CARDIOVASCULAR RESPONSE TO ECT IS UNAFFECTED BY EXTENT OF MOTOR SEIZURE MODIFICATION

Effect of the extent of motor seizure modification on cardiovascular responses in ECT was studied at the second ECT session in 50 (ULECT=25) consenting patients. Twenty five patients each received either 0.5 mg/kg or 1 mg/kg of succinylcholine in a random design. Blood pressure and heart rate were recorded on five occasions during the ECT session. Extent of motor seizure was assessed on a five point scale by two raters blind to succinylcholine dose. Two raters had good interrater agreement on the scale. Significantly more patients had poor modification with 0.5 mg/kg (68%) than with 1 mg/kg (12%) of succinylcholine. Rate-pressure-product (RPP=systolic BPx Heart rate) significantly changed over the five occasions, maximal being in ictal occasion, but the two succinylcholine dose groups did not differ. Ictal RPP positively correlated with post-anaesthesia RPP, ECT stimulus dose, seizure threshold and both seizure durations (Motor and EEG). Likewise, postictal RPP correlated with seizure threshold and actual ECT stimulus dose. Neither correlated with the motor seizure modification scores. In multiple, stepwise, linear regression models neither ictal nor post-ictal RPP variance was significantly explained by the extent of motor seizure modification scores. Hence, RPP changes during ECT may be reflecting cerebral mechanisms of ECT.