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
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
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
144
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).
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).
Benha University Hospitals
Banhā, Egypt
Incidence of Gastric insufflation (ultrasound-confirmed) during FMV
Time frame: At 30 seconds, 60 seconds, and 90 seconds after induction
Tidal volume (mL/kg ideal body weight) and peak inspiratory pressure
Time frame: at 30, 60, and 90 seconds of facemask ventilation (FMV)
Oxygen saturation (SpO₂)
Time frame: At baseline and 30 seconds, 60 seconds, and 90 seconds during FMV
End tidal CO2
Time frame: At baseline and 30 seconds, 60 seconds, and 90 seconds during FMV
Antral cross-sectional area
Time frame: at baseline (15 minutes before induction) and 30, 60, 90 seconds during FMV.
Heart rate
Time frame: At baseline, 30, 60, 90 seconds during facemask ventilation and one minute after endotracheal tube placement
Mean arterial blood pressure
Time frame: At baseline, 30, 60, 90 seconds during facemask ventilation and one minute after endotracheal tube placement
Hypoxia occurrence
Time frame: Monitored continuously from induction of anesthesia till one minute after endotracheal intubation
Aspiration events
Time frame: Continuously monitored, intraoperatively and postoperatively (24-hour follow-up).
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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).
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).