Fluid Responsiveness Evaluation by a Non-invasive Method in Children, Extended to PREterm Infants - FRENCH-PREMA

"Study of diagnostic accuracy (non-interventional, prospective, monocentric). Fluid expansion will be delayed for a few minutes while our index test is performed. After fluid expansion, patient will undergo an echocardiographic assessment of response to fluid expansion (gold-standard test). This will allow to test the diagnostic performance of the index test for the prediction of fluid responsiveness.~The index test is the ΔSVi-AC: indexed percentage of stroke volume variation between baseline and during a standardized abdominal compression. Stroke volume will be assessed by transthoracic echocardiography.~Patient will undergo 3 echocardiographic assessment: At baseline (stroke volume, cardiac output, left ventricular ejection fraction), During a standardized abdominal compression (stroke volume),After the 10 to 20ml/kg fluid expansion prescribed by the physician in charge (cardiac output)."