Finding the ventilation pressure that prevents air from entering the esophagus during anesthesia induction

The 90% Effective Ventilation Pressure (EP90) for Esophageal Insufflation Avoidance During Anesthesia Induction: A Bias-Coin Design With Up-and-Down Sequential Allocation Trial

This test tries to find the ventilation pressure during anesthesia induction that prevents air from entering the esophagus in adults having elective general surgery.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 60 (estimated)
• Ages: 18 Years to 65 Years
• Sex: All
• Sponsor: Affiliated Hospital of Jiaxing University (Academic / other)
• Locations: 1 site (Jiaxing)
• Trial ID: NCT07340255 on ClinicalTrials.gov

What this trial studies

The trial uses an adaptive bias-coin design to identify the 90% effective ventilation pressure (EP90) that avoids esophageal insufflation during mask ventilation at anesthesia induction. Adult elective surgical patients (ASA I–III, BMI 18–28) will undergo controlled mask ventilation with stepwise pressure adjustments while ultrasound and inflation monitoring detect any air entry into the esophagus. The adaptive design adjusts pressures based on earlier patients' responses to efficiently estimate the EP90. The overall aim is to produce a more precise, personalized ventilation pressure guideline to reduce the risk of gastric aspiration during induction.

Who should consider this trial

Good fit: Adults aged 18–65 scheduled for elective general anesthesia who are ASA I–III, have BMI 18–28, are appropriately fasted, and have low predicted difficulty with mask ventilation.

Not a fit: Patients with known upper gastrointestinal disease, recent respiratory infections, need for emergency surgery, pregnancy, high BMI, or severe cardiopulmonary comorbidities are unlikely to benefit from the study results or may be excluded.

Why it matters

Potential benefit: If successful, this could give clearer ventilation pressure guidance that reduces esophageal and gastric insufflation and lowers aspiration-related complications during induction.

How similar studies have performed: Previous work has used gastric insufflation thresholds to guide safe ventilation pressures, but using esophageal insufflation as the primary endpoint and targeting an EP90 is a newer approach with limited prior data.

Eligibility criteria

Inclusion Criteria:

1. Age: 18-65 years, regardless of gender;
2. ASA classification: I-III;
3. Scheduled for elective general anesthesia surgery;
4. BMI: 18.0-28.0 kg/m²;
5. Preoperative fasting: Solid food \>6 hours, liquid \>2 hours;
6. Less than two from five criteria predicting difficult mask ventilation as described by Langeron et al.(Prediction of difficult mask ventilation. Anesthesiology 2000; 92:1229-36);
7. No severe underlying conditions such as heart, lung, liver, or kidney disease;
8. Signed informed consent and ability to cooperate with the study protocol.

Exclusion Criteria:

1. Pregnant or breastfeeding women;
2. History of upper gastrointestinal diseases such as gastroesophageal reflux disease, peptic ulcers, or hiatal hernia;
3. Recent (within 2 weeks) respiratory infections, chronic cough, similar symptoms, and other known or predictable respiratory system diseases;
4. Need for emergency surgery or airway obstruction after anesthesia induction requiring urgent intubation;
5. Inability to achieve adequate oxygenation during mask ventilation (e.g., SpO₂ \< 92% for 30 seconds, unresponsive to treatment);
6. History of contraindications or allergies to study medications;
7. Inability to understand the study content or refusal to cooperate;
8. Oropharyngeal or facial pathology;
9. with an indwelling gastric tube, and who had previously undergone gastric surgery.

Where this trial is running

Jiaxing

• Affiliated Hospital of Jiaxing University — Jiaxing, China (Recruiting)

Study contacts

• Study coordinator: Qinghe Zhou

Conditions Airway Management; Induction of Anesthesia; Esophageal Insufflation; Ventilation; Bias-coin Design