Electroconvulsive therapy can benefit from controlled hyperventilation using a laryngeal mask

Abstract

Hypocapnia through hyperventilation is a well-known procedure in electroconvulsive therapy (ECT) to enhance seizure activity. However, it has mostly been applied in an uncontrolled manner. Originally intended for a better management of the supraglottic airway, laryngeal masks are more suited to monitor levels of CO(2) during hyperventilation than face masks and thereby provide for the possibility of controlled hyperventilation (CHV). The impact of CHV was retrospectively studied in 114 consecutive patients; 65 of them had received ECT with CHV and 49 had received ECT with uncontrolled hyperventilation (UHV) directly prior to the time period when the laryneal mask was introduced to the ECT treatment procedure. The CO(2) level in the CHV group was aimed at 30 mmHg or below. CHV considerably enhanced the seizure activity leading to changes in clinically determined parameters of the treatment course: the necessity for increasing the electric charge, for re-stimulations (trend) and for bilateral stimulations was lower in the CHV group as compared to the UHV group. The improvement in the Global Assessment of Functioning Scores was not different in both groups. CHV was associated with a higher amount of prolonged seizures, with a reduced number of delirious symptoms after treatments and an attenuating effect on heart rate. Concluding, CHV can help to maintain the applied electric charge low without worsening the clinical outcome. Therefore, it is a helpful technical improvement. However, it should be used carefully with regard to prolonged seizures.