Journal of Applied Physiology, Vol 55, Issue 5 1373-1378, Copyright © 1983 by American Physiological Society
Effect of high-frequency oscillation on lung lymph flow
A. L. Jefferies, P. Hamilton and H. M. O'Brodovich
We investigated the effect of high-frequency oscillation (HFO) on lung
lymphatic function under normal conditions and when lung lymph flow was
increased by air microembolization. In six experiments, sheep and goats
with chronic lung lymph fistulas and vascular catheters were anesthetized,
paralyzed, intubated, and ventilated according to the following protocol:
1) intermittent positive-pressure ventilation (IPPV) for 1 h, 2) HFO with a
frequency of 15 Hz and an estimated tidal volume of 1-2 ml/kg for 1-2 h,
and 3) IPPV for 0.5 h. Ventilator settings were adjusted to maintain
arterial Po2 above 100 Torr and a normal arterial Pco2. Vascular,
esophageal, and mean airway pressures were monitored continuously. Lymph
flow and cardiac output were recorded every 15 min. With this protocol,
there were no changes in pulmonary vascular or esophageal pressures, and
lymph flow remained stable throughout the experiment. In an additional five
experiments, air microemboli were infused for approximately 30 min during
HFO. Left atrial pressure was unchanged and lymph flow tripled. This
response was qualitatively and quantitatively similar to that previously
reported for unanesthetized spontaneously breathing sheep. We conclude that
HFO does not impair lymphatic function under resting conditions and that
lymphatics retain their ability to increase water and protein clearance
during HFO.
