Is the patient asleep?

Patients awareness while under general anesthesia has been noted since shortly after Morton's 1846 public demonstration. Only since 1950, however, has the phenomenon received the attention of researchers. Such awareness can be caused by insufficient anesthesia due to carelessness or equipment malfunction; or by the light levels of anesthesia allowed by the use of muscle relaxants. Members of the anesthesia and surgical teams should be alert to the possibility of awareness and conduct themselves in the operating room accordingly.