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

• Main Authors: Kyung Hun Nam, Hyung Koo Kang, Sung-Soon Lee, So-Hee Park, Sung Wook Kang, Jea Jun Hwang, So Young Park, Won Young Kim, Hee Jung Suh, Eun Young Kim, Ga Jin Seo, Younsuck Koh, Sang-Bum Hong, Jin Won Huh, Chae-Man Lim
• Format: Article
• Language: English
• Published: Korean Society of Critical Care Medicine 2021-08-01
• Series: Acute and Critical Care
• Subjects: carbon dioxide; hypercapnia; mechanical ventilation; nasal cannula
• Online Access: http://www.accjournal.org/upload/pdf/acc-2020-01102.pdf
• ISSN: 2586-6052; 2586-6060

Background 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. Methods 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. Results 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. Conclusions 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.