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

Официальное название

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

Обзор

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

Подробное описание

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.

Вмешательства

• Устройство "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).
• Устройство "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).
• Устройство "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).
• Устройство "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).

Первичные конечные точки

• Incidence of Gastric insufflation (ultrasound-confirmed) during FMV [Срок оценки: At 30 seconds, 60 seconds, and 90 seconds after induction]

Вторичные конечные точки (8)

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

Критерии участия

Критерии включения

• 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).

Критерии исключения

• • 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.

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Нет

Дизайн исследования

Распределение

Рандомизированное

Модель

Параллельные группы

Маскирование

Двойное слепое

Основная цель

Профилактика

Центры проведения

Египет · 1 центр

• Benha University Hospitals — Banhā

Идентификаторы

NCT: NCT07480031 · 3.7.2025

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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