Cardiorespiratory effects of meperidine, diazepam, and methohexital conscious sedation.

The effects of conscious sedation on the respiratory and cardiovascular systems of seven healthy volunteers were studied. With mean dosages of meperidine, 0.41 mg/kg, diazepam, 0.13 mg/kg, and methohexital titrated incrementally to effect, there were statistically significant changes in PaO2, PaCO2, and arterial blood pH, and no statistically significant change in cardiac output as determined by arterial blood gas analysis and impedance cardiac output monitoring. No clinically significant changes were observed in cardiorespiratory function, and all patients were conscious according to the definition proposed by the American Dental Society of Anesthesiology. The variation in PaO2 showed only marginal statistical significance. There was no clinical indication for supplemental oxygen.