Acute Crit Care.  2021 Aug;36(3):249-255. 10.4266/acc.2020.01102.

Effects of high-flow nasal cannula in patients with mild to moderate hypercapnia: a prospective observational study

  • 1Department of Medicine, Ajou University Intermediate Care Hospital, Suwon, Korea
  • 2Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
  • 3Department of Pulmonary and Critical Care Medicine, Kyung Hee University Hospital at Gangdong, Seoul, Korea
  • 4Department of Pulmonology, Ewha Womans University Seoul Hospital, Seoul, Korea
  • 5Department of Emergency Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
  • 6Intensive Care Nursing Team, Asan Medical Center, Seoul, Korea
  • 7Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea


Evidence for using high-flow nasal cannula (HFNC) in hypercapnia is still limited. Most of the clinical studies had been conducted retrospectively, and there had been conflicting reports for the effects of HFNC on hypercapnia correction in prospective studies. Therefore, more evidence is needed to understand the effect of the HFNC in hypercapnia.
We conducted a multicenter prospective observational study after applying HFNC to 45 hospitalized subjects who had moderate hypercapnia (arterial partial pressure of carbon dioxide [PaCO2], 43–70 mm Hg) without severe respiratory acidosis (pH <7.30). The primary outcome was a change in PaCO2 level in the first 24 hours of HFNC use. The secondary outcomes were changes in other parameters of arterial blood gas analysis, changes in respiration rates, and clinical outcomes.
There was a significant decrease in PaCO2 in the first hour of HFNC application (-3.80 mm Hg; 95% confidence interval, -6.35 to -1.24; P<0.001). Reduction of PaCO2 was more prominent in subjects who did not have underlying obstructive lung disease. There was a correction in pH, but no significant changes in respiratory rate, bicarbonate, and arterial partial pressure of oxygen/fraction of inspired oxygen ratio. Mechanical ventilation was not required for 93.3% (42/45) of our study population.
We suggest that HFNC could be a safe alternative for oxygen delivery in hypercapnia patients who do not need immediate mechanical ventilation. With HFNC oxygenation, correction of hypercapnia could be expected, especially in patients who do not have obstructive lung diseases.


carbon dioxide; hypercapnia; mechanical ventilation; nasal cannula
Full Text Links
  • ACC
export Copy
  • Twitter
  • Facebook
Similar articles
Copyright © 2022 by Korean Association of Medical Journal Editors. All rights reserved.     E-mail: