The Effect of Parasternal Block on Postoperative Pain in Patients Undergoing Coronary Artery Bypass Graft Surgery: A Randomized Controlled Trial

Abstract

Background and Objectives: This study aims to investigate the effects of intraoperative parasternal block (PSB) on postoperative analgesia in patients undergoing elective coronary artery bypass graft (CABG) surgery. Methods: This prospective, randomized, double-blind study included 78 patients aged 30 - 80 years with an American Society of Anesthesiologists (ASA) physical status III-IV, who were scheduled for elective CABG surgery. Patients were randomly assigned into two groups: The PSB group (n = 39), receiving a PSB with 0.25% bupivacaine, and the saline group (n = 39), receiving a PSB with 0.9% NaCl. All patients were administered a standard anesthesia protocol, and routine care and analgesia practices during the postoperative period were not interfered with. Patients in the intensive care unit (ICU) received intravenous paracetamol every eight hours for analgesia. If postoperative 24-hour pain scores in the ICU, assessed using the Behavioral Pain Scale (BPS) while intubated and the Numeric Rating Scale (NRS) while extubated, exceeded four, 1 mg/kg tramadol was administered. The timing and doses of the first tramadol administration, as well as extubation times, ICU stay durations, and discharge times, were recorded. Results: In the postoperative period, BPS scores at the 8th hour and NRS scores at the 4th and 12th hours were significantly lower in the PSB group than in the saline group (P < 0.005). The average extubation time was 8.76 hours in the PSB group and 14.76 hours in the saline group (P < 0.001). Among patients with pain scores of four or higher, the total tramadol consumption in the PSB group was 150 ± 64.72 mg, with the first tramadol administration occurring at 17.26 ± 4.78 hours. In the saline group, total tramadol consumption was 212.5 ± 82.23 mg, and the first administration occurred at 12.35 ± 5.75 hours. Conclusions: Our study demonstrated that PSB, as a component of multimodal analgesia, improved postoperative analgesia levels in CABG surgery. Therefore, we consider the PSB to be effective in pain management following median sternotomy.