The Role of Non-Invasive Mechanical Ventilation in the Management of Patients with Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Chronic Obstructive Pulmonary Disease (COPD) represents a major health concern, that causes a significant morbidity, a high risk of death and important health-care costs. The real dimension of this chronic disease is probably understimated both in its early and advanced stages and its prevalence is progressively rising in the general populations, because of both increase of elderly subjects and raised rates of smoke. To date it was estimated that COPD-related deaths represent the sixth leading cause of mortality worldwide. Acute exacerbations (AE) represent major events in the clinical course of COPD and negatively affect its outcomes, leading to lung function decrease, quality life worsening, high risks of hospital readmission, disability and death. Severe exacerbations of COPD are associated with acute respiratory failure (ARF), impairment of hypoxemia, various degree of carbon dioxide retention and acidosis. The ARF in COPD may occur as acute, chronic or acute-on-chronic failure. This condition worsens significantly the prognosis of these patients and may require an intensive treatment with ventilatory assistance combined with routine medical management. This therapeutic approach may be performed by means of invasive (IMV) or noninvasive mechanical ventilation (NIMV). The latter form is defined as the delivery of mechanical ventilation that avoids airway invasion. Two types of NIMV have been studied and applied to clinical practice in the last decades, they are represented by both external negative pressure and positive pressure ventilation modalities. In the last years noninvasive mechanical ventilation with positive pressure (NPPV) has been increasingly used as adjunctive therapeutic approach in these subjects. In addition several controlled trials and meta-analysis showed that this form of assisted ventilation is effective in the treatment of different diseases, including: COPD exacerbations, acute cardiogenic pulmonary edema, weaning from ventilator in COPD patients. The use of noninvasive mechanical ventilation in patients with COPD exacerbated and hypercapnic ARF is associated, in some instances, with a decreased need of endotracheal intubation, with lower incidence of adverse outcomes, as well as with reduced in hospital-mortality, length of hospitalisation and overall costs. This therapeutic approach is generally feasible, well-tolerated and may be successfully performed in different healthcare settings including: Emergency Departments, Intensive Care Units (ICUs), but also in Intermediate Respiratory Care Units (IRCUs) and, in selected cases, in non intensive units, such as General Wards. This report is a comprehensive review of the available studies, concerning the use of NIMV in the management of COPD patients with AE and respiratory failure and it describes its indications, limitations, proper locations and costs