Diagnostic accuracy of qualitative gastric ultrasound assessment for detecting high gastric fluid volume in children: a prospective randomised study.

Introduction: The diagnostic accuracy of gastric ultrasound in children has not been assessed thoroughly. We aimed to determine the sensitivity and specificity in children of a qualitative ultrasound examination of the gastric antrum in the supine 45° semi-recumbent position and a clinical algorithm for detecting a gastric fluid volume > 1.25 ml.kg ^-1 , reported to represent an 'at-risk stomach' for pulmonary aspiration.
Methods: We conducted a prospective, observer-blinded, randomised trial in healthy children fasted according to current pre-operative guidelines. An initial ultrasound assessment of gastric contents ensured that the stomach was empty. Children then drank a specific volume of water (0; 0.6; 1; 1.25; 1.5; or 2 ml.kg ^-1 ). Gastric ultrasound was performed after 3 min of fluid ingestion, in children lying supine and then in the right lateral decubitus position, with the head of the bed elevated to 45° (semi-recumbent). A clinical algorithm combining the qualitative assessment with calculation of gastric fluid volume was also completed. The sensitivity and specificity of the qualitative assessment in the supine semi-recumbent position and the clinical algorithm for the diagnosis of gastric fluid volume > 1.25 ml.kg ^-1 were estimated.
Results: Ninety children, median (IQR [range]) age 7 (4.5-9 [1-10]) y, were studied. The sensitivity and specificity of the qualitative assessment for detecting gastric fluid volume > 1.25 ml.kg ^-1 were 75% (95%CI 58-88%) and 85% (95%CI 73-93%), respectively. The sensitivity and specificity of the clinical algorithm were 86% (95%CI 71-95%) and 78% (95%CI 64-88%), respectively.
Discussion: In order to achieve high sensitivity of gastric ultrasound for the diagnosis of fluid volume > 1.25 ml.kg ^-1 in children, qualitative ultrasound assessment of gastric antrum contents should be combined with calculation of gastric fluid volume when fluid contents are seen in the gastric antrum.
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