Postoperative pain following coronary artery bypass grafting (CABG) via median sternotomy remains a significant clinical problem and is associated with increased opioid consumption and postoperative complications. Fascial plane blocks have emerged as part of multimodal analgesia strategies in cardiac surgery.

This prospective, randomized, controlled, single-blinded study aims to evaluate the effect of an induction-time multimodal fascial plane block package-consisting of bilateral superficial parasternal block, bilateral serratus anterior plane block, and adductor canal block-on postoperative analgesia, opioid consumption, and clinical outcomes in patients undergoing elective isolated CABG with saphenous vein graft harvesting.

Patients will be randomized in a 1:1 ratio to receive either the multimodal fascial plane block package in addition to standard postoperative analgesia or standard postoperative analgesia alone. The primary outcome is total opioid consumption within the first 24 postoperative hours. Secondary outcomes include pain scores, time to first opioid requirement, extubation time, postoperative pulmonary complications, atrial fibrillation, and length of ICU and hospital stay.

Median sternotomy, chest drains, and saphenous vein graft harvesting are major contributors to postoperative pain following CABG surgery. Inadequate pain control may impair respiratory mechanics, delay mobilization, and increase postoperative morbidity. Multimodal analgesic approaches aim to reduce opioid requirements and improve recovery profiles.

This single-center, prospective, randomized controlled trial will include adult patients (18-80 years) scheduled for elective isolated CABG with saphenous vein graft harvesting. After written informed consent, eligible participants will be randomly assigned to either the intervention group or the control group.

The intervention group will receive ultrasound-guided bilateral superficial parasternal block, bilateral serratus anterior plane block, and adductor canal block following induction of general anesthesia and prior to surgical incision. The control group will receive standard perioperative analgesia without regional block. All other perioperative management will be standardized.

The primary endpoint is total opioid consumption within the first 24 hours postoperatively. Secondary endpoints include pain scores at predefined time points (6, 12, 24, and 48 hours), time to first opioid requirement, extubation time, incidence of postoperative pulmonary complications and atrial fibrillation, ICU length of stay, hospital length of stay, and time to first mobilization.

The study is designed to assess whether a multimodal fascial plane block strategy can improve postoperative analgesia and reduce opioid use in cardiac surgery patients.

Inclusion Criteria:

• Age between 18 and 80 years
• Scheduled for elective isolated coronary artery bypass grafting (CABG) with saphenous vein graft harvesting
• ASA physical status II-IV
• Ability to provide written informed consent

Exclusion Criteria:

• Known coagulopathy or contraindication to regional anesthesia
• Use of anticoagulant therapy precluding regional block
• Known allergy to local anesthetics
• Local infection at planned block sites
• Chronic opioid use or chronic pain syndrome
• Emergency surgery
• Redo sternotomy
• Severe neurological disorder affecting pain assessment

Individual participant data will not be publicly shared due to institutional and privacy restrictions.

Outcome assessors responsible for postoperative pain scoring and data collection will be blinded to group allocation.