ABSTRACT

To calculate the effective dose (ED) of dexmedetomidine for caesarean section under spinal anaesthesia.

Consecutive parturients scheduled for caesarean section under spinal anaesthesia were included. The loading dose of dexmedetomidine was evaluated using the up-and-down method, starting at 1.0 µg kg−1 and a step size of 0.1 µg kg−1. The loading dexmedetomidine was administrated by the venous route for 10 min, and afterwards a maintenance dose began at a rate of 0.3 µg kg−1 h−1 in all parturients. Adequate sedation was defined as a Ramsay sedation score ≥3. The ED50 and ED95 of loading dexmedetomidine were calculated using probit regression.

The ED50 and ED95 of loading dexmedetomidine for adequate sedation were 0.82 µg kg−1 (95% confidence intervals [CI] 0.73–0.89 µg kg−1) and 0.96 µg kg−1 (95% CI 0.90–1.39 µg kg−1), respectively.

The ED50 and ED95 of loading dexmedetomidine to achieve adequate sedation were 0.82 µg kg−1 and 0.96 µg kg−1 for caesarean section under spinal anaesthesia.