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APPENDIX 1: DETERMINATION OF ECT ELECTRODE PLACEMENT AND STIMULUS DOSING A. The ECT Psychiatrist should be familiar with the use of both unilateral and bilateral stimulus electrode placement. The choice of unilateral versus bilateral technique should be made on the basis of an ongoing analysis of applicable risks and benefits. This decision should be made by the ECT psychiatrist in consultation with the consenter and the treating psychiatrist. B. Unilateral ECT (at least when involving the right hemisphere) is associated with significantly less verbal memory impairment than is bilateral ECT, but some data suggest that unilateral ECT may not always be as effective. Unilateral ECT is most strongly indicated in cases where it is particularly important to minimize the severity of ECT-related cognitive impairment. C. Bifrontal Bilateral: Unless compelling considerations favor unilateral ECT, bilateral ECT will be the recommended initial treatment. D. Electrode Placement: 1 With bitemporal ECT, electrodes should be placed on both sides of the head, with the midpoint of each electrode approximately one inch above the PILGRIM PSYCHIATRIC CENTER issue Date: 10/1197 Revision Date: 2/2012001 Facility Policy Reviewed Date:2/20/2001 Page 35 of 58 Issuing Office: Clinical Services Subject: ELECTROCONVULSIVE THERAPY (ECT) midpoint of a line extending from the tragus of the ear to the external canthus of the eye. 2. With bifrontal ECT, electrodes should be placed bilaterally on the forehead. 3. Unilateral ECT should be applied over a single cerebral hemisphere. Most practitioners using unilateral electrode placement routinely place both electrodes over the right hemisphere, since it is usually nondominant with respect to language even for the majority of left-handed individuals. Stimulus electrodes should be placed far enough apart so that the amount of current shunted across the scalp is minimized. A typical configuration involves one electrode in the standard frontotemporal position used with bilateral ECT and the midpoint of the second electrode one inch ipsilateral to the vertex of the scalp (d'Ella placement). 4. Care should be taken to avoid stimulating over or adjacent to a skull defect. E. Stimulus Dosing 1. The primary consideration with stimulus dosing is to produce an adequate ictal response. Regardless of the specific dosing paradigm used, whenever seizure monitoring indicates that an adequate ictal response has not occurred, restimulation should be carried out at a higher stimulus intensity. 2. When bilateral ECT is administered stimulus dosing will generally be individualized on the basis of the half-age formula. (i.e. The delivered percentage of maximal charge output is equal to half the age of the patient). C. When right unilateral ECT is administered, empirical stimulus titration will be used to identify the minimal electrical intensity that produces an adequate generalized seizure. The empirical titration procedure has the following characteristics: a. It is typically conducted at the first treatment b. It involves applying subconvulsive stimuli with stepwise increases in stimulus intensity (of 25 to 100%) c. It can require administration of up to four subconvulsive stimulations at a single treatment session (separated by a delay of at least 20 seconds.) 5. Once the threshold for seizure induction has been determined, subsequent stimulus dosing will be as follows: PILGRIM PSYCHIATRIC CENTER issue Date: 10/1/97 Revision Date: 2/20/2001 Facility Policy Reviewed Date:2/20/2001 Page 36 of 58 Issuing Office: Clinical Services es Subject: ELECTROCONVULSIVE THERAPY (ECT) a. 1.5 times the estimated threshold for bilateral electrode placement b. >5.5 times the estimated threshold for unilateral electrode placement. 6. Reasons for changing sitmulus dosage and/or switching electrode placements during the treatment course may include: a. Having an extremely high estimated threshold that precludes delivering an appropriately suprathreshold stimulus. b. Failure to show clinical improvement c. Showing a particularly slow clinical course d. Showing a high level of cognitive side effects. |
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