Journal of Applied Physiology, Vol 53, Issue 6 1418-1422, Copyright © 1982 by American Physiological Society
Gas exchange during high-frequency ventilation of the chicken
R. B. Banzett and J. L. Lehr
Recent studies have shown that high-frequency ventilation (HFV) at 1-30 Hz
is capable of maintaining adequate gas exchange in humans and dogs even
when tidal volumes are substantially less than dead space. We evaluated the
effectiveness of HFV in roosters by comparing CO2 elimination during
various frequencies and tidal volumes of HFV with CO2 elimination during
conventional mechanical ventilation. Sinusoidal oscillations were applied
at the tracheal cannula. A bias flow provided fresh gas at the top of the
tracheal cannula. Three conclusions emerge from the data. 1) HFV enhances
gas transport in the chicken as it does in mammals. 2) At low oscillatory
flows (amplitude X frequency) CO2 elimination depends on both frequency and
tidal volume, whereas at higher flows CO2 elimination depends more strongly
on tidal volume. The flow at which this transition occurs is relatively
lower than in humans and much lower than in dogs. 3) HFV at volumes below
dead space is usually not capable of maintaining adequate gas exchange in
the chicken in contrast to results in dogs and humans.
