E S Saravanan | PubMed Health

PubMed2000

Seizure threshold estimation by formula method: a prospective study in unilateral ECT.

Formula methods of estimating seizure threshold in bilateral electroconvulsive therapy (ECT) have been successful in 75% (at the first ECT) and 80% (at the sixth ECT) of treatments (Gangadhar et al., 1998). This study showed the same results for unilateral (UL) ECT patients. Its aim was to compare formula and titration methods for threshold determination. The seizure threshold (dependent variable) was determined by the titration method used at the first ECT in consecutive consenting patients (n = 80) prescribed UL ECT under general anesthesia. The independent variables were age, gender, diagnosis, illness severity, concurrent drugs, head circumference, and inion-nasion distance. Forward, step-wise, linear regression analysis showed age as the only significant predictor of seizure threshold (15% of variance). A formula based on regression analysis was prospectively applied in an independent sample (n = 30) of patients receiving UL ECT using the titration method for threshold determination. The results calculated a higher threshold than the actual threshold used in 14 patients, a threshold level in 8 patients, and below threshold in 8 patients. Formula-based estimates would have been successful in 22 (73%) patients, but the majority of them would have received higher than the recommended stimulus dose. Titration is the method preferred for clinical use. However, if a patient's doctor wishes to use the formula-based method, he or she should do so with specific considerations.

Adult↗

PubMed1999

An intrasubject comparison of two doses of succinylcholine in modified electroconvulsive therapy.

UNLABELLED: The electroconvulsive therapy (ECT) guideline of the Royal College of Psychiatrists recommends a 0.5 mg/kg of succinylcholine for ECT modification. Our clinical experience suggests that this dose is insufficient for Indian patients. The dose recommended by the Royal College of Psychiatrists (0.5 mg/kg) and a larger dose (1 mg/kg) were compared in 50 patients referred for ECT. In one ECT session, patients were equally randomized to receive one of the two doses and in the next session they were switched to the other dose. The extent of motor seizure modification was rated on a five-point scale by two independent raters who were blinded to the succinylcholine dose. The interrater reliability was good (K = 0.85). "Poor" seizure modification occurred in 48% and 12% of patients with the 0.5 and 1 mg/kg doses, respectively. Of the 24 patients who had poor modification with 0.5 mg/kg, 20 had "good" modification in the session with 1 mg/kg (P < 0.001). A small delay (mean = 55 s) occurred in time to recover from the respiratory paralysis with the 1 mg/kg dose of succinylcholine. No patient, however, had prolonged apnea requiring special measures. We recommend 1 mg/kg of succinylcholine dose be used in the first ECT session. For subsequent sessions, the dose may be altered, depending on the response for optimal motor seizure modification. IMPLICATIONS: The dose of muscle relaxant (succinylcholine) recommended in modified electroconvulsive therapy is not based on empirical research. In the same patients (n = 50), two doses-0.5 mg/kg and 1 mg/kg-were compared during different electroconvulsive therapy sessions. The larger dose was more effective in modifying the peripheral convulsion.

Adult↗