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 ≥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.

Keywords
Anesthesia, patient age, regional, sedation, spinal, surgery, TURP, urological