Body Position and Ultrasound Examination of the Gastric Antrum (POSIGAST)

Diagnostic Performance of the Ultrasound Examination of the Antrum to Detect a Full Stomach According to the Position of the Patient

Pulmonary aspiration of gastric contents is a complication causing significant morbidity and mortality related to anesthesia. Ultrasound examination of the gastric antrum allows the detection of preoperative gastric contents contributing to the preoperative assessment of pulmonary aspiration risk. In particular, this examination is based on the qualitative analysis of gastric contents performed in the supine and in the right lateral decubitus, using a qualitative score which makes it possible to discriminate a low liquid content of a large liquid volume. This score has been described in patients and volunteers installed on a bed without elevation of the upper section of the bed. However, in several studies, this qualitative score has been achieved in the 45° semirecumbent position, which may have affected the diagnostic performance of the examination thus performed, as suggested by the results of a study recently conducted by the investigating team. This study therefore aims to compare the diagnostic performance of the qualitative analysis of the gastric antrum performed in the supine and the right lateral decubitus for the diagnosis of gastric volumes higher than 50 ml and 100 ml, according to the bed angle: 45 ° elevation or no elevation of the upper section of the bed.

Study Overview

• Status: Completed
• Conditions: Pulmonary Aspiration of Gastric Contents
• Intervention / Treatment: Other: Qualitative and quantitative assessment of gastric content volume with bed elevation; Other: Qualitative and quantitative assessment of gastric content volume without bed elevation

• Study Type: Interventional
• Enrollment (Actual): 21
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Bron, France, 69500
    • Hospices Civils de Lyon

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Adults 18 years old or older
• Last consumption of solids at least 6 hours before the start of the study, last consumption of clear fluids at least 2 hours before the start of the study
• Informed consent must have been signed.
• No significant medical history (American Society of Anesthesiologists (ASA) class 1)

Exclusion Criteria:

• Adult unable to give informed consent
• Previous gastrointestinal surgery
• Medication affecting gastric motility
• Digestive diseases, gastroparesis, diabetes mellitus with insulin
• Pregnancy or breastfeeding
• Obesity (Body Mass Index (BMI) ≥ 30 kilograms/meter² (kg/m²))

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: 45° semirecumbent position	Other: Qualitative and quantitative assessment of gastric content volume with bed elevation; Ultrasound examination of the gastric antrum are performed 3 minutes after the ingestion of a volume of water (either 0, 50, 100, 150, or 200 milliliters (ml), determined by randomization). The procedure is repeated three times (three different volumes, the same volumes for each session with randomized order for each session).
Active Comparator: No elevation of the upper section of the bed	Other: Qualitative and quantitative assessment of gastric content volume without bed elevation; Ultrasound examination of the gastric antrum are performed 3 minutes after the ingestion of a volume of water (either 0, 50, 100, 150, or 200 milliliters (ml), determined by randomization). The procedure is repeated three times (three different volumes, the same volumes for each session with randomized order for each session).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Calculation of the sensitivity	Diagnostic performance of the qualitative examination of the gastric antrum in the 45° semirecumbent position.	3 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Calculation of the specificity	Diagnostic performance of the qualitative examination of the gastric antrum in full supine/right lateral decubitus position. The diagnostic performance will be calculated according to the results of the qualitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers.	3 minutes
Calculation of the positive predictive value,	Diagnostic performance of the qualitative examination of the gastric antrum in full supine/right lateral decubitus position. The diagnostic performance will be calculated according to the results of the qualitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers.	3 minutes
Calculation of the negative predictive value	Diagnostic performance of the qualitative examination of the gastric antrum in full supine/right lateral decubitus position. The diagnostic performance will be calculated according to the results of the qualitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers.	3 minutes
Calculation of the positive and negative likelihood ratio.	Diagnostic performance of the qualitative examination of the gastric antrum in full supine/right lateral decubitus position. The diagnostic performance will be calculated according to the results of the qualitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers.	3 minutes
Diagnostic performance of the qualitative examination of the gastric antrum for the detection of gastric fluid volume ≥ 0.8 milliliters/kilogram (ml/kg) in the full supine and right lateral decubitus position and in the 45° semirecumbent position	Calculation of the sensitivity. The diagnostic performance will be calculated according to the results of the qualitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Diagnostic performance of the qualitative examination of the gastric antrum for the detection of gastric fluid volume ≥ 0.8 milliliters/kilogram (ml/kg) in the full supine and right lateral decubitus position and in the 45° semirecumbent position	Calculation of the specificity The diagnostic performance will be calculated according to the results of the qualitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Diagnostic performance of the qualitative examination of the gastric antrum for the detection of gastric fluid volume ≥ 0.8 milliliters/kilogram (ml/kg) in the full supine and right lateral decubitus position and in the 45° semirecumbent position	Calculation of the positive predictive value negative The diagnostic performance will be calculated according to the results of the qualitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Diagnostic performance of the qualitative examination of the gastric antrum for the detection of gastric fluid volume ≥ 0.8 milliliters/kilogram (ml/kg) in the full supine and right lateral decubitus position and in the 45° semirecumbent position	Calculation of the negative predictive value. The diagnostic performance will be calculated according to the results of the qualitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Diagnostic performance of the qualitative examination of the gastric antrum for the detection of gastric fluid volume ≥ 0.8 milliliters/kilogram (ml/kg) in the full supine and right lateral decubitus position and in the 45° semirecumbent position	Calculation of the positive and negative likelihood ratio. The diagnostic performance will be calculated according to the results of the qualitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Cut-off value for antral area measured in the supine position (semirecumbent or full supine position) associated with the best diagnostic performance for the detection of a gastric volume ≥1.5 milliliters/kilogram (ml/kg).	The cut-off value will be calculated according to the results of the measurements performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Diagnostic performance of the qualitative examination of the gastric antrum in the semirecumbent position without bed elevation	Calculation of the sensitivity. The diagnostic performance will be calculated according to the results of the qualitative and quantitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Diagnostic performance of the qualitative examination of the gastric antrum in the semirecumbent position without bed elevation	Calculation of the specificity. The diagnostic performance will be calculated according to the results of the qualitative and quantitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Diagnostic performance of the qualitative examination of the gastric antrum in the semirecumbent position without bed elevation	Calculation of the positive predictive value. The diagnostic performance will be calculated according to the results of the qualitative and quantitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Diagnostic performance of the qualitative examination of the gastric antrum in the semirecumbent position without bed elevation	Calculation of the negative predictive value. The diagnostic performance will be calculated according to the results of the qualitative and quantitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Diagnostic performance of the qualitative examination of the gastric antrum in the semirecumbent position without bed elevation	Calculation of the positive and negative likelihood ratio. The diagnostic performance will be calculated according to the results of the qualitative and quantitative assessments performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes
Mathematical model for the calculation of the gastric fluid volume	Multiple linear regression including the antral surface measured in right lateral decubitus and the age, height, weight of the volunteer. The mathematical model will be built according to the results of the measurements performed 3 minutes after the ingestion of water (either 0, 50, 100, 150 or 200 milliliters (ml)) by the volunteers	3 minutes

Collaborators and Investigators

• Sponsor: Hospices Civils de Lyon
• Investigators: Principal Investigator: Sophie Barnoud, Dr, Hospices Civils de Lyon

Publications and helpful links

General Publications

• Bouvet L, Cordoval J, Barnoud S, Berlier J, Desgranges FP, Chassard D. Diagnostic performance of qualitative ultrasound assessment for the interpretation of point-of-care gastric ultrasound to detect high gastric fluid volume: A prospective randomized crossover study. J Clin Anesth. 2022 Oct;81:110919. doi: 10.1016/j.jclinane.2022.110919. Epub 2022 Jul 2.

Study record dates

Study Major Dates

• Study Start (Actual): November 27, 2019
• Primary Completion (Actual): September 6, 2021
• Study Completion (Actual): September 6, 2021

Study Registration Dates

• First Submitted: May 15, 2019
• First Submitted That Met QC Criteria: September 19, 2019
• First Posted (Actual): September 20, 2019

Study Record Updates

• Last Update Posted (Estimated): September 3, 2025
• Last Update Submitted That Met QC Criteria: August 26, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Respiratory Tract Diseases; Digestive System Diseases; Gastrointestinal Diseases; Respiration Disorders; Esophageal Diseases; Esophageal Motility Disorders; Deglutition Disorders; Laryngopharyngeal Reflux; Gastroesophageal Reflux; Respiratory Aspiration; Pathological Conditions, Signs and Symptoms; Respiratory Aspiration of Gastric Contents
• Other Study ID Numbers: 69HCL19_0244; 2019-A01333-54 (Other Identifier: ID-RCB)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No