Residency · Residency · Anesthesiology
Emergence Delirium and Postoperative Behavioral Changes in Children
Introduction
Emergence delirium is a transient state of dissociated consciousness occurring during emergence from general anesthesia in children, characterized by inconsolable crying, disorientation, thrashing, and failure to make purposeful eye contact with caregivers. It is distinct from emergence agitation due to pain, though the two conditions frequently overlap and can be difficult to differentiate clinically.
Epidemiology
The reported incidence of emergence delirium varies from 10% to 80% depending on the definition and assessment tool used. Peak incidence occurs in preschool-aged children between 2 and 5 years. Most episodes are self-limiting and resolve within 5 to 15 minutes, rarely persisting beyond 30 minutes without an underlying cause. Recurrence is notable, as children who experience emergence delirium are more likely to exhibit it in subsequent anesthetics.
Risk Factors
Patient Factors
Age 2 to 5 years is the strongest predictor of emergence delirium. Other patient factors include preoperative anxiety and temperament (particularly in shy, anxious, or poorly adaptive children), absence of premedication, no prior anesthesia experience, and certain procedures such as ENT surgery (tonsillectomy, myringotomy), ophthalmologic surgery, and dental procedures.
Anesthetic Factors
Among volatile agents, sevoflurane is most commonly implicated. Desflurane and isoflurane are also associated, though less frequently studied in children. Rapid emergence from anesthesia, short-duration procedures with minimal analgesic requirements, and the absence of coadministered sedative or analgesic agents (such as propofol, opioids, or regional anesthesia) all increase the risk.
Pathophysiology
The exact mechanism of emergence delirium remains poorly understood. Leading hypotheses include differential recovery of brain regions, in which limbic and cortical areas may recover at different rates producing a dissociative state. Rapid washout of sevoflurane may lead to a transient excitatory state in the central nervous system. Immature neurologic development in young children may predispose to disinhibition during emergence, and a contribution of paradoxical excitement similar to that seen with alcohol or benzodiazepine emergence has been proposed. EEG studies have demonstrated epileptiform activity during sevoflurane emergence in some children, though the clinical significance is debated.
Assessment and Scoring Tools
Pediatric Anesthesia Emergence Delirium (PAED) Scale
The PAED scale is a validated 5-item instrument scored from 0 to 20. The five items assessed are whether the child makes eye contact with a caregiver, whether the child's actions are purposeful, whether the child is aware of surroundings, whether the child is restless, and whether the child is inconsolable. Each item is scored from 0 to 4, with higher scores indicating greater severity. A score of 10 or greater is generally considered diagnostic of emergence delirium.
| PAED Item | Scoring Direction | 0 | 4 |
|---|---|---|---|
| Makes eye contact with caregiver | Reversed (4 = not at all) | Extremely | Not at all |
| Actions are purposeful | Reversed (4 = not at all) | Extremely | Not at all |
| Aware of surroundings | Reversed (4 = not at all) | Extremely | Not at all |
| Restless | Direct (4 = extremely) | Not at all | Extremely |
| Inconsolable | Direct (4 = extremely) | Not at all | Extremely |
Total score: 0–20. Score ≥10 = emergence delirium.
Watcha Scale
The Watcha scale is a simpler 4-point system: 1 indicates calm, 2 indicates crying but consolable, 3 indicates crying and not consolable, and 4 indicates agitated and thrashing. It is less validated than the PAED scale but useful for quick screening.
Differentiating ED from Pain
Pain and emergence delirium coexist in many cases and require systematic evaluation. A trial dose of fentanyl (0.5 to 1 mcg/kg IV) or morphine should be administered; if agitation resolves, pain is likely the primary cause. Clues suggesting emergence delirium rather than pain include failure to recognize parents, inconsolable behavior despite parental comfort, absence of purposeful guarding or localization, and no apparent surgical cause for severe pain (as in the case of myringotomy). If pain is adequately treated and agitation persists, the condition should be treated as emergence delirium.
Prevention Strategies
Pharmacologic
Propofol at a small dose of 1 mg/kg IV at the end of anesthesia, or TIVA with propofol throughout the case, significantly reduces the incidence of emergence delirium. Dexmedetomidine at 0.3 to 0.5 mcg/kg IV given intraoperatively is one of the most effective preventive agents, with a number needed to treat of approximately 3 to 4. Fentanyl at 1 to 2 mcg/kg at the end of surgery reduces emergence delirium, especially when pain is a contributing factor. Midazolam given as preoperative oral dosing at 0.5 mg/kg reduces preoperative anxiety and may decrease emergence delirium. Clonidine at 2 to 4 mcg/kg oral or IV has demonstrated efficacy in prevention. Ketamine at 0.25 to 0.5 mg/kg IV at the end of the case may also reduce the incidence.
Non-Pharmacologic
Parental presence at induction may reduce preoperative anxiety, though evidence regarding its effect on emergence delirium specifically is mixed. Preoperative preparation programs, child life specialists, and behavioral interventions may be helpful. Distraction techniques such as tablet devices and videos during induction, a calm, quiet, low-stimulation PACU environment during emergence, and allowing the child to emerge slowly without rushing the process are all recommended strategies.
Treatment
The immediate priority is reassurance and safety: the child should be gently restrained to prevent self-injury or dislodgement of IV lines and monitors. The environment should be kept calm, and parents should be present if possible. Reversible causes must be ruled out and treated, including pain, full bladder, hypoxia, hypercarbia, and hypothermia.
Pharmacologic treatment options include propofol at 0.5 to 1 mg/kg IV, which may be repeated and is highly effective. Dexmedetomidine at 0.5 mcg/kg IV over 5 minutes is another option. Midazolam at 0.02 to 0.05 mg/kg IV is less preferred due to the potential for paradoxical reactions. Most episodes resolve spontaneously within 5 to 15 minutes.
Postoperative Behavioral Changes
New-Onset Behavioral Changes
Up to 30 to 50% of children exhibit negative behavioral changes in the first 2 weeks after surgery and anesthesia. Common manifestations include sleep disturbances (nightmares, night waking, difficulty falling asleep), separation anxiety (clinging to parents, fear of strangers), regression (loss of previously acquired skills such as toilet training and speech), new fears (fear of doctors, hospitals, the dark), eating changes (appetite loss, food refusal), and aggression and temper tantrums.
Risk Factors for Postoperative Behavioral Changes
Risk factors include young age (under 5 years), high preoperative anxiety, emergence delirium (which is strongly associated), painful or distressing procedures, multiple anesthetics in a short period, and previous traumatic medical experiences.
Duration and Prognosis
Most behavioral changes resolve within 2 to 4 weeks. Approximately 10 to 20% of children exhibit changes persisting beyond 6 months. Recurrent exposure to anesthesia may increase the risk of persistent changes. There is no clear evidence of long-term neurocognitive harm from single, brief anesthetics in otherwise healthy children, as demonstrated by the GAS and PANDA studies.
Clinical Pearls
Emergence delirium is self-limiting but can be distressing for families and PACU staff; prophylaxis with dexmedetomidine or propofol is simple, effective, and well-supported by evidence. Pain should always be ruled out before diagnosing emergence delirium, and a trial of opioid should be the first step in an agitated postoperative child. The PAED scale with a score of 10 or greater is the best validated tool for diagnosing emergence delirium. Preoperative anxiety is the strongest modifiable predictor of both emergence delirium and postoperative behavioral changes. Parents should be counseled preoperatively about the possibility of transient behavioral changes, and reassurance along with consistent routines at home facilitates resolution.
References
- Sikich N, Lerman J. Development and psychometric evaluation of the Pediatric Anesthesia Emergence Delirium Scale. Anesthesiology. 2004;100(5):1138-1145.
- Dahmani S, Delivet H, Hilly J. Emergence delirium in children: an update. Curr Opin Anaesthesiol. 2014;27(3):309-315.
- Kanaya A, Kuratani N, Satoh D, Kurosawa S. Lower incidence of emergence agitation in children after propofol anesthesia compared with sevoflurane: a meta-analysis of randomized controlled trials. J Anesth. 2014;28(1):4-11.
- Kain ZN, Mayes LC, Caldwell-Andrews AA, et al. Preoperative anxiety, postoperative pain, and behavioral recovery in young children undergoing surgery. Pediatrics. 2006;118(2):651-658.