Comparison of lung protection strategies using conventional and high-frequency oscillatory ventilation

1 Pathophysiology Research Laboratory, National Children's Medical Research Center, Tokyo 154-8509, Japan; and 2 Division of Respiratory and Critical Care, Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada M5B 1W8 This study compared pathophysiological and biochemical indexes of acute lung injury in a saline-lavaged rabbit model with different ventilatory strategies: a control group consisting of moderate tidal volume (V T ) (10-12 ml/kg) and low positive end-expiratory pressure (PEEP) (4-5 cmH 2 O); and three protective groups: 1 ) low V T (5-6 ml/kg) high PEEP, 2-3 cmH 2 O greater than the lower inflection point; 2 ) low V T (5-6 ml/kg), high PEEP (8-10 cmH 2 O); and 3 ) high-frequency oscillatory ventilation (HFOV). The strategy using PEEP > inflection point resulted in hypotension and barotrauma. HFOV attenuated the decrease in pulmonary compliance, the lung inflammation assessed by polymorphonuclear leukocyte infiltration and tumor necrosis factor- concentration in the alveolar space, and pathological changes of the small airways and alveoli. Conventional mechanical ventilation using lung protection strategies (low V T high PEEP) only attenuated the decrease in oxygenation and pulmonary compliance. Therefore, HFOV may be a preferable option as a lung protection strategy. ventilator-induced lung injury; volume recruitment; tumor necrosis factor; conventional mechanical ventilation