Comparison of Analgesic Efficacy of Intrathecal Morphine and Ultrasound-Guided Bilateral Erector Spinae Plane Block in Patients Undergoing Open Heart Surgery with Midline Sternotomy: An Open Label Randomized Control Trial

BACKGROUND AND AIMS: Intrathecal morphine (ITM) and erector spinae plane block (ESPB) decrease postoperative pain in standard cardiac surgery. In this study, we compared the analgesic efficacy of ITM and B/L ESPB in patients undergoing open heart surgeries. METHODS: After approval from the institutional ethics committee and written informed consent from patients scheduled for open heart surgeries, they were randomized into two groups: Group ITM patients received ITM (5 mcg/kg), whereas Group ESPB patients received bilateral ESP block (0.3 mL/kg of 0.5% ropivacaine on either side). The primary outcome was to compare postoperative fentanyl consumption during the first 24 hours of ICU stay after extubation. Secondary outcomes were postoperative VAS at rest and on cough during the first 24 hours, pre- and postoperative pulmonary function, and number of rescue analgesics. Quantitative variables were presented as mean (SD) or median (IQR). Categorical variables were expressed as numbers or percentages. Spirometry variables were compared over time between the groups using Friedman test. RESULTS: The ITM group had significantly less median fentanyl consumption compared to the ESPB group during the first 24 hours postoperative period [0 (0-75) μg vs. 234 (160-336) μg (95% CI, 171.65, 255.38); P < 0.001]. The VAS score at rest and during cough was significantly better in the ITM group. FEV1 and FVC reduced postoperatively in both groups with significantly better values in the ITM group. CONCLUSION: ITM administered prior to induction provides superior postoperative analgesia compared to bilateral ESPB in patients undergoing open-heart surgery. It significantly reduces opioid requirements, improves patient satisfaction, and enhances postoperative pulmonary function.