Metabolic Fluid Responsiveness in Children

Who May Qualify: - Age less than or equal to 15 years old - Hospitalization in a pediatric intensive care unit after cardiac surgery - Prescription by the attending physician of a fluid expansion of 10ml/kg - Prescription of arterial and venous blood gas before and after the volume expansion to help manage acute circulatory failure - Patient implanted with a functioning arterial line - Patient implanted with a functioning central venous line in the superior vena cava territory Who Should NOT Join This Trial: - Patient less than 37 weeks' corrected gestational age - Hemodynamic instability making the delay necessary for any test dangerous - Supine position contraindicated or deleterious - Impairment of echocardiographic acoustic window or restless patient making ultrasonography impossible - Opposition to participate expressed by the patient or by a parent or legal guardian Always talk to your doctor about whether this trial is right for you.