Adults with interstitial lung disease and acute respiratory failure without hypercapnia: when should high flow nasal oxygen be used?

Interstitial lung diseases (ILDs) represent a heterogenous group of disorders affecting the lung parenchyma. Patients with ILD are frequently admitted to hospital secondary to respiratory decompensation which can result in acute respiratory failure (ARF). High flow nasal oxygen (HFNO) has increasingly been used in other causes of ARF following the recommendations of the European Respiratory Society. A review was undertaken to evaluate the question: in adults with ILD and ARF without hypercapnia, is HFNO better than conventional oxygen therapy (COT) at reducing symptoms and all-cause mortality outcomes? Medline via PubMed, EMBASE via OVID and the Cochrane Library were searched between 1975 and 20 June 2025. 2362 papers were identified with 17 undergoing full-text review. Two systematic reviews met inclusion criteria and directly answered the three-part question. Study information, participant demographics, key results and study weaknesses were established for each paper. Neither systematic review found HFNO improved mortality outcomes, when compared with COT, to a statistically significant threshold for patients with ILD with ARF. Reported median survival with HFNO use was 21.0 days (95% CI 13.0 to 61.0) and COT use 133 days (95% CI 26.0 to 374.0, p=0.1323). Inpatient mortality with HFNO use ranged between 26.5% and 59.1%. Symptomatically, one review reported a numerical improvement in the Quality of Death and Dying Score for the HFNO group versus the COT group (4.58 ± 0.67 vs 4.09 ± 0.96). There is limited evidence to suggest that HFNO improves mortality outcomes for patients with ILD in ARF. However, it may be beneficial for symptom management. Mortality remains high despite HFNO use, thus careful discussions with patients and their relatives are required should a trial be used in the setting of ARF.