Erector Spinae Plane Block Versus Quadratus Lumborum Block for Postoperative Analgesia After Laparoscopic Resection of Colorectal Cancer.

The study will be carried out at Beni-Suef university hospital, after approval by the department of Anesthesiology, Surgical Intensive Care and Pain management, faculty of medicine, Beni-Suef University. The study will be done from october 2022 for 1 year.

Setting: Beni-Suef University Hospital Participants: Eligible patients are aged 35-75 years, with an American Society of Anesthesiologists (ASA) physical status of I-III, and are scheduled to undergo laparoscopic resection of colorectal cancer. Patients willing to participate in the study will get information bedside, and written informed consent will be obtained. Recruitment can of course always be retracted before, during, or even after trial start and will have no influence on further treatment of patient. here is no anticipated harm and compensation for trial participation.

Intervention: All blocks were performed after securing the airway before the start of surgery.

ESPB group will receive bilateral ultrasound-guided erector spinae plane block using 20 ml of bupivacaine 0.25% with 4 mg dexamethasone for each side.

TQLB group will receive bilateral ultrasound-guided transmuscular quadratus lumborum block using 20 ml of bupivacaine 0.25% with 4 mg dexamethasone for each side.

Anesthetic technique:

All the patients will be underwent routine preoperative check-ups, routine haematological and biochemical analyses, and cardiac evaluation. The study protocol will be explained to all participants, including the visual analogue scale (VAS), which will be explained on the day of the preoperative evaluation. Standard monitoring will be established when patients were transferred to the operating room. Invasive arterial blood pressure monitoring, central venous catheter placement right jugular internal vein, and catheterization in the right neck will be performed. patient will receive midazolam 0.05 mg/kg IV 3 minutes prior to induction and ondansetron 4 mg IV. Anaesthesia will be induced by 2-2.5 mg/kg propofol, 2 μg/kg fentanyl \& 0.5 mg/kg atracurium for muscle relaxation. The patient will be ventilated using a face mask with 100% oxygen at a rate of 4 L/min and isoflurane 1.2 %. After 180 s, the patient will be intubated using an appropriately sized cuffed oral tube. Anaesthesia maintenance will be performed by isoflurane 1.2% in 100 % O2 and intravenous fentanyl infusion at a rate of 1-2 μg/kg/hr. Muscle relaxation will be continued by atracurium 0.1 mg/kg every 20 min. Mechanical ventilation will be performed for all participants to maintain end-tidal carbon dioxide levels between 35-40 mmHg. Intravenous fluid requirements will be assessed and provided to patients perioperatively, and normothermia will be maintained throughout the procedure. At the end of surgery, a reversal of the muscle relaxant will be done using neostigmine (0.04 mg/kg) and atropine (0.015 mg/kg). After extubation, all patients will be transmitted to the post anesthesia care unit (PACU). When patients were found to be fully awake and vitally stable, they will be transferred to surgical intensive care unit.

The following will be recorded:

• Patients' characteristics: Age, sex, BMI, ASA physical status.
• Time needed to perform technique (min): which was defined as the time needed for adequate ultrasonic visualization, needle introduction, and drug injection (time from placement of ultrasound probe on the patient's skin to the end of local anesthetic injection) .
• Duration of anesthesia, duration of surgery \& duration of PACU stay.
• Heart rate (HR), mean arterial blood pressure (MAP), were measured at baseline before induction of anesthesia and then continuously monitored and recorded every 10 min intraoperatively, but recorded at baseline, immediately after induction, at 20 min, 40 min, 1h, 2h after induction and finally at the end of surgery.
• Number of blocked dermatomes: were assessed after recovery of anesthesia using pinprick and cold loss sensation with iced solutions.
• Visual analogue scale (VAS) : was assessed at rest and during movement at 30 min, 1, 3, 6, 12, 24 h postoperatively. A score ≤ 3 was considered acceptable for pain relief. Supplementary rescue analgesia was administered in the form of nalbuphine IV 0.15 mg/kg (at VAS ≥ 4).
• 1st time to rescue analgesic (min): is the time to ask for the first postoperative analgesia (nalbuphine), and was calculated from the end of operation to patient reporting VAS ≥ 3.
• Total dose of rescue analgesia (nalbuphine) (primary outcome), that was consumed in the first 24 h postoperatively.
• Quality of Recovery (QoR)-15 questionnaire scores preoperatively and 24 h postoperatively [using the Korean version of the Quality of Recovery-15 scale ], which can be divided into two components: physical and mental well-being
• Intraoperative and postoperative complications related to the blocks as local anesthetic toxicity, needle injury to essential organs, retroperitoneal hematoma, hypotension, lower limb weakness, . . . etc
• The incidence and severity of postoperative complications, such as hypotension, bradycardia, respiratory depression, sedation, nausea, and vomiting, during the first 24 h postoperative were also recorded. A categorical scoring system (0 = none, 1 = nausea, 2 = retching, and 3 = vomiting) was used to evaluate nausea and vomitin . Sedation scores were evaluated using a sedation scale (0 = awake, 1 = drowsy, 2 = asleep but arousable, 3 = deeply asleep). Patients were considered sedated if they had a sedation score of > 0 at any time during the first 24 hours after surgery . Patient satisfaction was assessed as (1 = poor, 2 = moderate, 3 = good, and 4 = perfect) .