Determination of the hemodialysis ultrafiltration volume is guided by the clinician's estimate of dry weight. A poor estimate of this dry weight may result in insufficient fluid depletion causing a state of volume overload, which may be associated with long-term left ventricular failure, high blood pressure and excess of mortality. The diagnosis of fluid overload in haemodialysis patient is routinely based on clinical examination which consists of cardiopulmonary auscultation and edema palpation of limb member. Clinical examination can be completed by paraclinical examinations, and bioimpedance is an objective tool that assess fluid overload state. This test provides an individualized hydration status and fluid overload based on normal extracellular volume considering body composition. Echocardiography allows an accurate assessment of blood volume status by simultaneous studying left ventricular filling pressures, systolic pulmonary artery pressure and the diameter of the inferior vena cava. Lung ultrasound analyses the B-lines defined as artefactual images resulting from contact between air in "alveoli" and water in "septa". It can estimate pulmonary congestion. The aim of the study is to evaluate the lung ultrasound using "8 sites" score accuracy for estimating fluid overload of patients before hemodialysis session.

Inclusion Criteria:

• Age over 18 years old
• patients on hemodialysis for more than 3 months;
• patients without cardiological or infectious event for at least 3 months;
• patients having at least 2 dialysis session per week;
• patients affiliated with a health insurance plan;
• patients having signed an informed consent.

Exclusion Criteria:

• Pulmonary fibrosis or active lung disease;
• residual diuresis over 500 mL per day;
• body mass index (BMI) < 21 and > 28 Kg/m²;
• medical history of major amputation (subgonal or transfemoral);
• pacemaker carrier;
• patients with orthopedic prosthesis.