Electroconvulsive therapy

1. Background:
   • Seizures induced by ECT are generalized seizures that consist of a 2 to 3 second latent phase is followed by a tonic (prolonged muscular contraction) phase lasting 10 to 12 seconds, then a clonic (repeated contraction) phase of 30 to 50 seconds.
   • Seizure duration monitored by EEG; goal seizure duration 30-60 seconds. If seizure > 120s consider termination with midazolam/propofol.
   • Initial session may require a dose titration to determine the appropriate electrical stimulus to evoke a seizure, which requires an appropriate duration of anesthesia & neuromuscular blockade.
   • Configuration of electrode placement: Left unilateral, Right unilateral, & Bifrontal
     • Right unilateral most commonly used to minimize side effects of ECT (ex; short- term cognitive dysfunction)
   • Both the duration of individual Seizure & cumulative seizure time between treatments correlated with clinical improvement of depression. The total # of treatments determined by Pt’s clinical response.
   • Repeated rounds of ECT ↑ seizure threshold (try to decrease dose of methohexital or other induction agent if possible to limit size of electrical charge administered)
2. Morbidity and Mortality Rates:
   • Mortality risk <1 in 75,000 treatments.
   • Most common adverse events: Transient arrhythmias (10%–40%), gastric aspiration (2.5%), & MSK disorders (0.4%), including fractures.
   • Additional adverse events: Pulmonary edema, HA, memory disturbance, & agitation. Very rarely takotsubo cardiomyopathy, febrile reactions, or neurologic dysfunction may occur.
3. Indications:
   • Refractory Depression (unipolar and bipolar types), Depression with Psychotic features, Catatonia, and schizophrenia
4. ABSOLUTE Contraindications:
   • Untreated Pheochromocytoma
   • Intracranial mass/↑ ICP
   • Recent MI or Stroke w/in last 30 days  
5. Relative Contraindications:
   • Angina pectoris, CHF
   • COPD
   • Glaucoma, Retinal detachment
   • High-risk pregnancy
   • Severe osteoporosis (fracture risk)
   • Thrombophlebitis
6. Physiologic Changes:
   • ECT stimulus -> short initial parasympathetic response caused by vagal nerve stimulation followed by a large sympathetic discharge
   • Cardiovascular
     • 1st: Parasympathetic discharge may cause asystole, bradycardia, PVCs, hypotension, & ventricular escape rhythm.
       • If known profound parasympathetic response, can blunt with a small dose of glycopyrrolate pre-induciton
     • 2^nd: Sympathetic tone increases with seizure generation
       • Presents as increased HR, PVCs, bigeminy, trigeminy, sinus tachycardia, ST segment changes (↑ myocardial O2 consumption) & severe HTN.
       • Often resolves quickly, but if Pt requires intervention, consider esmolol or labetalol for tachycardia or HTN
   • Respiratory:
     • During initial parasympathetic discharge at risk for laryngospasm, bronchoconstriction/wheezing
   • Neuro:
     • Initial constriction of cerebral vessels is followed by ↑ cerebral blood flow (1.5–7 times baseline) secondary to ↑ cerebral O2 consumption & elevated BP -> ↑ ICP
     • Preoxygenation prevent cerebral hypoxia.
   • Neuroendocrine:
     • ↑ corticotropin, cortisol, & catecholamines.
     • Effects on glucose levels vary; consider Pre/Post glucose in insulin dependent patients.
   • GI: ↑ intragastric pressure
   • Eye: ↑ intraocular pressure
7. Pre-Induction Considerations:
   • Medication Management:
     • Can continue MAO inhibitors, TCAs, SSRIs, & antipsychotics w/ ECT
     • MAO Inhibitors: Avoid ephedrine (indirect-acting sympathomimetics cause exaggerated BP). Be aware they ↓ plasma cholinesterase activity → ↑ succinylcholine duration
     • Lithium – Risk for delayed awakening, memory loss, and postictal confusion. Hold for 12hr before ECT
     • Benzodiazepines – Hold for 12hr before ECT. May need to give flumazenil before ECT to have an adequate seizure duration.
   • Pacemaker vs Implantable Cardioverter-Defibrillator (ICD):
     • Pacemaker
       • If Not dependent on the device, a magnet should be available in event of device failure.
       • If Dependent on pacemaker, program device to asynchronous mode & a backup pacing mode should be available.
     • ICD:
       • Risk that the device misinterprets muscle movements as an abnormal cardiac rhythm and a discharge is possible.
       • Device should be deactivated & an external defibrillator should be immediately available with placement of external defibrillator pads strongly considered.
     • For a patient with an ICD & who is pacemaker dependent, the EP service should be consulted or in any other cases with pacing concerns.
8. Position: Supine or with HOB elevated
9. Monitors: Standard ASA monitors with 5 lead ECG. Single lead EEG
10. Access: PIV x 1
11. Management of Induction & Seizure Sequelae:
    1. Induction:
       • Methohexital (Brevital) 0.5 to 1 mg/kg; least effect on Sz threshold
       • Etomidate: 0.2 to 0.3 mg/kg; maintains hemodynamic stability
       • Propofol: ↑ seizure threshold & ↓ seizure duration. Need higher stimulus voltages to achieve adequate seizure. May be useful in patients with history of long seizures.
       • Ketamine: can cause post-ECT
       • Remifentanil 200-400 mcg as an adjunct to lower dose of methohexital needed; net ↓ Sz threshold. Watch out for chest wall rigidity (difficult to mask) give succinylcholine asap if unable to ventilate.
       • Sevoflurane can be used for inhalational induction when no IV access possible.
    2. Paralytic:
       1. Succinylcholine 1- 1.5 mg/kg, titrate to adequate paralysis
       2. Rocuronium - Low dose & only if patient has contraindication to succinylcholine (reverse with sugammadex)
    3. Initial PARAsympathetic discharge:
       1. Glycopyrrolate 0.2mg to prevent bradycardia. Usually given prior to induction agents
    4. Subsequent Sympathetic discharge:
       1. Nitroglycerin &/ot Beta blockers (esmolol, labetalol) can be used to attenuate sympathetic response.
       2. Hyperglycemia often seen in insulin dependent Pt -> BG Pre/Post
    5. Post-ECT delirium (or if flumazenil given Pre-Induction):
       1. Midazolam
12. General Procedural Steps:
    1. Preoxygenate well prior to induction
    2. Once induction medications given & patient unconscious start mask ventilating & give paralytic
    3. Hyperventilate -> Hypocarbia (↓ seizure threshold)
    4. Bite guard placed prior to ECT initiation
    5. After ECT & seizure completed remove bite guard and provide supportive airway management until patient regains consciousness.