NIH funded researchers identify and explore different aspects of anesthesia

Anesthesia helps many of us during our lives, whether we need a local painkiller at the dentist, numbing eye drops for laser vision correction or general anesthesia for major surgery. But even though anesthetics have been used in many procedures for more than 150 years, doctors and scientists still don't know exactly how these medicines work in the body.

Researchers funded by the National Institutes of Health have helped identify and explore different aspects of anesthesia. Here are a few things they've learned:

•General anesthesia consists of several components, including sedation, unconsciousness, immobility, analgesia (lack of pain) and amnesia (lack of memory). Drugs can act on these elements separately, enabling anesthesiologists to tailor the regimen to each procedure and patient.

•Anesthetics don't work by acting on fatty molecules in cell membranes, as previously thought. The bulk of the evidence now supports the idea that the drugs target specific protein molecules embedded in nerve cell membranes and interfere with neurotransmission.

•New general anesthetics, both inhaled and intravenous, act quickly and disappear rapidly from the bloodstream, so patients can go home sooner after surgery. Side effects are less common and usually not as serious as they once were.

•Local and regional anesthetics can be used to block specific nerves, offering an alternative to general anesthesia for many procedures and allowing patients to remain conscious and comfortable during surgery.

•Advances in patient monitoring, such as electronic devices that continually display vital signs, have dramatically improved the safety of general anesthesia and make it possible to operate on many patients who were previously considered too sick to undergo surgery.

•The processes of going under and waking up from anesthesia are different. Knowing more about how the brain transitions between conscious and unconscious states could improve our understanding of sleep disorders and states of impaired consciousness such as comas.

•Genetic differences may explain why some people require more anesthetic than others.

Despite these advances in understanding anesthesia, general anesthetics are still among the most dangerous drugs used by doctors, and more localized ones remain difficult to always deliver to the right spot. A key goal of research in this area is to design anesthetics that are more targeted within the body and that are more effective and safer, with fewer side effects.

Research into anesthesia also could reveal more about pain, conditions such as epilepsy and coma, and the nature of consciousness itself.