Hơn nữa, nó không phải là dứt khoát thành lập bằng cách sử dụng khối lượng thủy triều thấp (6 ml / kg) thông gió ở những bệnh nhân với ARDS là tốt hơn so với sử dụng khối lượng thủy triều bình thường (8-10 ml / kg) [35]. | 338 . Teboul X. Monnet and C. Richard Furthermore it is not definitively established that using low tidal volume 6 ml kg ventilation in patients with ARDS is better than using normal tidal volumes 8-10 ml kg 35 . Even if the detection of fluid responsiveness is of particular use in the decision making process concerning volume expansion in patients with circulatory shock two important points must be kept in mind. First since both ventricles of healthy subjects operate on the steep portion of the preload stroke volume relationship volume responsiveness is a physiological phenomenon related to a normal preload reserve. Therefore detecting volume responsiveness must not systematically lead to the decision to infuse fluid. Such a decision must be based on the presence of signs of cardiovascular compromise and must be balanced with the potential risk of pulmonary edema formation and worsening gas exchange. Second it is reasonable to postulate that volume loading should be more beneficial in a hypotensive patient with low cardiac output and volume responsiveness than in a hypotensive patient with a relatively high cardiac output and some degree of volume responsiveness in whom early administration of a vasopressive agent should be more logical. This emphasizes the great interest of new commercially available devices that monitor and automatically display both cardiac output and indices of volume responsiveness such as PPV from beat-to-beat analysis of the arterial pressure waveform. Passive Leg Raising Passive leg raising is a maneuver that transiently and reversibly increases venous return by shifting venous blood from the legs to the intrathoracic compartment 36 37 . The passive leg raising 45 elevation results in an increase in right 38 and left 39 40 ventricular preload. In this extent passive leg raising can mimic the effects of fluid loading and has been proposed for a long time as a first line therapy of hypovolemic shock autotransfusion effect . The way in .
