Anesthesia Stages

Excerpt

General anesthesia is a medically-induced loss of consciousness with concurrent loss of protective reflexes due to anesthetic agents. Various medications may be prescribed to induce unconsciousness, amnesia, analgesia, skeletal muscle relaxation, and the loss of autonomic system reflexes. During this state, the patient is unarousable to verbal, tactile, and painful stimuli. Upper airway obstruction during general anesthesia usually necessitates the insertion of a laryngeal mask airway or endotracheal tube to preserve airway patency. Likewise, the patient's spontaneous ventilation is often inadequate, requiring partial or full mechanical support with positive pressure ventilation. The patient's cardiovascular function may also become impaired.