4.2 Emergence phenomena: 

Emergence excitement occurs in some patient when recovering from general anesthesia.

• It is characterized by tachycardia, restlessness, disorientation, altered pain responsiveness, crying, moaning, and irrational talking during recovery from general anesthesia.
• In some cases, patients become delirious, shout, scream and trash about, posing a danger to themselves and recovery room staff.
• The incidence of excitement is higher after surgical procedure with emotional over tones such as breast surgery with fear of mutilation or cancer than routine minor procedures. It is more common in young patient.
• Predicting which patients will have adverse psychological reactions is difficult. Emergence reactions are prevalent in children and young adults. In young children, anxiety is heightened by parental separation. Patients with mental retardation, psychiatric disorders, organic brain dysfunction, or hostile preoperative interactions manifest those problems after surgery.
• Inability to speak secondary to tracheal intubation generates frustration or fear that exaggerates emergence reactions. Ethnic, cultural, and psychological characteristics play some role.
• Recall of intraoperative events can generate severe panic and anxiety during emergence.
• Ketamine can cause dysphoria (a state of general dissatisfaction) and hallucination (experience of seeing an imaginary scene or hearing an imaginary sound as clearly as if it were really there). Administration of ketamine with combination of a benzodiazepine (diazepam) may be indicated to limit the unpleasant emergence reactions and also increase amnesia.
• Anticholinergics such as scopolamine and atropine cause delirium, hallucinations, memory disturbances, and agitation in postoperative patients. Emergence excitement is transient and self-limited in most patients, and treatment is largely supportive. Analgesic therapy often aborts decreases the severity of excitement. Physostigmine, which penetrates the blood-brain barrier, reverses the effects of scopolamine within 5 to 10 minutes of administration and markedly improves the mental status of patients.
• Pain amplifies agitation, confusion, and aggressive behavior during emergence; therefore, it is helpful to ensure adequate postoperative analgesia. Urinary urgency or gastric distention generates discomfort and agitation, as do tight dressings, painful phlebotomy, and poor positioning. Endotracheal or nasogastric tubes and urinary catheters are equally discomforting.
• Suspect seizures in patients with epilepsy, head trauma, and chronic alcohol or cocaine abuse. Cerebral hypoperfusion (decreased blood flow to the brain) can produce disorientation, agitation, and combativeness. This is a medical emergency that requires aggressive solution.
• Disorders of mentation (mental activity) commonly occur in elderly patients recovering from anesthesia. These disorders include disorientation, short term memory lapse, and problems with languages ability. The incidence of immediate postoperative confusion in elderly patients is so high postoperative mental function begins at least 6 hours after surgery.