Clinical effect of hypobaric ropivacaine in spinal anesthesia in the elderly undergoing hip replacement

Objective Ropivacaine has been widely used in epidural anesthesia,peripheral nerve block and postoperative analgesia of local,but reports on spinal anesthesia with hypobaric ropivacaine are rare yet.This research is to observe the clinical effect of hypobaric ropivacaine in spinal anesthesia in the elderly undergoing hip replacement.Methods Eighty patients,65 years or older,ASA class Ⅰ-Ⅲ,scheduled for hip replacement,were randomly allocated to 4 groups.A spinocath catheter was advanced 3cm into subarachnoid space at L2-3 interspace.Experimental group,group Ⅰ: 0.75% ropivacaine 2ml+sterile water for injection 1ml,group Ⅱ: 0.75% ropivacaine 1.5ml+sterile water for injection 1.5ml,group Ⅲ: 0.75% ropivacaine 1ml+sterile water for injection 2ml;Control group: 0.5% bupivacaine 2ml+5% glucose 1ml.The onset time of sensation and motor block,the highest plane of analgesia,the time to reach the highest plane of analgesia,the degree of motor block,the time of the sensation and motor regressive and the adverse effects were recorded.Results There was no significant difference in sensory block including onset time and maximum cephalad spread level among 4 groups.The complete sensory block appeared in most patients.The onset time and duration of motor blockage in Experimental group Ⅲ were longer than those in Control group and Experimental group Ⅰ(P0.01).On the affected extremity,the maximum Bromage score,duration of anesthesia,sensory or motor regressive time in Control group were higher or longer than those in all Experimental groups(P0.05 or P0.01).Descending of heart rate and blood pressure occurred on one patient in Experimental group Ⅰ,and 2 patients in Experimental group Ⅲ had incomplete blockage.Conclusion Continuous spinal anesthesia with hypobaric ropivacaine 11.25 mg is safe and efficient for hip replacement surgery in elderly patients.