Clinical Research Directory

Inclusion Criteria: * Children aged 0 to 10 years old, of both sexes. * Perioperative period of surgery under general anesthesia requiring admission to surgical resuscitation (before and / or after the surgical procedure). * Patients admitted for severe trauma. * Patient installation: supine position. * Intubation and mechanical ventilation: tidal volume: 7 to 8 ml / kg, Positive expiratory pressure : 3-4 cm H2O, inspiration / expiration: 1 / 1.5 to 1/2; respiratory rate: 1 month up to 2 years = 30 / min; children 2-8 years = 20 / min; children\> 8 years = 15 / min. * Patients with arterial catheters. * Need for a volume expansion : indication given by the doctor in charge of the patient. * Non-opposition expressed by the holders of parental authority. Exclusion Criteria: * Cardiac rhythm disorders (in particular atrial fibrillation, junctional tachycardia, ventricular arrhythmias), with the exception of sinus tachycardia, respiratory variations of heart rate and sporadic atrial / ventricular extrasystoles whom will allow inclusion. * Cardiopathy: severe systolic dysfunction (shortening fraction \<28%, ejection fraction \<50%); valvulopathy (significant narrowing or valvular insufficiency); left-right shunt, persistent arterial duct. * Unstable hemodynamic status related to active bleeding requiring vascular filling \> 2 mL / kg / min or requiring vasopressor or inotropic therapy whose dosage had to be changed in the last five minutes. * Need for mechanical ventilation with a tidal volume\> 10 mL / kg or \<7 mL / kg. * Refusal of the patient or the holders of parental authority to exploit the collected data. * Impossibility to carry out measurements.