Group P (ultrasound guided parasternal; PIFP block): patients will be injected with 0.4 mL/kg 0.25 bupivacaine in the fascial plane between the pectoralis major and internal intercostal muscles on each side of the sternum after induction of anesthesia and before skin incision under ultrasound guidance.

Group S: After sternal closure, the surgeon will inject bupivacaine (0.5- to 2-mL aliquots depending on the weight) in the fascial plane under direct vision between the 5 anterior (2nd-6th) intercostal spaces on each side 1 to 1.5 cm lateral to the sternal edge using 25-gauge, 50 mm needle. The surgeon will inject the same dose and concentration of bupivacaine used in the ultrasound technique. This technique was prescribed before by Chaudhary et al (23).

In both techniques, the maximum dose of bupivacaine will never be exceeded (2 mg/kg). In addition, all patients were administered 2 mL of 0.25% bupivacaine at the site of the mediastinal drain location.

Patients in group P will be injected with 0.4 mL/kg of 0.25 bupivacaine in the fascial plane between the internal intercostal and pectoralis major muscles on each side of the sternum after induction of anesthesia and before skin incision under ultrasound guidance.

The first analgesic request after extubation

Amount of rescue analgesia (total dose of fentanyl) after extubation.

Postoperative pain will be assessed by modified objective pain score (MOPS) in children at 0, 2, 6, 12, 16, 20, and 24 h after extubation. Wilson and Doyle modified the objective pain score by replacing blood pressure with posture. MOPS consists of 5 items (crying, movements, agitations, posture, and verbal). The minimum score is 0 (No pain) and the maximum is 10 (most sever pain).