Effect of hyperventilation on seizure length during electroconvulsive therapy.

Hyperventilation reportedly prolongs the seizures during eletroconvulsive therapy (ECT) (Bridenbaugh et al. 1972; Holmberg 1953; Holmberg et al. 1956; Weiner 1979; Chater and Simpson 1988). As these studies did not measure the pCO2 concentration it is unclear if prolongation of seizures was due to hyperoxygenation or hypocapnia. In a controlled study Bergsholm et al. (1984) demonstrated an increase in seizure length by hypocapnia but not by hyperoxygenation. The effect of different levels of hyperventilation-induced hypocapnia as measured by end-tidal pCO2 on seizure duration in ECT was evaluated in the present study to establish its practical utility in a clinic~ setting.