High-pressure NIV for acute hypercapnic respiratory failure in COPD: improved survival in a retrospective cohort study.

Introduction: Updated treatment guidelines for acute hypercapnic respiratory failure (AHRF) in chronic obstructive pulmonary disease (COPD) with non-invasive ventilation (NIV) in 2016 recommended a rapid increase in inspiratory positive airway pressure (IPAP) to 20 cm HO with possible further increase for patients not responding. Previous guidelines from 2006 suggested a more conservative algorithm and maximum IPAP of 20 cm HO.

Aim: To determine whether updated guidelines recommending higher IPAP during NIV were related with improved outcome in patients with COPD admitted with AHRF, compared with NIV with lower IPAP.

Methods: A retrospective cohort study comparing patients with COPD admitted with AHRF requiring NIV in 2012-2013 and 2017-2018.

Results: 101 patients were included in the 2012-2013 cohort with low IPAP regime and 80 patients in the 2017-2018 cohort with high IPAP regime. Baseline characteristics, including age, forced expiratory volume in 1 s (FEV), pH and PaCO at initiation of NIV, were comparable. Median IPAP in the 2012-2013 cohort was 12 cm HO (IQR 10-14) and 20 cm HO (IQR 18-24) in the 2017-2018 cohort (p<0.001). In-hospital mortality was 40.5% in the 2012-2013 cohort and 13.8% in the 2017-2018 cohort (p<0.001). The 30-days and 1-year mortality were significantly lower in the 2017-2018 cohort. With a Cox model 1 year survival analysis, adjusted for age, sex, FEV and pH at NIV initiation, the HR was 0.45 (95% CI 0.27 to 0.74, p=0.002).

Conclusion: Short-term and long-term survival rates were substantially higher in the cohort treated with higher IPAP. Our data support the current strategy of rapid increase and higher pressure.