Results
pruritus
GROUP B
The ED50 (mean [95% confidence interval (CI)]) of the dose of intravenous butorphanol infusion for preventing moderate to severe pruritus was lower in Group P + B (3.29 µg/kg/min [3.25–3.34 µg/kg/min]) than in Group B (3.57 µg/kg/min [3.47–3.67 µg/kg/min]) (