Effects of postoperative bilateral standard and modified erector spinae plan block applications in cardiac surgery

Postoperative pain management after cardiac surgery is one of the important factors affecting the success of the procedure. Inadequate pain control in the postoperative period increases the surgical stress response, cardiovascular and pulmonary complications. In recent years, due to the emergence of opioid-related side effects and multimodal analgesia approach, interest in thoracic wall blocks, one of the regional anesthesia applications, has increased in postoperative pain management after cardiac surgery. Many different block methods are being investigated and erector spinae plane block (ESPB) among these methods gives very good results. In our study, we investigated the effects of standard and modified ESPB applications with different approaches on postoperative pain management, opioid consumption and complications in patients undergoing cardiac surgery. Our study was conducted by prospectively evaluating the patients who electively underwent CABG and/or valve surgery at Başkent University Faculty of Medicine Ankara Hospital after the approval by Başkent University Institutional Ethics Committee (Project No: KA21/428). The patients were randomly selected and divided into 3 groups: the control group (Group C), the standard ESPB group (Group S) and the modified ESPB group (Group M). Two different approaches were applied bilaterally to two ESPB groups at the T5 transverse process level with 25 mL of solution containing 0.25% bupivacaine and 4 mg dexamethasone at the postoperative 24th hour. In the standard ESPB group, all of the solution was administered under the erector spina muscle, in the modified ESPB group, 10 mL of the solution was administered on the superior costotransverse ligament and 15 mL under the erector spina muscle. No procedure was applied to the control group. Rescue analgesic protocol was administered intravenously to the patients in all groups. Postoperative static (rest) and dynamic (exercise) pain scores, intravenous analgesic consumption, volumetric spirometry values, PaO2/FiO2 ratios, pain scores during block application and removal of chest drainage tubes, patient satisfaction, postoperative vasoactive-inotropic drug needs, intensive care and hospital stays, complications, morbidity and mortality rates of all patients were evaluated. Demographic and intraoperative data of patients in all groups included in the study were similar. The pain scores of the standard ESPB group at the 4th, 6th, 12th, 18th and 48th hours after the block, and the pain scores of the modified ESPB group at the 6th, 12th, and 18th hours after the block were found to be statistically significantly lower than the control group. The consumption of paracetamol and tramadol in the postoperative 24-48 hours of the standard and modified ESPB groups was found to be lower than the control group. There was no significant difference between the groups in terms of volumetric spirometry values; PaO2/FIO2 ratios of the standard ESPB group at 12th, 18th, and 24th hours after the block and the modified ESPB group at the 18th and 24th hours after the block were found to be statistically significantly higher than the control group. In terms of pain management, patient satisfaction scores were found to be significantly higher in the ESPB groups compared to the control group. Postoperative intensive care unit length of stay was found to be significantly shorter in ESPB groups than in the control group. No significant difference was found in any of the parameters examined between the standard and modified ESPB groups. There was no significant difference between the groups in terms of pain scores during block application and removal of chest drainage tubes, postoperative vasoactive-inotropic drug needs, total hospital stay, complications, morbidity and mortality rates. In conclusion, ESPB application in the postoperative period in patients undergoing cardiac surgery has a significant analgesic effect, reduces the need for intravenous analgesics and opioids, improves oxygenation by positively affecting respiratory parameters, shortens the length of intensive care stay, and thus provides better pain management and more comfortable recovery in the postoperative period. We think that larger-scale studies are needed to evaluate the superiority of different ESPB methods against each other.