Background: Current guidelines suggest the use of non-invasive ventilation (NIV) in hypercapnic chronic obstructive pulmonary disease (COPD) exacerbations in patients presenting with a pH of 7.25-7.35. The aim of this study was to investigate the role of NIV in COPD patients with chronic hypercapnic respiratory failure admitted to the hospital with acute exacerbations and an arterial pH of 7.35 or higher.
Methods: Forty-seven COPD patients with chronic hypercapnic respiratory failure admitted for exacerbations and with a pH of 7.35 or higher were randomized to receive standard medical therapy (control group) or medical therapy plus NIV (NIV group). Arterial blood gases were measured at baseline, after 1 h, 6 h, 12 h, 24 h, 48 h, and at discharge. Need for admission to intensive care unit (ICU), death, and duration of hospitalization were recorded. The final analysis included 42 patients (21 controls and 21 NIV patients).
Results: NIV resulted in a shorter hospital stay (5.5+/-2.6 vs 10.1+/-4.4 days for controls, p=0.0004). Two patients from the control group were admitted to the ICU and one eventually died, whereas all NIV patients were successfully discharged. The NIV group showed a faster improvement in PaCO(2) and pH. At discharge, the NIV group had a lower PaCO(2) (6.5+/-0.6 kPa vs 7.5+/-1.1 kPa, p=0.01) but a comparable pH (7.43+/-0.03 vs 7.43+/-0.04, p=0.93). PaO(2) and PaO(2)/FiO(2) levels showed similar improvement in both groups at discharge.
Conclusion: Early administration of NIV in COPD patients with chronic hypercapnic respiratory failure admitted for acute exacerbations with a pH of 7.35 or higher results in a reduced hospital stay and faster improvement of arterial blood gases.