High-flow nasal cannula versus conventional oxygen therapy in patients with dyspnea and hypoxemia before hospitalization

ABSTRACT

Introduction: Patients with dyspnea and hypoxemia are common in emergency departments. However, it is unknown whether high-flow nasal cannula (HFNC) reduces the risk of requiring more advanced ventilation support and whether HFNC relieves dyspnea better than conventional oxygen therapy (COT).

Areas covered: We searched the PubMed, Cochrane Library, Ovid, and Embase databases from inception to 1 September 2019 to identify relevant-randomized controlled trials comparing the effect of HFNC with COT in emergency departments regarding the severity of dyspnea, hospitalization rate, intubation rate, and hospital mortality. We identified four studies. HFNC was associated with a lower rate of requiring more advanced ventilation. HFNC reduced the rate of dyspnea, lowered the dyspnea scale score, and decreased patients’ respiratory rate significantly. However, there was insufficient evidence to show a significant effect on HFNC regarding patients’ oxygenation and hospital mortality.

Expert opinion: For patients with dyspnea and hypoxemia before hospitalization, the short-term effect of HFNC was undeniable. HFNC reduced the risk of requiring more advanced ventilation and relived dyspnea better than COT. HFNC might be considered as a first-line therapy even before making a clear diagnosis for dyspnea.

More studies are needed to explore the effect of HFNC on oxygenation and patients’ prognosis.

KEYWORDS:

• High-flow nasal cannula
• dyspnea
• hypoxemia
• emergency

Article highlights

• How to relieve dyspnea, a common condition, in emergency departments, as soon as possible before hospitalization and a clear diagnosis remains hot topics.

• The sensation of dyspnea has resulted from the mismatch between the increased central neural output induced by hypoxemia and inadequate airflow or ventilation due to the dysfunction of the respiratory system.

• HFNC, a new oxygen therapy measure, might have a better effect on the relieving dyspnea than the commonly used oxygen inhalation technique via low-flow devices, to date, very few literature pooled this evidence.

• This meta-analysis indicated HFNC relieved dyspnea better than COT and reduced the risk of requiring more advanced ventilation support, which implied HFNC might be considered as a first-line therapy in the emergency department.

• More studies are needed to explore the effect of HFNC on oxygenation and patients’ prognosis. We believe HFNC would be used more commonly in emergency and even in ambulance considering its advantages and ability to quickly relieve dyspnea in most patients.

Acknowledgments

We thank Jane Charbonneau, DVM, from Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac) for editing the English text of a draft of this manuscript.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

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Additional information

Funding

This study was supported by the National Nature Science Foundation of China [Project Number 81400051] and the Key Project of Henan Higher Education [Project number 19A430073].