What is the initial high flow (HF) oxygen therapy rate in liters per minute (L/min) for a 1 year 10 months old child weighing 10.9 kilograms (kg)?

High Flow Oxygen Therapy for a 22-Month-Old Child

For a 1 year 10 months old child weighing 10.9 kg, start high flow oxygen therapy at 1-2 L/kg/min, which equals approximately 11-22 L/min, typically beginning at the lower end (10-15 L/min) and titrating upward based on clinical response.

Initial Flow Rate Calculation

The standard approach for pediatric high flow nasal cannula (HFNC) therapy uses weight-based dosing:

• Weight-based formula: 1-2 L/kg/min is the typical starting range for infants and young children 1, 2
• For this 10.9 kg child: Initial flow would be 10.9-21.8 L/min
• Practical starting point: Begin at 10-15 L/min and titrate upward to achieve target oxygen saturation 3, 4

Target Oxygen Saturation

Since this child is older than 1 year (at 22 months), specific saturation targets apply:

• Target SpO2: Maintain >93% based on American Thoracic Society guidelines for children ≥1 year old 5
• Hypoxemia definition: Spending 5% of time with SpO2 ≤93% constitutes hypoxemia in this age group 5
• Normal range: Children >1 year typically maintain mean SpO2 of 97.6% during wakefulness and 97.8% during sleep 5

Titration Strategy

Flow rate adjustment:

• Start at lower end of range (10-15 L/min) to assess tolerance 3
• Maximum flows for HFNC systems typically reach 30-60 L/min in adults, but pediatric patients require lower flows 1, 2
• Increase flow by 5 L/min increments if SpO2 remains <93% or respiratory distress persists 4
• Monitor for decreased respiratory rate and improved work of breathing as indicators of effectiveness 3

FiO2 adjustment:

• HFNC allows precise FiO2 delivery by preventing ambient air entrainment at adequate flow rates 6
• Adjust oxygen concentration (FiO2) in addition to flow rate to achieve target saturation 2, 4
• Higher flows (30+ L/min) provide more consistent FiO2 delivery, though this may exceed comfort in small children 6

Physiological Benefits at Appropriate Flow

When properly dosed, HFNC provides:

• Positive end-expiratory pressure (PEEP): Generates 2-4 cmH2O with mouth closed, less with mouth open 6
• Dead space washout: High flow flushes upper airway CO2, reducing work of breathing 1, 2
• Consistent FiO2: Prevents dilution from ambient air entrainment 6
• Improved comfort: Heated and humidified gas reduces airway dryness and improves mucociliary clearance 3, 4

Critical Monitoring Requirements

Continuous assessment is mandatory:

• Monitor SpO2 continuously to ensure maintenance >93% 5
• Assess respiratory rate—expect decrease with effective therapy 3
• Evaluate work of breathing (retractions, nasal flaring, accessory muscle use) 2
• Ensure capability for immediate escalation to intubation if HFNC fails 1

Common Pitfalls to Avoid

Flow rate errors:

• Too low (<1 L/kg/min): May not provide adequate PEEP or dead space washout, functioning merely as standard oxygen therapy 2, 6
• Too high initially: May cause discomfort and poor tolerance, though HFNC generally has good comfort scores 3

Mouth position matters:

• Open mouth significantly reduces PEEP effect (from 2 cmH2O to 0.6 cmH2O) 6
• Encourage mouth-closed breathing when possible, though this is difficult to control in young children 6

Delayed escalation:

• HFNC is not a substitute for mechanical ventilation in severe respiratory failure 1
• If no improvement within 1-2 hours or worsening respiratory status, escalate to non-invasive or invasive ventilation 1, 2
• Patients on HFNC remain critically ill and require ICU-level monitoring 1

Fluid Management Consideration

While managing this child's respiratory status, maintain appropriate fluid balance:

• Maintenance fluids: 100 mL/kg/day for first 10 kg = 1000 mL/day, plus 50 mL/kg/day for remaining 0.9 kg = 45 mL/day, totaling approximately 1045 mL/day (43-44 mL/hour) 7
• Use isotonic fluids (0.9% saline or balanced crystalloids) to prevent hyponatremia in acute illness 7