Unilateral spinal anesthesia with hyperbaric bupivacaine in knee arthroscopy: 5 mg vs 4 mg [Günübi̇rli̇k di̇z artroskopi̇si̇nde hi̇perbari̇k bupi̇vakai̇n,i̇le uni̇lateral spi̇nal anestezi̇: 5 mg vs 4 mg]

Objective: the purpose of this study was to compare the anesthetic efficacy,durations of motor and sensorial blocks and of unilateral spinal anesthesia with 5 and 4 mg hyperbaric bupivacaine in patients undergoing arthroscopic knee surgery (aks) and find out if there is a reduction in discharge times. method: after obtaining ethics committee approval and informed consent 90 asa physical status 1-2 outpatients undergoing aks,aged between 18-65 years,were enrolled. the patients were randomized to two groups: spinal anesthesia was performed with hyperbaric bupivacaine in group b5 5 mg (1 ml) and in group b4 4 mg (0.8 ml) at the l3-4 level in lateral decubitus position and patients were kept in the same position for at least 15 minutes to make unilateral spread possible. bilateral levels of motor and sensorial blocks were evaluated; onset time to surgical anesthesia was recorded. induction of general anesthesia was accepted as a failure of spinal anesthesia. results: spinal anesthesia was unsuccessful in one patient in group b5 (2.2%) and three patients in group b4 (6.7%). onset time to surgical anesthesia was 16 min (min.- max.: 9-25 min) in group b5 and 17 min (min.- max.: 11-25 min) in group b4. the median value of cephalad spread of sensory block on the operative side were t10 (min.- max.: t7-t10) and t11 (min.- max.: t7-t11) in group b5 and group b4 respectively. complete unilateral motor block was seen in 38 cases (84.4%) in group b5 and in 42 (93.3%) in group b4. duration of motor block was shorter in group b4 (86±31 min vs. 110±40 min,p<0.05). time to discharge home was shorter in group b4 (127±42 min vs. 101±34 min,p<0.05). conclusion: both solutions produced reliable spinal anesthesia for aks. it was shown that the 4 mg dose produced more selective blocks and allowed early home discharge.