AANA journal course: update for nurse anesthetists--carbon monoxide poisoning: role of the anesthesia machine's carbon dioxide absorption system.

Carbon monoxide is a colorless, odorless, and tasteless gas that, when inhaled, is toxic to humans. In 1965, Middleton reported the detection of carbon monoxide in the closed anesthetic circuits of patients undergoing surgery. In recent years, anesthesia providers from at least four American hospitals have reported instances of intraoperative carbon monoxide poisoning in anesthetized patients undergoing surgery. Although no deaths were associated with these incidents, carboxyhemoglobin levels ranged from 8.5% to 32%. In virtually all reported cases, the incidents occurred in surgical suites that had not been used for at least 2 days. This facet of the phenomenon advanced the theory that a slow chemical reaction, probably involving soda lime or barium hydroxide lime, was responsible for the liberation of carbon monoxide within the anesthesia circuit. Recent research has attributed this generation of carbon monoxide to the degradation of volatile anesthetic agents by desiccated carbon dioxide absorbents. Although carbon monoxide poisoning of patients undergoing anesthesia with volatile anesthetics is probably a rare occurrence, it is a potential problem for all anesthesia providers.