Comparison of ropivacaine and bupivacaine in unilateral spinal anesthesia undergoing unilateral knee arthroscope operation

Objective To compare the analgesic effect of hypobaric ropivacaine 0.3% to hypobaric bupivacaine 0.3% in unilateral spinal anesthesia in patient undergoing unilateral knee arthroscope operation.Methods 48 patients(ASA Ⅰ-Ⅱ) scheduled for unilateral knee arthroscope operation were selected and randomized into two groups(24 cases each):group R(0.3% ropivacaine was made by a combination of 0.75% ropivacaine and 3mlwater for injection) and group B(bupivacaine 0.3% was made by made by a combination of 0.75% bupivacaine and 3mlwater for injection dose=3ml).The onset and duration of motor and sensory blocks were compared between the 2 groups.The side effects were also recorded.Besides,we monitored the respiratory and circulatory system during operation.Results The two groups had similar quality of analgesia and the same highest block level on the limb,but the onset of sensory blocks was slower and lasted for shorter time in group R than in group B(P0.05).The extent of motor block of lower limb was lower and restored more quickly in group R than in group B.Both motor and sensory block in healthy limb were slighter and restored sooner in group R than in group B.More cases of uroschesis were reported in group B,but hemodynamics of both groups was rather stable.Conclusions Both hypobaric local anesthetics for unilateral spinal anesthesia can be effectively used in unilateral knee arthroscope operation.But compared with bupivacaine,isodose 0.3% hypobaric ropivacaine was more suitable in knee arthroscope operation that lasts short time,for it has less effect on lower limb motion,quicker restoration,less side effect,and more stable hemodynacmics than bupivacaine.