The comparison of the effects of the spinal anesthesia with low dose of bupivacaine and sufentanil with normal dose of bupivacain for orthopedic surgery of lower limb

One of the effective strategies to reduce the hypotension after spinal anesthesia is using low dose of local anesthetics. The aim of this study was to compare the effects of spinal anesthesia with small dose of bupivacaine and sufentanil with traditional dose of bupivacaine for orthopedic surgery of lower limb. In this clinical-trial study, 150 patients were registered for lower limb orthopedic surgery from 2009 to 2010. Patients were randomly divided in to two groups, case group (n=75) who underwent spinal anesthesia with 7.5 mg bupivacaine 0.5% and 5 µg sufentanil and control group (n=75) who underwent spinal anesthesia with 15 mg bupivacaine 0.5%. Factors associated with spinal anastesia such as changes in blood pressure, block anesthesia pains and itching during and after spinal anesthesia were measured and recorded. Data were analyzed using t-test and fisher test. Demographic variables were not significantly different between two groups. Hypotension occurred in the first 10 minutes after spinal anesthesia and more common in control group so need to use vasopressor more in control group. Changes in systolic blood prepsure in the minutes 1-3, 3-5 and 5-10 (P=0.01) and changes in systolic blood presses in the minutes 1-3, 5-10, 10-15 were significant between the two groups (P<0.05). Also changes in the mean blood pressure in the minutes 1-3, 5-10, 10-15, (P<0.05) and the maximun of motor block were significant berween the two groups (P<0.01). Vomiting and the need for injection were more in case groups P<0.01, while itching was more observed in control group (P<0.05). Findings showed that spinal anesthesia with small dose of bupivacaine and sufentanil provided successful analgesia respect to spinal anesthesia with usual dose of bupivacaine and this method decrease the need for catecholamine and hypotension. So, it, s recommended to use low dose of bupivacaine and sufentanil in lower surgery limb.