An interventional study of Ultrasonic and inflation determination in Airway Management and Induction of Anesthesia, sponsored by Affiliated Hospital of Jiaxing University. Recruiting at 1 site in China. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-01-14.
Sponsored by Affiliated Hospital of Jiaxing University · Not applicable, Interventional, and Diagnostic
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.
Pulmonary aspiration of gastric contents has been identified as one of the leading causes of anesthesia-related mortality. Even in fasting patients or those without known aspiration risks, such complications can still occur. In fact, in patients with unprotected airways during apnea, the introduction of air into the lungs during ventilation may become a potential trigger for gastric content aspiration. The entry of air can increase gastric pressure, leading to the reflux of gastric contents into the esophagus, which may subsequently result in hemodynamic instability and pulmonary failure. Therefore, airway management during anesthesia induction is crucial, particularly in the precise control of ventilation pressure, as it directly impacts the safety of the patient during surgery.
Previous studies have used gastric insufflation as the primary endpoint for evaluating the safety of ventilation pressures, often assessing the appearance of gastric gas in the stomach during mask ventilation. However, gastric insufflation typically occurs only after gas has passed through the esophagus and cardia, entering the gastric cavity-this process is a "terminal event" triggered by higher pressures. The esophagus, being structurally weaker than the stomach, is less tolerant to pressure. When gas first enters the esophagus, the cardia is not fully open, and if ventilation pressure continues to rise, it is easy to cause esophageal insufflation, further leading to gastric insufflation and even gastric content reflux. Since esophageal insufflation occurs earlier and has a lower pressure threshold, it can serve as a more sensitive indicator, providing an early warning to anesthesiologists about potential airway management issues.
To address this issue, determining the optimal ventilation pressure to avoid esophageal insufflation is particularly important. the 90% effective ventilation pressure (EP90) refers to the ventilation pressure that can avoid esophageal insufflation in 90% of cases, providing anesthesiologists with a quantitative reference for ventilation pressures.
This study employed a Sequential Allocation with Biased Coin Design (SABCD) trial, utilizing precise statistical methods to explore the EP90 for avoiding esophageal insufflation during anesthesia induction. The goal was to determine the optimal ventilation pressure for preventing esophageal insufflation during anesthesia induction and to explore its implications for anesthesia management. The ultimate aim is to provide a more precise and personalized ventilation pressure setting standard for clinical anesthesia, thereby enhancing the safety of the anesthesia induction phase.
Affiliated Hospital of Jiaxing University is the lead sponsor of 17 studies on the registry; 10 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Anesthesia machine settings: pressure control mode, inspiratory-to-expiratory ratio of 1:2, respiratory rate of 15 breaths/min, 100% oxygen, no PEEP applied. Mask ventilation duration was standardized to 120 seconds, followed by tracheal intubation.
Other: 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.
EP90
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.
Time frame: Perioperative
EP95
The 95% effective ventilation pressure (EP95) for avoiding esophageal inflation refers to the minimum effective airway pressure (measured in cmH₂O) at which 95% of patients do not experience esophageal inflation during pressure-controlled mask ventilation during anesthesia induction.
Time frame: Periprocedural
EP98
The 98% effective ventilation pressure(EP98) for avoiding esophageal inflation refers to the minimum effective airway pressure (measured in cmH₂O) at which 98% of patients do not experience esophageal inflation during pressure-controlled mask ventilation during anesthesia induction.
Time frame: Periprocedural
Ventilation-related respiratory parameters
pulse oxygen saturation (SpO₂) was recorded at multiple time points during mask ventilation and 30/60/90/120 seconds after tracheal intubation.
Time frame: Periprocedural
Ventilation-related respiratory parameters
end-tidal carbon dioxide (EtCO₂) was recorded at multiple time points during mask ventilation and 30/60/90/120 seconds after tracheal intubation.
Time frame: Periprocedural
Ventilation-related respiratory parameters
end-tidal oxygen concentration (EtO₂) was recorded at multiple time points during mask ventilation and 30/60/90/120 seconds after tracheal intubation.
Time frame: Periprocedural
Ventilation-related respiratory parameters
minute leak volume was recorded at multiple time points during mask ventilation and 30/60/90/120 seconds after tracheal intubation.
Time frame: Periprocedural
Ventilation-related respiratory parameters
peak airway pressure (Ppeak) was recorded at multiple time points during mask ventilation and 30/60/90/120 seconds after tracheal intubation.
Time frame: Periprocedural
Ventilation-related respiratory parameters
tidal volume (Vt) was recorded at multiple time points during mask ventilation and 30/60/90/120 seconds after tracheal intubation.
Time frame: Periprocedural
Incidence of complications Incidence of complications
Including gastric distension, signs of aspiration, failure rate of mask ventilation \[such as pulse oxygen saturation (SpO₂) \< 92% lasting for 30 seconds\], intubation condition score (Cormack-Lehane classification), hypoxemia and other adverse events.
Time frame: Periprocedural
Plan to share: No
Started Sep 2025 (actual). Primary completion is estimated for Feb 2026, 5 months after the start.
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Affiliated Hospital of Jiaxing University