A55-01 Comparative Efficacy of High-Flow Nasal Oxygen and Non-Invasive Ventilation in Acute Hypercapnic Respiratory Failure

Abstract Aim Non-invasive ventilation (NIV) has long been regarded as the standard of care in acute hypercapnic respiratory failure (AHRF); however, emerging evidence indicates that high-flow nasal oxygen (HFNO) may also provide clinical benefits in this setting. Robust clinical trials are needed to compare HFNO with NIV in AHRF. This study aims to evaluate the comparative efficacy of HFNO versus NIV in AHRF and to investigate whether established severity and early warning scores (APACHE II, SAPS II, SOFA, NEWS2, MEWS) can predict treatment failure. Methods Between December 2023 and December 2024, a total of 167 patients meeting the inclusion criteria were prospectively enrolled from 350 individuals admitted to the ICU with AHRF. Patients were randomly assigned in a 1:1 ratio to receive either NIV or HFNO upon ICU admission. The primary outcome was defined as failure of NIV or HFNO treatment, specified as death or the need for invasive mechanical ventilation within 28 days. Secondary outcomes included overall survival, improvement in CO2 retention, and the predictive performance of established severity and early warning scores. Results The median age was 70 years, and 56% of patients were male. Patients received HFNO (49%) or NIV (51%). Primary etiologies included pneumonia (55%), COPD exacerbation (47%), heart failure (38%), and obesity hypoventilation (18%). Rates of treatment failure (19% vs. 18%, p = 0.757), escalation to invasive mechanical ventilation (5% vs. 9%, p = 0.257), early mortality (17% vs. 14%, p = 0.598), and overall mortality (29% vs. 22%, p = 0.307) were comparable between the HFNO and NIV groups. The HFNO group required a longer duration of therapy compared to the NIV group (23.2 vs. 8.5 hours, p = 0.001), and their ICU stay was correspondingly extended (24.4 vs. 19.0 days, p = 0.049). Hospital length of stay, however, did not differ significantly between the two groups (27.8 vs. 23.9 days, p = 0.142). Regardless of etiology, treatment failure and mortality rates were similar between the HFNO and NIV groups. Both groups demonstrated a reduction in CO2 retention within the first 12 hours from baseline. Elevated severity and early warning scores were associated with treatment failure in both HFNO and NIV cohorts. Conclusion The results indicate that both NIV and HFNO exhibit comparable efficacy with respect to treatment failure rates, PaCO2 reduction, and overall survival. Moreover, ICU scoring systems and early warning scores effectively predicted treatment failure for both modalities in AHRF. However, in this study, HFNO was associated with longer therapy duration and prolonged ICU stay compared with NIV. This abstract is funded by: None