Volume expansion (VE) is often administered in intensive care (ICU)-patient to improve arterial oxygen delivery. Such effect is secondary to an increase in stroke volume and cardiac output. However, cardiac output increase in response to VE (fluid responsiveness) only occurs when the heart is preload-dependant. Increasing evidence of the deleterious effects of inappropriate fluid administration encourages the development of variables predicting fluid responsiveness, but few have been validated in spontaneously breathing patients.

Central venous pressure (CVP) variation in spontaneously patients during standardized or unstandardized inspiratory maneuver may represent an easy tool to predict fluid responsiveness. The hypothesise is that inspiratory maneuver may increase CVP variation in fluid responsiveness patient whereas no or few variation may reflect fluid unresponsiveness.

Inclusion Criteria

• Spontaneous breathing without mechanical assistance
• Central venous catheter (superior vena cava) and monitoring of central venous pressure
• Urinary catheter and monitoring of intra-abdominal pressure

Exclusion Criteria:

• Intolerance to ventilatory manœuvre including Severe basal dyspnea/Symptomatic heart failure (pulmonary edema)
• Contraindication to passive leg raising (intracranial hypertension)
• Passive leg raising unsuitable for measuring hemodynamic response : High grade aortic insufficiency/ Poor echogenicity unsuitable to measure the velocity-time /integral of aortic blood flow/ Pregnancy/Abdominal hypertension with abdominal compartment syndrome/ Lower leg amputation
• Necessity of urgent hemodynamic therapy (within 90 min)
• Modification of hemodynamic therapy during study protocol (vascular filling, increase catecholamine dose

Patient hospitalized in one of intensive care unit of Roger Salengro university hospital CHU Lille