Abstract
Gabriel et al.1 analyzed gasometric parameters in groups I and II cardiopulmonary bypass (CPB) and their respective subgroups. For achieving that goal, we standardized the blood sample withdrawal process as follows: Preoperative blood samples were withdrawn from the right pulmonary vein and right internal carotid artery following pericardiotomy. Postoperative blood samples were taken from the same sites but because mechanical ventilation might have an influence on gasometric parameters, these were taken on coming off CPB immediately before restoring mechanical ventilation.
