Delayed emergence - NYSORA

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Contributors

Delayed emergence

Delayed emergence

Learning objectives 

  • Identify the causes leading to delayed emergence
  • Explain the risk factors associated with an increased risk of delayed emergence
  • Manage delayed emergence

Definition and mechanism

  • Failure to regain consciousness or alertness following general anesthesia after surgery
  • The transition from unconsciousness to complete wakefulness occurs along a normal trajectory, although slowed down
  • Alternatively, the awakening trajectory proceeds abnormally, possibly leading to emergence delirium
  • Most cases of delayed return of consciousness are rapidly treatable 

Causes

Pharmacodynamic causesGenetic variations
Hypothermia
Drug interaction
Serotonin syndrome
Neuromuscular blockers
Heroin or opioid toxicity
IV anesthetic agents (Total intravenous anesthesia (TIVA))
Central anticholinergic syndrome
Metabolic alterationsHypoglycemia
Hyperglycemia
Hyponatremia
Hypernatremia
Metabolic acidosis
Neurological rare causesHypoperfusion/ischemia
Intracranial hemorrhage
Venous thromboembolism
Seizures
Myxedema coma
Functional coma
Brainstem stroke
Psychiatric rare causesConversion disorder

Risk factors

Patients conditionsOlder age
Body habitus
Gender
Preexisting clinical conditionsPsychological disorders
Neurologic conditions
Cardiac diseases
Hypertension
Pulmonary diseases
Chronic kidney disease
Liver diseases
Hypothyroidism
Drug or alcohol abuse
Metabolic alterations
Intraoperative conditionsDrugs (e.g. Heroin or opioid toxicity)
Metabolic alterations (intraoperative)
Chronic pharmacotherapyBenzodiazepines
Barbiturates
Anticholinergics
Antidepressants
Antipsychotics
Herbal medications

Diagnostic steps 

  • Vital signs (including temperature)
  • neuromuscular monitor
  • Neurologic exam (pupils, cranial nerves, reflexes, response to pain)
  • Fingerstick glucose
  • Arterial blood gas with electrolytes

Differential diagnosis

Drug effectsResidual anesthetic (volatile, propofol, barbiturates, ketamine)
Excess narcotics
Inadequate reversal or no reversal of muscle relaxation
Pseudocholinesterase deficiency
Alcohol or street drugs
Herbal medicines (valerian root, St. John’s wort)
Infection
InfectionEncephalitis
Meningitis
Sepsis
Metabolic disordersHypercarbia
Hypoxemia
Metabolic acidosis
Acidosis
Hypoglycemia/Hyperglycemia
Hyponatremia/electrolyte abnormalities
Hypothermia/Malignant hyperthermia
Uremia
Hepatic encephalopathy
Osmolality problems
Myxedema coma
Neurologic disordersNew ischemic event
Subarachnoid hemorrhage
Seizures or postictal state
Increased intracranial pressure or pre-existing obtundation
Perioperative stroke (ischemic or hemorrhagic)
Hydrocephalus
Diffuse anoxic injury
Pneumocephalus
Cerebral hyperperfusion syndrome

Management

Delayed emergence, GCS, focal signs, pupils, symmetric motor movement, ABC ckeck, blood pressure, ECG, fluazenil, nalaxone, neostigmine, phsysiostigmine, sugammadex, glycopronium bromide, glucose, CT, neurological causes

Additional facts

  • Recent studies indicate that induction and awakening are asymmetric processes
  • Neural circuits that mediate induction do not completely overlap those that mediate emergence for anesthesia

Suggested reading

  • Cascella M, Bimonte S, Di Napoli R. Delayed Emergence from Anesthesia: What We Know and How We Act. Local Reg Anesth. 2020 Nov 5;13:195-206.
  • Thomas E, Martin F, Pollard B. Delayed recovery of consciousness after general anaesthesia. BJA Educ. 2020 May;20(5):173-179.
  • Rafizadeh S, Kerry-Gnazzo AR, DeWalt K. An Unresponsive Patient in Postanesthesia Care Unit: A Case Report of an Unusual Diagnosis for a Common Problem. A A Pract. 2020 Aug;14(10):e01293.
  • Yonekura H, Murayama N, Yamazaki H, Sobue K. A Case of Delayed Emergence After Propofol Anesthesia: Genetic Analysis. A A Case Rep. 2016 Dec 1;7(11):243-246.

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