Comparison of analgesic efficacy of different local anesthetic volumes for erector spinae plane block in thoracotomy patients; a prospective randomized trial

Background: Erector spinae plane block (ESPB) is a thoracic wall block that has been used frequently in recent years. It was aimed to compare the analgesic efficacy of bupivacaine in different volumes for ESPB in patients undergoing thoracotomy. Methods: Patients who were in the age range of 18 to 65 years, ASA I–III, had a body mass index (BMI) of 18–30 kg/m2 and were undergoing thoracotomy were included in the study. Patients were assigned to ESPB with 30 ml 0.25% bupivacaine (Group-1) or ESPB with 20 ml 0.25% bupivacaine (Group-2) groups according to the analgesia protocol. In the postoperative care unit, intravenous morphine was administered via a patient-controlled analgesia pump for 24 h. A paracetamol dose of 1 g every 8 h and a dexketoprofen dose of 50 mg twice daily were administered iv for multimodal analgesia. Results: Visual analog scale (VAS) resting scores, the 1st (p = 0.001), 2nd (< 0.001), 4th (< 0.001), 8th (< 0.001), 16th (< 0.010), 24th (< 0.044), and 48th (< 0.005)-hour VAS resting results were found to be statistically significantly higher in the 20 ml group than the 30 ml group. VAS cough scores were statistically significantly higher in the 20 ml group at the 1st (< 0.003), 2nd (< 0.001), 4th (< 0.001), 8th (< 0.001), 16th (< 0.004), 24th (< 0.031), and 48th (< 0.009)-hour. Morphine consumption, and additional analgesic use were found to be statistically significantly higher in the 20 ml group than in the 30 ml group (p < 0.001, p = 0.001, respectively). There was no statistically significant difference between the groups in terms of side effects (p > 0.05). Conclusions: The results of ESPB applied with 20 ml and 30 ml of local anesthetic before the surgical incision in thoracotomy patients showed that the use of 30 ml of local anesthetic provided more effective analgesia. In addition, similar side-effect rates show that 30 ml of local anesthetic can be used safely.