9.2 ECT Flashcards
A 55-year-old patient is due to have electro-convulsive therapy (ECT) for severe depression.
a) What are the specific preoperative considerations for ECT? (5 marks)
- > > Capacity for consent;
patient may be under section. - > > Psychiatric illness
may make it difficult to obtain full medical history from
the patient,
may affect compliance with treatment for comorbidities,
may affect recent oral intake
(consider dehydration and electrolyte disturbance). - > > Anaesthetic assessment:
check for significant reflux
(usually do not use airway adjuncts in ECT),
dentition (bite block will be used). - > > Assess for comorbidities
that specifically affect suitability for ECT:
significant ischaemic heart disease,
cardiac failure
(ventricular dysfunction noted in normal
hearts for up to six hours afterwards),
significant valvular disease,
raised intracranial or intraocular pressure,
untreated cerebral aneurysm,
recent cerebrovascular accident,
unstable fracture or cervical spine
(patient is 55 years old, increasing the likelihood of some of these issues being present).
5. >> Check for implantable cardioverter defibrillator (ICD) (which should be deactivated) or permanent pacemaker (which may be set into a fixed mode, depending on underlying pathology). Liaise with cardiac physiologist.
6. Remote Site >> ECT tends to happen in site remote from main theatres: ensure full staffing, monitoring, equipment, recovery facilities – if patient has significant comorbidities, consider need for relocation to more central, supported site.
b) What are the physiological effects of ECT (7 marks)
Physiological effects of ECT:
Airway:
risk of laryngospasm,
increased salivation
secondary to parasympathetic phase.
Respiratory:
risk of aspiration.
Cardiovascular:
brief (15 seconds) parasympathetic response
with bradycardia (risk of asystole),
followed by prominent sympathetic response;
increased heart rate and blood pressure,
therefore increased myocardial oxygen consumption.
Neurological:
increased cerebral oxygen consumption
and intracranial pressure.
Risk of intracranial haemorrhage,
transient ischaemic defects,
status epilepticus.
More commonly, disorientation and memory loss.
Gastrointestinal:
increased gastric pressure risking reflux.
Cutaneomusculoskeletal:
seizure increases peripheral oxygen
consumption and results in raised lactate,
raised temperature and myalgia
b) Which physical injuries may occur during ECT? (3 marks)
Physical injuries that may occur during ECT:
> > Dental damage due to seizure plus bite block.
> > Intraoral damage due to biting.
> > Musculoskeletal damage and
fractures rare since use of muscle relaxant.
> > Myalgia due to seizure and use of suxamethonium.
c) The patient is taking lithium and fluoxetine. What are the anaesthetic implications of these agents
during ECT? (5 marks)
Lithium:
» Potentiation of effect of
neuromuscular blocking drugs
and volatile agents.
> > Nephrogenic diabetes insipidus –
consider patient fluid status.
> > Narrow therapeutic index –
ensure recent level check.
> > Renally excreted.
NSAIDs reduce lithium excretion
and can result in toxic levels.
> > Cardiac arrhythmias are a side effect,
worse if toxic.
> > Omit for 24 hours prior to anaesthesia.
Fluoxetine:
What are the anaesthetic implications of these
agents during ECT?
> > Tramadol and meperidine contraindicated – risk of serotonin syndrome.
Inhibits CYP2D6, thus preventing metabolism from codeine to morphine
so no analgesic effect would be obtained.
ECT Explained
ECT:
» Used for severe, medication-resistant depression, mania, catatonia.
> > Tonic–clonic seizure of specific duration (15–120 seconds) is induced.
> > Both electrodes on the non-dominant hemisphere minimises cognitive side effects.
> > Electrode each side if speed of recovery is the most important factor.
> > Repeat twice a week for up to four weeks or until no further improvement
