High frequency oscillation ventilation

Background

  • High Frequency Oscillation Ventilation (HFOV) is an alternative method for mechanical ventilation in difficult to oxygenate in critically ill ARDS patients.
  • Studied in patients with PaO2/FiO2 < 200
  • Goal is to maintain alveolar recruitment for adequate gas exchange and decrease lung injury/atelectrauma
    • Low tidal volumes based around mean airway pressures to keep alveoli open
    • Delivered at high frequency

Pros

  • Limits VILI
  • May improve oxygenation when ECMO not available

Cons

  • No difference or likely to cause harm in adult ARDS patients
  • Requires heavy sedation
  • Increase mean airway pressures may result in more hemodynamic instability

Procedure

Example protocol from Oscillate trial[1]

  • Set FiO2 at 100%
  • Recruitment maneuver of 40 cmH2O PEEP for 40 seconds
  • I:E time of 1:2
  • Initiate high frequency ventilation → 3-15 Hz
  • VT minimized to keep pH >7.25
    • Goal of 1-4 ml/Kg
  • Maintain mean airway pressure of 30 cmH2O with pressure adjusted to maintain a PaO2 of 55-80 mmHg
  • Reversion to standard ventilation of mean airway pressure was ≤24 cmH2O for 12 hours or anytime when ≤20 cmH2O
  • Re-initiation of HFOV if FIO2 >0.4 or PEEP >14 cmH2O for >1 hour in the subsequent 48 hours

Targets

  • pH>7.25
  • SpO2 >88% or PaO2 >55mmHg

Oxygenation altered by:

  • FiO2
  • Mean airway pressures

Ventilation altered by:

  • Frequency
    • Decrease frequency to increase TV and ventilation
  • Inspiratory time
  • Amplitude of oscillations

See Also

Mechanical Ventilation Pages

External Links

References

  1. Fergusson N, Cook D, Guyatt G. High-frequency Oscillation in Early Acute Respiratory Distress Syndrome. NEJM 2013; 368:795-805