Am. J. Respir. Crit. Care Med.,
Volume 164, Number 2, July 2001, 237-242
Effects of High-Frequency Oscillation on Endogenous
Surfactant in an Acute Lung Injury Model
CAROLYN L.
KERR,
RUUD A. W.
VELDHUIZEN,
and
JAMES F.
LEWIS
Departments of Physiology and Medicine, Lawson Research Institute, St. Joseph's Health Centre, The University of Western Ontario, London,
Ontario, Canada
This study evaluated the effects of high-frequency oscillation (HFO)
and conventional mechanical ventilation (CMV) on gas exchange
and the pulmonary surfactant system in an acute lung injury model.
Following induction of lung injury with N-nitroso-n-methylurethane, adult rabbits were anesthetized and randomized to one of the following ventilatory strategies: HFO for 120 min, CMV for 120 min,
HFO for 60 min, followed by CMV for 60 min, CMV for 60 min followed by HFO for 60 min or CMV for 60 min. Separate animals
were ventilated using CMV with a lower tidal volume and a positive end-expiratory pressure level that was increased throughout
the experimental period. Oxygenation was significantly greater in
animals ventilated with HFO compared with animals ventilated
with CMV. The proportion of surfactant in large aggregate forms
was significantly greater following ventilatory support with HFO
compared with CMV. Surfactant aggregate conversion was also
significantly lower during HFO compared with CMV. We conclude
that in our model of acute lung injury, HFO was a superior mode
of ventilation and reduced the conversion of alveolar surfactant
large aggregates into small aggregate forms, resulting in a greater
percentage of large aggregate forms in the alveolar space.
Keywords: surfactant; mechanical ventilation; ARDS
