Abstract
Nitrous oxide, popularly referred to as "laughing gas" because of its ability to cause euphoria, has been known for almost two centuries.1 By the middle of the 19th century it was being used frequently and successfully as an anesthetic, and it has been widely administered ever since in both hospital operating rooms and dental offices.In the past two decades, epidemiologic studies have shown that serious health consequences may be associated with prolonged exposure to low levels of nitrous oxide. Although most studies have examined cognitive, neurologic, hepatic, and hematopoietic side effects, there has also been some evidence suggesting an . . .