Different Concentrations of Bupivacaine in Erector Spinae Plane Block in Hip Surgeries

The patient will be placed in Lateral Decubitus with a surgical side upwards. A curvilinear array ultrasound probe will be placed in a transverse orientation at L4 level to identify the tip of the L4 transverse process. The tip of the transverse process will be centered on the ultrasound screen and the probe will be then rotated into a longitudinal orientation 2-3 cm lateral to vertebral column. The lumbar skin region will be sterilized, local infiltration of the skin and subcutaneous tissue will be applied by 2-3ml of lidocaine 2%. Then, using ultrasound guidance, A 38-mm 22-gauge (22-G, 50-mm 'Stimuplex A'; BBraun, Melsung, Germany) regional block needle will be advanced in plane to the ultrasound beam in a cranial-to-caudal direction until contact will made with the L4 transverse process. Local anesthetic solution will be injected and its type will be selected according to the studied group and patients were placed in a supine position and general anesthesia will be started.

Induction of general anaesthesia will be performed using a regimen of IV 2 μg/kg fentanyl and propofol IV 2 mg /kg. Tracheal intubation will be facilitated using 0.5 mg/kg IV of rocuronium. Anaesthesia will be maintained with inhaled sevoflurane 1-1.5% in oxygen enriched air (FiO2=0.5). Maintenance doses of rocuronium o.1 m\\kg will be provided every 30 minutes. Rescue analgesia of fentanyl 1 μg/kg will be given if the mean arterial blood pressure or heart rate rises above 20% of baseline levels. At the end of surgery, residual neuromuscular blockade will be reversed using neostigmine (0.05 mg/kg) and atropine (0.02 mg/kg), and will extubation be performed after complete recovery of the airway reflexes.