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Cardiopulmonary bypass (CPB) leads to a generalized inflammatory reaction, resulting in increased postoperative leucocyte counts and decreased pulmonary function. In adults, removal of leucocytes from the residual heart-lung machine blood after CPB improved postoperative oxygenation. In children, however, the clinical effects of leucocyte filtration of the residual heart-lung machine blood are unknown. Therefore, we measured postoperative leucocyte counts and arterial blood oxygenation in children undergoing congenital cardiac surgery in a randomized prospective study. Anaesthesia and CPB were standardized. After CPB, the residual heart-lung machine blood was collected as usual. In a group of 25 children, this blood was filtered with a leucocyte depletion filter before transfusion. A control group of 25 children received this blood unfiltered. We found that the postoperative leucocyte counts were significantly lower in the filter group than in the control group (p = 0.02, repeated measurements ANOVA). This difference reached a maximum on the second postoperative day (12.9 x 10(9)/L filter versus 15.9 x 10(9)/L control, p = 0.02, Student's t-test). Values for the arterial blood oxygenation on the first postoperative day were not different between the two groups (15.5 +/- 1 kPa filter versus 14.6 +/- 1.3 kPa control, p = 0.57, Student's t-test). We conclude that leucocyte filtration of the residual heart-lung machine blood reduced systemic leucocyte counts, but did not improve arterial blood oxygenation in children after congenital heart surgery. [ABSTRACT FROM AUTHOR]

Improved filter technology may enable the removal of specific substances such as lipids from the blood. Lipids form a heterogeneous group of compounds, but during surgery, the main interest is focussed on triglycerides, glycerol and free fatty acids. Fat emboli have been demonstrated in the brain after cardiac surgery and are associated with ischaemic brain injury. Fat emboli have also been demonstrated in lung and kidney tissue. Lung tissue and leucocytes are especially vulnerable to the effects of free fatty acids. The surgical wound suction blood during cardiac surgery contains a considerable quantity of microemboli. Therefore, as a first step to determining the place of fat filtration during cardiac surgery, the use of a fat removal filter for surgical wound suction blood is advocated. [ABSTRACT FROM AUTHOR]

Background: Neutrophil elastase is known to be released from the activated leukocytes as a result of cardiopulmonary bypass (CPB). However, its biological effect on organ injury is questionable because it is quickly bound by natural proteinase inhibitors (PIs). Recently, membrane-bound elastase (MBE) was found to be able to resist the PIs' process and, thus, is biologically more active. This paper studies the effect of CPB on the kinetic change of MBE and its possible link to postoperative inflammation and organ function., Method: Ten consecutive patients undergoing elective coronary artery bypass grafting (CABG) surgery with CPB were recruited into the study. Blood samples were taken before sternotomy, after aortic declamping, at the end of CPB, three and six hours after CPB and on the first postoperative day. MBE was determined by substrate assay from isolated neutrophils. Inflammation and organ function markers methods., Results: MBE slightly increased after aortic declamping, while it significantly increased and reached its peak at the end of CPB; it returned to its preoperative level on the first postoperative day. In contrast to lung sequestration of neutrophils, there was no transpulmonary gradient of MBE between left and right atria after aortic declamping. Neither MBE nor total MBE activity was positively correlated with postoperative inflammation markers such as blood lactate and C-reactive protein and organ function markers such as creatine phosphokinase and alanine aminotransferase., Conclusions: CPB induces increased MBE expression on neutrophils with its peak at the end of CPB. Lack of association between neutrophil MBE and clinical markers suggests that multiple systems might be involved in the post-CPB inflammatory reaction and organ dysfunction.

The results of leucocyte filtration during cardiac surgery are conflicting. This may be due to timing and duration of the filtration procedure, and to flow and pressure conditions in the filter. Therefore, we prospectively compared three major leucocyte filtration strategies in cardiac surgical patients. Forty patients were randomly divided into four groups. Group I: leucofiltration of arterial blood throughout cardiopulmonary bypass (CPB) (associated with high-flow and pressure gradients), Group II: leucofiltration of a part of the venous return blood in the rewarming phase during CPB (associated with intermediate flow, but high pressure), Group III: leucofiltration of residual heart-lung machine blood during transfusion into the patient after CPB (associated with low flow and low pressure), Group IV: control group without leucofiltration. We measured circulating leucocyte counts, plasma elastase levels and arterial blood oxygenation. Filters were postoperatively examined using scanning electronmicroscopy (SEM). Leucocyte counts increased over time and oxygenation decreased in all groups, without significant differences between the groups. SEM demonstrated extensive protein deposits and damaged leucocytes in the deeper layers of the filters from Group I. This was not observed in the filters from Group III. The postoperative plasma elastase levels increased in Groups II and IV and decreased in Groups I and III. In conclusion, we could not demonstrate a clinical difference among the three leucocyte depletion strategies. However, our laboratory results suggest that leucocyte filtration at low flow and pressure conditions is associated with less leucocyte damage and less release of elastase.