Noninvasive ventilation

Use of NPPV has rapidly proliferated during the past decade. Previously, body ventilators such as negative pressure devices were the main noninvasive means of assisting ventilation. After the introduction of the nasal mask to treat obstructive sleep apnea during the mid-1980s and the subsequent development of nasal ventilation, NPPV became the ventilator mode of first choice to treat patients with chronic respiratory failure. More recently, NPPV has been attaining acceptance for certain indications in the acute setting, as well. On the basis of controlled trials demonstrating marked reductions in intubation rates as well as improvements in morbidity, mortality, and complication rates, NPPV is now considered the ventilatory mode of first choice in selected patients with COPD exacerbations. The indications for NPPV are not as clear in patients with non-COPD causes of acute respiratory failure. For acute pulmonary edema, CPAP alone drastically reduces the need for intubation, although studies have not demonstrated reductions in morbidity or mortality rates. NPPV avoids intubation and reduces complication rates in patients with hypoxemic respiratory failure, but more controlled trials are needed to establish precise indications. In the meantime, NPPV administration to patients with non-COPD causes of acute respiratory failure appears to be safe as long as patients are selected carefully with particular attention to the exclusion of inappropriate candidates. A possible role is also emerging for NPPV in the facilitation of weaning patients from invasive mechanical ventilation. In this context, noninvasive ventilation can be used to permit earlier removal of invasive airways than would otherwise be the case, to prevent reintubation in patients developing post-extubation respiratory failure, and to serve a prophylactic role in postoperative patients who are at high risk for pulmonary complications. For chronic respiratory failure, a wide consensus now favors the use of NPPV as the ventilatory mode of first choice for patients with neuromuscular diseases and chest wall deformities, despite a lack of randomized controlled trials. Central hypoventilation and failure of obstructive sleep apnea to respond to CPAP are also considered acceptable indications, although evidence to support these latter applications is sparse. For patients with severe stable COPD, some evidence supports the use of NPPV in severely hypercapnic patients, particularly if there is associated nocturnal hypoventilation. However, the data are conflicting and do not permit the formulation of firm selection guidelines. NPPV has emerged as the noninvasive ventilation mode of first choice over alternatives such as negative pressure ventilation or abdominal displacement ventilators. However, these latter techniques are still used in some areas of the world and may be effective for patients who fail NPPV because of mask intolerance. Noninvasive ventilation has undergone a remarkable evolution over the past decade and is assuming an important role in the management of both acute and chronic respiratory failure. Appropriate use of noninvasive ventilation can be expected to enhance patient comfort, improve patient outcomes, and increase the efficiency of health care resource utilization. Over the next decade, continued advances in technology should make noninvasive ventilation even more acceptable to patients. Future studies should better define indications and patient selection criteria, further evaluate efficacy and effects on resource utilization, and establish optimal techniques of administration.