Interscalene Brachial Plexus Analgesia following Arthroscopic Shoulder Surgery: Pharmacodynamics of BupivacaineBolus Injection at Different Time Intervals

摘要

Objective: To determine the effect of bupivacaine bolusinjection at different time intervals on post-operative painfollowing arthroscopic shoulder surgeryDesign: Double-blinded, randomized, controlled trialSetting: King Khalid University Hospital, Riyadh, SaudiArabiaSubjects: Sixty adult patients were classified into threegroups with 20 patients each. Ultrasound-guided interscaleneblock was performed with catheter insertion. In the postoperativeperiod, bupivacaine 0.2% was given as bolusinjection at three time intervals every 6, 8 and 12 hours.Interventions: Numerical rating scale (NRS) was used forpain assessment. Sensory and motor block were assessedbefore the block, 20 minutes after block, in the post anesthesiacare unit (PACU), and at 2, 6, 12, and 24 hours postoperatively.Patient satisfaction and the analgesicconsumption of morphine were assessed in the first 24 hours.Main outcome measures: There was no statistical differencein 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 thePACU, 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 groupsrespectively. Patients and surgeons were satisfied. There wasno statistical significance in morphine consumption duringthe study period among the three groups.Conclusion: There was no statistical difference in the timingof the bolus injection, whether it was given at 6, 8 or 12 hourintervals; further studies are required with a larger samplesize.