Three sets of measurements of hemodynamic parameters and sub-aortic VTI were performed: before and at the end of 15 seconds end-expiratory occlusion and after 250 mL saline administration over 10 minutes. Patients were considered responders to fluid loading after an increase in sub-aortic VTI of more than 10% following a volume expansion. SPSS was used for statistic study. A p < 0.05 was considered significant. The investigators performed univariate and then multivariate analysis.

The patients included were in the supine position in a prone position at 30°. They had continuous monitoring by: electrocardioscopy; pulse oximetry and invasive blood pressure. Diuresis was monitored hourly.

A venous access to the superior vena cava territory (central venous catheter) was set up.

The patients were sedated with a Ramsay score > 4 and ventilated in controlled assisted mode.

The sub-aortic TVI (in cm) was measured in an apical 5-chamber section by pulsed Doppler using a 1-5 MHz ultrasound probe (M-Turbo sonosite). Three sets of measurements of hemodynamic parameters and sub-aortic VTI were performed: before and at the end of 15 seconds end-expiratory occlusion and after 250 mL saline administration over 10 minutes. At each point, the investigators noted the hemodynamic, ultrasound and biological parameters.

Inclusion Criteria:

• Patients under mechanical ventilation and sedation in the intensive care units
• patients for whom the decision of 250 mL saline administration was taken for : hypotension (systolic pression under 90 mmHg or diatolic pression under 40 mmHg or tachycardia more than 90 pulse per minute or oliguria or the increase in cathecholamin needs.

Exclusion Criteria:

• Pulmonary Edema
• arrythmia
• dialysis
• Prone position

Sixty patients were included. The main causes of admission in intensive care were traumatic causes, post operative care or medical causes. 35 were responders avec 25 non responders to fluid load.