The Effect of Bilateral Rectus Sheath and Oblique Subcostal Transversus Abdominis Plane Block on Mechanical Power

The OSTAP block will be conducted in-plane using a 100mm 22 G needle and a linear probe under ultrasound (USG) guidance. The 20cc block will contain 10cc of 0.5% bupivacaine and 10cc of normal saline. Bilateral OSTAP will be administered with 20cc (10cc per side). To apply the block, position the linear probe parallel to the rib edge immediately below it on the anterior abdominal wall. Visible will be the external, internal, transversus abdominis, and rectus muscle junction. The needle tip will move toward the TAP space (between the internal oblique and transversus abdominis muscles). To ensure medication delivery, the needle tip will be visible in the TAP and the drug will be aspirated negatively. USG will also observe drug distribution at the rectus abdominis muscle-TAP space junction.

When the patient is in the supine position, the ultrasound (USG) linear probe is held in the transverse plane at the level just above the umbilicus, where the posterior rectus sheath is best visualized. Using the in-plane technique with a 100mm 22 G needle under USG guidance, the drug prepared will be administered between the rectus muscle and the posterior rectus sheath. For this block, a volume of 20cc will be prepared, consisting of 10cc of 0.5% bupivacaine and 10cc of normal saline. Bilateral Rectus Sheath Block (RSB) will be applied with a total volume of 20cc, 10cc to each side.