency to help patients during surgery or other painful diagnostic and therapeutic procedures, or when movement must be minimized for a prolonged period (for example, in children during certain radiology exams).
Figure 1: Prosperi painting depicting Morton's demonstration of anesthesia at MGH in 1846. The models for this painting are MGH physicians, including Warren Zapol, Chief of DACCPM, as Morton (holding a glass device used to deliver ether).
Difficult to Define
General anesthesia is difficult to define. Appropriating a quote from another field, most anesthetists don't know what general anesthesia is, but they know it when they see it. This is an inadequate definition for research, and a debate has progressed in the literature for decades, with a consensus yet to emerge. For a more detailed review of general anesthesia and mechanisms see link at right.
A loose definition of general anesthesia is a reversible pharmacologically-induced state where a patient (or other animal) is unresponsive to a wide range of stimuli from benign to noxious. This definition has the virtue of providing experimentally quantifiable stimulus-response tests, once we specify the stimuli and the responses. In clinical anesthesia, the major goals of an anesthetic include providing unconsciousness (lack of awareness), amnesia, and immobility (lack of movement in response to pain). Other clinical considerations include blocking adrenergic reflexes (tachycardia and hypertension) and providing analgesia. These clinically beneficial effects are summarized in Figure 2.
Campagna et al. New England Journal of Medicine 2003;348:2110
Back to Forman Lab Main Page