ESPB vs SPSIP for Postoperative Analgesia After CABG

This prospective, randomized, active-controlled, double-blind, parallel-group study compares the postoperative analgesic efficacy and safety of ultrasound-guided bilateral Erector Spinae Plane Block (ESPB) versus bilateral Serratus Posterior Superior Intercostal Plane Block (SPSIPB) in adult patients (45-85 years, ASA I-III) undergoing elective coronary artery bypass graft surgery. The primary outcome is postoperative pain intensity assessed by Numeric Rating Scale (NRS) at 2, 4, 8, 16, 24, and 48 hours after surgery. Secondary outcomes include intraoperative fentanyl/remifentanil consumption, postoperative morphine consumption, patient-controlled analgesia (PCA) demand/delivery parameters (if PCA is used), need for rescue analgesics, extubation and mobilization times, peak inspiratory flow measured by incentive spirometry at predefined time points, ICU and hospital length of stay, recovery quality (QoR-15 at 0, 24, and 48 hours), mortality, and block-related adverse events.

Inclusion Criteria: * Age 45-85 years * Scheduled for elective coronary artery bypass graft (CABG) surgery * American Society of Anesthesiologists (ASA) I-II-III * Patients who provide written informed consent and agree to participate in the study Exclusion Criteria: * Emergency cases * ASA IV-V * Known allergy to local anesthetics * Coagulopathy (platelet count \1.5, aPTT \>1.5× normal) * Infection at the block injection site * Pregnancy * Patients who do not provide written informed consent or decline to participate after being informed