The Efficacy of High-Flow Nasal Cannula (HFNC) Treatment in Patients with Chronic Type II Respiratory Failure Secondary to COPD

<b>Background:</b> The use of HFNC (High Flow Nasal Cannula) in the management of acute respiratory failure has been fully established in clinical practice. Conversely, less data is available supporting its use in chronic hypoxemic-hypercapnic respiratory failure. The aim of the present study is to evaluate the efficacy of HFNC in chronic hypercapnic respiratory failure associated with stable COPD. <b>Methods:</b> In this retrospective single-center longitudinal observational study, 40 patients treated with HFNC at home followed at the COPD Clinic of Respiratory Diseases (University of Campania L. Vanvitelli Monaldi Hospital, Naples) were included. All patients are re-assessed at our clinic at T0, T3, T6 and T12 months through functional respiratory tests and blood gas analysis. <b>Results:</b> After 12 months, significant reductions in pCO₂ (arterial partial pressure of carbon dioxide) (from 58.5 to 48.0 mmHg) and lactates (from 1.60 to 0.90 mmol/L) were observed, and MIP and MEP improved significantly. Patients receiving HFNC flows ≥50 L/min experienced greater reductions in pCO₂ and fewer exacerbations. Multivariate analysis identified HFNC flow rate (<i>p</i> = 0.0046), hours of use/day (<i>p</i> = 0.0157), lactate levels (<i>p</i> = 0.0301), and FEV₁ (forced expiratory volume in 1 s) (<i>p</i> = 0.0491) as independent predictors of reduction in PaCO₂. Higher BMI and greater airway obstruction were associated with a reduced response. <b>Conclusions:</b> Treatment with HFNC represents a reasonable therapeutic choice to reduce AEs-COPD and reduce PaCO₂ and lactates in stable COPD patients.