Abstract
Objective: To determine the effect of bupivacaine bolus injection at different time intervals on post-operative pain following arthroscopic shoulder surgery
Design: Double-blinded, randomized, controlled trial
Setting: King Khalid University Hospital, Riyadh, Saudi Arabia
Subjects: Sixty adult patients were classified into three groups with 20 patients each. Ultrasound-guided interscalene block was performed with catheter insertion. In the postoperative period, bupivacaine 0.2% was given as bolus injection at three time intervals every 6, 8 and 12 hours.
Interventions: Numerical rating scale (NRS) was used for pain assessment. Sensory and motor block were assessed before the block, 20 minutes after block, in the post anesthesia care unit (PACU), and at 2, 6, 12, and 24 hours post-operatively. Patient satisfaction and the analgesic consumption of morphine were assessed in the first 24 hours.
Main outcome measures: There was no statistical difference in the timing of the bolus injection, whether it was given at 6, 8 or 12 hour intervals.
Results: The pain scores were similar in all the groups. In the PACU, the pain scores were 1.4, 1.45 and 1.16. After 24 hours, the pain scores were 1.58, 1.16 and 1.84 in the three groups respectively. Patients and surgeons were satisfied. There was no statistical significance in morphine consumption during the study period among the three groups.
Conclusion: There was no statistical difference in the timing of the bolus injection, whether it was given at 6, 8 or 12 hour intervals; further studies are required with a larger sample size.