Temporal trends in survival following ward-based NIV for acute hypercapnic respiratory failure in patients with COPD.

Abstract

Non-invasive ventilation (NIV) is recommended for treatment of acute hypercapnic respiratory failure (AHRF) in acute exacerbations of COPD. National UK audit data suggests that mortality rates are rising in COPD patients treated with NIV. To investigate temporal trends in in-hospital mortality in COPD patients undergoing a first episode of ward-based NIV for AHRF. Retrospective study of hospitalised COPD patients treated with a first episode of ward-based NIV at a large UK teaching hospital between 2004 and 2017. Patients were split into two cohorts based on year of admission, 2004-2010 (Cohort 1) and 2013-2017 (Cohort 2), to facilitate comparison of patient characteristics. In total, 547 unique patients were studied. There was no difference in in-hospital mortality rate between the time periods studied (17.6% vs 20.5%, P=.378). In Cohort 2 there were more females, a higher rate of co-morbid bronchiectasis and pneumonia on admission and more severe acidosis, hypercapnia and hypoxia. More patients in Cohort 2 had NIV as the ceiling of treatment. Patients in Cohort 2 experienced a longer time from AHRF diagnosis to application of NIV, higher maximum inspiratory positive airway pressure, lower maximum oxygen and shorter duration of NIV. Finally, patients in Cohort 2 experienced a shorter hospital length of stay (LOS), with no differences observed in rate of transfer to critical care or intubation. In-hospital mortality remained stable and LOS decreased over time, despite greater comorbidity and more severe AHRF in COPD patients treated for the first time with ward-based NIV.