Ultrasound-guided PIFB procedure
Bilateral PIFB was conducted in the supine position under ultrasound guidance after anesthesia induction. A high-frequency linear ultrasound probe (EPIQ7C, PHILIPS, Holland) was placed 2–3 cm lateral to the edge of the sternum at the fourth intercostal space to identify anatomic landmarks (Fig. Procedures of PIFB and RSB. 