Apport de l'échocardiographie Doppler chez les patients à haut risque d'échec de sevrage du respirateur

The transition from positive pressure ventilation to spontaneous ventilation induces abrupt variations of cardiac loading conditions and multiple pathophysiologic phenomena that may result in the development of a weaning-induced pulmonary edema. High-risk patients are predominantly, but not exclusively, those with an underlying left ventricular systolic dysfunction. Although the diagnosis of weaning-induced pulmonary edema has long relied on the invasive measurement of pulmonary artery occlusion pressure using right heart catheterization, transthoracic echocardiography recently appeared as a promising alternative, rapid-to-perform and strictly non-invasive technique. This imaging modality allows helping to identify patients at high risk of cardiac-related weaning failure and rapidly confirming the diagnosis of weaning-induced pulmonary edema. In addition, echocardiography provides valuable information regarding the mechanism of weaning failure from cardiac origin. Limits of echocardiography are the availability of an experienced operator in this setting and the requirement of good image quality to obtain relevant information. The clinical value of combining biological markers such as circulating natriuretic peptides and echocardiography to optimize the management of patients who enter the process of weaning from the ventilator remains to be determined.