Diagnostic Performance of Gastric Ultrasound in Children

Study Overview
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Brief Summary
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Pulmonary aspiration of gastric contents is a complication responsible for the third highest cause of anaesthesia-related mortality in France, and for 50% of airway management-related mortality in the UK. The occurrence of pulmonary aspiration of gastric contents is often the result of a poor assessment of the risk of a full stomach, and could therefore often be avoided if the preoperative gastric contents were known to the anaesthetist. It is therefore useful to be able to discriminate easily between patients at risk of aspiration and those at low risk before general anaesthesia, and this can be done by ultrasound examination of the gastric contents in the gastric antrum, non-invasively (abdominal ultrasound) using a 2-5 MHz abdominal ultrasound probe or a high-frequency linear probe in small children (under 10 kg). European recommendations on preoperative fasting in paediatrics recommend that the examination should be interpreted in a qualitative manner only, without measuring the antral surface. However, the diagnostic performance of this qualitative approach alone has never been evaluated. The aim of this study was to determine the diagnostic performance of the qualitative assessment of gastric contents by ultrasound in children, and to compare it with that of the clinical algorithm, for the detection of a volume of fluid greater than 1.25 ml/kg. Children will present themselves in the morning after fasting. Upon arrival, if their weight is not known, the children will be weighed. Subsequently, they will be positioned on an examination table in a supine inclined position at 45° (head of the bed elevated). An initial gastric ultrasound will be performed by a physician (investigator 1) who will not conduct the study ultrasounds. This initial ultrasound aims to confirm the absence of gastric content in the supine and right lateral decubitus positions, thereby establishing gastric emptiness. Investigator 1 will then proceed with the random selection of the clear liquid volume to be ingested for the study. The child will then be asked to drink this determined volume of clear liquid (water or apple juice according to their preference), as per the randomization results, under the supervision of the first investigator who performed the initial ultrasound. Subsequently, investigator 2 will perform a gastric ultrasound blindly with respect to the ingested liquid volume, three minutes after the consumption of the clear liquid. The examination will last a maximum of 3 minutes. Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance. The diameters (longitudinal D1 and anteroposterior D2) of the antrum will also be measured in the supine (semi-seated and lying) and right lateral positions in the sagittal plane passing through the abdominal aorta and the left lobe of the liver, for the calculation of the antral section area, given by the formula: Antral area = π x D1 x D2 / 4.

Official Title
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Assessment of the Diagnostic Performance of Qualitative Ultrasound Assessment of Gastric Contents for the Detection of Gastric Fluid Volume ≥ 1.25 ml/kg in Children

Conditions
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Healthy Volunteer

Intervention / Treatment
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* Other: the initial gastric ultrasound
* Other: the gastric ultrasound last 3 minutes


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Children aged between 1 and 10 years Healthy volunteer, with no significant medical history (American Society of Anesthesiologists class ASA 1) Fasting according to the 2022 recommendations of the European Society of Anaesthesia: minimum fasting time of 1 h for clear liquids, 3 h for breast milk, 4 h for infant formula, 6 h for solid non-fatty foods and milk, 8 h for richer meals Informed consent signed by the child's legal representatives, affiliated to a social security scheme Exclusion Criteria: Agitation of the child preventing gastric ultrasound scans from being performed Non-compliance with fasting instructions Previous oeso-gastro-duodenal surgery Treatments affecting gastric motility (erythromycin, metoclopramide, etc.) Obesity defined by a body mass index ≥ 30 kg/m². Pathologies that may affect gastric volume: insulin-dependent or requiring diabetes, gastro-oesophageal reflux, scleroderma, etc.

Ages Eligible for Study
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Minimum Age: 1 Year
Maximum Age: 10 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 0 ml/kg of water<br>The child does not drink water, and then the gastric ultrasound is performed 3 minutes later blindly to the ingested volume. | Other: the initial gastric ultrasound<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>Other: the gastric ultrasound last 3 minutes<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>|
| Experimental: 0.6 ml/kg of water<br>The child drinks 0.6 ml/kg water, and then the gastric ultrasound is performed 3 minutes later blindly to the ingested volume. | Other: the initial gastric ultrasound<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>Other: the gastric ultrasound last 3 minutes<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>|
| Experimental: 1 ml/kg of water<br>The child drinks 1 ml/kg water, and then the gastric ultrasound is performed 3 minutes later blindly to the ingested volume. | Other: the initial gastric ultrasound<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>Other: the gastric ultrasound last 3 minutes<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>|
| Experimental: 1.25 ml/kg of water<br>The child drinks 1.25 ml/kg water, and then the gastric ultrasound is performed 3 minutes later blindly to the ingested volume | Other: the initial gastric ultrasound<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>Other: the gastric ultrasound last 3 minutes<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>|
| Experimental: 1.5 ml/kg of water<br>The child drinks 1.5 ml/kg water, and then the gastric ultrasound is performed 3 minutes later blindly to the ingested volume. | Other: the initial gastric ultrasound<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>Other: the gastric ultrasound last 3 minutes<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>|
| Experimental: 2 ml/kg of water<br>The child drinks 2 ml/kg water, and then the gastric ultrasound is performed 3 minutes later blindly to the ingested volume. | Other: the initial gastric ultrasound<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>Other: the gastric ultrasound last 3 minutes<br>* Non-invasive gastric antrum ultrasound examinations will utilize a probe with a frequency of 2-5.5 MHz and a linear probe with a frequency of 10 MHz, enabling the evaluation of the gastric antrum's appearance<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensitivity and specificity of the qualitative examination of the gastric antrum for the detection of gastric fluid volume ≥ 1.25 ml/kg in the 45° semirecumbent position | Calculation of the sensitivity and specificity | 3 minutes after the ingestion of water | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Positive predictive value, negative predictive value, positive and negative likelihood ratio of the qualitative examination of the gastric antrum for the detection of gastric fluid volume ≥ 1.25 ml/kg in the 45° semirecumbent position | Calculation of the positive predictive value, negative predictive value, positive and negative likelihood ratio | 3 minutes after the ingestion of water | 
| Diagnostic performance of a clinical algorithm used for the interpretation of gastric ultrasound for the detection of gastric fluid volume ≥ 1.25 ml/kg in the 45° semirecumbent position | Calculation of the sensitivity, specificity, positive predictive value, negative predictive value, positive and negative likelihood ratiovalue, positive and negative likelihood ratio | 3 minutes after the ingestion of water |