High-Flow Nasal Cannula (HFNC)
High-Flow Nasal Cannula (HFNC)
Overview
High-Flow Nasal Cannula is a non-invasive respiratory support system that delivers heated, humidified oxygen at flows higher than traditional nasal cannula, providing improved oxygenation and ventilation support in pediatric patients.
Key Mechanisms of Action
- Physiological Effects:
- Washout of nasopharyngeal dead space
- Reduction in upper airway resistance
- Provision of positive end-expiratory pressure (PEEP)
- Improved mucociliary clearance
- Decreased work of breathing
- Flow Rates:
- Neonates: 4-8 L/min
- Infants: 8-12 L/min
- Toddlers: 12-20 L/min
- School-age: 20-30 L/min
- Adolescents: Up to 60 L/min
System Setup & Components
Essential Components
- Flow Generator
- Air/oxygen blender
- Flow meter
- Pressure monitoring system
- Safety alarms
- Humidification System
- Heated humidifier
- Temperature control
- Water chamber
- Heated wire circuits
- Patient Interface
- Age-appropriate nasal cannula
- Securing mechanism
- Skin protection
Size Selection
- Cannula Sizing
- Neonatal: Prong outer diameter ≤ 2.4 mm
- Infant: 2.4-3.0 mm
- Pediatric: 3.0-4.0 mm
- Adult small: 4.0-5.0 mm
- Proper Fit Guidelines
- Prongs should occupy ≤50% of nares
- No pressure on septum
- Allow for patient movement
- Check for air leak around prongs
Clinical Applications
Primary Indications
- Respiratory Conditions
- Bronchiolitis
- Pneumonia
- Asthma
- Post-extubation support
- Acute hypoxemic respiratory failure
- Other Applications
- Apnea of prematurity
- Cardiac conditions with respiratory compromise
- Pre-oxygenation before procedures
- Sleep-disordered breathing
Initial Settings
- Flow Rate Initiation
- Start at age-appropriate flow
- Titrate based on work of breathing
- Monitor patient comfort
- Assess response within 1-2 hours
- FiO2 Management
- Start at FiO2 needed for SpO2 target
- Wean as tolerated
- Monitor oxygen requirements
Contraindications
- Absolute
- Nasal obstruction
- Base of skull fractures
- Severe coagulopathy
- Relative
- Severe respiratory acidosis
- Hemodynamic instability
- Altered mental status
- Excessive secretions
Monitoring & Troubleshooting
Patient Assessment
- Clinical Monitoring
- Respiratory rate and effort
- SpO2 and heart rate trends
- Work of breathing
- Mental status
- Comfort level
- System Checks
- Water level
- Circuit temperature
- Cannula position
- Circuit condensation
Common Problems & Solutions
- Inadequate Response
- Verify flow rate adequacy
- Check for air leaks
- Assess cannula position
- Consider escalation of care
- Equipment Issues
- Circuit temperature alarms
- Water depletion
- Cannula displacement
- Flow interruption
Weaning Protocol
- Readiness Assessment
- Clinical improvement
- Stable oxygen requirements
- Adequate work of breathing
- Stable vital signs
- Weaning Steps
- Reduce FiO2 first
- Gradually decrease flow
- Monitor tolerance
- Have rescue plan ready
