From the Guidelines
High flow nasal cannula (HFNC) is recommended for patients with increased respiratory effort, but its effectiveness for apnea is limited, and it should not be relied upon as the sole treatment for this condition. HFNC delivers heated, humidified oxygen at flow rates of 20-60 L/min, which creates a small amount of positive pressure in the airways (1-3 cmH2O) 1. This modest pressure can reduce work of breathing by washing out carbon dioxide from anatomical dead space, decreasing inspiratory resistance, and providing some end-expiratory pressure. The European Respiratory Society task force panel recommends the use of HFNC over conventional oxygen therapy (COT) in hypoxaemic acute respiratory failure (ARF), and suggests that HFNC can be used alongside other noninvasive forms of respiratory support in adults with ARF 1.
Some key benefits of HFNC include:
- Improved oxygenation
- Reduced sensation of breathlessness
- Decreased work of breathing
- Ability to provide temporary support for patients with respiratory distress. However, for true apneas, especially obstructive sleep apnea, HFNC is generally insufficient as it doesn't provide enough pressure to maintain airway patency during sleep 1.
In clinical practice, the use of HFNC should be guided by the patient's specific condition and needs, and it is essential to monitor the patient's response to treatment and adjust the therapy as needed. The recent guidelines from the European Respiratory Society provide evidence-based recommendations for the use of HFNC in acute care settings, and clinicians should consider these guidelines when making decisions about the use of HFNC in their patients 1.
From the Research
Effects of High-Flow Nasal Cannula on Apnea and Respiratory Effort
- High-flow nasal cannula (HFNC) has been shown to reduce respiratory effort in patients with acute respiratory failure 2, 3.
- A study found that HFNC significantly reduced esophageal pressure variations, esophageal pressure-time product/min, and work of breathing/min in adult patients recovering from acute respiratory failure 2.
- Another study demonstrated that HFNC improved oxygenation, lowered respiratory rate, and reduced inspiratory effort in patients with acute hypoxemic respiratory failure 3.
- HFNC has also been used as apneic oxygenation during endotracheal intubation in critically ill patients, and was found to be noninferior to standard of care regarding incidence of severe hypoxemia and in-hospital mortality 4.
Comparison with Other Therapies
- A systematic review and meta-analysis found that HFNC was noninferior to standard oxygen therapy in terms of treatment failure, but probably made little or no difference in mortality 5.
- A study comparing HFNC with continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnea found that CPAP provided superior control of sleep apnea, but HFNC may be a viable option for patients intolerant to CPAP 6.
Clinical Implications
- HFNC may be beneficial in reducing respiratory effort and improving oxygenation in patients with acute respiratory failure 2, 3.
- HFNC may be considered as an alternative to standard oxygen therapy or CPAP in certain patient populations, such as those with mild hypoxemia or those who are intolerant to CPAP 5, 4, 6.