Warm Saline Irrigation Before Omentopexy to Reduce Early Bleeding After Laparoscopic Sleeve Gastrectomy (WARM-LSG)

Warm Staple-Line Irrigation (37-40 °C) Before Omentopexy Reduces Early Bleeding After Laparoscopic Sleeve Gastrectomy: A Prospective Randomized Trial

This prospective randomized clinical trial evaluates whether warming saline irrigation (37-40 °C) applied to the gastric staple line before performing omentopexy during laparoscopic sleeve gastrectomy (LSG) can reduce early postoperative bleeding compared with conventional room-temperature saline irrigation.

Staple-line bleeding remains one of the most relevant early complications after LSG and may lead to hemoglobin drop, prolonged drainage, blood transfusion, or re-intervention. Although reinforcement techniques such as oversewing or buttressing materials are commonly used, they may increase operative time and cost. Irrigation of the operative field is routinely performed during LSG to improve visualization; however, the potential effect of irrigation temperature on hemostasis has not been previously evaluated in bariatric surgery.

In this trial, 200 adult patients undergoing primary LSG were randomized in a 1:1 ratio to receive either warm saline irrigation (37-40 °C) or standard room-temperature saline irrigation (22-24 °C) applied directly to the staple line before omentopexy. All other operative steps were standardized.

The primary outcome is early postoperative bleeding within 48 hours. Secondary outcomes include hemoglobin drop, drain output, need for additional hemostatic maneuvers, operative efficiency, postoperative pain, length of hospital stay, and 30-day complications.

This study investigates a simple, low-cost, and easily applicable intraoperative modification that may enhance staple-line hemostasis and improve early recovery following LSG.

Study Overview

• Status: Completed
• Conditions: Obesity; Postoperative Hemorrhage
• Intervention / Treatment: Procedure: Warm Saline Irrigation; Procedure: Room Temperature Saline Irrigation

Detailed Description

Study Design and Rationale:

This study is a prospective, randomized, controlled clinical trial conducted at two high-volume tertiary bariatric centers. The aim is to evaluate whether irrigation of the gastric staple line with physiologically warm saline (37-40 °C) before performing omentopexy improves intraoperative hemostasis and reduces early postoperative bleeding following laparoscopic sleeve gastrectomy (LSG).

Irrigation of the operative field is standard practice during laparoscopic surgery to clear blood and enhance visualization. However, the effect of irrigation temperature on staple-line hemostasis in bariatric surgery has not been previously studied. Warm irrigation has demonstrated hemostatic and recovery benefits in other surgical specialties. This trial compares two clinically relevant strategies: warm saline versus conventional room-temperature saline.

Participants:

A total of 200 adult patients (18-60 years) undergoing primary LSG were enrolled. Inclusion criteria included BMI ≥ 40 kg/m² or ≥ 35 kg/m² with obesity-related comorbidities. Patients with coagulopathy, recent anticoagulant use, prior major upper abdominal surgery, advanced organ failure, pregnancy, or inability to complete follow-up were excluded.

Randomization and Allocation:

Patients were randomized in a 1:1 ratio using a computer-generated sequence with allocation concealment via sealed opaque envelopes. Surgeons were aware of the irrigation temperature, while postoperative assessors and patients were blinded to group allocation.

Intervention:

After completion of gastric transection using a 36-French bougie calibration, patients received:

• Warm Irrigation Group: 400 mL sterile saline at 37-40 °C applied along the staple line.
• Control Group: 400 mL sterile saline at 22-24 °C applied identically.

After irrigation and complete suctioning, the staple line was inspected and any active bleeding was controlled using bipolar cautery or clips. Standardized omentopexy was then performed in all patients using interrupted 2-0 PDS sutures spaced 2 cm apart.

No buttressing material, sealants, or additional reinforcement techniques were used in either group.

Primary Outcome:

Early postoperative bleeding within 48 hours, defined as any of the following:

• Hemoglobin drop ≥ 2 g/dL
• Drain output ≥ 150 mL sanguineous fluid within 24 hours
• Clinical signs of bleeding
• Need for endoscopic or surgical hemostasis

Secondary Outcomes:

• Hemostasis-phase duration
• Hemoglobin drop (continuous variable)
• 24-hour drain output
• Additional intraoperative hemostatic maneuvers
• Postoperative pain scores
• Postoperative nausea and vomiting
• Length of hospital stay
• 30-day complications (Clavien-Dindo classification)
• Reoperation or readmission

Follow-up:

Patients were evaluated during hospitalization and followed at 1 week, 1 month, and 3 months postoperatively. All randomized patients completed follow-up and were included in intention-to-treat analysis.

Statistical Considerations:

Sample size was calculated to detect reduction in bleeding incidence from 15% to 5% with 80% power. Statistical significance was defined as p < 0.05.

This study evaluates a safe, inexpensive, and easily reproducible intraoperative modification that may improve staple-line hemostasis and early recovery after LSG.

• Study Type: Interventional
• Enrollment (Actual): 200
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Cairo, Egypt
    • Ain Shams University

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Age between 18 and 60 years
• BMI ≥ 40 kg/m², or BMI ≥ 35 kg/m² with at least one obesity-related comorbidity (e.g., type 2 diabetes, hypertension, obstructive sleep apnea)
• Eligible for primary laparoscopic sleeve gastrectomy
• Provided written informed consent

Exclusion Criteria:

• Previous major upper abdominal surgery with expected adhesions
• Known bleeding disorders
• Use of anticoagulant or antiplatelet therapy within 7 days before surgery
• Advanced hepatic or renal disease
• Unstable cardiac conditions
• Pregnancy
• Immunosuppression
• Active systemic infection
• Inability to comply with follow-up schedule

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Warm Saline Irrigation; Warm saline irrigation (37-40°C) applied to the gastric staple line before omentopexy during laparoscopic sleeve gastrectomy.	Procedure: Warm Saline Irrigation; Irrigation of the gastric staple line using warm saline (37-40°C) prior to omentopexy.
Active Comparator: Room Temperature Saline; Standard room-temperature saline irrigation applied to the gastric staple line before omentopexy.	Procedure: Room Temperature Saline Irrigation; Irrigation of the gastric staple line using room-temperature saline prior to omentopexy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of early postoperative bleeding (composite outcome)	Composite endpoint defined as the occurrence of any of the following within 48 hours after surgery: Clinical evidence of bleeding; Hemoglobin drop ≥2 g/dL on postoperative day 1; Drain output >150 mL within 24 hours; Need for endoscopic or surgical hemostasis	Within 48 hours after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hemostasis-phase duration (minutes)	Time required to achieve complete staple-line hemostasis after sleeve transection and prior to omentopexy (measured intraoperatively, in minutes).	During surgery (intraoperative)
Additional intraoperative hemostatic maneuvers	Proportion of participants requiring additional hemostatic maneuvers (e.g., bipolar coagulation and/or clipping) to control staple-line bleeding.	During surgery (intraoperative)
Hemoglobin drop (ΔHb) from baseline to postoperative day 1 (g/dL)	Change in hemoglobin level (g/dL) calculated as preoperative hemoglobin minus postoperative day 1 hemoglobin (continuous outcome).	From preoperative baseline to postoperative day 1
Drain output volume in the first 24 hours (mL)	Total drain output volume (mL) during the first 24 hours after surgery; measured every 8 hours and summed (continuous outcome).	Postoperative 0-24 hours
Postoperative pain intensity at 24 hours	Pain intensity assessed at 24 hours after surgery using the Visual Analog Scale (0-10). Higher scores indicate worse pain.	24 hours after surgery
Postoperative nausea and vomiting (PONV) within 48 hours	Occurrence of postoperative nausea and/or vomiting and/or need for antiemetics in the early postoperative period.	Postoperative day 0 to day 2 (within 48 hours)
Length of hospital stay (days)	Total duration of index hospitalization measured in days from the date of surgery to the date of hospital discharge. Reported as a continuous outcome (mean number of days).	Perioperative
30-day postoperative complications (Clavien-Dindo)	Binary outcome (Yes/No) indicating the occurrence of any postoperative complication within 30 days after surgery, classified according to the Clavien-Dindo system. The outcome is reported as the proportion of participants experiencing at least one complication.	Within 30 days after surgery

Collaborators and Investigators

• Sponsor: Ain Shams University

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2024
• Primary Completion (Actual): June 30, 2025
• Study Completion (Actual): June 30, 2025

Study Registration Dates

• First Submitted: February 12, 2026
• First Submitted That Met QC Criteria: March 14, 2026
• First Posted (Actual): March 16, 2026

Study Record Updates

• Last Update Posted (Actual): March 16, 2026
• Last Update Submitted That Met QC Criteria: March 14, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: bariatric surgery; randomized clinical trial; hemostasis; laparoscopic sleeve gastrectomy; omentopexy; postoperative bleeding; warm saline irrigation; staple line
• Additional Relevant MeSH Terms: Postoperative Complications; Pathologic Processes; Nutrition Disorders; Overnutrition; Body Weight; Hemorrhage; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity; Postoperative Hemorrhage
• Other Study ID Numbers: FMASU-REC-49/2024

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No