Comparison of Oral versus Intramuscular Clonidine for the Prolongation of Bupivacaine Spinal Anesthesia in Patients Undergoing Lower Abdominal and Lower Limb Surgeries.

Abstract

Background: Spinal subarachnoid block (SAB) is the first choice anesthesia in lower abdominal and lower limb surgeries. It produces a varying degree of sensory analgesia, motor blockade, and sympathetic blockade depending on the dose, concentration, and volume of the local anesthetic given. This study was undertaken to assess the degree of sensory and motor block with 150 μg of oral versus intramuscular clonidine as an adjuvant to bupivacaine for spinal anesthesia.

Aims and objective: To compare the efficacy of oral versus intramuscular clonidine as an adjuvant to bupivacaine for the prolongation of sensory and motor block in patients undergoing lower abdominal and lower limb surgeries under SAB.

Materials and methods: After institutional ethical clearance, 90 patients were randomized into three groups scheduled for lower abdominal and lower limb surgeries under spinal anesthesia. • Group O: Bupivacaine 0.5% (heavy) 3.0 mL and oral clonidine 150 μg 1 h before spinal anesthesia. • Group I: Bupivacaine 0.5% (heavy) 3.0 mL and intramuscular clonidine 150 μg 1 h before spinal anesthesia. • Group C: Control group - 3 mL bupivacaine 0.5% (heavy) alone.

Result: The onset of sensory block in Group O was 4.9 ± 0.52 min, whereas in Group I, it was 4.6 ± 0.42 min than Group C (5.1 ± 0.60). Onset of motor block was also significantly lower in Group O and Group I (3.9 ± 0.53 and 3.7 ± 0.42 min) than in Group C (4.4 ± 0.6 min) which was a control group. There was also a significant difference in the duration of the sensory block between Group O (206.4 ± 9.2 min), Group I (219 ± 8.6 min), and Group C (184.3 ± 9.1 min). The duration of motor block was significantly higher in Group O (183.6 ± 8.2 min) and Group I (197.8 ± 9.6 min) when compared to Group C (162.8 ± 8.9 min). The timing of rescue analgesia in Group O was 222.4 ± 11.7 min, whereas in Group I, it was 243.46 ± 10.9.

Conclusion: On the basis of finding of our study, we conclude that the use of clonidine as a premedication at a dose of 150 μg significantly increased the duration of sensory block, motor block, and duration of analgesia and shortened the time of onset of sensory and motor blockade.