From the Guidelines
For patients with tachypnea, high-flow nasal cannula (HFNC) is preferred over Bilevel Positive Airway Pressure (BiPAP) as the first-line therapy due to its better comfort, ease of use, and ability to deliver oxygen at high flows. The recent European Respiratory Society clinical practice guidelines recommend the use of HFNC over conventional oxygen therapy and noninvasive ventilation in adults with acute respiratory failure 1. HFNC has been shown to be effective in reducing respiratory rate and improving oxygenation in patients with mild to moderate tachypnea. The guidelines suggest starting HFNC at 30-40 L/min and titrating based on respiratory rate and work of breathing.
Some key benefits of HFNC include:
- Better comfort and ease of use compared to BiPAP
- Ability to deliver oxygen at flows of 30-60 L/min with FiO2 up to 100%
- Physiological benefits from washout of anatomical dead space, provision of some positive pressure, and improved mucociliary clearance
- Reduced need for intubation and mechanical ventilation in some patients 1
BiPAP should be considered when HFNC fails to improve tachypnea or for patients with hypercapnic respiratory failure, neuromuscular weakness, or COPD exacerbations. Typical BiPAP settings include IPAP of 10-16 cmH2O and EPAP of 4-6 cmH2O, adjusted based on patient response. However, BiPAP requires a tight-fitting mask which some patients find uncomfortable and may cause skin breakdown with prolonged use 1. Overall, the choice between HFNC and BiPAP depends on the specific clinical situation and the patient's individual needs.
From the Research
Comparison of HFNC and BiPAP for Relieving Tachypnea
- There are no direct comparisons between High Flow Nasal Cannula (HFNC) and Bilevel Positive Airway Pressure (BiPAP) in the provided studies for relieving tachypnea (rapid breathing) 2, 3, 4, 5, 6.
- However, the studies compare HFNC with conventional oxygen therapy (COT) and noninvasive ventilation (NIV), which includes BiPAP, in various clinical settings.
- HFNC has been shown to be effective in reducing dyspnea and improving oxygenation in respiratory failure, and its use has been increasing for various clinical indications 2, 3, 5.
- A systematic review and meta-analysis found that HFNC reduced the risk of treatment failure and reintubation rate compared to COT, and reduced intubation rate compared to NIV when used as initial support 4.
- A randomized controlled non-inferiority trial found that HFNC was not non-inferior to NIV in terms of treatment failure rate in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) with acute-moderate hypercapnic respiratory failure 6.
- The studies suggest that HFNC can be a useful alternative to COT and NIV in certain clinical settings, but its effectiveness compared to BiPAP specifically for relieving tachypnea is not directly addressed 2, 3, 4, 5, 6.
Clinical Settings and Indications
- HFNC has been used in various clinical settings, including hypoxemic respiratory failure, hypercapneic respiratory failure, post-extubation respiratory failure, and pre-intubation oxygenation 2, 3, 5.
- The indications for HFNC are not absolute, and much of the proven benefit remains subjective and physiologic 5.
- HFNC has been shown to be effective in reducing treatment failure and reintubation rate in certain clinical settings, but its effectiveness compared to BiPAP in these settings is not directly addressed 4, 6.
Physiologic Effects
- HFNC provides oxygen at high flows with an optimal degree of heat and humidification, which is well tolerated and easy to use in all clinical settings 2.
- HFNC reduces the anatomical dead space and improves carbon dioxide wash-out, reduces the work of breathing, and generates a positive end-expiratory pressure and a constant fraction of inspired oxygen 2.
- The physiologic effects of HFNC are thought to contribute to its effectiveness in reducing dyspnea and improving oxygenation in respiratory failure 2, 5.