What are the guidelines for using high flow nasal cannula (HFNC) in the Neonatal Intensive Care Unit (NICU) for premature infants or those with respiratory distress?

High Flow Nasal Cannula in the NICU

HFNC can be used safely in the NICU for post-extubation respiratory support in preterm infants ≥28 weeks gestation and ≥1000g, but should NOT be used as primary respiratory support immediately after birth, where CPAP remains superior. 1, 2

Primary Respiratory Support (Immediately After Birth)

Do not use HFNC as first-line primary support for preterm infants with respiratory distress. The evidence clearly demonstrates HFNC is inferior to nasal CPAP when used as initial respiratory support:

• Treatment failure rates are significantly higher with HFNC (26.3%) compared to CPAP (7.9%) in the first 72 hours of life, with an 18.4 percentage point risk difference. 2
• This finding holds true across both moderate and severe respiratory distress subgroups. 2
• Meta-analysis confirms no advantage of HFNC over CPAP for primary support, with similar treatment failure rates overall but concerning trends toward worse outcomes. 3
• CPAP should be the default initial non-invasive support for preterm infants with respiratory distress, mixed disease, and mild-to-moderate cardiorespiratory failure if no contraindications exist. 4

Critical Caveat

The Paediatric Mechanical Ventilation Consensus Conference states there is insufficient data to recommend HFNC use in obstructive airway, restrictive, or mixed disease in pediatric populations, reflecting the lack of outcome data showing superiority over any intervention. 4

Post-Extubation Respiratory Support

HFNC is an acceptable alternative to CPAP following extubation in preterm infants ≥28 weeks gestation and ≥1000g, with specific advantages:

Efficacy Outcomes

• No difference in reintubation rates between HFNC and CPAP (RR 0.91,95% CI 0.68-1.20). 5
• No difference in death or chronic lung disease rates between HFNC and CPAP post-extubation. 5
• Treatment failure rates are similar overall, though CPAP shows slightly lower failure rates in meta-analysis (RR 1.23,95% CI 1.01-1.50). 3

Safety and Comfort Advantages of HFNC

• Significantly reduced nasal trauma with HFNC compared to CPAP (RR 0.64,95% CI 0.51-0.79), translating to a 14% absolute risk reduction. 5
• Reduced pneumothorax rates with HFNC (RR 0.35,95% CI 0.11-1.06), with a 2% absolute risk reduction. 5, 3
• Better patient comfort and tolerance compared to CPAP. 6, 7

Practical Implementation for Post-Extubation

• Extubate to HFNC when ventilator settings are low enough to suggest readiness for non-invasive support. 8
• Infants can be successfully extubated from higher ventilator rates to HFNC (mean 32.6 breaths/min) compared to historical CPAP controls. 8
• Flow rates should be at least 2-8 L/min for neonates, with specific guidelines recommending individualized flows based on weight and clinical response. 1

Weaning from CPAP

HFNC is superior to CPAP for weaning from non-invasive respiratory support:

• Preterm infants transitioned from CPAP to HFNC have reduced duration of hospitalization compared to those remaining on CPAP. 5
• This represents an appropriate step-down strategy once infants are stable on CPAP but still require some respiratory support. 5

Monitoring and Escalation Criteria

Close monitoring in the first 1-2 hours is critical to identify treatment failure early:

• Persistent tachypnea despite HFNC indicates need for escalation to CPAP or intubation. 6
• Monitor respiratory rate, work of breathing, SpO2/FiO2 ratio, and clinical appearance continuously. 6, 9
• Use validated prediction scores like the HACOR scale to predict failure within the first hour if considering escalation. 6, 9
• If HFNC fails post-extubation, rescue with CPAP first before proceeding to reintubation, as 32 of 35 infants who failed HFNC were successfully rescued with CPAP. 2

Specific Population Considerations

Gestational Age and Weight Limits

• Minimum criteria: ≥28 weeks gestation and ≥1000g birth weight based on the strongest RCT evidence. 2
• Evidence for extremely preterm infants (<28 weeks) is insufficient, and further trials are needed in this population. 5
• Late preterm infants also lack adequate evidence for specific recommendations. 5

Contraindications

• Inability to protect airway. 9
• Hemodynamic instability or impending cardiac arrest. 9
• Severe hypoxemia with PaO2/FiO2 <100 mmHg despite optimized oxygen delivery. 9

Equipment and Technical Specifications

• Heated and humidified gas delivery is essential to prevent mucosal damage and maintain airway patency. 7, 1
• Flows of 50-60 L/min in older children can generate positive airway pressure of approximately 7 cm H2O, though neonatal flows are lower (2-8 L/min). 6, 1
• Different HFNC delivery systems show no significant outcome differences, allowing institutional preference. 5

Additional Benefits

• Reduced ventilator-associated pneumonia rates compared to prolonged mechanical ventilation (18.5 vs 11.4 days on ventilator). 8
• Improved discharge weights in infants managed with HFNC protocols despite similar length of stay. 8
• Fewer total days on mechanical ventilation when early extubation to HFNC protocols are implemented. 8