Clinical Anaesthesia

Anaesthesia for electroconvulsive therapy

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Stripp TK, Jorgensen MB, Olsen NV. Anaesthesia for electroconvulsive therapy – new tricks for old drugs: a systematic review. Acta Neuropsychiatr. 2018 Apr;30(2):61-69. doi: 10.1017/neu.2017.12. Epub 2017 May 2. PMID: 28462732.

 

Physiology and Physical Effects

    • Cardiovascular effects:
      • Secondary to autonomic nervous system activation
      • Initial parasympathetic discharge
        • Bradycardia
        • Hypotension
        • Asystole
      • Prominent sympathetic response follows.
        • Systolic BP increases by 30-40%
        • HR increases by 20% or more
        • Myocardial oxygen consumption increases
        • Cardiac arrhythmias can occur at this point
        • This is the point at which myocardial ischaemia is most likely to occur
        • LV systolic and diastolic function can remain decreased up to 6hrs after ECT

 

    • Cerebral effects:
      • Cerebral O2 consumption, blood flow, and intracranial pressure all increase
      • Rare complications of TIA, intracranial haemorrhage, cortical blindness, and prolonged seizures have been reported.
      • More common are: disorientation, impaired attention, and memory impairment
        • Memory problems usually resolve within 6 months, though permanent loss is possible
        • Both retrograde and anterograde amnesia can occur
      • Unilateral electrode placement and increased inter-ECT interval can reduce cognitive effects
    • Intraocular and intragastric pressure increases, but the latter effect does not appear to be clinically significant
    • Fractures and dislocations are rare, but myalgia, headaches, mild dental damage, oral lacerations, drowsiness, weakness, nausea, and anorexia can occur
    • Mortality is ~1 per 10,000, similar to that of anaesthesia for minor surgical procedures.
      • Cardiovascular (arrhythmia, MI) and pulmonary (laryngospasm and aspiration) complications are the main causes of death and serious morbidity.

Pre-operative Assessment

    • Patients can be poor historians in the setting of major depressive disorder and psychosis
    • There are several relative contraindications:
      • MI or CVA within 3 months
      • Raised ICP
      • Uncontrolled cardiac failure
      • Cerebral aneurysm
      • DVT until anticoagulated
      • Cochlear implant
      • Unstable major fracture
      • Severe osteoporosis
      • Phaechromocytoma
      • Retinal detachment
      • Glaucoma
    • In all cases, these risks should be weighed up with the risks of untreated depression/psychosis.
    • Many psychiatric drugs can interact with anaesthetic drugs:
      • SSRIs can cause SIADN
      • Lithium can cause nephrogenic diabetes
      • Indirect sympathomimetics cause hypertensive crises with tricyclics or MAOIs
      • Meperidine or tramadol can cause serotonin syndrome with SSRIs
      • Interactions with anaesthetic drugs needed in ECT very rarely cause adverse effects
    • Physical exam requires assessment for evidence of:
      • Cardiac failure
      • Severe valvular disease
      • Dysrhythmia
      • Uncontrolled hypertension
      • Poor dentition
      • Dehydration requiring fluid therapy
      • Blood tests and ECG should only be performed as clinically indicated

Performing the Anaesthetic


    • Sedative agents interfere with seizures and should be avoided
    • Patients should be encouraged to empty their bladder beforehand
    • The aim is to have rapid onset and offset of unconsciousness and muscle relaxation
    • The dose of induction agent is initially titrated to patient age, comorbidities and weight, but then modified according to previous response to ECT and changing seizure thresholds.
    • Succinylcholine 0.5mg/kg (up to 1.5mg/kg in some cases) is typically used to reduces convulsions and injury risk.
    • Adverse parasympathetic effects may be controlled with atropine or glycopyrrolate ( is rarely used in our practice)
      • Glycopyrrolate has super anti-sialagogue effects, no central nervous system AEs, and results in less post-ECT tachycardia.
    • Deleterious sympathetic effects may be controlled with beta blockers
      • Atenolol pre-procedurally
      • Labetalol or esmolol intra-procedurally
    • Calcium channel blockers can be used to control arterial pressure
    • Glyceryl trinitrate and dexmedetomidine also blunt the hyperdynamic response and should be considered in patients at high risk of myocardial ischaemia
    • The patient should be pre-oxygenated
    • Ventilation can be gently assisted via facemask after induction
    • Hyperventilation lowers the seizure threshold

 

 

 

 

 

 

 

Post-operative considerations

  • Standard monitoring should be applied during recovery
  • O2 should be applied until saturations are adequate on air
  • Most patients recover quickly
  • The commonest side-effects are confusion, agitation, violent behaviour, amnesia, headache, myalgia, and nausea/vomiting
    • Emergence agitation can be the most challenging problem to treat; small doses of midazolam may be useful if simple methods (e.g secluded, calm recovery environment) do not help.
  • Cardiovascular complications can still occur in recovery

 

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