Electroconvulsive Therapy (ECT)

ECT Overview

Intentional inducement of a generalized seizure of the CNS, lasting adequate time for treatment of severe neuropsychiatric disorders

Other uses are mania, catatonia, vegetative dysregulation (disturbance of the balance between sympathetic and parasympathetic systems), inanition (exhaustion from lack of nutrition or vitality), suicidal drive, and schizophrenia

ECT is considered a safe and effective treatment for severe and medication-resistant major depression

80-90% respond with ECT as first-line treatment

50-60% who are unresponsive to medical treatment with combinations such as nortriptyline and lithium carbonate

ECT treatments exceed the total number of coronary revascularizations, herniorrhaphy, and appendectomy procedures in the US

Nortriptyline

Aventyl/Pamelor: tricyclic antidepressant

• Blocks reuptake of norepinephrine and serotonin into nerve endings, increasing action in nerve cells

Lithium Carbonate

Antimanic, anti-psychotic

May alter Na, K ion transport across cell membrane in nerve and muscle cells

May balance biogenic amines of norepinephrine and serotonin in CNS area involved in emotional responses

• Used for bipolar disorders (manic phase)
• Prevention of manic-depressive psychosis

Most patients receive three treatments/week and can undergo between 6-12 treatments overall

Theories of ECT

? Profound changes in brain chemistry, such as enhancement of dopaminergic, serotonergic, and adrenergic neurotransmission

? Release of hypothalamic or pituitary hormones with antidepressant effects

Anticonvulsant effects raise seizure threshold and decrease seizure duration, which is thought to have a positive impact on the brain

Anesthetic considerations

Ultra-brief general anesthesia provides a lack of consciousness and amnesia.

Usually, three treatments/week, up to 6-12 total - some improvement after 3-5

Consider # of treatments. You may apply cricoid pressure during the seizure to avoid repeated intubations

NPO status

Consent signed

Regular medications ok up to one hour before the procedure with a sip of water

Pre-oxygenate before induction

IV access

Monitors

Pulse oximeter, ECG, NIBP, Temp, PNS, rubber bite blocks

ETCO2 as hypercarbia and hypoxemia shorten seizure duration

Hyperventilation/hypocapnia may prolong seizure duration

A tourniquet to lower extremity/arm to evaluate the length of the induced convulsion

• Prevents NMBD reaching that body part

Seizure lasts 30-90 seconds, motor shorter than EEG tracings

Increases in seizure threshold can be seen with multiple treatments

If the has a PPM/ICD, have a magnet readily available

Cardiovascular effects

Parasympathetic response during the tonic phase

• Decreased HR, hypotension, bradyarrhythmias, and increased secretions
• Tonic = start of seizure, short, possible vocalization
• Premedicate with Glycopyrrolate
  • Prevent profuse secretions and attenuate bradycardia

Sympathetic response during the clonic phase causes tachycardia, hypertension, tachydysrhythmias

• Clonic=convulsions
• NTG, Nifedipine, alpha- and beta-adrenergic blockers to control sympathetic response

Cerebral

Increased cerebral blood flow (100-400%)

Increased ICP

Increased intraocular pressure

Increased intragastric pressure

Contraindications

Absolute

Pheochromocytoma, recent MI <3 months, CVA <1 month, intracranial surgery or lesion, unstable cervical spine

Relative

Angina, CHF, PM, ICD, AICD, pulmonary disease, major bone fracture, glaucoma, retinal detachment, thrombophlebitis, pregnancy

Cognitive impairments post-procedure

Postictal confusion lasting up to 30 min

• The hypothesis is that it stems from high plasma lactate (more muscle relaxants?)

Anterograde memory dysfunction

• Patients may rapidly forget new information

Retrograde memory dysfunction

• Forgets memories from several weeks to several months before ECT

Potential for headache, muscle aches

• Prevent with Rocuronium 0.1 mg/kg to minimize fasciculations and post myalgias with succinylcholine

Nausea

Drugs

Anticholinergics

Atropine 0.4-1mg IV or IM / Glycopyrrolate 0.005 mg/kg IV or IM

Anesthetics

Alfentanyl 0.2-0.3 mg/kg IV

Etomidate 0.1-0.3 mg/kg IV

Ketamine 0.5-1 mg/kg IV (note increased ICP)

Propofol 0.75-1.5 mg/kg IV

Muscle relaxants

Succinylcholine / Cisatracurium 0.15-0.25 mg/kg IV - onset 1-2 min

Atracurium 0.3-0.4 mg/kg IV - onset 6 min

Rocuronium 0.3-0.9 mg/kg IV - onset 1-2 min

Seizure-prolonging drugs

Aminophylline, caffeine (125-250 mg given slowly can prolong seizure), clozapine (for schizophrenia), Etomidate, Ketamine, and Methohexital with remifentanil

Seizure-shortening drugs

The seizure threshold increased, and seizure duration decreased, so use small doses

Diltiazem, diazepam, fentanyl, lidocaine, lorazepam, midazolam, propofol, sevoflurane, thiopental

New therapies for depressive disorders

Depression seems to stem from dysfunction within the frontal cortical-subcortical-brainstem neural network, where ECT and antidepressant medications do not act

Repetitive transcranial magnetic stimulation (rTMS)

An electromagnetic coil is placed on the scalp, and convulsions are initiated by trains of rTMS

Therapy is determined by the use of motor threshold (MT), which elicits a twitch of the abductor pollicis muscle of the thumb

Reduced cognitive side effects and more rapid recovery compared to ECT

Magnetic seizure therapy (MST)

Higher intensity, more frequent, longer-duration magnetic seizure-inducing dose

Localized, but does not produce the rigid bilateral masseter muscle contractions seen with ECT, but can produce elevated BP and HR

Vagus nerve stimulation (VNS)

Surgical implantation of a programmable battery-powered electrical stimulator connecting to the patient's left vagus nerve

Implanted in the chest, they must be motionless during the procedure due to proximity to vital structures and organs

Initially improved for treatment-resistant epilepsy, VNS has now been approved for major depressive episodes not responding to four antidepressant medication trials