Noninvasive Management of Acute Respiratory Failure in the Morbidly Obese Patients

Abstract

Acute respiratory failure is common but nevertheless a challenging situation in morbidly obese patients. Extreme obesity can lead to numerous respiratory disorders including reduced functional residual capacity and limited expiratory flow especially in the supine position, increased work of breathing, abnormal upper airway collapsibility, gravitational atelectasis, and blunted central ventilatory response to hypercapnia and hypoxaemia. Good understanding of the physiological mechanisms involved in obesity-associated respiratory failure is mandatory to early identify and to improve management of morbidly obese patients with acute respiratory failure. Sitting position and noninvasive ventilation (NIV) are the two cornerstones of the initial therapeutic management of those patients. In the setting of type2 respiratory failure, early noninvasive management is almost constantly successful and prevents escalation to intubation. Conversely, type-1 respiratory failure is the leading cause of NIV failure and death especially when caused by a pneumonia. In that case, given the multiple organ disorders associated with extreme obesity, invasive procedures and aggressive management in the intensive care unit are usually doomed to failure in the frail morbidly obese patients.