Depth of Anesthesia During Electroconvulsive Therapy

Study Overview
=================
Brief Summary
-----------------
Aim: To describe anesthetic depth using spectal edge frequency (SEF) and density spectral array (DSA) and its relation to treatment effect of electroconvulsive therapy (ECT). Study design: Observational study Primary outcomes: SEF, DSA and treatment effect of ECT. Method: SEF and DSA si measured using a commercially available monitor for depth of anesthesia. Treatment effect of ECT will be evaluated using hemodynamic, electroencephalographic and clinical variables.

Detailed Description
-----------------
Background Electroconvulsive therapy (ECT) is an effective therapy for severe depression where an electric current is applied to the brain to induce an epileptic seizure (1). The success of ECT is dependent upon the degree and quality of epileptic activity (2). ECT is normally administered after administering a muscle relaxant to prevent the seizure activity from causing muculoskeletal injuries. To tolerate the muscle relaxant the entire procedure is performed under general anesthesia. Most hypnotics have anti-convulsant effects and therefore counteract the effects of ECT (3). This implies that deep anesthesia hinders an optimal treatment effect of ECT which is supported by observational data (4). This relation has been proven with lighter anesthesia measured through bispectral index (BIS) correlating to longer seizure duration (5). BIS is not optimized to estimate the depth of anesthesia under very dynamic anesthetic protocols as there is an inherent latency in the computation of the BIS value. Anesthesia for ECT generally consists only of induction and recovery with no stable anesthetic phase making BIS an inappropriate measure of anesthetic depth. Indices of anesthetic depth that are derived directly from the processed EEG-signal have a negligent latency and can therefore be used with more precision during anesthesia for ECT. Spectral edge frequency (SEF) is the frequency under which 95 % of the total amplitude of the EEG-signal is found and it decreases with increasing depths of anesthesia. The density spectral array (DSA) is a graphic representation of the frequency and amplitude of the EEG signal over time and it is possible to interpret the DSA in real time without extensive training. The SEF and DSA have not, to our knowledge, been previously tested during general anesthesia for ECT. In the postictal phase during recovery from ECT some patients become agitated and confused (6). This condition is not clearly defined in the literature but is commonly referred to as postictal agitation (PIA) and due to differing definitions the incidence is difficult to estimate. Incidences in the range of 10-20 % have been reported (7). In the post-operative period after cardiac surgery decreased regional cerebral oxygen saturation (SrcO2) has been linked to post-operative confusion (8). A possible link between decreased SrcO2 and PIA has not been studied before. Aim The aim of this research project is two-fold: To study the relation between anesthetic depth measured with SEF and DSA and the quality of epileptic activity during ECT. To study the relation between SrcO2 and PIA during ECT. Hypotheses Lighter depths of anesthesia as measured by SEF and DSA have a positive correlation with epileptic seizure quality during ECT. SrcO2 during ECT has an inverse correlation with the incidence of PIA. Method Setting and recruitment The study will be performed at the ECT-unit of the university hospital in Örebro. General anesthesia is provided by a nurse specially trained in anesthesia and an anesthesiologist. ECT is provided by specially trained nurses and staff at the ECT-unit. Patients recover from the postictal phase in an adjacent recovery room. Patients undergoing ECT through the outpatient clinic will be recruited to the study. Anesthetic protocol The protocol for anesthesia and ECT will be the same as is being used clinically at the ECT-unit. After preoxygenation anesthesia is induced using thiopental. After confirmation of adequate anesthetic depth (failure to respond to verbal command) suxamethonium is administered. Doses are chosen by the anesthesiologist. Patients are admitted to the recovery room when breathing spontaneously and can maintain a patent airway. Data collection SEF and DSA will be measured continuously from before pre-oxygenation to admittance to the recovery room using a SedLine® (Masimo, Irvine, CA, USA) monitor. The monitor will be blinded during the procedure so as not to affect the staff in any way. SrcO2 will be measured using the same monitor during the same period. Data regarding the seizure duration will be gathered from the electronic patient records. The staff caring for the postictal patients will estimate the degree of PIA according to previously used numerical scale (9).Data will be presented as mean ± SD or median (IQR) according to their distribution. Statistical analysis will be performed using a logistic regression model adjusted for potential confounders such as type of psychiatric medication, age, bilateral or unilateral stimulation.

Official Title
-----------------
Depth of Anetshesia During Electroconvulsive Therapy

Conditions
-----------------
Mood Disorders, Psychotic Disorders

Intervention / Treatment
-----------------
* Device: Depth of anesthesia monitor, SedLine® (Masimo, Irvine, CA, USA)


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Admitted for a course of ECT Exclusion Criteria: Not able to attach electrodes for measurement of depth of anesthesia due to eg. skin condition.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| ECT-patients<br>Patients receiving routine ECT. | Device: Depth of anesthesia monitor, SedLine® (Masimo, Irvine, CA, USA)<br>* The device monitors the patient's electroencephalogram using electrodes applied to the forehead.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in spectral edge frequency | The spectral edge frequency of the patients electroencephalogram | Monitored before, during and after ECT. Total monitoring time is apporximately 30 minutes per patient. | 
| Change in density spectral array | The density spectral array of the patients electroencephalogram | Monitored before, during and after ECT. Total monitoring time is approximately 30 minutes per patient. | 
| Duration of convulsive activity | Measures the duration of both motor and encephalographic convulsions directly following ECT. | Monitored immediately after administration of ECT. | 
| Postictal supression | Measures the degree of encephalographic supression directly following ECT | Monitored immediately after administration of ECT. | 
| Need for restimulation | Measures if there is a need for restimulation directly after evaluating the effect of an administered ECT. | Monitored immediately after administration of ECT. | 
| Change in heart rate. | Mesaures the increase in heart rate directly following ECT. | Monitored immediately after administration of ECT. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Awareness | Patients will be asked if they can recall any part of the tratment from induction of anesthesia until administration of ECT. | Patients are asked at a follow up visit approximately 1 week after a course of several ECT:s. | 
| Adverse effects of ECT | Occurence of adverse effects following ECT, evaluated using the CRPS-memory questionnaire. | Patients are asked at a follow up visit approximately 1 week after a course of several ECT:s. | 
| Desaturation | Occurence of saturation <92 % at any point during anesthesia and ECT. | Monitored immediately before pre-oxygenation, during the entire ECT and until the patient has recovered. Approximately 1 hours of total monitoring time. | 
| End-tidal CO2 | Measurement of end-tidal CO2 | During induction of general anesthesia | 
| Change in depressive symtoms | Effect of ECT on patients' symptoms and quality of life. Evaluated using the self-asessed Montgomery Åsberg Depression Rating Scale (MADRS-S), 0-57 points. A higher score indicate more severe disease. | Patients are asked at a follow up visit approximately 1 week after a course of several ECT:s and before ECT. | 
| Clinical assessment of depth of anesthesia | The treating anesthesiologist will be asked to asses the depth of anesthesia. The anesthesiologist is asked after induction of general anesthesia. The terms too heavily sedated, too lightly sedated and adequate level of sedation is used. | Monitored immediately before pre-oxygenation, during the entire ECT and until the patient leaves the recovery ward. Approximately 1 hour of total monitoring time. | 
| Regional cerebral oxygen saturation | Measured using near-infrared spectroscopy | Before, during and after anesthesia and ECT | 
| Occurence of post-ictal agitation | Registered in the recovery ward following ECT. A scale using three levels of agitation is used by the recovery staff. Higher scores indicate increasing levels of agitation. | Monitored in the recovery suite | 
| Change in quality of life | Effect of ECT on patients' symptoms and quality of life. Evaluated using EruroQol 5-Dimensions score (EQ-5D), each quiestion is scored 1-3 or 1-5 points. A higher score indicates worse health related problems. | Patients are asked at a follow up visit approximately 1 week after a course of several ECT:s and before ECT. | 
| Change in illness severity | Effect of ECT on patients' symptoms and quality of life. Evaluated using Clinial global impressions scale (CGI), each question is scored 1-7 points. A higher score indicates higher illness severity. | Patients are asked at a follow up visit approximately 1 week after a course of several ECT:s and before ECT. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
General anesthesia, Electroencephalogram, Awareness, Depth of anesthesia, Depression