32. ECT Flashcards
A 52-year-old male with a long history of manic depression is scheduled
for electro-convulsive therapy. He is a heavy smoker and a recently
diagnosed hypertensive. He is taking a tricyclic antidepressant and an
anti-hypertensive.
Tell me what you know about ECT
ECT involves direct stimulation of the brain with an electrical current
applied via transcutaneous electrodes.
The resultant spike and wave activity seen on the EEG is accompanied by a
generalized motor seizure and an acute cardiovascular response
Effects
CNS effects include a marked increase in both cerebral blood flow and
intracranial pressure..
The long-term benefits are improvement in the symptoms of depression,
mania and some types of schizophrenia, particularly drug-resistant
conditions.
The typical cardiovascular response to ECT is a biphasic autonomic nervous system stimulation
CVS response
Initial parasympathetic response
Transient bradycardia lasting 10 to 15 seconds
Increased salivation
Occasionally, asystole, especially with repeated stimuli.
Followed immediately by a more prominent sympathetic response
Transient tachycardia and hypertension lasting 5 min or longer
Occasionally myocardial ischaemia and infarction.
Do you routinely do anything to attenuate these cardiovascular
responses?
Parasympathetic effects can be attenuated with an anticholinergic drug
Glycopyrrolate is more appropriate than atropine
It does not cross the blood–brain barrier and is effective in treating
bradycardias and as an antisialogogue.
Atropine can cause confusion in this susceptible population.
The sympathetic responses can be blunted by administration of:
Short-acting opioids such as alfentanyl or fentanyl
Short-acting -blockers such as esmolol or labetalol.
Bearing this in mind, what pre-operative assessment should be
undertaken in this patient?
Standard anaesthetic and medical history and assessment should be
performed.
His history of smoking and hypertension puts him at risk of ischaemic heart
disease and this should be looked for carefully.
History of exercise tolerance, chest pains, cardiac failure
Clinical examination looking for signs of heart failure or end-organ
damage
12-lead ECG as baseline
Dynamic testing if appropriate (Exercise ECG, stress echo)
U&Es and urine dipstick to look for evidence of renal impairment
Transthoracic echocardiogram if concerns about ventricular function.
If this patient had ischaemic heart disease, is it safe to proceed with ECT?
Treatment can be undertaken in those with co-existing medical problems,
but their cases should be considered carefully by the multi-disciplinary team,
led by consultant psychiatrist and anaesthetist.
If the patient has a condition refractory to conventional treatment, then
ECT may be in his best interests, balancing the risks of the treatment against
the potential benefit.
Stable ischaemic heart disease is not an absolute contra-indication to ECT.
Appropriate precautions would include:
Cardiology review to ensure optimisation
Availability on-site of senior anaesthetic and critical care facilities (i.e. not
suitable for isolated-site ECT)
Controlling the pressor response with opioids and alpha or -blockers
Invasive arterial monitoring may be required.
When we give anaesthetics for ECT, we cause attenuation of the seizures
with anaesthetic drugs. Is this important?
EEG seizure activity lasting 25–50 seconds is associated with the optimal
antidepressant response.
Induction agents have anticonvulsant properties and would be expected to
reduce seizure activity in a dose-dependent manner.
Delicate balance between achieving adequate anaesthesia and optimal
duration of EEG seizure.
Often need relatively larger doses of induction agents though, as patients
are often on chronic medications, such as benzodiazepines, or take
enzyme-inducing drugs (including alcohol).
Which induction agent would you use?
Propofol has been shown to limit the ECT-induced seizure activity and there
have been concerns that its routine use may limit the effectiveness of the
therapy. However, it is commonly used in reduced doses of 0.75 mg/kg. Its
cardiovascular effects blunt the sympathetic responses well and it has a
rapid recovery profile.
Methohexitone was considered the gold standard for ECT, but is no longer
available.
Why do you give muscle relaxants during ECT?
Tonic–clonic seizure activity can cause injury and severe myalgias so patients would require physical restraint.
Use of muscle relaxants reduce myalgias and can prevent serious injuries
such as fractures and dislocations.
A reduced dose of suxamethonium is recommended by the Royal College of Anaesthetists −0.5 mg/kg
What potential problems are there with using suxamethonium
Bradyarrhythmias can occur especially when associated with the
parasympathetic phase of the seizure.
Myalgias
Hyperkalaemia
Suxamethonium apnoea
Malignant hyperpyrexia in those susceptible.
What alternatives are there to suxamethonium?
Mivacurium is the only practical alternative.
Other NDMRs have been used, but they have a prolonged action.
ECT – further information
ECT – further information
ECT to provoke a generalized epileptic seizure was first described in
1938 and was performed without anaesthesia for almost 30 years
subsequently.
ECT is most useful for the treatment of severe and medicationresistant
depression and mania.
It has also been used more recently in the treatment of schizophrenic
patients with affective disorders, suicidal drive, delusional symptoms
and catatonic symptoms.
Typically, the acute phase of ECT is performed three times a week for 6
to 12 treatments.
In successful cases, initial clinical improvement is usually evident after
3 to 5 treatments.
Maintenance ECT can be performed at progressively increasing
intervals from once a week to once a month to prevent relapses.
Short-term memory loss is common after ECT and more serious
cognitive dysfunction has been described
