Background and Goal of Study: Modified electroconvulsive therapy (MECT) is a common therapy for mental illnesses. Although MECT is known to remarkably increase mean blood pressure (MBP), little is known about the effects of MECT on cardiac output (CO) and systemic vascular resistance (SVR). The ClearSight System® (CS) provides continuous non-invasive measurement of hemodynamic parameters including MBP, CO, and SVR. Thus, in order to elucidate the mechanisms of hemodynamic changes induced by MECT, we used the CS during MECT under general anesthesia.

Materials and Methods: After approval of the Ethics Committee of our institution, written informed consent was obtained from each patient enrolled in this study (n=20). MBP, HR, CO, and SVR were continuously measured every 20 seconds by the CS. Central venous pressure was assumed to be 5 mmHg in all patients. After preoxygenation, general anesthesia was induced with propofol (1.0 – 2.0 mg/kg). After confirmation of loss of consciousness, a tourniquet around the right arm was pressurized to 250 mmHg. Thereafter, succinylcholine (0.6 – 1.0 mg/kg) was administered. After fasciculation had disappeared, MECT stimulus was applied. Bag-mask ventilation was restarted and continued until the patient resumed spontaneous ventilation. One-way analysis of variance was used to compare the differences in parameters. A p-value less than 0.05 was considered to be significant. Data are presented as means ± SDs.

Results and Discussion: The hemodynamic changes during MECT are shown in the figure. The CS successfully evaluated the hemodynamic parameters in all patients. MBP significantly increased from 82 ± 4 to 102 ± 15 mmHg after MECT stimuli (p < 0.01). SVR significantly increased from 1660 ± 661 to 2304 ± 1081 dyne·sec·cm-5 (p < 0.01). On the other hand, MECT did not significantly affect CO or HR. There were no patients with hypertension defined as MBP greater than 140 mmHg or hypotension defined as MBP less than 60 mmHg.

Conclusion:The CS revealed that MECT induces acute hemodynamic responses. Our results suggest that the increase in MBP after MECT is attributed to an increase in SVR, not to an increase in CO.

09 / Assessment of hemodynamic variables during modified electroconvulsive therapy using a non-invasive hemodynamic monitor