Sedation in patients above 60 years of age undergoing urological surgery under spinal anesthesia

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 > or = 60 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's Assessment of Alertness/Sedation Scale. Perioperative sedation, hemodynamics and respiratory events were monitored. STATISTICAL ANALYSIS: The analysis for parametric data was done using Student's unpaired t test and the incidence data using Chi-square test. RESULTS: The onset (13.0+/-4.2 vs. 18.8+/-4.2 min, P < 0.001) and offset (8.9+/-2.8 vs. 12.5+/-3.5 min, P < 0.001) of sedation were faster and the duration of adequate sedation longer (44.7+/-12.5 vs. 29.8+/-12.9% 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 +/- 2.80 vs. US$ 0.33 +/- 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.