Ultrasound-guided erector spinae plane block versus oblique subcostal transversus abdominis plane block for postoperative analgesia in laparoscopic cholecystectomy: Randomized controlled double blinded trial

INTERVENTION: In the operating room, all of the patients will receive a standard monitoring including electrocardiography, non‐invasive blood pressure, peripheral oxygen saturation and bi‐spectral index monitoring. An anesthesiologist will perform anesthesia inductions with intravenous 2‐3 mg kg‐1 propofol, 1 mcg kg‐1 fentanyl and 0.6 mg kg‐1 rocuronium bromide. After each patient's BIS score decreases to 40–60, endotracheal intubation will be performed. Intravenous 4 mg ondansetron will be applied for postoperative nausea and intravenous 50 mg dexketoprofen trometamol will be applied as a part of multimodal analgesia. Immediately after intubation, the patients in the first group (Group ESP) will be placed in lateral decubitus position. The anesthesiologist of the operating room will locate a high‐frequency linear ultrasound probe in longitudinal orientation at the level of T5 spinous process and then place 3 cm laterally from the midline. The ultrasound landmark T5 transverse process will be identified. Under aseptic conditions, the anesthesiologist will insert a 80 mm 21‐gauge block needle in‐plane at an angle of 30‐40 degrees in cranial‐to‐caudal direction until the tip contact the T5 transverse process. After the hydrodissection with 2‐3 mL of isotonic saline solution confirms correct needle tip position, 20 mL of 0.25% bupivacaine will be injected deep into the erector spinae muscle. The same procedure will be performed to the contralateral side. All of the patients will receive 4‐6% end‐tidal desflurane in the 3 lt of 40% O2 and 60% N2O for maintenance of anesthesia. The minimum alveolar concentration of desflurane will be targeted to reach a BIS value between 40‐60. At the end of the operation, postoperative analgesia will be maintained with intravenous patient‐controlled analgesia (PCA) device in all of the patients. The PCA device will administer 10 mg tramadol as bolus dose with a 15 minute lock‐time, and no basal infusion. CONDITION: cholelithiasis postoperative pain PRIMARY OUTCOME: To assess the postoperative opioid consumption in the first 24 hours by calculating the tramadol dose administered by patient controlled analgesia device. SECONDARY OUTCOME: To assess intraoperative fentanyl consumption by using data‐linkage to surgical records To assess pain scores of the patients by using 11‐points numerical rating scale (NRS) at the postoperative 5th minute, 30th minute, 60th minute (primary time‐point), 12th hour and 24th hour INCLUSION CRITERIA: Patients with ASA physical status I‐III, between 18‐70 years old, scheduled for a laparoscopic cholecystectomy