Seizure duration in unilateral electroconvulsive therapy. A comparison of the anaesthetic agents etomidate and Althesin with methohexitone.

Seizure duration in unilateral electroconvulsive therapy (ECT) was recorded by means of EEG in an intraindividual comparison of etomidate (dissolved in a soy-bean oil emulsion) 0.3 mg/kg and Althesin (alphaxalone 9 mg and alphadolone 3 mg/ml) 0.6 mg/kg with methohexitone 1 mg/kg body weight. The patients were intubated and alveolar CO2- and O2-concentrations kept constant at 3% (3 kPa) and 92% (92 kPa) respectively. Seizure duration was the same when either etomidate or methohexitone were used, whereas Althesin significantly shortened seizure duration in comparison with methohexitone. Local pain on injection and a subsequent superficial thrombophlebitis occurred frequently with methohexitone. This did not occur with etomidate or Althesin.