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For nearly 60 years, clinicians and investigators have explored the possibility that non-invasive ventilatory assistance might improve the function of patients with stable severe chronic obstructive pulmonary disease (COPD).1 Early studies used negative pressure ventilators with the idea that the rest of the respiratory muscles would make them stronger, but these were poorly tolerated.2 For the past 30 years, studies using non-invasive positive pressure ventilation (NIV) have been performed to see if gas exchange and sleep quantity and quality would improve but results have been conflicting. As recently as 2013, a Cochrane analysis concluded that NIV for stable severe hypercapnic COPD ‘had no clinically or statistically significant effect on gas exchange, exercise tolerance, quality of life, lung function, respiratory muscle strength or sleep efficiency’ and should only be used in the context of a clinical trial’.3
Over the past 5 years, though, several important studies have been published that have altered thinking about the role of NIV for stable severe COPD. Kohnlein et al4 randomised almost 200 severe stable patients (PaCO2 >6.67 kPa) to receive ‘high-intensity’ NIV (inspiratory pressure to lower PaCO2 by at least 20% and backup rate 2 breaths/min below spontaneous), or standard home oxygen. Twelve-month mortality (12% vs 33%) and St George’s Respiratory Questionnaire score were significantly better in the NIV group. More recently, Murphy et al5 using ‘high-pressure NIV’ (with a lower set respiratory rate to allow spontaneous triggering) showed significant prolongation of the time to rehospitalisation or death in the NIV group compared with the standard oxygen group (4.3 vs 1.4 months) in patients with hypercapnic COPD recovering from acute exacerbations. However, another randomised controlled trial examining the role of …
Contributors NSH is the sole contributor.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests The author is a consultant for Philips Respironics.
Patient consent for publication Not required.
Provenance and peer review Commissioned; externally peer reviewed.
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