Ultrasound-guided Thoracic Paravertebral Block for Postoperative Pain Treatment after Thoracoscopic Surgery

Abstract

Background: Acute pain management following thoracoscopic surgery (TS) presents challenges for anaesthesiologists. In this manuscript we compared the efficacy of three different techniques for postoperative pain treatment following TS.Methods: Thirty patients scheduled to undergo TS under general anaesthesia were randomly allocated into 3 groups (10 patients each group) according to pain relief modality to be used postoperatively.Group A: Patients received ultrasound guided thoracic paravertebral block (USGTPV) with bupivacaine 0.5%, consisting of a 10 ml bolus and continuous infusion of bupivacaine 0.0625%, 4 to 6 ml/hr. Rescue analgesia using patient controlled IV analgesia (PCA) was available, using 1 mg bolus Morphine with a 6 minute lock-out.Group B: Patients received patient controlled IV analgesia alone, morphine 1 mg/ml with lock out time of 6 minutes postoperatively.Group C: Patients received interpleural spray of 0.5% bupivacaine (20 ml) at the end of surgery followed by PCA morphine at same setting for groups A and B. Postoperative pain was assessed using the 11-point numeric rating score (NRS) at 7 different intervals (immediately on admission to PACU, every 2 hours for the next 8 hours then at 12 and at 24 hours postoperatively). Pain was assessed at rest, during deep inspiration and whilst coughing. Total dosages of morphine used in the first 24 hours postoperatively were recorded for each group. Non-Parametric Kruskal-Wallis Test was used for comparisons between the three groups and Spearman�s correlation coefficient (rs) was used to identify the correlations between morphine dose and pain at different conditions in the three groups. Mann-Whitney Test was used for comparisons within each group where P values 0.05).The median values (range) of morphine consumption in the first 24 hours were 2 (0-30), 26.5 (10-47) and 10 (4-15) mg in groups A, B and C respectively with significant differences (P < 0.0001).Conclusions: Compared to interpleural bupivacaine or conventional systemic analgesics with morphine, USGTPV block with bupivacaine provided superior postoperative analgesia following thoracoscopic surgery.