What are the guidelines for the utilization of High Frequency Oscillatory Ventilation (HFOV) in pediatric patients?

Guidelines for High Frequency Oscillatory Ventilation (HFOV) in Pediatric Patients

High Frequency Oscillatory Ventilation (HFOV) should be considered as a rescue therapy when conventional mechanical ventilation fails in pediatric patients with severe respiratory failure, using an open lung strategy to maintain optimal lung volume. 1

Indications for HFOV in Pediatric Patients

• HFOV may be considered in pediatric patients with severe respiratory failure when conventional ventilation fails 1
• HFOV can be used in various disease conditions including:
  • Acute hypoxemic respiratory failure 1
  • Restrictive lung disease 1
  • Mixed disease 1
  • Obstructive airway disease (with caution) 1
  • Cardiac children with severe respiratory failure 1
  • Chronically ventilated children or those with congenital disorders experiencing acute exacerbations 1

Implementation Strategy

• Timing of Intervention: Early intervention with HFOV (within the first 24 hours of respiratory failure) is associated with better survival outcomes compared to late intervention 2
• Open Lung Strategy: Use an open lung strategy with HFOV to maintain optimal lung volume 1
• Monitoring Parameters:
  • Monitor arterial blood gases, SpO2, and end-tidal CO2 1
  • Measure peak inspiratory pressure, plateau pressure, and mean airway pressure 1
  • Monitor pressure-time and flow-time scalars 1

Special Considerations for Specific Patient Populations

• Cardiac Patients:

  • Careful use of HFOV can be considered in cardiac children who develop severe respiratory failure 1
  • Particular caution is advised in children with passive pulmonary blood flow or right ventricular dysfunction 1
  • HFOV can be judiciously performed in cardiac children, including those with a Fontan circulation 1

• Obstructive Airway Disease:

  • HFOV can be used with caution in obstructive airway disease 1
  • High-frequency jet ventilation (HFJV) should NOT be used in obstructive airway disease due to the risk of dynamic hyperinflation 1

Efficacy and Outcomes

• A mortality benefit of HFOV in acute hypoxemic respiratory failure has not been definitively shown 1
• Some retrospective analyses suggest a potential increase in mortality with HFOV, similar to adult observations, though methodological issues have been raised regarding these studies 1
• HFOV has demonstrated rapid and sustained improvements in oxygenation in pediatric patients failing conventional ventilation 3
• In studies, HFOV has shown significant decreases in P(A-a)O2 and oxygenation index at 1 and 4 hours respectively, sustained up to 12 hours 3

Ventilator Settings and Management

• Mean Airway Pressure:

  • Use incremental increases in mean airway pressure to achieve optimal lung volume 4
  • Target arterial oxygen saturation of ≥90% with FiO2 ≤0.6 4

• Plateau Pressure Limitations:

  • In the absence of transpulmonary pressure measurements, limit plateau pressure ≤28 cmH2O 1
  • For restrictive lung disease, mixed disease, and children with congenital/chronic disorders, plateau pressure may be limited to ≤29-32 cmH2O if chest wall elastance is increased 1
  • For obstructive airway disease, limit plateau pressure ≤30 cmH2O 1

Transition to ECMO

• Consider extra-corporeal devices (ECMO) where available in reversible diseases if conventional ventilation and/or HFOV fails 1
• If ECMO is not available, early consultation with an ECMO center is recommended as transport of patients requiring ECMO can be hazardous 1

Sedation and Muscle Relaxation

• Caution is advised when using sedation and muscle relaxation in patients with cardiac dysfunction 1
• In severely ill children with obstructive airway disease, restrictive disease, or mixed disease requiring high ventilator settings, controlled mechanical ventilation with continuous sedation and/or muscle relaxants may be necessary 1

Potential Complications and Monitoring

• Monitor for hemodynamic compromise, though studies suggest high mean airway pressure during HFOV does not appear to significantly compromise oxygen delivery 4
• Assess response to HFOV after 1 hour by monitoring oxygenation parameters (PaO2/FiO2 ratio) 5
• Studies have shown significant improvements in PaO2/FiO2 ratio after 1 hour of HFOV compared to conventional ventilation 5

Weaning from HFOV

• Consider returning to conventional mechanical ventilation when:
  • Mean airway pressure is between 15-20 cmH2O 2
  • FiO2 <0.6 2
  • No evidence of air leak 2
  • Improved chest X-rays 2
  • Patient does not desaturate during airway suctioning 2