This is a randomized controlled study assessing the effect of pre-emptive hyperventilation on ECT seizure duration, cerebral desaturation and remission of depressive symptoms in patients with Major Depressive Disorder. Comparison of etomidate and ketamine on remission of depressive symptoms with and without pre-emptive hyperventilation will also be studied.
Electroconvulsive therapy (ECT) is an effective treatment for medication-resistant forms of depression, including major depressive disorder and mania. Therapeutic success of ECT is related to the duration and quality of Electroencephalogram (EEG) and motor seizures. Previous studies have demonstrated that deliberate hyperventilation augments seizure duration in anesthetized subjects. It has also been shown that seizure activity significantly increases cerebral metabolic rate, predisposing the patient to potentially severe cerebral desaturation events. These desaturation events are predicted to be exacerbated by pre-emptive hyperventilation which has a potent cerebral vasoconstrictive effect. Despite the widespread use of ECT, little is known about the effect of hyperventilation on cerebral metabolism in this setting. Ketamine has recently been demonstrated to have anti-depressant properties in patients with major depressive disorder, suggesting that patients treated with ketamine anesthesia and then ECT, may benefit clinically from the additive effects of both treatment modalities, compared to ECT alone. The investigators hypothesize that hyperventilation will facilitate prolonged seizure duration and faster remission of depressive symptoms. As well there may be significant cerebral desaturation and cardiovascular side effects of ECT therapy following hyperventilation. Lastly, the effect of hyperventilation on the efficacy of ECT therapy may be improved when ketamine anesthesia is used simultaneously. To test this hypothesis this study will compare ketamine anesthesia to etomidate anesthesia. Etomidate is a short acting anesthetic that is commonly used in these procedures. The study objectives (primary and secondary) are as follows: 1. To quantify the effect of hyperventilation and type of anesthetic agent on ECT-induced seizure duration 2. To assess the effect of hyperventilation immediately prior to ECT on cerebral metabolism as measured by cerebral oximetry 3. To determine the effect of hyperventilation and anesthetic agent on the remission of symptoms in Major Depressive Disorder 4. To assess the side effect profile of hyperventilation during ECT on hemodynamics
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
48
Etomidate will be administered as a bolus intravenously to induce an adequate depth of anesthesia just prior to ECT at a dose of 0.3 mg/kg
Ketamine will be administered as a bolus intravenously to induce an adequate depth of anesthesia just prior to ECT at a dose of 0.5 to 1.0 mg/kg.
Hyperventilation will be performed in patients after full pre-oxygenation and induction of anesthesia, by administering 20 breaths in 30 seconds using a well-fitting face mask immediately before application of the ECT electrical stimulus.
Health Sciences Centre
Winnipeg, Manitoba, Canada
RECRUITINGEEG seizure duration (seconds)
Duration of seizure spike wave morphology will be assessed by the attending psychiatrist and independently by a second psychiatrist.
Time frame: Up to 3 minutes post ECT
ECT-induced seizure duration (seconds)
Duration of motor seizures will be assessed by timing the onset and offset of appropriate motor twitches in the intrinsic foot muscles and extra-ocular muscles by the attending psychiatrist.
Time frame: Up to 3 minutes post ECT
Changes in cerebral metabolism assessed by cerebral saturation (%)
Cerebral metabolism will be assessed by continuous cerebral oximetry measurements using the ForeSight Cerebral Oximeter, from immediately prior to ECT to 5 minutes post ECT
Time frame: Up to 5 minutes post ECT
Remission of depressive symptoms assessed by HAM-D
Patients will be assessed using a clinician-administered Hamilton Depression Rating Scale (HAM-D) both prior to, and at intervals of 2, 4 and 8 weeks after completion of the study. The HAM-D is a validated healthcare professional-administered assessments of clinical depressive symptoms including: hopelessness, guilt or depressed mood and physical symptoms such as agitation, restlessness and fatigue.
Time frame: Approximately one week prior to, and at 2, 4 and 8 weeks post ECT
Remission of depressive symptoms assessed by MADRS
Patients will be assessed using a clinician-administered Montgomery-Asberg Depression Scale (MADRS) both prior to, and at intervals of 2, 4 and 8 weeks after completion of the study. The MADRS is a validated healthcare professional-administered assessments of clinical depressive symptoms including: hopelessness, guilt or depressed mood and physical symptoms such as agitation, restlessness and fatigue.
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Bilateral, bitemporal electrode placement will be utilized to elicit a seizure via a SpECTrun 5000Q (MECTA Inc.). The electrical dose required will be determined in advance by the patient's attending psychiatrist.
Time frame: Approximately one week prior to, and at 2, 4 and 8 weeks post ECT
Effect on blood pressure
Systolic, diastolic and mean blood pressure will be recorded every minute from immediately prior to 7 minutes post ECT.
Time frame: Up to 7 minutes post ECT
Effect on heart rate
Heart rate (bpm) will be continuously recorded from immediately prior to 7 minutes post ECT.
Time frame: Up to 7 minutes post ECT
Duration of stay in post-anesthesia care unit (hours)
Time frame: Up to 2 hours post arrival in post-anesthesia care unit (PACU).
Incidence of nausea in post-anesthesia care unit (%)
The number of instances of nausea while in PACU will be recorded.
Time frame: Up to 2 hours post arrival in PACU.
Incidence of vomiting in post-anesthesia care unit (%)
The number of instances of vomiting while in PACU will be recorded.
Time frame: Up to 2 hours post arrival in PACU.