ABSTRACT

Objective

Early identification of non-invasive ventilation (NIV) failure in patients with acute hypercapnic respiratory failure due to chronic obstructive pulmonary disease (COPD) exacerbation remains a critical clinical challenge, particularly in emergency department settings. This study aimed to evaluate whether early arterial blood gas changes after NIV initiation predict intensive care unit (ICU) admission and in-hospital intubation, and to develop a simple predictive model based on early physiological response.

Methods

This multicenter retrospective study included 319 patients with COPD exacerbation complicated by acute hypercapnic respiratory failure who were initiated on NIV in the emergency departments of three hospitals. Arterial blood gas parameters were recorded before NIV and 1–3 hours after initiation. Early response was defined as the change in PaCO2 (ΔPaCO2). Multivariable logistic regression models were constructed for ICU admission and intubation. Model discrimination was assessed using receiver operating characteristic (ROC) curve analysis.

Results

During hospitalization, 138 patients (43.3%) required ICU admission and 70 patients (21.9%) required intubation. Lower post-NIV pH, insufficient reduction in ΔPaCO2, and prior ICU admission independently predicted both ICU requirement and intubation. The model demonstrated good discriminative performance for ICU admission (area under the curve [AUC] = 0.787; 95% CI: 0.737–0.837) and intubation (AUC = 0.810; 95% CI: 0.746–0.873).

Conclusion

Early physiological response to NIV, particularly post-treatment pH and the magnitude of PaCO2 reduction, provides clinically meaningful prognostic information and may assist early decision-making in emergency settings. External validation is warranted.