A study assessing the potential benefit of continued ventilation during cardiopulmonary bypass

It has been suggested that maintaining ventilation during bypass might reduce lung injury, which is a common complication of cardiac surgery. In order to assess this, a study is being undertaken to examine the effect upon a number of parameters that may be indicative of lung injury, of continued ventilation compared with discontinued ventilation whilst on bypass. The following parameters have been assessed: extravascular lung water, static and dynamic compliance, ratio of left atrial/right atrial white blood count, alveolar arterial oxygen gradient and the respiratory index together with clinical end points. Provisional results are reported. Twenty-three elective patients for coronary artery surgery have to date been randomised to either ventilation (VB) (n=12) or non-ventilation on bypass (NVB) (n=11). The post-bypass extravascular lung water was significantly smaller in the VB group compared to the NVB group (530+/-50 ml vs. 672+/-32 ml; P=0.028). Extubation time was also significantly shorter in the VB group (3.6+/-0.3 h vs. 4.8+/-0.4 h; P=0.038). The provisional results of this work in progress are suggestive that continued ventilation during bypass may reduce lung injury.