Emergence delirium

Emergence delirium

Anesthetic relevance	High
Anesthetic management	Use of sedative/anxiolytic/analgesic agents (Precedex, Ketamine, Fentanyl) for prevention
Specialty	Anesthesiology
Signs and symptoms	Agitation, confusion, hyperarousal
Diagnosis	{{{diagnosis}}}
Treatment	Reorientation, adequate analgesia
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Emergence delirium or post-anesthetic delirium is a transient state of agitation, confusion/disorientation, and irritability that occurs after the withdrawal of anesthesia. It is associated with prolonged post-op recovery time and increases the risk for other perioperative complications.

This article will discuss risk factors and management considerations. The topic of delayed emergence is a related but separate discussion.

Anesthetic implications

Emergence delirium is a well known phenomenon in pediatric anesthesia. Pediatric anesthesia providers are particularly wary due to concern for laryngospasm. Regardless of age, emergence delirium in both pediatric and adult patients can carry with it a higher risk of post-op pulmonary and surgical complications, particularly those with additional comorbidities (e.g. low FRC due to morbid obesity, chronic hypoxemia due to COPD or interstitial lung disease, risk of aspiration, delicate surgical sites at the head/neck).

Related surgical procedures

It has been noted that there is an increased risk of emergence delirium in pediatric patients undergoing tonsillectomy/adenoidectomies, eye surgery, and middle ear surgery as well as adult patients undergoing nasal surgery. Patients undergoing emergency surgery (as opposed to elective surgery) may also be at higher risk.

Pathophysiology

Inhalational agents (Sevofluorane)

Inhalational agents, notably sevofluorane, have been shown to increase the incidence of emergence delirium. In a 2007 study of 189 preschool and school-age children receiving either propofol or sevofluorane as their primary anesthetic, the incidence of emergence delirium was found to be significantly higher in both sevofluorane age groups (as high as 42% in the preschool sevofluorane group 5 minutes after extubation). A proposed explanation for this is that sevoflurane may cause "differential recovery rates in brain function, due to differences in clearance of inhalational anesthetics from the central nervous system...whereas [auditory centers] and locomotion recover first, cognitive function recovers later, resulting in [agitation]."

Pediatric patients between the ages of 2 and 5

Neuronal excitability is higher in pediatric patients which may contribute to emergence delirium. Studies have shown an increase in epileptiform discharges in children undergoing sevofluorane anesthesia. Sevofluorane targets GABA receptors "enhancing neuronal inhibition, [blocks] potassium and hyperpolarization-activated cyclic nucleotide-gated cation channels, and binds [NMDA] receptors blocking glutamate release which may result in enhanced neuronal hyperexcitability."

Other risk factors

• Rapid awakening
• Preoperative anxiety or baseline neuropsychiatric conditions (migraine, ADHD, epilepsy)
• Preoperative medications (benzodiazepines, scopolamine)
• Perioperative pain

Signs and symptoms

Emergence delirium may manifest as:

• Increased agitation or hyperexcitability
• Disinhibition
• Confusion

Management

Intraoperative management

A 2022 metanalysis of pediatric cases using sevofluorane as maintenance showed a significant reduction in emergence delirium with the use of Precedex (Dexmedetomidine), Ketamine, and Fentanyl.

Precedex

Precedex is a selective alpha-2 agonist which acts on the central nervous system to treat pain, provide sedation/anxiolysis, and decrease sympathetic tone. It can be bolused in small increments (4 mcg/dose) or run as a low-dose infusion intraoperatively and is commonly used in pediatrics for the prevention of emergence delirium and has been shown to significantly reduce agitation, cough, pain, post-op nausea/vomiting (PONV), and shivering in the PACU. Its use may be limited by hemodynamic effects (bradycardia, hypotension).

Ketamine and Fentanyl

Ketamine is an NMDA receptor antagonist which also has sedative and analgesic effects. In the above study, it had almost equal efficacy in treating emergence delirium when compared to Precedex. Similar to Precedex, it can be given in small boluses (10 mg/dose) or run as a low-dose infusion intraoperatively. Its use may be limited by concern for its dissociative effects. These are usually decreased with perioperative administration of benzodiazepine (i.e. Versed) but can also be prevented with concurrent use of Precedex. In a corresponding manner, ketamine provides hemodynamic stability which may balance/prevent the bradycardia and hypotension observed with Precedex when used in combination.

Fentanyl is a mu-opioid receptor agonist which may nonspecifically reduce emergence delirium by treating perioperative pain. It may be limited by an increased risk of PONV.

Postoperative management

• Reorientation

• Treat acute pain

• Consider other sources of discomfort (full bladder, hypothermia)
• If acutely agitated and danger to self/others, consider haloperidol
• Avoid additional benzodiazepines as this may worsen delirium