Sedation in patients above 60 years of age undergoing urological surgery under spinal anesthesia: Comparison of propofol and midazolam infusions

Context : Propofol and midazolam are commonly used sedatives during regional anesthesia in adults. Smaller doses of these drugs are required in older age due to altered pharmacokinetics and pharmacodynamics. Aims : To study the sedation, side-effects and the costs involved with smaller doses of propofol and midazolam in patients aged above 60 years during spinal anesthesia. Settings and Design : A randomized single-blind study was conducted in 60 ASA I-II patients aged 6560 years undergoing urological surgery under spinal anesthesia. Materials and Methods : Sedation was administered after spinal anesthesia using propofol (bolus 0.4 mg/kg-1; infusion 3 mg/kg/hr) or midazolam (bolus 0.02 mg/kg; infusion 0.06 mg.kg-1/h-1 ) and titrated to achieve a sedation score of 3 on the modified Observer\u2032s Assessment of Alertness/Sedation Scale. Perioperative sedation, hemodynamics and respiratory events were monitored. Statistical Analysis : The analysis for parametric data was done using Student\u2032s unpaired t test and the incidence data using Chi-square test. Results : The onset (13.0\ub14.2 vs. 18.8\ub14.2 min, P < 0.001) and offset (8.9\ub12.8 vs. 12.5\ub13.5 min, P < 0.001) of sedation were faster and the duration of adequate sedation longer (44.7\ub112.5 vs. 29.8\ub112.9% of total infusion time, P < 0.001) with propofol than midazolam. More patients receiving propofol compared to midazolam had hypotension (16 [50%] vs.4 [14.3%], P= 0.003). Airway obstruction occurred frequently in both the groups. Sedation was significantly more expensive with propofol than midazolam (US$ 9.83 \ub1 2.80 vs. US$ 0.33 \ub1 0.06, P 0.001). Conclusions : Propofol provided better titration and adequacy of sedation than midazolam in patients above 60 years of age, but caused hypotension. Lighter sedation is recommended in this age group