Commentary Explores the Use of High-Flow Nasal Therapy in Patients With AECOPD

Commentary regarding the usage of high-flow nasal therapy (HFNT) in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) compared the technology with noninvasive ventilation (NIV), discussed the mechanisms of HFNT, and more.

Data were published in the Journal of Comparative Effectiveness Research.

NIV is the standard of care for respiratory support of patients with AECOPD who are developing acute hypercapnic respiratory failure (AHRF). The treatment method has been proven to reduce patient’s work of breathing and mortality and can be feasibly implemented in health care settings at different times, based on the severity of AHRF.

Although NIV is still considered the gold standard for patients with AECOPD, the implementation of HFNT as a new noninvasive respiratory support gained increased popularity during the COVID-19 pandemic and is currently recommended for use among patients with acute hypoxemic respiratory failure. Through the delivery of mixed heated and humidified air, with or without supplemental oxygen, HFNT an adjustable flow rate ranging from 20 to 60 L/m through a nasal cannula.

HFNT improves ventilatory efficiency and respiratory mechanics while reducing respiratory rate and inspiratory effort. The technique advantageously proves an accurate fraction of inspired oxygen (FiO2) matching a patient’s inspiratory peak flow, clears out anatomical dead space reducing CO2 rebreathing, provides a small degree of positive airway pressure that may counteract intrinsic positive end-expiratory pressure, and delivers warmed humidified gas that may enhance secretion removal. The interface of the technology promotes patients’ activities, allowing them to speak, cough, feed, and take oral medications.

Given its physiological advantages, HFNT may be clinically beneficial for patients with COPD with acute worsening of symptoms, like increased sputum volume and breathlessness. Further, the positive airway pressure created by HFNT during the patient’s expiration of breath may improve the patient’s breathing pattern.

An observational study of 138 patients admitted to intensive care units across 5 centers in Argentina demonstrated that HFNT delivered through high-velocity nasal insufflation, as an initial ventilatory strategy in patients with moderate to severe COPD with AHRF, led to a significant reduction in PaCO2 (57 vs 52 mm Hg; P < .001) and respiratory rate (29 vs 21 breaths/min; P < .001) compared with baseline.

In a similar study, the use of HFNT in patients with AECOPD and copresence of bronchiectasis was shown to significantly improve dyspnea (Borg scale: from mean [SD] 6.7 [1.4] to 4.1 [1.3]; P < .001) and mucus production (1.1 [0.6] vs 2.4 [0.7]; P < .001), as well as decrease the respiratory rate from a mean (SD) 29.6 (2.7) to 23.2 (2.9) breaths/min (P < .001) and pCO2 after 24 hours (58.4 [13] vs 51.7 [8.2]; P = .003).

The investigators were unable to draw definitive conclusions regarding HFNT because of the heterogeneity among the published studies concerning the severity of AHRF, the HFNT operational settings, the follow-up time points and instruments (scales of measurements) used for patient-centered outcomes assessment, and the clinical settings where the treatment was performed. Therefore, clinicians must exercise caution and use wise clinical judgement when considering HFNT for a patient with AECOPD to ensure the support is being used appropriately.

A combination strategy involving NIV and HFNT may promote the advantages of both techniques regarding respiratory mechanics, gas exchanges, and comfort. Further research in this are should focus on exploring whether the combined use of HFNT during breaks off NIV might be a successful strategy to exploit the physiological effects and the ergonomic features of HFNT in patients with AECOPD, concluded the authors.

Reference

Crimi C, Cortegiani A. Why, whether and how to use high-flow nasal therapy in acute exacerbations of chronic obstructive pulmonary disease. J Comp Eff Res. 2021;10(18):1317-1321. doi:10.2217/cer-2021-0220