Background and Goal of Study: Current standards in general anaesthesia (GA) for Electroconvulsive Therapy (ECT) include oropharyngeal airways and facial masks (FM) to open and maintain the patients airway.
The aim of this study was to verify the effectiveness of Laryngeal Mask (LM)1 when compared with FM in GA for outpatient ECT.
Materials and Methods: Clinical controlled trial (prospective, randomized, double blind and matched pairs study). Local Ethics and Clinical Investigation Committee approval and informed consent in all cases.
14 ASA I-III patients, 75% of them women and schedulled for outpatient maintenance ECT were included in the study.
Both LM and FM groups (matched pairs) had identical anaesthetic and psychiatric management in every ECT procedure; they differed only in a 45% reduction in ECT energy dose applied to LM group and in the use of FM or LM when randomized for each patient.
Monitoring: Heart Rate (HR), Non Invasive Blood Pressure (NIBP), Pulse Oximetry (SpO2), End Tidal CO2 (ETCO2), average expiratory Tidal Volume (TV), Central and Peripheral Convulsion (C&PC) times. Servo 900C Ventilator (SIEMENS) for anaesthesia and Spectrum 5000Q (MECTA) for ECT in all cases.
Statistical analysis with SPSS 14.0 for Windows: Kolmogorov-Smirnov Normality Test, Levene Homogeneity Test, ANOVA, Student T Test for paired data and Pearson Correlation Test were used as needed. Choosed significance level was a= 5%.
Results and Discussion: Higher energy doses in FM group failed to get longer C&PC, yet led to worse hemodynamic or ventilatory parameters.
Central and peripheral convulsions were longer in ECT procedures performed with LM, even though ECT energy dose had been reduced by 45% in those procedures (p< 0.05).
Bigger hemodynamic changes in HR and NIBP in FM group (p< 0.05). Better ventilatory parameters in SpO2, ETCO2 and TV in LM group (p< 0.05)2.
Conclusion(s): Both analyzed airway maintenance methods, LM or FM are suitable for GA in TEC.
However, LM has proved its superiority in this study and therefore we recommend it for GA in ECT.
Moreover, the difficulty in a daily clinical basis of reproducing study conditions with FM ventilation, reinforces our recommendation to use LM for GA in ECT.
Finally, LM ventilation may be the only option for outpatient ECT anaesthesia in those difficult psychiatric patients with no central convulsion even with maximum energy doses.