Tolerability and Safety of High-Flow Nasal Therapy in Patients Hospitalized with an Exacerbation of COPD

The effect of high-flow nasal therapy (HFNT) in individuals with an exacerbation of chronic obstructive pulmonary disease (COPD) and hypercapnia is not well studied. We assessed patient tolerance and impact of air-gas therapy delivered by humidified HFNT (20-35 L/min) on gas exchange in hypercapnic COPD patients during hospitalization for COPD exacerbation. We hypothesized that HFNT use would be safe and well tolerated in individuals hospitalized for COPD exacerbation regardless of the degree of hypercapnia.

Patients hospitalized for a COPD exacerbation were included if they were hypercapnic (arterial partial pressure of carbon dioxide [PaCO₂] > 45 mmHg), ≥ 10 pack-year history, and agreed to treatment with HFNT, along with daily arterial blood gas (ABG) samples and bedside spirometry. They were placed on a HFNT system following admission for at least 3 days with an air-gas blend to maintain a flow rate between 20-35 L/min and fraction of inspired oxygen (FiO₂) titrated to keep oxygen saturation (SaO₂) values > 90%. Patient tolerance of HFNT and evidence of clinical deterioration as defined by worsening hypoxia or hypercapnia was the primary endpoint.

Ten consecutive patients participated in the study. The patients had frequent prior exacerbations, were hypercapnic, dyspneic, and gas trapped. Participants received an air-gas flow rate (median [interquartile range (IQR)] 25 (IQR 20-30) L/min and FiO₂ of 30 (IQR 30-30) %. There was no increase in PaCO_2- levels (p = 0.26) or dyspnea (Borg scale, p= 0.52) while using HFNT. No patient discontinued HFNT, had further decompensation, required non-invasive ventilation or intubation during the study period.

In a pilot study, patients experiencing a severe COPD exacerbation were able to tolerate continuous HFNT safely regardless of degree of hypercapnia.