Ultrasound-Guided Esophageal Compression During Adult Mask Ventilation

Ultrasound-Guided Esophageal Compression During Adult Mask Ventilation: A Prospective Observational Study

A total of 103 elective surgery patients who met the inclusion criteria were selected. After screening for eligibility according to the inclusion and exclusion criteria and signing informed consent, they were randomly divided into two groups. Upon entering the operating room, routine ECG monitoring was initiated, and a peripheral vein was opened. Ultrasound was used to measure the baseline cross-sectional area (CSA) of the gastric antrum in the supine position. After general anesthesia induction, positive pressure ventilation was applied via face mask. Group A received no external compression, while Group B underwent esophageal compression under ultrasound guidance.

Study Overview

• Status: Completed
• Conditions: Laparoscopic Surgery; Ultrasonography; Stomach Distended; Compression of Esophagus
• Intervention / Treatment: Behavioral: Compression of esophageal

Detailed Description

Upon entering the operating room, intravenous access is established, and oxygen is administered. Standard vital sign monitoring is initiated, including heart rate, non-invasive blood pressure, peripheral oxygen saturation, temperature monitoring, and BIS monitoring. Ultrasound is used to measure the cross-sectional area (CSA) of the gastric antrum before the onset of FMV.

Oxygen is administered via face mask for denitrogenation, with 100% pure oxygen (6 L/min flow rate). Intravenous medications are sequentially administered: midazolam 0.03 mg/kg, propofol 1-2 mg/kg, sufentanil 0.5 μg/kg, remifentanil 1 μg/kg, and rocuronium bromide 0.6 mg/kg. After the patient loses consciousness and the eyelash reflex is absent, FMV is initiated. The trial employs a pressure-controlled ventilation (PCV) mode with a pressure of 18 cmH2O, a level sufficient to provide adequate alveolar ventilation while staying below the threshold for significant gastroesophageal regurgitation. The respiratory rate is set at 14 breaths per minute with an inspiration-to-expiration ratio of 1:2.

After three minutes of FMV, the gastric antrum CSA is measured again in supine, semi-recumbent, and right lateral decubitus positions. Video laryngoscopy is used to record POGO scores before and after ultrasound-guided esophageal compression, and after 4 minutes of ventilation, tracheal intubation is performed. Grouping:

Group A (Control Group): No esophageal compression is applied, and FMV is performed for 4 minutes.

Group B (Intervention Group): Ultrasound-guided esophageal compression plus FMV: before the start of FMV, ultrasound is used to locate the esophagus, and pressure is applied to the esophagus at the cricoid level to collapse the esophageal lumen. Esophageal pressure is released just before tracheal intubation following 4 minutes of ventilation.

• Study Type: Interventional
• Enrollment (Actual): 103
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Jiangsu
    • Nanjing, Jiangsu, China, 210006
      • Nanjing First Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18 to 65 years
• American Society of Anesthesiologists (ASA) Physical Status Classification I-II.
• Body Mass Index (BMI) between 18 and 28 kg/m².
• Patients undergoing elective tracheal intubation for general anesthesia.
• Patients scheduled for laparoscopic surgery.
• Fasting for ≥8 hours and abstaining from liquids for ≥2 hours before surgery, with low risk of gastroesophageal regurgitation and aspiration.

Exclusion Criteria:

• Suspected difficult FMV (e.g., age >55 years, BMI >26 kg/m², edentulous, history of snoring, and long beard; presence of two or more factors).
• Pre-existing respiratory, pharyngeal, laryngeal, facial, or neck pathology.
• History of gastrointestinal surgery, gastroesophageal reflux disease (GERD), or high risk of aspiration.
• Severe cardiac, cerebral, pulmonary, hepatic, or renal diseases.
• Patients requiring non-invasive ventilation prior to surgery.
• Patients currently participating in other clinical trials or who refuse to participate.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Group A (Control Group); No esophageal compression is applied, and FMV is performed for 4 minutes.
Experimental: Group B (Intervention Group); Ultrasound-guided esophageal compression plus FMV: before the start of FMV, ultrasound is used to locate the esophagus, and pressure is applied to the esophagus at the cricoid level to collapse the esophageal lumen. Esophageal pressure is released just before tracheal intubation following 4 minutes of ventilation.	Behavioral: Compression of esophageal; Before the start of FMV, ultrasound is used to locate the esophagus, and pressure is applied to the esophagus at the cricoid level to collapse the esophageal lumen. Esophageal pressure is released just before tracheal intubation following 4 minutes of ventilation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The incidence of gastric distension	Defined as a significant increase in gastric antrum CSA with acoustic shadowing or the characteristic "comet-tail sign," or when the enlarged gastric antrum obstructs the surgical field	During anesthesia induction

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The positional relationship between the esophagus and trachea	Observe the position of the esophagus relative to the trachea without the application of pressure on the patient, and assess whether there is any positional change of the esophagus relative to the trachea under ultrasound guidance after esophageal compression, ensuring the accuracy and safety of esophageal compression.	Before anesthesia induction
Tidal volume	Observe whether tidal volume is affected after ultrasound-guided esophageal compression and evaluate the impact of esophageal compression on ventilation quality. Effective esophageal compression should maintain a tidal volume of no less than 6 ml/kg for the patient.	During anesthesia induction
Oxygen saturation	Observe whether oxygen saturation is affected after ultrasound-guided esophageal compression and evaluate the impact of esophageal compression on ventilation quality. Effective esophageal compression should maintain the patient's oxygen saturation at no less than 95%.	During anesthesia induction
Airway plateau	Observe the values of airway plateau pressure during esophageal compression to evaluate the mechanical impact of esophageal compression on the airway. An airway plateau pressure not exceeding 20-25 cmH₂O indicates effective esophageal compression.	During anesthesia induction
The percentage of glottic opening (POGO) score	The percentage of glottic opening (POGO) score represents the portion of the glottis visualized. It is defined anteriorly by the anterior commissure and posteriorly by the interarytenoid notch. The score ranges from 0% when none of the glottis is seen to 100% when the entire glottis including the anterior commissure is seen. A POGO score of 100% denotes visualization of the entire glottic opening in linear fashion from the anterior commissure to the posterior cartilages . If none of the glottic opening is seen, then the POGO score is 0%. The higher the POGO value, the less impact effective esophageal compression has on ventilation performance.	During tracheal intubation, immediately
Surgeon's evaluation of gastric insufflation	The degree of gastric distention is assessed by the same surgeon through laparoscopy. A score of 0 is given when there is no significant gastric distention, a score of 1 is given when there is noticeable gastric distention that does not affect the surgical procedure, and a score of 2 is given when there is significant gastric distention that affects the surgery, requiring the placement of a gastric tube for decompression. The number of postoperative vomiting episodes is recorded: 0 episodes is scored as 0, 1-2 episodes is scored as 1, and more than 2 episodes is scored as 2. A lower score indicates better esophageal compression effectiveness.	Upon the start of surgery, immediately
Rate of esophageal diameter change	Compare the diameter before and after esophageal compression and calculate the percentage change in diameter. After esophageal compression, the diameter of the esophagus should decrease. The percentage change in diameter is usually expressed as a negative value, indicating that the esophagus has constricted after compression. If the percentage change is positive, it suggests that the compression effect is not ideal, and the esophagus may not have been effectively compressed.	During anesthesia induction
Esophageal compression pressure	Recording esophageal compression pressure can ensure that the applied pressure is within an effective range, help understand the relationship between compression intensity and ventilation efficacy, and promptly identify potential complications, such as airway compression or esophageal injury caused by excessive pressure, allowing for necessary interventions.	During anesthesia induction

Collaborators and Investigators

• Sponsor: Liu Han

Study record dates

Study Major Dates

• Study Start (Actual): September 25, 2024
• Primary Completion (Actual): September 12, 2025
• Study Completion (Actual): December 31, 2025

Study Registration Dates

• First Submitted: October 15, 2024
• First Submitted That Met QC Criteria: November 13, 2024
• First Posted (Actual): November 14, 2024

Study Record Updates

• Last Update Posted (Actual): April 24, 2026
• Last Update Submitted That Met QC Criteria: April 21, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Digestive System Diseases; Gastrointestinal Diseases; Stomach Diseases; Gastric Dilatation
• Other Study ID Numbers: KY20240924-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No