In contrast, during NIV the upper airway might play a role in the efficiency of delivered ventilation. During invasive ventilation the endotracheal tube bypasses the upper airway and the cuff of the endotracheal tube provides an air-tight seal in the trachea. How can ventilation be inadequate with NIV, but adequate with similar levels of support after endotracheal intubation? An important difference in the application of NIV versus invasive ventilation is, evidently, the involvement of the upper airway. Today, the pathophysiology of NIV failure is incompletely understood. A low pH (<7.25) is a strong predictor of NIV failure, but an improvement in pH 1 to 2 hours after the initiation of NIV accurately predicts NIV success. In particular, careful selection is of major importance in patients with chronic obstructive pulmonary disease. These factors include careful selection of patients, properly timed intervention, a comfortable and well-fitting interface, coaching and encouragement of patients, careful monitoring, and a skilled and motivated team. Several factors have been identified that increase the success rate of NIV. However, failure rates of NIV range between 5 and 50% and most of these patients require endotracheal intubation.

An important goal of NIV is to prevent endotracheal intubation and thereby reduce the complications related to invasive ventilation. Noninvasive ventilation (NIV) is increasingly used in acute respiratory failure, for instance in patients with exacerbation of chronic obstructive pulmonary disease or acute heart failure.

2008 ram pressure vent