Combined lung compliance and oxygenation dynamics predict high-flow nasal cannula failure in acute respiratory distress syndrome: a retrospective cohort study.

Objectives: To evaluate the combined predictive value of lung compliance and dynamic oxygenation parameters for high-flow nasal cannula (HFNC) outcomes.

Methods: In this single-center retrospective cohort study, 154 patients with acute respiratory distress syndrome (ARDS) treated with HFNC (flow ≥50 L/min, fraction of inspired oxygen [FiO] ≥0.5) between 2019 and 2022 were analyzed. Data collected included baseline characteristics, lung compliance (measured via mechanical ventilation or computed tomography [CT]), blood gas parameters-partial pressure of arterial oxygen to FiO ratio (PaO/FiO) and its 24-hour change (ΔPaO/FiO) and clinical outcomes. Multivariate logistic regression and receiver operating characteristic (ROC) curve analyses were performed to identify predictors. A nomogram was constructed based on the regression model and validated using ROC curves and calibration plots.

Results: Low baseline lung compliance (<30 mL/cmHO) was independently associated with HFNC failure (odds ratio [OR] =3.52, 95% confidence interval [CI]: 1.92-6.45, P<0.001), as was ΔPaO/FiO<20% at 24 hours (OR=2.84, 95% CI: 1.48-5.43, P=0.002). The combined model yielded superior predictive performance (area under the curve [AUC] =0.88) compared to lung compliance (AUC=0.82) or ΔPaO/FiO alone (AUC=0.73). The nomogram demonstrated good calibration (Hosmer-Lemeshow test, P=0.41) and potential clinical utility. Patients with HFNC failure had longer ICU stays (median 14 vs. 7 days, P<0.001) and higher complication rates, including ventilator-associated pneumonia (34.8% vs. 8.3%, P<0.001) and barotrauma (10.9% vs. 1.9%, P=0.032).

Conclusions: The combination of lung compliance and ΔPaO/FiO improves early identification of HFNC failure and mortality risk, facilitating timely escalation to invasive ventilation. Prospective multicenter studies are needed to validate these findings.