[Effects of Etomidate on ventilation and blood gases]

17 surgical patients, agent 49 to 87, are studied. Their anaesthetic induction was performed by an intravenous injection of Etomidate on a 0,23 mg/kg body weight basiis. Respiratory frequency and minute ventilation were put on continuous recording, PO2, PCO2 and arterial blood pH were measured 1,3 and 5 minutes after injection of the drug. Anaesthetic induction, occuring 10 seconds after injection of the drug, was followed by an increase in respiratory frequency (32 p 100) and a rather modest increase of minute ventilation (9,2 p. 100). Among blood gases measurements, only PaO2 showed a decrease of 6,7 p. 100, when PO2 and pH remained practically unchanged. The small increase in minute ventilation, compared with a relatively important increase in respiratory frequency, suggests some decrease in efficient alveolar ventilation without however affecting blood gases in an important fashion.