Rectus Sheath Block as an Adjunct to General Anesthesia for Midline Laparotomy Pain (RSB-MIDLINE)

Effectiveness of Rectus Sheath Block as an Adjunct to General Anesthesia for Postoperative Pain and Inflammation in Patients Undergoing Midline Incision Laparotomy at RSUP Sanglah

This study evaluates whether adding an ultrasound-guided rectus sheath block (RSB) to general anesthesia can improve pain control after midline laparotomy. Adult patients undergoing midline incision laparotomy will be randomly assigned to receive either general anesthesia alone or general anesthesia plus bilateral RSB with local anesthetic (bupivacaine 0.25%). After surgery, pain will be assessed using the Numeric Rating Scale (NRS) at 15 minutes, 1 hour, 3 hours, 6 hours, 12 hours, and 24 hours. The study will also compare the time to first opioid request, total opioid use during the first 24 hours after surgery, and changes in inflammation measured by the neutrophil-to-lymphocyte ratio (NLR). The goal is to determine whether RSB can reduce postoperative pain and opioid requirements and help limit postoperative inflammatory response.

Study Overview

• Status: Completed
• Conditions: Postoperative Pain; Abdominal Surgery by Laparotomy
• Intervention / Treatment: Procedure: Ultrasound-guided rectus sheath block

Detailed Description

This is a double-blind randomized controlled trial conducted in adult patients (18-64 years) undergoing midline incision laparotomy under general anesthesia at Sanglah Hospital. Eligible participants are enrolled consecutively and randomized using permuted block randomization with sealed envelopes into two parallel groups:

Group A (Control): General anesthesia without rectus sheath block.

Group B (Intervention): General anesthesia plus bilateral ultrasound-guided posterior rectus sheath block (RSB) using bupivacaine 0.25%.

Anesthetic management is standardized. Patients receive IV midazolam 0.02 mg/kg as premedication. Induction is performed with propofol 1-2 mg/kg and fentanyl 2 mcg/kg, followed by atracurium 0.5 mg/kg for intubation. Maintenance includes pressure-controlled ventilation (FiO₂ 40%, flow 2 L/min) and propofol infusion 50-150 mcg/kg/min. Intraoperative analgesia is supplemented with fentanyl 0.5 mcg/kg every 45 minutes. Hemodynamics are maintained within 20% of baseline.

RSB technique (Group B): After intubation, the abdominal skin is disinfected. A linear ultrasound probe is placed lateral to the umbilicus to identify the rectus abdominis muscle and posterior rectus sheath. Using an in-plane approach, a 50 mm needle is advanced from lateral to medial until the needle tip lies between the rectus abdominis muscle and posterior rectus sheath. After negative aspiration, 20 mL of bupivacaine 0.25% is injected as a single-shot on one side with aspiration every 3 mL, visualizing separation of the rectus muscle from the posterior sheath. The procedure is then repeated on the contralateral side (bilateral block).

Postoperative management and assessments: Pain is evaluated by an independent observer using the Numeric Rating Scale (NRS 0-10) at T1 (15 minutes in the recovery room), T2 (1 hour), T3 (3 hours), T4 (6 hours), T5 (12 hours), and T6 (24 hours) postoperatively. Postoperative analgesia includes patient-controlled analgesia (PCA) morphine demand-only (1 mg per demand dose) for patients with GCS 15, plus oral paracetamol 500 mg every 6 hours. The time to first opioid request is recorded (minutes), and total morphine consumption during the first 24 hours is collected.

Inflammation assessment: Neutrophil-to-lymphocyte ratio (NLR) is measured from complete blood count (CBC) preoperatively (one day before surgery) and postoperatively (in the recovery room).

Key outcomes include postoperative NRS scores (T1-T6), time to first opioid request, total opioid requirement in the first 24 hours, and perioperative changes in NLR.

• Study Type: Interventional
• Enrollment (Actual): 46
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Indonesia
  • Bali
    • Denpasar, Bali, Indonesia, 80111
      • Ngoerah Hospital, Denpasar, Bali, Indonesia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults aged 18-64 years.
• Patients undergoing midline laparotomy incision (incision extending above to below the umbilicus) for digestive, obstetric, or oncology cases (corresponding to T7-T12 dermatomes) under general anesthesia.
• ASA physical status I-III.
• Body mass index (BMI) 18.5-30 kg/m².
• Willing and able to provide written informed consent.

Exclusion Criteria:

• Refusal to participate.
• Infection or wound at the planned block site.
• Decreased level of consciousness.
• Known allergy to local anesthetics or opioids.
• Coagulation disorder.
• History of chronic pain.
• Hyperalgesia.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control: General Anesthesia Only; Participants receive standard general anesthesia without rectus sheath block. Postoperative analgesia follows institutional protocol (e.g., PCA morphine and paracetamol).
Experimental: Intervention: General Anesthesia + Bilateral Rectus Sheath Block; Participants receive standard general anesthesia plus bilateral ultrasound-guided posterior rectus sheath block (single-shot) using bupivacaine 0.25%, 20 mL per side, performed after induction of anesthesia.	Procedure: Ultrasound-guided rectus sheath block; Bilateral posterior rectus sheath block performed under ultrasound guidance after induction of general anesthesia. Single-shot injection of bupivacaine 0.25% (20 mL per side) between the rectus abdominis muscle and posterior rectus sheath.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative Pain Intensity (Numeric Rating Scale, NRS)	Pain intensity measured using the Numeric Rating Scale (0-10; 0 = no pain, 10 = worst imaginable pain) by a blinded assessor.	15 minutes, 1 hour, 3 hours, 6 hours, 12 hours, and 24 hours after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to First Opioid Request	Time from arrival in recovery room to first request for opioid analgesia (minutes).	Up to 24 hours after surgery
Total Opioid Consumption	Total morphine consumption recorded from PCA during the first 24 hours after surgery (mg)	24 hours after surgery
Change in Neutrophil-to-Lymphocyte Ratio (NLR)	NLR calculated from complete blood count measured preoperatively and postoperatively in the recovery room.	Preoperative (1 day before surgery) and postoperative (in recovery room)
Postoperative Nausea and Vomiting (PONV	Incidence of nausea/vomiting within 24 hours postoperatively.	Up to 24 hours after surgery

Collaborators and Investigators

• Sponsor: Udayana University
• Collaborators: RS Prof. Dr. I.G.N.G Ngoerah
• Investigators: Principal Investigator: I Made Prema Putra, Udayana University

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2022
• Primary Completion (Actual): April 30, 2022
• Study Completion (Actual): April 30, 2022

Study Registration Dates

• First Submitted: January 30, 2026
• First Submitted That Met QC Criteria: January 30, 2026
• First Posted (Actual): February 6, 2026

Study Record Updates

• Last Update Posted (Actual): February 6, 2026
• Last Update Submitted That Met QC Criteria: January 30, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Opioid Consumption; Postoperative Analgesia; Numeric Rating Scale; Midline Laparotomy; Neutrophil-to-Lymphocyte Ratio; Rectus Sheath Block; Ultrasound-Guided
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative
• Other Study ID Numbers: 2022.02.1.0341 (Other Identifier: Faculty of Medicine, Universitas Udayana); EC-UNUD-82.0-2022 (Other Identifier: Research Ethics Committee, Faculty of Medicine, Universitas Udayana)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: De-identified individual participant data (IPD) will not be shared publicly. Data may be considered for sharing upon reasonable request to the principal investigator, subject to institutional and ethics approval

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No