[The effects of midazolam on oxygen consumption and the level of vigilance. The possibility of the sedative effect of the plexiglas dome (canopy) of the Deltatrac indirect calorimetry device]

Abstract

Objective: To assess the effects of midazolam on oxygen consumption (VO2) and the level of vigilance. To search for a possible "sedative effect" of the canopy of the Deltatrac (Datex) when a placebo is administered instead of midazolam.

Study design: Prospective, comparative, randomized, double-blinded, cross-over study.

Patients: Eight healthy volunteers of ASA physical class 1, not under stress, fasting and at rest.

Methods: The volunteers were administered at T0 either midazolam (0.07 mg.kg-1, IM), or a placebo at a one week interval in an order at random. The VO2 was measured with a Deltatrac. Circulatory status was monitored with non invasive methods and the level of vigilance assessed using the Ramsay scale. Statistical analysis was obtained with Anova for repeated measurements with two within factors (drug and time).

Results: VO2 decreased similarly and significantly between T0 and T45 min (P < 0.05). The decrease continued only after midazolam until T60 min. However the variation of VO2 between the midazolam and placebo group was not significant. The haemodynamic variables remained unchanged. Midazolam had a stronger sedative effect at T120 min.