Effect of high-frequency oscillation on pressure delivered by high flow nasal cannula in a premature infant lung model.

OBJECTIVE

This study describes the effect of high-frequency oscillation on airway pressure generated by high flow nasal cannula (HFNC) in a premature infant lung model.

DESIGN/METHODS: A premature in 0.5 or 1.0 mL/cmH O, respiratory rate (RR) of 40 or 60 breaths per min, and tidal volume of 6 mL. Oscillation was achieved by passing the HFNC supply flow through a 3-way solenoid valve operating at 4, 6, 8, or 10 Hz. Airway pressure at the simulated trachea was recorded following equilibration of end-tidal CO both with and without oscillation.

RESULTS

Superimposing high-frequency oscillations onto HFNC resulted in an average decrease in mean airway pressure of 17.9% (P = .011). The difference between the maximum and minimum airway pressures, ∆ P significantly increased as oscillation frequency decreased ( P < .001). Airway pressure during oscillation was 12.8% greater with the 1.0 vs the 0.5 mL/cmH O compliance at flows > 4 L/min ( P = .031). CO clearance was 13.1% greater with the 1.0 vs 0.5 mL/cmH O compliance at oscillation frequencies less than 8 Hz ( P = .015).

CONCLUSION

In this in-vitro study we demonstrate that delivered mean airway pressure decreases when applying high-frequency oscillation to HFNC, while still improving CO clearance. The combination of improved CO clearance and reduced pressure delivery of this novel noninvasive modality may prove to be a useful improvement in the respiratory care of infants in respiratory distress.