Microaggregate blood filtration in patients with compromised pulmonary function.

To determine the effect of microaggregate blood filtration on patients with compromised pulmonary function, we divided 50 patients having elective coronary bypass surgery into two groups. One group received all blood transfusions via a 170-micron standard filter (SF). The other group received blood through a 20-micron microaggregate blood filter (MF). Patients were monitored pre- and postoperatively for changes in arterial blood gases and cardiopulmonary function. Mean transfusion volume was seven units (SF) and six units (MF). Preoperatively, patients in both groups showed abnormal lung function with elevated intrapulmonary shunting (Qs/Qt) and alveolar-arterial gradients (A-aO2). Postoperatively, no significant differences (p greater than 0.05) were found between the groups for any of the tests of cardiopulmonary function evaluated. Posttransfusion, none of the patients in either group showed clinical signs of respiratory distress. We conclude that even for patients with some degree of pretransfusion pulmonary dysfunction, use of a microaggregate blood filter for six- to seven- unit transfusions does not provide significant clinical benefit.