Implication of bupivacaine volume changes in the duration and rate of complications of femoral and sciatic nerve block for lower limb surgery

Objective : The aim of this study was to study the implication of volume change of bupivacaine in the duration of motor and sensory blocks for early ambulation of the patient and in the rate of complications among patients. Patients and methods A total of 80 adult patients of ASA I, II, or III status, scheduled for lower limb surgery under regional anesthesia by femoral and sciatic nerve blocks, were included in this randomized prospective study. Patients were randomly divided into two equal groups (group I and group II). A total volume of 40 ml of bupivacaine 0.3% was used for peripheral nerve blockade in group I: 20 ml for femoral nerve blockade and 20 ml for sciatic nerve blockade; and a total volume of 60 ml of bupivacaine 0.3% was used in group II: 30 ml for femoral nerve blockade and 30 ml for sciatic nerve blockade. Assessment of the sensory and the motor blocks was carried out including onset of anesthesia and duration of both sensory and motor blocks. The assessment was carried out intraoperatively at 10, 20, and 30 min after the establishment of the procedure, and then at 6, 12, and 24 h after performing the block. Results The onset of the block was signifi cantly shorter in group II. The sensory block was signifi cantly denser in group II at 12 h. The motor block was less dense in group II at 12 and 24 h. The pain scale was less in group II at 6 and 12 h. Conclusion This study revealed that increasing the volume of the local anesthetics hastened the onset of the anesthesia and increased the duration and the density of the sensory block.