High-Flow Nasal Cannula in COPD: An Update in Current Evidence.

High-flow nasal cannula (HFNC) oxygen therapy continues to attract interest as an alternative or adjunct to established respiratory support strategies in COPD. Over the past two years, multiple randomized trials, meta-analyses, and physiological investigations have been published, particularly in the settings of COPD exacerbations and during exercise or pulmonary rehabilitation. Concurrently, the expanding literature has revealed substantial heterogeneity in study design, patient selection, and outcome definitions, contributing to variability in reported findings and interpretations. This year-in-review synthesizes evidence published in 2024-2025 within the context of the broader pre-2024 literature, with a balanced focus on clinical outcomes and physiological mechanisms. Emphasis is placed on HFNC use during COPD exacerbations and in the context of exercise or pulmonary rehabilitation, where the most recent data have meaningfully advanced the field. Overall, recent studies reinforce noninvasive ventilation as the standard of care for COPD exacerbations, whereas HFNC may represent a reasonable alternative or complementary strategy in selected patients and appears particularly promising during exercise and pulmonary rehabilitation. Contemporary physiological and clinical findings support an individualized, context-specific approach to HFNC use, guided by careful monitoring, appropriate flow titration, and timely escalation when indicated.