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
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- 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
- Cardiovascular effects:
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- 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.
- Cerebral effects:
Pre-operative Assessment
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- 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
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- 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