Effects of oxygen and ventilation on pulmonary mechanics and ultrastructure during cardiopulmonary bypass

The effects of three different methods of ventilation on pulmonary pathology during cardiopulmonary bypass are evaluated in twenty-one dogs in terms of lung mechanics and light and electron microscopy. Although air pressure-volume studies revealed essentially equal degrees of impairment resulting from all three methods, there was less ultrastructural damage when the lungs were statically inflated with 100 per cent oxygen during the bypass period. This evidence suggests that static 100 per cent oxygen inflation is of more value in preventing the initial pathologic change leading to development of the post-perfusion lung syndrome than either intermittent ventilation or static deflation.