Specificities of Weaning from Mechanical Ventilation in ICU Obese Patients

Abstract

Comorbidities (chronic obstructive pulmonary disease, hypertension, diabetes, coronary artery disease and heart failure) more frequent in obese patients, respiratory physiological changes such as decreased compliance of the respiratory system, atelectasis and hypoxemia related to decreased functional residual capacity and limitation of expiratory flow, and diaphragmatic dysfunction, contribute to difficulties or failures of weaning and extubation in obese patients. The half-sitting or sitting position is a necessary prerequisite for the weaning of these patients. Some pulmonary function tests performed at the bedside can help in the management of weaning: vital capacity and maximum inspiratory pressure to assess the readiness to wean. In difficult weaning, the same parameters and maximum expiratory pressure are suggested as a prerequisite before considering extubation. The PS-PEEP mode is preferred in difficult weaning. Because of the triad atelectasis / pulmonary shunt / hypoxemia and the need to counterbalance intrinsic PEEP, PEEP withdrawal will be gradual. The use of prophylactic NIV in these patients reduces extubation failure and may be recommended. An impact on survival is observed in some hypercapnic obese patients, and prophylactic NIV for 48 hours after extubation should be systematic in this situation.