This study will be performed in Fayoum University hospital after approval of the institutional ethics committee and written informed consent. This study will be conducted as a prospective, randomized, double-blind, parallel-group clinical trial.~Inclusion criteria:~American Society of Anesthesiologists (ASA) physical status I, II patients who will be scheduled for elective abdominal hysterectomy.~Age range above 18.~Exclusion criteria:~Patient refusal.~Significant renal, hepatic and cardiovascular diseases.~History of allergy to one of the study drugs.~Any contraindication to regional anesthesia such as local infection or bleeding disorders.~Chronic opioid use, history of chronic pain and cognitive disorders.~The patients will be randomized into two groups: ESP block group who will receive preoperative US-guided bilateral ESP block with 20 ml of bupivacaine 0.25% on each side and Control group who will undergo the same procedure but with an injection of 20 ml of saline on a 1:1 ratio using a computer-generated random table. The patient's assigned group information will be elicited from a sealed opaque envelope by the anesthesiologist who will perform the ESP block and will not be involved in further data collection or patient care. The patients and both the surgical and anesthesia teams, who are responsible for patient care and data collection are blinded from the group assignments.
This study aims to evaluate the effects of erector spinae plane block on intraoperative fentanyl consumption in patients undergoing abdominal hysterectomy under general anesthesia.~To our knowledge, no study in the literature demonstrates this effect.