Intertransverse Process Block for Postoperative Acute Pain After Coronary Bypass Surgery

A bilateral intertransverse process block (ITPB) will be performed under ultrasound guidance using 20 mL of 0.25% bupivacaine per side prior to coronary artery bypass grafting. The block targets the dorsal rami of thoracic spinal nerves to provide postoperative analgesia.

A bilateral placebo injection (20 mL of 0.9% saline per side) will be administered at the same anatomical site under ultrasound guidance prior to coronary artery bypass grafting, mimicking the ITPB procedure without active drug.