Electroconvulsive Therapy. Presented by 許仲寬 91-0 9-17. Current condition in 西址 OR. Monitor setup, EEG Preoxygenation, bite protection Rapifen 1ml, Pentothal 150mg~250mg One lower leg isolated with tourniquet Succinylcholine 60~80mg ECT discharge
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Electroconvulsive Therapy Presented by 許仲寬 91-09-17
Current condition in 西址 OR • Monitor setup, EEG • Preoxygenation, bite protection • Rapifen 1ml, Pentothal 150mg~250mg • One lower leg isolated with tourniquet • Succinylcholine 60~80mg • ECT discharge • Recovering (Trandate if necessary) • Recheck v/s, pupil reflex
ECT • Programmed electrical stimulation of the CNS to initiate seizure activity. The precise mechanism remains unknown. • The electrical stimulus results in generalized tonic activity for approximately 10 seconds, followed by generalized clonic activity for a variable period ranging from a few seconds to more than 1 minute.
Overall seizure duration is a primary determinant of treatment efficacy • 25~50s optimal, <15s, >120s ineffective • Duration depends on age, energy of stimulus delivered, electrode placement, seizure threshold, and medications administered, including anesthetics. • Electrodes may be placed bilaterally or unilaterally. Bilateral is more effective, but results in greater cognitive side effects
Indication of ECT • severe and medication-resistant depression and mania • schizophrenic patients with affective disorders, suicidal drive, delusional symptoms, vegetative dysregulation, inanition, and catatonic symptoms • 75~85% favorable response
Mortality: 1 per 10,000 (1997, APAC) • Cause – cardiovascular decompensation, prolonged apnea, status epilepticus, cerebral herniation • Morbidity: cardiovascular complication, bone fractures, musculoskeletal injuries, oral injuries • Side effect: headache, muscle pain, nausea • Cognitive dysfunction: amnesia, Postictal Delirium
Physiology • Initial parasympathetic discharge,10~15s, manifested by bradycardia, occasional asystole, and/or premature atrial and ventricular contractions. Hypotension and salivation may be noted. • Followed by sympathetic discharge, associated with tachycardia, hypertension, premature ventricular contractions, and rarely ventricular tachycardia. The tachycardia peaks at 2 minutes after stimulus and is normally self-limited. • ECG changes including ST-segment depression and T-wave inversion may also be seen, without myocardial enzyme changes consistent with myocardial infarction.
SBP is transiently increased by 30%–40%, and HR is increased by 20% or more, resulting in a two- to fourfold increase in the rate-pressure product (RPP), an index of myocardial oxygen consumption • Increases in cerebrovascular resistance followed immediately by increased cerebral blood flow and cerebral metabolic rate • Hyperventilation-induced hypocapnia appears to augment the HR and RPP responses compared with normocapnic conditions
Methohexital: gold standard 0.75-1 mg/kg • Thiopental 1.5-2.5mg/kg: shorten duration, increase bradycardia & PVC, higher MCA flow velocity than propofol • Etomidate 0.15-0.3 mg/kg: longer duration, accentuate hemodynamic response • Propofol 0.75 mg/kg: potent anticonvulsant, cardiovascular depressant, in larger dose 1.5mg/kg, duration shortened but improvement not affected
Ketamine: intrinsic sympathomimetic activity, shortened duration • Benzodiazepine: avoided, anticonvulsant • Sevoflurane: 1.7% Sev + 50% nitrous oxide, or 3.4% Sev alone, similar to thiopental, for late stages of pregnancy to reduce uterine contraction
Succinylcholine: 0.5, 0.75-1.5 mg/kg, avoided in malignant hyperthermia, neuroleptic malignant syndrome • Mivacurium 0.2mg/kg: most often alternative • Atracurium 0.5mg/kg: onset 6 min, recovery 16min • Rocuronium: no clinical reports
Glycopyrrolate: drug of choice, reduce oral secretion and bradycardia • Esmolol 1-1.3 mg/kg • Labetalol 0.1-0.2 mg/kg • Sublingual nifedipine 10mg, 20 min before • NTG 3ug/kg 2 min before • Nitroprusside + b-blocker: for intracranial aneurysm, dissecting aortic aneurysm, aortic stenosis • Opioid: Alfentanil 10ug/kg prolong • Fentamyl 1.5ug/kg shorten
Suggested Technique • NPO overnight, clear fluid allowed 1 h before • To prevent myalgias, aspirin, acetaminophen, ketorolac given as premedication • Oral airway required for both ventilation and protection • EEG, EMG, tourniquet technique to isolate an extremity for seizure activity quantification
Special condition • Cerebral aneurysm - propofol, atenolol 50mg, nitroprusside 30ug • Subdural hemorrhage, intracranial mass - unilateral electrode away from the lesion - pretreat with steroid, diuretic, hyperventilation • Cardiovascular disease • B-blocker for CAD • Anticoagulation for AF • Atropine & avoid large dose SCC for bradycardia • Pheochromocytoma should be excluded
NMS - Avoid succinylcholine & sevoflurane • Pregnancy - tocolytic, sevoflurane, rapid sequence induction • Inadequate seizure activity - etomidate, reduced methohexital in combination with alfentanil / remifentanil, aminophylline, caffeine
References • Anesthesia for electroconvulsive therapy (Anesth Analg 2002;94:1351-64) • Treatment of Psychiatric Disorders (Glen O. Gabbard, p1267-1293) • Anesthesia (Miller, Ch.70 p2269-2273) • Clinical Anesthesiology (Morgan, Ch 27, p594-596) • Clinical Anesthesia Procedures of MGH (Hurford, Ch 31, p558-561)