General anesthesia (GA) is the state produced when a patient receives medications for amnesia, analgesia, muscle paralysis, and sedation. An anesthetized patient can be thought of as being in a controlled, reversible state of unconsciousness. Anesthesia enables a patient to tolerate surgical procedures that would otherwise inflict unbearable pain, potentiate extreme physiologic exacerbations, and result in unpleasant memories.
The combination of anesthetic agents used for general anesthesia often leaves a patient with the following clinical constellation:
1. Unarousable even secondary to painful stimuli
2. Unable to remember what happened (amnesia)
3. Unable to maintain adequate airway protection and/or spontaneous ventilation as a result of muscle paralysis
4. Cardiovascular changes secondary to stimulant/depressant effects of anesthetic agents