Les variations respiratoires de la pression artérielle pulsée sont-elles un monitorage fiable de l'hypovolémie ?

Optimization of cardiac output and blood volume in hemodynamically unstable patients remains a real challenge for anesthesiologists and intensivists. Fluid replacement is one of the most commonly used treatments in patients in shock. However, excessive fluid loading may lead to fluid overload and its own complications. Mechanical ventilation induces cyclic changes in the trans-pulmonary pressure associated, in patients with a preload reserve, with pulse pressure variations (delta PP). Indices evaluating these changes are defined as preload dependent dynamic indices, and are used to guide fluid therapy in patients in unstable hemodynamic conditions. This review aims at discussing the pathophysiology and the concept of dynamic indices of the preload dependency with a special focus on delta PP, the thresholds values reported in the literature are discussed for their applicability and limits at bedside.