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Delayed emergence and emergence delirium in adults

Sher-Lu Pai, MD
Section Editor
Natalie F Holt, MD, MPH
Deputy Editor
Nancy A Nussmeier, MD, FAHA


Failure to return to normal consciousness in a timely fashion following administration of general anesthesia may manifest as delayed emergence or emergence delirium. In most cases, these conditions are temporary and gradually resolve as anesthetic agents are metabolized and eliminated. Rarely, the cause is a serious medical or neurologic condition that requires urgent intervention.

This topic will review the causes and management of delayed emergence and emergence delirium after general anesthesia. Management of persistent postoperative delirium is addressed separately. (See "Diagnosis of delirium and confusional states".)

Other problems that occur in the post-anesthesia care unit (PACU) are discussed separately. (See "Overview of post-anesthetic care for adult patients".)


Emergence is the gradual return of consciousness after discontinuing administration of anesthetic and adjuvant agents at the end of the surgical procedure. Most patients transition smoothly from a surgical anesthetic state (Stage III) to an awake state with intact protective reflexes (Stage I) (table 1) [1]. After emergence in the operating room, transport to the post-anesthesia care unit (PACU) is typically accomplished when the patient has been extubated and is breathing spontaneously with adequate oxygenation and ventilation, is hemodynamically stable, and can be aroused to follow simple verbal commands (eg, eye opening or hand squeezing).

Most patients become more fully conscious (ie, awake and aware of surroundings and identity) within approximately 15 minutes of extubation, and all patients should be responsive within 60 minutes after the last administration of any sedative, opioid, or anesthetic agent [2-4]. However, the time required for return of consciousness varies depending on the specific anesthetic agents employed; dosing, duration, and timing of last administration; the type and duration of the surgical procedure; and the patient's preoperative physical and mental status. (See 'Risk factors' below.)

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Literature review current through: Nov 2017. | This topic last updated: Jun 06, 2017.
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