Seizure duration in unilateral electroconvulsive therapy

Abstract
Seizure duration in unilateral electroconvulsive therapy (ECT) was recorded by means of EEG in an intraindividual comparison under different alveolar O2- and CO2-concentrations. Hypocapnia induced by hyperventilation to an alveolar CO2-concentration of 2% (2 kPa [kilopascal]) resulted in a highly significant increase in seizure duration compared to a normal CO2 of 5%, when the alveolar O2-concentration was constant at 92%. O2 ventilation to an alveolar O2-concentration of 92% gave no significant increase in seizure duration compared to 15%, obtained by ventilation with air, when the CO2-concentration was kept constant at 5%. Seizure duration seems to augment progressively with decreasing alveolar CO2-concentration.