Predictive Value of Chest Ultrasound Observation on Extubation Failure

The use of mechanical ventilation in intensive care concerns the majority of patients, most often to compensate for respiratory failure, but for other organic failures requiring therapeutic artificial coma. During the sedation phase, many elements of management can modify the patient's clinical parameters.

Indeed, mechanical ventilation with a positive expiratory pressure mainly modifies the venous return by decreasing it, and therefore many modifications of the hemodynamic parameters result from it. In addition, other elements of management, such as iterative fillings, vasopressor and inotropic amines, as well as sedative drugs not only modify the hemodynamics, but also the ventilatory mechanics.

Extubate a patient in intensive care is always complex, because the assessment must be multifactorial and this is not without risk for the patient. Many complications can arise if it ends in failure. They can be linked to mechanical causes (laryngeal oedema, tracheal stenosis, pneumothorax...) but also to non-mechanical causes, such as inappropriate sedation, overload, neuromuscular deficit. Extubation is primarily based on the patient's level of consciousness, as well as the successful progress of the patient during a ventilatory weaning trial, carried out after a return to spontaneous ventilation with inspiratory support. This ventilatory weaning test precedes extubation and is performed for any patient intubated for more than 48 hours.

Since the 1950s, ultrasounds have become more and more important in the field of medical diagnosis and therapeutic decision support, even more recently in the world of intensive care. The contribution of echocardiography in a patient in the process of extubation has already been evaluated and has proven to be a valuable aid. For nearly 20 years, the use of pulmonary ultrasound has emerged and allows rapid diagnosis at the patient's bedside of mechanical anomalies such as gaseous or liquid effusion, an anomaly in the compliance of the pulmonary parenchyma, possibly in link with diaphragmatic dysfunction or even signs in favor of a picture of pulmonary overload, thanks to ultrasound artefacts such as B lines or even alveolar derecruitment by atelectasis.

The role of pulmonary ultrasound in helping to decide on extubation remains poorly established, we propose an observational study evaluating the predictive value of chest ultrasound in pre-extubation with the aim of determining if ultrasound signs are able to predict a potential failure of this extubation. Indeed, the risks of extubation failure being much higher than those of ventilatory weaning failure, it seems necessary to focus our research on this component.

This study must include patients in spontaneous mechanical invasive ventilation with pressure support, presenting the criteria for a ventilatory weaning test in view of a potential extubation.