ANAESTHESIA FOR ELECTRO-CONVULSIVE THERAPY

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ANAESTHESIA FOR ELECTRO-CONVULSIVE THERAPY:

ANAESTHESIA FOR ELECTRO-CONVULSIVE THERAPY Dr Akin-Williams OO

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INTRODUCTION HISTORICAL BACKGROUND INDICATIONS CONTRAINDICATIONS ADMINISTRATION OF ECT CONCULSION

INTRODUCTION TO ELECTROCONVULSIVE THERAPY :

INTRODUCTION TO ELECTROCONVULSIVE THERAPY Electroconvulsive therapy (ECT) is a treatment for severe mental illness in which a brief application of electrical stimulus is used to produce a generalized seizure.

HISTORICAL BACKGROUND:

HISTORICAL BACKGROUND Ladislas von Meduna : 1934 successfully treated a catatonic man through chemically induced epileptic fits. Electroconvulsive therapy {ECT} was first performed in 1937. For almost 30 years it was performed without any anaesthetic agents.

Cerletti and Bini (1937): ECT:

Cerletti and Bini ( 1937): ECT Initially done without muscle blocker or anesthetic

INDICATIONS FOR ECT:

INDICATIONS FOR ECT Severe depression: if drug treatment fails or is not tolerated Bipolar disorder: manic or depressed phase Acute or Catatonic Schizophrenia Patient is severely withdrawn or starving: effects seen in days rather than weeks Depression in pregnancy: with acute mania

ECT DEVICE:

ECT DEVICE

CONTRAINDICATIONS TO ECT:

CONTRAINDICATIONS TO ECT CV Recent MI < 3 months; Severe angina, CHF Aneurysm of major vessel Pheochromocytoma CNS Cerebral tumor or aneurysm Recent CVA <1 month Respiratory System Severe respiratory failure Pregnancy Thyrotoxicosis Cardiac dysrhythmias Glaucoma Retinal detachment RELATIVE ABSOLUTE

ADMINISTRATION OF ECT:

ADMINISTRATION OF ECT A n electrical current is applied transcutaneously to the brain via two electrodes positioned either bilaterally or unilaterally Bilateral ECT : used more commonly and is preferred when speed of clinical recovery takes priority. Unilateral ECT: performed on the non-dominant hemisphere M inimal cognitive adverse effect Typically, ECT is performed twice weekly until there is a lack of further improvement (on average, 3–4 weeks).

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(a) Bilateral ECT. © The Author [2010]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournal.org

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Generalized seizures for 30-60 seconds in duration are required for therapeutic effects. O ptimal seizure duration remains unclear. Too short (<10 s) or too long (>120 s) may reduce clinical efficacy . A mount of current delivered is more important than length of seizure 75-90% of patients exhibit a dramatic and sustained improvement Transient neurological dysfunction does occur but permanent neuronal injury is very rare

PHYSIOLOGIC EFFECTS OF ECT ON THE CARDIOVASCULAR SYSTEM :

PHYSIOLOGIC EFFECTS OF ECT ON THE CARDIOVASCULAR SYSTEM Initial Parasympathetic Discharge (15 seconds) Coincident with the tonic phase Bradycardia: <30 bpm or transient asystole Sustained Sympathetic Discharge (1-3 min ) Coincident with the clonic phrase Tachycardia Hypertension Dysrhythmias and T-wave abnormalities

Effect of ECT :

Effect of ECT CNS Initial vasoconstriction Sustained increase in cerebral blood flow Increase cerebral metabolism Resulting increase in intracranial pressure TIA , intracranial haemorrhage , cortical blindness cognitive adverse effects . Disorientation, impaired attention, and short-term memory impairment lasting several weeks occurs in more than 50% of the patients. OTHERS Intraocular and intragastric pressure increases

GENERAL PHYSICAL EFFECTS:

GENERAL PHYSICAL EFFECTS Unmodified ECTs : high incidence of fractures and dislocation, but these are now rare. Headache, myalgia {either from the seizures or suxamethonium} Drowsiness, weakness ,nausea and anorexia Increased salivation Dental damage and oral cavity laceration

ANAESTHETIC TECHNIQUE:

ANAESTHETIC TECHNIQUE Procedure is usually performed at remote sites. Anaesthesia should be provided by an experienced anaesthetist A ppropriate resuscitation equipment and drugs must be immediately available . T he Association of Anaesthetists of Great Britain and Ireland's standards for monitoring, trained assistance, and recovery facilities must be available.

PREOPERATIVE ASSESSMENT:

PREOPERATIVE ASSESSMENT The evaluation should include the medical history and physical examination. Patients may be delusional, paranoid, or uncommunicative. Previous anesthetic history, allergies, and current medications used are integral parts of the evaluation A review of systems, particularly the neurologic and cardiovascular systems, may identify potential problems.

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A complete examination, including airway examination, must be performed. The cardiovascular, pulmonary, and neurologic examinations are particularly important for the possible physiologic changes during ECT.

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Premedication: Sedative premedication delay emergence and interfere with seizure generation ,hence should be avoided. P sychiatric drugs interact with anaesthetic drugs. (e.g. indirect sympathomimetics causing hypertensive crises with either tricyclic antidepressants or monoamine oxidase inhibitors). Informed consent Fasting guidelines

CONDUCT OF ANAESTHESIA:

CONDUCT OF ANAESTHESIA OBJECTIVE: To provide ultra-brief, light general anesthesia with moderate degree of muscular relaxation while minimizing the aforementioned physiological and physical effects. Many anaesthetic agents however have anticonvulsant properties. The choice of drugs is therefore a balance between providing adequate anaesthesia without adversely affecting the efficacy of ECT

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Attach monitors Take baseline vital signs {BP, PR, RR, SPO 2 } Place an intravenous access. Preoxygenate. Give induction agent Isolate right or left foot by inflating BP cuff to 100mmHg above systolic BP. Give muscle relaxant. After fasciculation, stand clear of patient ,then the shock will be delivered. Continue assisted ventilation till return of spontaneous breathing . Place in L lateral positon .

INDUCTION AGENTS:

INDUCTION AGENTS An ideal agent: rapid unconsciousness, painless on injection, no hemodynamic effects, no anticonvulsant properties, rapid recovery, and inexpensive Methohexital : 0.5-1 mg/kg thiopental: 2-4 mg/kg ketamine: 0.5-2 mg/kg propofol: 1.5-3 mg/kg etomidate: 0.15-0.3 mg/kg

METHOHEXITAL:

METHOHEXITAL GOLD STANDARD METHYLBARBITURATE WHITE POWDER WITH 6% ANHYDROUS SODIUM CARBONATE INDUCTION IS SIMILAR TO STP WITH GREATER INCIDENCE OF INVOLUNTARY MOVEMENTS, HICCUPS AND LARYGOSPASM. RECOVERY WITHIN 3-4 MIN AFTER SINGLE DOSE PAIN ON INJECTION REDUCED BY MIXING WITH 1% LIDOCAINE. LESS CARDIOVASCULAR AND RESPIRATORY DEPRESSION THAN STP CAUSES CONVULSION IN EPILEPTIC PATIENTS.

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METHOHEXITAL PROPOFOL STP KETAMINE MIDAZOLAM ETOMIDATE SEVOFLURANE CLASS OF DRUG BARBITURATE PHENOL BARBITURATE PENCYCLIDINE DERIVATIVE BENZODIAZEPAM Carboxylated imidazole INHALATIONAL AGENT DOSE 1mg/kg 1mg/kg 1.5-2.5mg/kg 2-4mg/kg 0.5-5mg 0.15-0.3mg/kg 3.4% ONSET +++++ +++++ +++ ++ +++ +++ + SEIZURE THRESHOLD ±↑ ↑↑↑ ↑↑ ↓ ↑↑↑ ↓ -____ SEIZURE DURATION ↓ ↓↓↓ ↓↓ ↑↑↑ ↓↓↓↓ ↑↑↑↑ ↓↓

MUSCLE RELAXANTS:

MUSCLE RELAXANTS OBJECTIVE: To prevent injuries to the musculoskeletal system and to improve airway management . Muscle paralysis facilitates oxygenation, ↓ oxygen utilization by muscles during the seizure Complete paralysis may be associated with prolonged apnea The adequacy of muscular relaxation should be ascertained before applying the ECT stimulus. This process is done by testing for a reduction in deep tendon reflexes and muscle tone .

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Succinylcholine : 0.3-1 mg/kg. Atracurium, 0.3-0.5 mg/kg Mivacurium , 0.15-0.2 mg/kg Rocuronium , 0.45-0.6 mg/kg Common side effects of succinylcholine include arrhythmia, ↑ intraocular or intraabdominal pressure. nondepolarizing muscle relaxants→more prolonged paralysis,

CONCULSION:

CONCULSION Appropriately administered, ECT is safe and effective. Anaesthetists must be aware of not only the physiological response to ECT and how to modify these, but also understand the anaesthetic factors that may influence the efficacy of ECT

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