Effect of Volume of Bupivacaine on Postoperative Pain after Shoulder Surgery under Interscalene Block of Brachial Plexus

Abstract

Shoulder surgeries result in remarkably postoperative pain and several analgesia methods can be used in order to pain control. Interscalence brachial plexus block has been introduced to be an effective technique in postoperative pain control. Considering discrepancy in results of different studies, we aimed to evaluate different bupivacaine volume effect on postoperative interscalene brachial plexus block (ISBB) efficacy and durability in patients underwent shoulder surgery. Method and Material In this double-blinded controlled trial study 54 patients’ candidate for shoulder surgery and further ISBB, enrolled and randomly assigned to study groups. Anesthesia inducted with same regimen in all patients. Analgesics solution was 15 ml of 0.5% bupivacaine in first group and second group received 30 ml of 0.25% bupivacaine. Postoperative pain measured in recovery room via visual analogue scale (VAS) and patients first requisition to receive analgesics recorded. Bupivacaine side effects during 24 hours postoperative evaluated in terms of nausea and vomiting, vertigo, drowsiness and respiratory suppression

Results No significant difference observed in terms of demographic variables between groups. There was no significant difference in any time in term of pain severity, similarly, pain severity change pattern was no different between group (P: 0.053). Eight patients of high volume bupivacaine and 6 patients of low volume bupivacaine had demand to receive analgesics, that revealed no significant difference between groups (P: 0.379). However, comparing time interval to analgesics requisition by patients between study groups, showed higher time interval in patients received high volume bupivacaine (P: 0.005).