Dysfonction cardiaque gauche lors du sevrage de la ventilation mécanique

The transfer from positive pressure mechanical ventilation to negative pressure spontaneous ventilation may induce a left-side cardiac dysfunction that may lead to weaning failure. This left-side cardiac dysfunction results from several pathophysiological mechanisms that are the consequences of heart-lung interaction. In particular, weaning from mechanical ventilation increases the left ventricular afterload and may induce a myocardial ischemia. In patients with a pre-existing heart disease, these phenomena result in an increase in the left ventricular filling pressures. The diagnosis of weaning-induced pulmonary edema is based at best on the measurement of the pulmonary artery occlusion pressure. This measurement also enables to guide therapy that aims at preventing the occurrence of myocardial ischemia and at reducing the left ventricular afterload during weaning.