Effect of PEEP and Trendelenburg on Ultrasound Size of Internal Jugular and Subclavian Veins

There is no recommendation for the management of the positive end-expiratory pressure (PEEP) during setting of a central venous catheter (CVC) in a ventilated patient. Several non-randomized studies have investigated the cross-sectional area (AST) ultrasound minor axis for different pressure levels by evaluating a single vessel every time or by not displaying the right or left side in the evaluation. Another study showed that there could be unpredictable size differences between the 2 subclavian veins. In ventilated patient, the PEEP, which is intrathoracic, will result in a decrease of venous return and thus possibly a superior vena cava dilation, located outside the pleura, depending on their capacitance. Different pressure levels showed an increase of AST with the increase of intra-thoracic pressure on certain veins, in a heterogeneous and not randomized manner. The primary purpose of the study is to measure the effect of PEEP (0, 5, 10 or 15 cm H2O) and the patient's position (supine or Trendelenburg strict -15-20 °) on the cross-sectional area of the jugular and subclavian veins.