Electroconvulsive therapy

Electroconvulsive therapy

Anesthesia type
Airway
Lines and access
Monitors
Primary anesthetic considerations
Preoperative
Intraoperative
Postoperative
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Electroconvulsive therapy (ECT) is a medically induced generalized seizure that consists 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. It is used for refractory depression (unipolar and bipolar types), depression with psychotic features, schizophrenia, and catatonia.

ECT is monitored by EEG, with electrodes placed in left unilateral, right unilateral (most common, fewer memory side effects), and bifrontal. Goal seizure duration is 30-60 seconds. For seizures lasting longer than 120 seconds, termination can be achieved with midazolam/propofol. The initial session may require a dose titration to determine the appropriate electrical stimulus to evoke a seizure. Both the duration of individual seizure & cumulative seizure time between treatments correlated w/ clinical improvement of depression, with total number of ECT sessions determined by patient's clinical response. Repeated rounds of ECT have been shown to increase seizure threshold (try to decrease dose of methohexital or other induction agent if possible to limit size of electrical charge administered).

Mortality risk is extremely low, at <1 in 75,000 treatments. Most common adverse events include transient arrhythmias (10%–40%), gastric aspiration (2.5%), and MSK disorders (0.4%) including fractures. Additional adverse events include pulmonary edema, headache, memory disturbance, and agitation. Very rarely Takotsubo cardiomyopathy, febrile reactions, or neurologic dysfunction may occur.

Absolute contraindications include:

• Untreated Pheochromocytoma
• Intracranial mass/↑ ICP
• Recent MI or Stroke w/in last 30 days

Relative contraindications include:

• Angina pectoris, CHF
• COPD
• Glaucoma, Retinal detachment
• High-risk pregnancy
• Severe osteoporosis (fracture risk)
• Thrombophlebitis

Generally speaking, anesthetic considerations for the procedure are as follows:

1. Pre-oxygenate 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.

Preoperative management

Patient evaluation

System	Considerations
Neurologic
Cardiovascular
Respiratory
Gastrointestinal
Hematologic
Renal
Endocrine
Other

Patient preparation and premedication

• Psychiatric 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.

Intraoperative management

Monitoring and access

PIV x 1

Standard ASA monitors with 5 lead ECG. Single lead EEG

Induction and airway management

• 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 confusion.
  • Remifentanil 200-400 mcg as an adjunct to lower dose of methohexital needed; net ↓ Sz threshold. Monitor for ↓HR/↓BP & chest wall rigidity. If unable to ventilate or very small TV, consider succinylcholine.
  • Sevoflurane can be used for inhalational induction when no IV access possible.
• 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)
• Initial PARAsympathetic discharge:
  1. Glycopyrrolate 0.2mg to prevent bradycardia. Usually given prior to induction agents
• Subsequent Sympathetic discharge:
  1. Nitroglycerin &/or Beta blockers (esmolol, labetalol) can be used to attenuate sympathetic response.
  2. Hyperglycemia often seen in insulin dependent Pt -> BG Pre/Post

Positioning

Supine or with HOB elevated

Maintenance and surgical considerations

• ECT stimulus -> short initial parasympathetic response caused by vagal nerve stimulation followed by a large sympathetic discharge
• Cardiovascular
  • 1st: Parasympathetic response may cause asystole, bradycardia, PVCs, hypotension, & ventricular escape rhythm.
    • If known profound parasympathetic response, can blunt w/ glycopyrrolate pre-induciton
  • 2^nd: Sympathetic tone ↑ with seizure generation -> ↑ HR, PVCs, bigeminy, trigeminy, sinus tachycardia, ST segment changes (↑ myocardial O2 consumption) & severe HTN.
    • Often resolves quickly, but if Pt requires intervention consider nitroglycerin, esmolol, or labetalol
• Respiratory: 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 & ↑BP -> ↑ICP
• Neuroendocrine: ↑ corticotropin, cortisol, & catecholamines.
  • Effects on glucose levels vary; consider Pre/Post glucose in insulin dependent patients.
• GI: ↑ intragastric pressure
• Eye: ↑ intraocular pressure

Postoperative management

Potential complications

• Post-ECT Delirium (or if flumazenil given pre-induction): treat with midazolam 1-2mg

Procedure variants

	Variant 1	Variant 2
Unique considerations
Position
Surgical time
EBL
Postoperative disposition
Pain management
Potential complications