Noninvasive mechanical ventilation:
Noninvasive mechanical ventilation (NIV) improves respiratory acidosis and decreases respiratory rate, severity of breathlessness, intubation rate, length of hospital stay, and mortality in patients with COPD who are experiencing acute on chronic respiratory failure [198–202]. Despite the success of NIV for acute respiratory failure, the effects of long-term NIV in patients with COPD who have chronic respiratory failure remain controversial [203, 204]. Some studies have shown benefits in health status, dyspnoea, or blood gases, but there has been little or no impact on other outcomes such as re-hospitalisation rates or mortality [205–207]. An exception is a recent study that found that NIV may improve survival in patients with COPD with chronic respiratory failure [208]. Uncertainty about the effects of NIV in patients with COPD with chronic respiratory failure has led to the use of NIV on an individual basis; more studies are necessary to confirm the effects of NIV and identify patients who are likely to benefit from NIV.