Determination of the Optimal Inspiratory Pressure to Decrease Incidence of Gastric Insufflation With Adequate Ventilation During Facemask Ventilation in Morbidly Obese Patients

Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation in Morbidly Obese Patients to Prevent Gastric Insufflation: A Randomized Clinical Trial

The goal of this randomized clinical trial is to optimize the inspiratory pressure during facemask ventilation (FMV) in morbidly obese patients (BMI ≥40 kg/m²), to ensure adequate ventilation while minimizing the risk of gastric insufflation by real-time ultrasound guidance

Study Overview

• Status: Not yet recruiting
• Conditions: Gastric Insufflation
• Intervention / Treatment: Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"

Detailed Description

Morbid obesity, defined as a body mass index (BMI) ≥ 40 kg/m², presents significant challenges during the management of the airway and ventilation under general anesthesia. One of the critical issues is the increased risk of gastric insufflation during facemask ventilation (FMV), which can lead to pulmonary aspiration, reduced lung compliance, and impaired oxygenation. Therefore, optimizing inspiratory pressure to ensure adequate ventilation while minimizing the risk of gastric insufflation is paramount in this population.

Ultrasound imaging has emerged as a valuable, non-invasive tool for real-time assessment of gastric content and volume. Recent studies have demonstrated the utility of gastric ultrasonography in detecting gastric insufflation during positive pressure ventilation. By visualizing the antrum and measuring the cross-sectional area , anesthesiologists can identify even small volumes of air entering the stomach, which might not be clinically apparent.

• Study Type: Interventional
• Enrollment (Estimated): 144
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: mohamed a mustafa, MSC; Phone Number: +201144616418 +201022708985; Email: mhmdabdelrazik248@gmail.com
• Study Contact Backup: Name: alaa b mohamed, MBBCH; Phone Number: +201098073650 +201019680699; Email: alabam7m@gmail.com

Study Locations

• Egypt
  • Banhā, Egypt
    • Benha University Hospitals
    • Contact: nasser k el-gizawy, MD; Phone Number: 0020133231012 0020133231011; Email: info@bu.edu.eg

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Adult patients (18-65 years old) scheduled for elective surgery under general anesthesia requiring facemask ventilation.

  • Morbid obesity (BMI ≥40 kg/m²).
  • American Society of Anesthesiologists (ASA) physical status II-III.
  • Normal upper gastrointestinal anatomy (no history of gastric surgery, esophageal strictures, or hiatus hernia).
  • Fasted for at least 6 hours for solids and 2 hours for fluids (standard preoperative fasting guidelines).

Exclusion Criteria:

• • Emergency surgery (due to inability to ensure proper fasting or preoperative assessment).

  • Known or suspected difficult airway (Mallampati class IV, limited neck mobility, or history of difficult intubation).
  • Gastroesophageal reflux disease (GERD) or high aspiration risk (e.g., pregnancy, symptomatic hiatal hernia).
  • Contraindications to facemask ventilation (facial trauma, beard/mask seal interference).
  • Severe cardiopulmonary disease (e.g., severe COPD, pulmonary hypertension, or unstable angina).
  • Neuromuscular disorders affecting respiratory function.
  • Refusal to participate or inability to provide informed consent.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: group A; This arm will be subjected to inspiratory pressure 10 cmH₂O	Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group A will be subjected to an inspiratory pressure of 10 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group B will be subjected to an inspiratory pressure of 15 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group C will be subjected to an inspiratory pressure of 20 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group D will be subjected to an inspiratory pressure of 25 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).
Experimental: group B; This arm will be subjected to inspiratory pressure 15 cmH₂O	Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group A will be subjected to an inspiratory pressure of 10 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group B will be subjected to an inspiratory pressure of 15 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group C will be subjected to an inspiratory pressure of 20 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group D will be subjected to an inspiratory pressure of 25 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).
Experimental: group C; This arm will be subjected to inspiratory pressure 20 cmH₂O	Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group A will be subjected to an inspiratory pressure of 10 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group B will be subjected to an inspiratory pressure of 15 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group C will be subjected to an inspiratory pressure of 20 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group D will be subjected to an inspiratory pressure of 25 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).
Experimental: group D; This arm will be subjected to inspiratory pressure 25 cmH₂O	Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group A will be subjected to an inspiratory pressure of 10 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group B will be subjected to an inspiratory pressure of 15 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group C will be subjected to an inspiratory pressure of 20 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).; Device: "Ultrasound-Guided Optimization of Inspiratory Pressure During Facemask Ventilation"; Description: Group D will be subjected to an inspiratory pressure of 25 cmH₂O. A curvilinear ultrasound probe will be placed in the epigastric region to visualize the antrum. Baseline gastric ultrasound will be performed to confirm an empty stomach. During FMV, ultrasound images will be obtained at 30, 60, and 90 seconds. Gastric insufflation will be detected by the change in gastric cross-sectional area (ΔCSA).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Incidence of Gastric insufflation (ultrasound-confirmed) during FMV	At 30 seconds, 60 seconds, and 90 seconds after induction

Secondary Outcome Measures

Outcome Measure	Time Frame
Tidal volume (mL/kg ideal body weight) and peak inspiratory pressure	at 30, 60, and 90 seconds of facemask ventilation (FMV)
Oxygen saturation (SpO₂)	At baseline and 30 seconds, 60 seconds, and 90 seconds during FMV
End tidal CO2	At baseline and 30 seconds, 60 seconds, and 90 seconds during FMV
Antral cross-sectional area	at baseline (15 minutes before induction) and 30, 60, 90 seconds during FMV.
Heart rate	At baseline, 30, 60, 90 seconds during facemask ventilation and one minute after endotracheal tube placement
Mean arterial blood pressure	At baseline, 30, 60, 90 seconds during facemask ventilation and one minute after endotracheal tube placement
Hypoxia occurrence	Monitored continuously from induction of anesthesia till one minute after endotracheal intubation
Aspiration events	Continuously monitored, intraoperatively and postoperatively (24-hour follow-up).

Collaborators and Investigators

• Sponsor: Benha University

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): April 15, 2027

Study Registration Dates

• First Submitted: March 11, 2026
• First Submitted That Met QC Criteria: March 14, 2026
• First Posted (Actual): March 18, 2026

Study Record Updates

• Last Update Posted (Actual): March 18, 2026
• Last Update Submitted That Met QC Criteria: March 14, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 3.7.2025

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