Ultrasonic and inflation determination: Before induction, during ventilation, and after intubation, the anesthesiologist used a 7-14 MHz linear array probe for transverse (supraclavicular) positioning to monitor the left paratracheal esophageal region in real time. The main criterion for assessment was the absence of esophageal gas during ventilation, which was considered a positive response. If gas was detected entering the esophagus on ultrasound, it was recorded as a negative response.
Additionally, the anesthesiologist performed a preoperative ultrasound examination of the gastric antrum to record baseline gastric antrum parameters. After successful tracheal intubation, a follow-up ultrasound of the gastric antrum was conducted to obtain postoperative gastric antrum parameters.
Study summary
Exploring the 90% Effective Ventilation Pressure (EP90) for Esophageal Insufflation Avoidance During Anesthesia Induction: The aim is to determine the optimal ventilation pressure for esophageal insufflation avoidance during anesthesia induction and to explore its guiding significance for anesthesia management. The goal is to provide a more precise and personalized ventilation pressure setting standard for clinical anesthesia, thereby enhancing the safety of the anesthesia induction phase.
Eligibility
Sex
ALL
Min age
18 Years
Max age
65 Years
Healthy volunteers
No
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.
Primary outcome measure(s)
EP90 — Perioperative The 90% effective ventilation pressure (EP90) for avoiding esophageal inflation refers to the minimum effective airway pressure (measured in cmH₂O) at which 90% of patients do not experience esophageal inflation during pressure-controlled mask ventilation during anesthesia induction.
Trial sites (1)
Facility
City
Region
Status
Affiliated Hospital of Jiaxing University
Jiaxing
China
Recruiting
More Affiliated Hospital of Jiaxing University trials in China
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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