Delayed Emergence

This is an anaesthetic crisis
Priority is to: * Rapidly identify and reverse immediately treatble causes

#####Immediate Management

• Scan monitors
  ECG, BP, ETCO₂, SpO₂, temperature.

• Confirm all anaesthetic agents are ceased
  Inhalational & intravenous.

• Apply nerve stimulator & evaluate for residual paralysis
  Reverse as required:

• Check BSL
  25-50ml of 50% dextrose if BSL ⩽3mmol/L (or higher, if the patient has poorly controlled DM).

• Apply processed EEG

• Check syringes and ampoules for drug error

• Consider:

  • Narcotic reversal
    Naloxone 40μg IV Q2 minutes.
  • Benzodiazepine reversal
    Flumazenil 0.2-1mg IV Q1 minutes.
  • Inhalational reversal
    Physostigmine 0.5-1mg IV.
  • Anticholinergic reversal
    Physostigmine 0.5-1mg IV.

• Check ABG

  • Electrolytes
  • CO₂

• Check temperature
  Actively warm if ⩽34°C.

Causes

Failure to wake from anaesthesia requires a broad differential:

• Drugs
  • Drug error
  • Anaesthetic drugs
    • Opioids
    • Hypnotics
    • Paralytics
      • Suxamethonium apnoea
    • Anticholinergics
      Central anticholinergic syndrome.
    • Local anaesthetic
  • Other drugs
    • Antiepileptics
• Infection
  • Sepsis
  • Meningitis/encephalitis
• Metabolic
  • Gas
    • Hypoxia
    • Hypercarbia
  • Electrolyte
    • Hyponatraemia
    • Hypo/hyperglycaemia BSL ⩾14mmol/L.
  • Endocrine
    • Hyperthyroidism
    • Hypothyroidism
  • Hepatic encephalopathy
  • Hypo/hyperthermia
  • Uraemia
  • Ammonaemia
• Structural
  • Blood
    • CVA
    • Cerebral hyperperfusion syndrome
  • Brain
    • Hypoxic brain injury
    • Cerebral oedema
    • Seizure/post-ictal state
  • CSF
    • Hydrocephalus
    • Pneumocephalus

Investigations:

Bedside:

• ABG

Laboratory:

• FBE
• UEC/
• LFTs
• TFTs
• Toxicology screen

Imaging:

• CTB
  Consider repeating at 6-8 hours if no improvement in ICU.
• MRI

Management

Examination and consider further investigations:

• Focused exam:
  • Neurological
    • GCS
    • Pupil
    • Gag/cough
    • Focal signs
  • Cardiovascular
    Adequacy of perfusion.
• Investigations

Consider disposition:

• ICU
• Neurology

---

References

1. Sinclair RCF, Faleiro RJ. Delayed recovery of consciousness after anaesthesia. Contin Educ Anaesth Crit Care Pain. 2006 Jun 1;6(3):114–8.
2. Ether. Delayed Emergence from Anesthesia. Standford School of Medicine. Accessed 7/2019.
3. Kazemi P, et al. Delayed Emergence. Anaesthesia Considerations. Accessed 7/2019.