Ultrasound Guided Erectror Spinae Block Versus Intracavitary During Medical Thoracoscopy

On the lateral decubitus position, under full aseptic technique; a high frequency (5-13 MHz) linear probe (or curvilinear in obese patients) of ultrasound covered sterilely will be placed in a parasagittal longitudinal orientation approximately 3 cm lateral to the spinous process to identify the trapezius, rhomboid major (if present), erector spinae muscle and thehyperechoic transverse process with its acoustic shadow, with the target being the fascial plane deep to the erector spinae muscle and superficial to the transverse process; the needle will be inserted in-plane in a cranial-to-caudal direction under real-time ultrasound guidance until it contacts the transverse process, after which 1-3 ml of normal saline is injected to confirm correct plane by lifting the erector spinae muscle off the transverse process, then following negative aspiration 20 ml of 0.25% bupivacaine at each level (10 ml 0.5% bupivacaine + 10 ml normal saline ) will be injected incrementally

After skin infiltration with lidocaine 2%, at the entry point of the trocar, small (2-4 cm) skin incision in the chest wall will be done, A trocar will be introduced into the pleural cavity. If necessary, air is introduced to allow the lung to collapse, creating space to view the pleural surface. The thoracoscope will be inserted to visualize the pleura. The interventional pulmonologist will receive the pre-prepared syringe from the block anaesthetist and will administer the solution intracavitarily via the thoracoscope working channel, without knowledge of its contents. In both groups, a total volume of 40 mL of solution is administered: 20 mL is sprayed over the costal, diaphragmatic, and mediastinal pleura via the thoracoscope working channel, and an additional 20 mL is injected through the chest tube inserted at the end of the procedure , 10-mL normal saline flush, and the chest tube is then clamped for 5 minutes