Letters to the Editor
Effects of Propofol on Electroconvulsive Therapy Seizure Duration
Dear Editor:
Propofol is an anesthetic agent alternative to methohexital. It is widely used because it is associated with smaller hemodynamic response during electroconvulsive therapy (ECT) (1). Studies have shown that propofol reduces seizure duration, and reports of reduced seizure duration with ECT under propofol anesthesia have led to concerns that propofol may diminish the efficacy of this treatment (2,3). However, although propofol has been associated with shorter seizures when given for ECT anesthesia, the reduced seizure duration has not been associated with smaller therapeutic effect when compared with methohexital anesthesia (4,5).
We compared the effects of propofol on seizure duration with ECTs performed without anesthesia. We retrospectively studied 26 patients consecutively referred for ECT. All patients were hospitalized and treated in Trakya University Psychiatry Clinic, Edirne, Turkey, between January 1, 2001, and December 31, 2003. Until March 2002, ECT treatments in this clinic were performed without anesthesia. Of the 26 patients, 15 had ECT treatments under anesthesia, and 11 had treatments without anesthesia. Propofol was used as an anesthetic agent and succinylcholine was used as a muscle relaxant in the 15 patients who received anesthesia. Patients in both groups were treated with the same ECT machine (Thymatron™ DGx, Somatics Inc, Lake Bluff, IL). Bilateral electrode placement was applied for all patients. Seizure duration measurements were based on the machine’s automated seizure duration determinations. The groups were compared without taking into consideration the patients’ diagnosis, the drugs that they used, or their psychiatric outcomes.
Results
The groups were similar in terms of sex and mean age. Major depression was the most frequent diagnosis in both groups. The number of ECT treatments in the propofol anesthesia group (mean 9.67, SD 2.99) did not differ significantly from the nonanesthesia group (mean 9.27, SD 2.05; t = 0.37; P = 0.71). When the seizure durations were compared, seizure duration was longer in the propofol anesthesia group (mean 44.38, SD 14.52) than in the nonanesthesia group (mean 39.45, SD 3.47). However, this difference was not significant (t = 1.26, P = 0.22). Mean (SD) propofol dosage was 98.68 (4.48) mg. We found no linear correlation between the propofol dosage and seizure duration (r = 0.24, P = 0.41). We assessed the effect of both the number of ECTs and having anesthesia on seizure duration; no effects for ECT number (F1,11 = 1.80, P > 0.05) or patient group (F = 0.81, P < 0.05) were revealed, nor was there any significant interaction between the number of ECTs and the patient group (F1,11 = 1.55, P < 0.05).
Discussion
Contrary to previous studies (6–8), we did not find that propofol had any considerable effect on seizure duration. Our study design was different from other studies in that they compared 2 different induction agents (9–11); in our study, seizure durations of patients who received propofol anesthesia were compared with seizure durations of patients who received ECT treatments without anesthesia. Current standards, especially for research purposes, would preclude the use of ECT without anesthesia, but because our study was retrospective, we must assume that this ethical concern was not an issue.
Our study found that propofol did not shorten seizure duration. Although anesthesia with propofol has been associated with shorter ECT seizures, other anesthetic agents used for comparison with the propofol may have affected earlier results. Our study suggests the importance of the control group who received ECTs without anesthesia for comparing the effects of anesthetic agents on seizure duration: results that are more reliable could be obtained and controversial conclusions minimized.
References
1. Avramov MN, Husain MM, White PF. The comparative effects of methohexital, propofol, and etomidate for electroconvulsive therapy. Anesth Analg 1995;81:596–602.
2. Mitchell P, Torda T, Hickie I, Burke C. Propofol as an anaesthetic agent for ECT: effect on outcome and length of course. Aust N Z J Psychiatry 1991;25:255–61.
3. Fear CF, Littlejohns CS, Rouse E, McQuail P. Propofol anaesthesia in electroconvulsive therapy: reduced seizure duration may not be relevant. Br J Psychiatry 1994;165:506–9.
4. Fredman B, d’Etienne J, Smith I. Husain MN. Anesthesia for electroconvulsive therapy: effects of propofol and methohexital on seizure activity and recovery. Anesth Analg 1994;79:75–9.
5. Malsch E, Gratz I, Mani S, Backup C, Levy S. Efficacy of electroconvulsive therapy after propofol and methohexital anesthesia. Convuls Ther 1994;10:212–9.
6. Stadtland C, Erfurth A, Ruta U, Michael N. A switch from propofol to etomidate during an ECT course increases EEG and motor seizure duration. J ECT 2002;18(1):22–5.
7. Martensson B, Bartfai A, Hallen B, Hellstorm C, Junthe T, Olander M. A comparison of propofol and methohexital as anesthetic agents for ECT: effects on seizure duration, therapeutic outcome, and memory. Biol Psychiatry 1994;35:179–89.
8. Simpson KH, Halsall PJ, Carr CM, Stewart KG. Propofol reduces seizure duration in patients having anaesthesia for electroconvulsive therapy. Br J Anaesth 1988;61:343–4.
9. Krystal AD, Weiner RD, Dean MD, Lindhal VH, Tramontozzi LA, Falcone G, and others. Comparison of seizure duration, ictal EEG, and cognitive effects of ketamine and methohexital anesthesia with ECT. J Neuropsychiatry Clin Neurosci 2003;15(1):27–34.
10. Geretsegger C, Rochowanski E, Kartnig C, Unterrainer AF. Propofol and methohexital as anesthetic agents for electroconvulsive therapy (ECT): a comparison of seizure-quality measures and vital signs. J ECT 1998;14(1):28–35.
11. Nguyen TT, Chhibber AK, Lustik SJ, Kolano JW, Dillon PJ, Guttmacher LB. Effect of methohexitone and propofol with or without alfentanil on seizure duration and recovery in electroconvulsive therapy. Br J Anaesth 1997;79:801–3.
Okan Caliyurt, MD
Erdal Vardar, MD
Cengiz Tuglu, MD
Ercan Abay, MD
Edirne, Turkey
|
