Abstract
Emergence delirium is a type of delirium: a transient, self-limited state of agitation, confusion, and dissociation that appears as a person wakes from general anesthesia. It is most common in young children recovering from the volatile anesthetics sevoflurane and desflurane, in whom a child may thrash, cry inconsolably, fail to recognise a parent, and make no eye contact, before settling spontaneously within the hour. First described by James Eckenhoff in 1961 as postanesthetic excitement, the state became measurable only with the Pediatric Anesthesia Emergence Delirium scale in 2004, which separated true delirium from the much commoner confound of postoperative pain. This article sets out what emergence delirium is, how it is scored, its anesthetic and developmental risk factors, its uncertain mechanisms, and its prevention with propofol and dexmedetomidine, with interactive demonstrations of its scoring, time course, and prevention.
Keywords: emergence delirium, emergence agitation, delirium, anesthesia, consciousness
Anyone who has watched a small child wake from a routine operation has seen how unsettling the first minutes of recovery can be. The surgery went well, the anesthetic was uncomplicated, and yet the child surfaces not into calm grogginess but into a brief storm: inconsolable, flailing, staring through the parent who is trying to soothe them, unreachable by the usual comforts. A few minutes later it is over, and the child remembers none of it. This is emergence delirium — a disturbance not of the operation but of the transition back to waking consciousness, and one that for decades was lumped together with pain, fear, and ordinary fussing until a measurement instrument finally pulled it apart.
- Emergence delirium is a disorder of the transition to waking, not of the surgery. It is a short-lived state of agitation, confusion, and dissociation that appears in the first minutes after general anesthesia and resolves on its own, usually within half an hour (Eckenhoff et al., 1961; Mason, 2017). - It is mainly a problem of young children and volatile anesthetics. Incidence is highest in preschool children recovering from sevoflurane or desflurane, and far lower after intravenous propofol (Aono et al., 1997; Costi et al., 2014). - It became a real object of study only when it could be measured. The Pediatric Anesthesia Emergence Delirium (PAED) scale turned a vague clinical impression into a reproducible score, and crucially helped separate delirium from postoperative pain (Sikich & Lerman, 2004; Somaini et al., 2015). - It can be prevented pharmacologically. Propofol, dexmedetomidine, and adequate analgesia all reduce its incidence, which is why prevention is built into modern anesthetic practice (Dahmani et al., 2010; Rao et al., 2020). - It is not only a childhood phenomenon. Emergence agitation occurs in adults too, where it carries real risks of self-injury and dislodged lines, though it is studied far less (Fields et al., 2018; Lee & Sung, 2020).
What Emergence Delirium Is
Emergence delirium — also called emergence agitation — is a disturbance of consciousness and behaviour that occurs during emergence, the period in which a patient returns from general anesthesia to the waking state. MeSH classifies it as a form of delirium, and the kinship is apt: like delirium of any cause, it is an acute, fluctuating disturbance of awareness and attention. What makes it distinctive is its timing and its course. It begins within minutes of waking, often in the operating room or the post-anesthesia care unit, and it is self-limited — it resolves spontaneously, usually within fifteen to forty-five minutes, without any specific treatment (Mason, 2017; Vlajkovic & Sindjelic, 2007).
The clinical picture is most vivid in children. The child is agitated and often inconsolable, crying or thrashing in a way that is hard to soothe; critically, they appear dissociated from their surroundings — they do not make eye contact, do not recognise familiar faces, and are not aware of, or oriented to, the environment. This non-purposeful, non-interactive quality is what distinguishes genuine delirium from a child who is simply frightened, in pain, or angry at being held down, each of which produces agitation that is directed, purposeful, and responsive to comfort (Sikich & Lerman, 2004).
The distinction matters because it is easy to get wrong. A child screaming in recovery might be delirious, might be in pain, or might be both, and the behaviours overlap heavily at the bedside. The entire modern literature on emergence delirium turns on this problem of telling apart superficially identical agitation with very different causes — a measurement problem before it is a clinical one (Somaini et al., 2015).
Delirium, Pain, or Both
Agitation on emergence is a final common pathway: several quite different states converge on the same thrashing, crying child, and distinguishing them determines what should be done. The useful division is between true emergence delirium, pain-driven agitation, and ordinary awakening distress, with the recognition that two or three can coexist in the same patient.
True emergence delirium is marked by the dissociative quality described above: the child is not oriented, not interacting, not making eye contact, and the agitation is non-purposeful. It is not relieved by a parent's presence or by being picked up, because the child is not, in the relevant sense, there to be comforted. This is the state the PAED scale was designed to capture (Sikich & Lerman, 2004).
Pain-driven agitation looks similar from across the room but differs in kind: the child is oriented and interactive, the distress is purposeful and directed at the source of discomfort, and it responds to analgesia. Because pain is so common after surgery and produces agitation that mimics delirium, it is the single most important confound in both diagnosing and studying the syndrome — an apparent case of emergence delirium that resolves with an analgesic was, by definition, pain (Somaini et al., 2015).
Awakening distress — fear, disorientation, and the general unpleasantness of surfacing in a strange place among strangers — is the mildest and most transient, shading into normal behaviour. The practical difficulty, and the reason measurement was essential, is that these categories are defined partly by their response to treatment, so they cannot always be separated in the moment; the clinician must often act on a judgement that is only confirmed in retrospect (Vlajkovic & Sindjelic, 2007).
Table 1
States of agitation on emergence from anesthesia and how they differ
| State | Hallmark | Responds to comfort or analgesia? | Orientation and interaction |
|---|---|---|---|
| True emergence delirium | Dissociation; non-purposeful agitation; no eye contact or recognition | No; self-limited and resolves on its own | Absent; not aware of surroundings |
| Pain-driven agitation | Purposeful distress directed at the source of pain | Yes; settles with adequate analgesia | Preserved; interacts and can be consoled |
| Awakening distress | Fear and disorientation of surfacing in a strange place | Partly; eases with reassurance and a parent | Largely preserved; shades into normal behaviour |
Who Is at Risk
Emergence delirium is not evenly distributed; it concentrates in identifiable circumstances, and knowing them is the basis of prevention. The two strongest associations are with young age and with volatile anesthetics.
Children, especially preschool children between about two and six years old, are far more susceptible than older children or adults, a pattern noted since the earliest systematic observations and confirmed repeatedly since (Aono et al., 1997; Cole et al., 2002). The developing brain's immature capacity to re-establish organised, oriented consciousness after the profound disruption of anesthesia is the usual explanation, though it remains more description than mechanism.
The anesthetic agent matters as much as the patient. The modern volatile anesthetics sevoflurane and desflurane, which are prized precisely because they allow a rapid emergence, carry a markedly higher incidence of delirium than intravenous propofol — a contrast confirmed by a Cochrane systematic review (Costi et al., 2014). The very speed of the transition these agents permit may be part of the problem, hurrying the brain through the reorganisation that waking requires. Several further factors raise the risk: preoperative anxiety in the child, certain procedure types (notably ear, nose, throat, and ophthalmic surgery), rapid emergence, and — importantly — inadequately treated pain, which both causes agitation in its own right and appears to worsen genuine delirium (Voepel-Lewis et al., 2003; Dahmani et al., 2010). The anxiety association is well documented: in a prospective study, children who were more anxious at induction were markedly more likely to develop emergence delirium and to show maladaptive behaviour in the days after surgery, which both strengthens the case for anxiety as a genuine predictor and points to its management as a route to prevention (Kain et al., 2004).
Measuring Emergence Delirium
For most of its history emergence delirium could not be measured, only noticed, and that is why it resisted study for four decades after Eckenhoff named it. The decisive advance was the Pediatric Anesthesia Emergence Delirium (PAED) scale, published by Nancy Sikich and Jerrold Lerman in 2004, the first instrument developed and psychometrically validated specifically for this state (Sikich & Lerman, 2004).
The scale rates five behavioural items, each from 0 to 4: whether the child makes eye contact with the caregiver, whether the child's actions are purposeful, whether the child is aware of the surroundings, whether the child is restless, and whether the child is inconsolable. The first three items are reverse-scored — absence of eye contact, of purposeful action, and of awareness each count toward delirium — because these dissociative features are the heart of the construct the scale was built to capture, the very features that separate delirium from mere distress. The five item scores are summed to a total from 0 to 20, with higher scores indicating more severe delirium (Sikich & Lerman, 2004).
A widely used threshold of 10 or greater identifies likely emergence delirium, and the scale's great contribution was to make the syndrome countable, comparable across studies, and trackable over the minutes of recovery. It has since been applied well beyond its original setting, including validation in other populations, which both confirmed its usefulness and exposed the limits of any single cut-off (Bong & Ng, 2009). Its one persistent weakness is the pain confound: because restlessness and inconsolability are shared by delirium and pain, a child in severe pain can score highly on the PAED scale without being delirious, which is why careful studies pair the scale with a separate pain assessment (Somaini et al., 2015). The demonstration below lets the reader set each of the five items and watch the total and the verdict update against the threshold.
Score the five PAED items
The Pediatric Anesthesia Emergence Delirium scale rates five behaviours, each from 0 to 4, and sums them to a total out of 20. The first three items are reverse-scored — the absence of eye contact, purposeful action, and awareness each count toward delirium, because that dissociation is the heart of the construct. Set each item and watch the total cross the threshold of 10.
18 of 20 — at or above the threshold of 10, by 8 points (18/20 = 0.90).
A total of 10 or more identifies likely emergence delirium; the three reverse-scored dissociative items are what separate it from pain (after Sikich & Lerman, 2004).
Worked Example
How does the PAED scale turn a chaotic bedside scene into a number? Consider a four-year-old in the recovery unit a few minutes after a sevoflurane anesthetic for grommet insertion. The recovery nurse rates the five items. The child makes no eye contact with the caregiver, so that item — scored for the absence of a normal behaviour — is high, say 4. The child's actions are not purposeful: another 4. The child is not aware of the surroundings: 4. The child is markedly restless: 3. The child is inconsolable: 3.
The three reverse-scored items (eye contact, purposeful action, awareness) contribute 4 + 4 + 4 = 12, and the two directly scored items (restless, inconsolable) contribute 3 + 3 = 6. The PAED total is the simple sum of all five:
12 + 6 = 18 out of 20.
Against the common threshold of 10, a score of 18 is 18 − 10 = 8 points above the cut-off, so this child screens clearly positive for emergence delirium. In proportional terms the score is 18 / 20 = 0.90 of the maximum, a severe presentation. Before concluding it is delirium rather than pain, the nurse checks a separate pain score; the grommet procedure is minimally painful and the child's distress is non-purposeful and non-interactive, which points to true delirium. No specific treatment is given beyond ensuring safety, and a repeat PAED rating fifteen minutes later has fallen to 6 — below the threshold — as the state resolves on its own. That trajectory, a high score settling spontaneously without analgesia, is itself the signature of emergence delirium. The demonstration below traces that time course, letting the reader move through the minutes of recovery and watch the PAED score rise to its peak and then resolve on its own below the threshold.
The self-limited time course
Emergence delirium is defined as much by its course as by its signs: the PAED score spikes in the first minutes after waking and then falls back on its own, usually within the hour, with no specific treatment. Drag the time since waking and watch the score rise to its peak and resolve below the threshold of 10. The curve is a schematic illustration of the characteristic trajectory, not patient data.
At 5 min: PAED 18 of 20 — above threshold; the delirium is at or near its peak.
A high score that settles spontaneously without analgesia is the signature of emergence delirium (after Mason, 2017).
What Happens in the Brain
The mechanism of emergence delirium is genuinely unsettled, and the honest summary of the literature is that no single account yet explains it. What is clear is the shape of the problem: anesthesia profoundly suppresses and reorganises brain activity, and emergence is the reverse process, in which the networks that support oriented, attentive consciousness must come back online in a coordinated way. Delirium on emergence is what happens when that reassembly is disorderly (Mason, 2017).
Several non-exclusive ideas are in play. One emphasises the speed of emergence: the modern volatile agents wake the brain quickly, and a cortex that regains arousal before the slower networks of orientation and attention have re-established themselves may produce a window of awake-but-disoriented consciousness — aroused yet not oriented — that manifests as delirium (Vlajkovic & Sindjelic, 2007). A second points to differential recovery of brain regions, with the agent clearing unevenly so that some systems are functional while others lag. A third notes that volatile anesthetics have distinct effects on inhibitory and excitatory neurotransmission, and that their particular pharmacology — rather than anesthesia in general — may be responsible, which would fit the strong agent-specific pattern favouring propofol (Costi et al., 2014).
Figure 1
The dissociated-recovery model: arousal returning ahead of orientation
The developmental dimension is woven through all of these. The immature brain's networks for sustaining organised attention and orientation are less robust, which may be why the same rapid, uneven emergence that an adult tolerates produces florid delirium in a preschooler (Moore & Anghelescu, 2017). None of this amounts to a settled circuit-level account, and the gap between a well-characterised clinical syndrome and a poorly understood mechanism is one of the defining features of the field.
Preventing and Managing It
Because emergence delirium is brief and self-limited, the emphasis falls on prevention rather than treatment, and here the evidence is relatively strong. The most direct lever is the choice of anesthetic: substituting or supplementing a volatile agent with propofol, particularly a propofol bolus or infusion at the end of a sevoflurane anesthetic, reduces the incidence substantially (Costi et al., 2014; Dahmani et al., 2010).
Pharmacological prophylaxis is the other main approach. A meta-analysis of prevention studies found that several agents reduce volatile-anesthetic emergence agitation, and the alpha-2 agonist dexmedetomidine has since emerged as a particularly effective option, confirmed by its own meta-analysis in children (Dahmani et al., 2010; Rao et al., 2020). Reducing the child's preoperative anxiety is a further lever, consistent with the finding that anxious children are more prone to emergence delirium; calmer, less frightening inductions — whether through behavioural preparation, parental presence, or anxiolytic premedication — are used with this in mind, though the measured effect on delirium specifically is more modest than the effect of the anesthetic choice (Kain et al., 2004). Adequate analgesia is both a treatment for the pain that masquerades as delirium and a genuine preventive measure, since poorly controlled pain worsens true delirium as well. When an episode does occur, management is largely supportive: ensuring the child cannot injure themselves or dislodge lines, minimising stimulation, and allowing the state to pass, with a small dose of propofol or dexmedetomidine reserved for severe or prolonged cases (Moore & Anghelescu, 2017; Mason, 2017).
Weigh the risk and prevention factors
Emergence delirium concentrates in identifiable circumstances, and each is a lever for prevention. Toggle the anesthetic, the patient, and the preventive measures and watch the predicted incidence move. The figure is a transparent illustrative model of direction and relative size — it shows why propofol and dexmedetomidine lower the risk — not a validated clinical calculator.
Predicted incidence 55% — a volatile anesthetic is the single largest driver here; adding dexmedetomidine prophylaxis would lower it further.
Propofol and dexmedetomidine are the best-supported preventive levers; treating pain removes a contributor and its confound (after Dahmani et al., 2010; Rao et al., 2020).
Emergence Agitation in Adults
Although emergence delirium is overwhelmingly studied in children, it is not confined to them. Adults, too, can wake from general anesthesia in a state of agitation, confusion, and non-purposeful movement, and when they do the consequences can be serious: a large, disoriented, thrashing adult can injure themselves, pull out surgical drains and intravenous lines, and endanger staff (Fields et al., 2018).
The adult literature is thinner and the picture less clear-cut, partly because the dramatic pediatric presentation drew most of the research attention and partly because the PAED scale was built for children and does not transfer cleanly to adults. Studies of adult post-anesthesia care units nonetheless find emergence agitation at non-trivial rates, with risk factors that overlap with the pediatric ones — volatile anesthetics, certain surgeries, and the presence of irritating stimuli such as a breathing tube or urinary catheter on waking — alongside adult-specific contributors (Fields et al., 2018; Lee & Sung, 2020). The relative neglect of the adult syndrome, despite its real risks, is one of the clearer gaps in the field.
Discussion
The history of emergence delirium is, like that of several syndromes, a story about the power of measurement. Eckenhoff described postanesthetic excitement in 1961, but for more than forty years it remained a loose clinical impression, tangled up with pain and fear and impossible to study rigorously because there was no agreed way to count it (Eckenhoff et al., 1961). The PAED scale changed that in 2004, and almost everything systematic that is known about the syndrome — its incidence, its risk factors, the superiority of propofol, the efficacy of dexmedetomidine — depends on having an instrument that made it a measurable outcome (Sikich & Lerman, 2004; Rao et al., 2020).
Yet the same history exposes the field's central unresolved tension. The PAED scale made the syndrome countable but could not fully separate it from pain, because the two share their most visible behaviours; the pain confound is not a flaw to be engineered away so much as a reflection of how genuinely alike the two states appear (Somaini et al., 2015). And the mechanism remains obscure: a syndrome that can be reliably produced by sevoflurane in a preschooler and reliably prevented by propofol or dexmedetomidine is nonetheless not understood at the level of circuits (Mason, 2017; Vlajkovic & Sindjelic, 2007). The open problems are correspondingly practical and theoretical at once: a measure that cleanly distinguishes delirium from pain, a mechanistic account that explains the age and agent specificity, and a serious extension of the work to adults (Fields et al., 2018).
Cognitive and Psychological Implications
Beyond the operating room, emergence delirium is a striking natural experiment on the architecture of waking consciousness. Ordinarily the return from deep sleep or anesthesia is so smooth that its components are invisible; emergence delirium pulls them apart. The delirious child is aroused — eyes open, moving, vocal — but not oriented, not attending, not aware of or interacting with the surroundings. That dissociation makes vivid a distinction cognitive psychology draws in theory: arousal and the contents of oriented, attentive awareness are separable processes that normally rise together but need not (Mason, 2017).
The syndrome is in this sense a transient, reversible failure of the systems that bind arousal to orientation and attention — the same binding whose chronic failure defines delirium more generally. It also sits instructively alongside the other disorders of disordered action and awareness: it is the awakening-transition cousin of psychomotor agitation, and a counterpart, in the register of consciousness, to the motor-volitional derailment of catatonia. That a routine anesthetic can briefly and harmlessly decouple arousal from awareness, and that the decoupling can be measured on a five-item scale, makes emergence delirium one of the more accessible windows onto how the brain reassembles a waking mind.
Current Directions
Three threads run through the recent literature. The first is pharmacological prevention: dexmedetomidine has moved from a promising option to a well-supported one, with meta-analytic evidence for its efficacy in children, and work continues on optimal agents, doses, and timing (Rao et al., 2020). The second is measurement: the recognition that the PAED scale cannot fully separate delirium from pain has driven efforts to refine assessment so that studies measure the syndrome rather than its confound, a prerequisite for progress on mechanism (Somaini et al., 2015; Lee & Sung, 2020). The third is the extension to adults, where emergence agitation is increasingly recognised as a real and under-studied problem with its own risk profile and consequences (Fields et al., 2018). Across all three the unifying aim is to convert a syndrome that is easy to see and easy to prevent into one that is also understood — to close the gap between a well-characterised clinical picture and the disorderly return of consciousness that underlies it.
Common Misconceptions
- Emergence delirium means the anesthetic went wrong.
- It does not. Emergence delirium occurs after entirely uncomplicated anesthesia; it is a feature of the normal transition back to waking in susceptible patients, especially young children after volatile agents, not a sign of an error or of awareness during surgery (Mason, 2017).
- A screaming child in recovery is always in pain.
- Not always. Pain and delirium produce very similar agitation, but true emergence delirium is dissociative and non-purposeful and does not respond to analgesia, whereas pain-driven distress is purposeful and settles when the pain is treated. Telling them apart is the central clinical problem (Somaini et al., 2015).
- Emergence delirium is dangerous and needs urgent sedation.
- It is usually brief and self-limited, resolving on its own within the hour, and management is mainly about keeping the patient safe. Medication is reserved for severe or prolonged episodes, not used routinely (Vlajkovic & Sindjelic, 2007).
- It only happens to children.
- Children are by far the most affected, but adults experience emergence agitation too, where a large, disoriented patient can cause real harm by dislodging lines or injuring themselves. The adult form is simply studied far less (Fields et al., 2018).
Glossary
- Alpha-2 agonist.
- A class of drugs, including dexmedetomidine, that act on alpha-2 adrenergic receptors to produce sedation and reduce sympathetic activity; used to prevent and treat emergence delirium.
- Awakening distress.
- The fear and disorientation of surfacing from anesthesia in an unfamiliar place; milder than true delirium and partly relieved by reassurance.
- Desflurane.
- A volatile anesthetic allowing very rapid emergence; associated, like sevoflurane, with a higher incidence of emergence delirium than propofol.
- Dexmedetomidine.
- An alpha-2 agonist with sedative and analgesic properties, supported by meta-analysis as an effective prophylaxis against emergence agitation in children.
- Dissociation.
- In emergence delirium, the lack of eye contact, awareness, and purposeful interaction with the surroundings; the core feature distinguishing delirium from pain or fear.
- Emergence delirium (emergence agitation).
- A transient, self-limited state of agitation, confusion, and dissociation on waking from general anesthesia, most common in young children after volatile anesthetics.
- Emergence.
- The period of recovery in which a patient returns from general anesthesia to the waking state, during which emergence delirium occurs.
- PAED scale.
- The Pediatric Anesthesia Emergence Delirium scale: five behavioural items each scored 0-4 to a total of 0-20, the standard instrument for identifying and grading the syndrome.
- Post-anesthesia care unit (PACU).
- The recovery area where patients are monitored as they emerge from anesthesia, and where emergence delirium is usually observed and scored.
- Postanesthetic excitement.
- Eckenhoff's original 1961 term for the agitated state on emergence, the historical name for emergence delirium.
- Propofol.
- An intravenous anesthetic associated with a markedly lower incidence of emergence delirium than the volatile agents; used to prevent it.
- Self-limited.
- Resolving spontaneously without specific treatment; emergence delirium characteristically settles within fifteen to forty-five minutes.
- Sevoflurane.
- A widely used volatile anesthetic favoured for smooth, rapid induction and emergence; the agent most strongly associated with emergence delirium in children.
- Volatile anesthetic.
- An inhaled anesthetic agent such as sevoflurane or desflurane; as a class, associated with a higher incidence of emergence delirium than intravenous propofol.
Key Researchers
Souhayl Dahmani
(contemporary). Professor of Anesthesiology at Robert-Debré University Hospital (AP-HP) and Université de Paris; lead author of the meta-analysis quantifying the pharmacological prevention of volatile-anesthetic emergence agitation in children. ORCID - Google Scholar - Faculty
Jerrold Lerman
(contemporary). Clinical Professor of Anesthesiology at the University at Buffalo; co-developer of the Pediatric Anesthesia Emergence Delirium (PAED) scale, the standard instrument for scoring the syndrome. ORCID - Google Scholar - Faculty
Keira P. Mason
(contemporary). Professor of Anaesthesia at Harvard Medical School and Senior Associate in Anesthesia at Boston Children's Hospital; author of the comprehensive review and interpretation of the paediatric emergence-delirium literature. Faculty
Terri Voepel-Lewis
(contemporary). Research Professor of Anesthesiology and Nursing at the University of Michigan; lead author of the prospective post-anesthesia care unit cohort study of pediatric emergence agitation and its predictors. Google Scholar - Faculty
Frequently Asked Questions
What is emergence delirium in simple terms?
Emergence delirium is a short period of agitation and confusion that some people, especially young children, go through as they wake up from general anesthesia. The child may cry, thrash, and seem not to recognise their parents or know where they are, even though the surgery and the anesthetic went normally. It passes on its own, usually within half an hour, and the child does not remember it afterwards (Mason, 2017).
Is emergence delirium the same as being in pain?
No, though the two look very similar and often occur together. A child in pain is usually aware of their surroundings and reaches toward the source of discomfort, and settles when the pain is treated. A child with true emergence delirium is dissociated, not making eye contact or interacting, and does not settle with pain relief. Telling them apart is the hardest and most important part of recognising the condition (Somaini et al., 2015).
Who is most likely to get emergence delirium?
Young children, especially preschoolers between about two and six years old, are by far the most affected, particularly after the inhaled anesthetics sevoflurane and desflurane. Preoperative anxiety, certain operations such as ear, nose, and throat surgery, and poorly controlled pain all increase the risk (Aono et al., 1997; Voepel-Lewis et al., 2003).
How is emergence delirium measured?
With the Pediatric Anesthesia Emergence Delirium scale, usually called the PAED scale. It rates five behaviours (eye contact, purposeful action, awareness of surroundings, restlessness, and inconsolability), each from 0 to 4, for a total out of 20. A score of 10 or more suggests emergence delirium, and the scale lets recovery staff track how the state changes over time (Sikich & Lerman, 2004).
Can emergence delirium be prevented?
To a large extent, yes. Using intravenous propofol instead of, or at the end of, a volatile anesthetic lowers the risk, and the drug dexmedetomidine is an effective preventive, supported by meta-analysis in children. Treating pain well also helps, because untreated pain both mimics and worsens delirium (Dahmani et al., 2010; Rao et al., 2020).
How is an episode treated when it happens?
Mostly by keeping the child safe and letting it pass, since it is brief and resolves by itself. Staff reduce stimulation and prevent the child from injuring themselves or pulling out lines. For a severe or prolonged episode, a small dose of propofol or dexmedetomidine may be given, but routine sedation is not needed (Moore & Anghelescu, 2017).
Do adults get emergence delirium too?
Yes, although it is studied much less than in children. Adults can wake agitated and disoriented, and because they are larger and stronger this can be dangerous, leading to self-injury or dislodged surgical drains and lines. The risk factors overlap with those in children, including volatile anesthetics and irritating tubes or catheters on waking (Fields et al., 2018; Lee & Sung, 2020).
What causes emergence delirium in the brain?
The precise mechanism is not known. The leading idea is that waking from anesthesia requires many brain networks to come back online in a coordinated way, and that when arousal returns faster than orientation and attention, as the rapidly clearing volatile anesthetics may allow, the result is a brief state of being awake but disoriented. Why children are so much more affected is thought to reflect the immaturity of their attention and orientation networks (Vlajkovic & Sindjelic, 2007; Moore & Anghelescu, 2017).
References
Aono, J., Ueda, W., Mamiya, K., Takimoto, E., & Manabe, M. (1997). Greater incidence of delirium during recovery from sevoflurane anesthesia in preschool boys. Anesthesiology, 87(6), 1298-1300. https://doi.org/10.1097/00000542-199712000-00006
Bong, C. L., & Ng, A. S. B. (2009). Evaluation of emergence delirium in Asian children using the Pediatric Anesthesia Emergence Delirium scale. Paediatric Anaesthesia, 19(6), 593-600. https://doi.org/10.1111/j.1460-9592.2009.03024.x
Cole, J. W., Murray, D. J., McAllister, J. D., & Hirshberg, G. E. (2002). Emergence behaviour in children: Defining the incidence of excitement and agitation following anaesthesia. Paediatric Anaesthesia, 12(5), 442-447. https://doi.org/10.1046/j.1460-9592.2002.00868.x
Costi, D., Cyna, A. M., Ahmed, S., Stephens, K., Strickland, P., Ellwood, J., Larsson, J. N., Chooi, C., Burgoyne, L. L., & Middleton, P. (2014). Effects of sevoflurane versus other general anaesthesia on emergence agitation in children. Cochrane Database of Systematic Reviews, 2014(9), CD007084. https://doi.org/10.1002/14651858.CD007084.pub2
Dahmani, S., Stany, I., Brasher, C., Lejeune, C., Bruneau, B., Wood, C., Nivoche, Y., Constant, I., & Murat, I. (2010). Pharmacological prevention of sevoflurane- and desflurane-related emergence agitation in children: A meta-analysis of published studies. British Journal of Anaesthesia, 104(2), 216-223. https://doi.org/10.1093/bja/aep376
Eckenhoff, J. E., Kneale, D. H., & Dripps, R. D. (1961). The incidence and etiology of postanesthetic excitement: A clinical survey. Anesthesiology, 22(5), 667-673. https://doi.org/10.1097/00000542-196109000-00002
Fields, A., Huang, J., Schroeder, D., Sprung, J., & Weingarten, T. (2018). Agitation in adults in the post-anaesthesia care unit after general anaesthesia. British Journal of Anaesthesia, 121(5), 1052-1058. https://doi.org/10.1016/j.bja.2018.07.017
Kain, Z. N., Caldwell-Andrews, A. A., Maranets, I., McClain, B., Gaal, D., Mayes, L. C., Feng, R., & Zhang, H. (2004). Preoperative anxiety and emergence delirium and postoperative maladaptive behaviors. Anesthesia & Analgesia, 99(6), 1648-1654. https://doi.org/10.1213/01.ANE.0000136471.36680.97
Lee, S. J., & Sung, T. Y. (2020). Emergence agitation: Current knowledge and unresolved questions. Korean Journal of Anesthesiology, 73(6), 471-485. https://doi.org/10.4097/kja.20097
Mason, K. P. (2017). Paediatric emergence delirium: A comprehensive review and interpretation of the literature. British Journal of Anaesthesia, 118(3), 335-343. https://doi.org/10.1093/bja/aew477
Moore, A. D., & Anghelescu, D. L. (2017). Emergence delirium in pediatric anesthesia. Pediatric Drugs, 19(1), 11-20. https://doi.org/10.1007/s40272-016-0201-5
Rao, Y., Zeng, R., Jiang, X., Li, J., & Wang, X. (2020). The effect of dexmedetomidine on emergence agitation or delirium in children after anesthesia: A systematic review and meta-analysis of clinical studies. Frontiers in Pediatrics, 8, 329. https://doi.org/10.3389/fped.2020.00329
Sikich, N., & Lerman, J. (2004). Development and psychometric evaluation of the Pediatric Anesthesia Emergence Delirium scale. Anesthesiology, 100(5), 1138-1145. https://doi.org/10.1097/00000542-200405000-00015
Somaini, M., Sahillioglu, E., Marzorati, C., Lovisari, F., Engelhardt, T., & Ingelmo, P. M. (2015). Emergence delirium, pain or both? A challenge for clinicians. Paediatric Anaesthesia, 25(5), 524-529. https://doi.org/10.1111/pan.12580
Vlajkovic, G. P., & Sindjelic, R. P. (2007). Emergence delirium in children: Many questions, few answers. Anesthesia & Analgesia, 104(1), 84-91. https://doi.org/10.1213/01.ane.0000250914.91881.a8
Voepel-Lewis, T., Malviya, S., & Tait, A. R. (2003). A prospective cohort study of emergence agitation in the pediatric postanesthesia care unit. Anesthesia & Analgesia, 96(6), 1625-1630. https://doi.org/10.1213/01.ANE.0000062522.21048.61