Retransfusion of cardiotomy suction blood impairs haemostasis: ex vivo and in vivo studies.

OBJECTIVES: Cardiotomy suction blood in volumes corresponding to 10-20% of the systemic blood volume is retransfused during cardiopulmonary bypass. We hypothesized that retransfusion of unwashed cardiotomy suction blood influences coagulation and platelet function. DESIGN: Systemic blood samples collected during cardiopulmonary bypass were supplemented ex vivo with autologous wound blood (5, 10 and 20%, respectively). Clot formation and platelet function were assessed with thromboelastometry and platelet aggregometry. In an in vivo pilot study 30 patients were randomized into a retransfusion and a no-retransfusion group. Clot formation, platelet aggregability and thrombin generation capacity were compared between the groups. RESULTS: Cardiotomy suction blood had markedly impaired clot stability and reduced levels of fibrinogen and platelets compared with systemic blood. Ex vivo addition of 10% and 20% suction blood to systemic blood impaired platelet aggregability and clot stability. Retransfusion of small amounts of wound blood in vivo (mean volume 280 ml, corresponding to 5% of the blood volume) did not significantly influence haemostasis. CONCLUSIONS: The ex vivo results suggest that addition of unwashed cardiotomy suction blood in clinically relevant volumes impairs systemic haemostasis. Retransfusion of smaller volumes in vivo has no or limited impact. Avoiding retransfusion of larger amounts of unwashed cardiotomy suction may improve postoperative haemostasis.

Hemodynamic effects of cardiotomy suction blood.

OBJECTIVE: Cardiac surgery induces a systemic inflammatory activation, which in severe cases is associated with peripheral vasodilation and hypotension. Cardiotomy suction blood contains high levels of inflammatory mediators, but the effect of cardiotomy suction blood on the vasculture is unknown. We investigated the effect of cardiotomy suction blood on systemic vascular resistance in vivo and whether cell-saver processing of suction blood affects the vascular response. METHODS: Twenty-five patients undergoing coronary surgery (mean age, 68 +/- 2 years; 80% men) were included in a prospective randomized study. The patients were randomized to retransfusion of cell-saver processed (n = 13) or cell-saver unprocessed (n = 12) suction blood during full cardiopulmonary bypass. Mean arterial blood pressure was continuously registered during retransfusion, and systemic vascular resistance was calculated. Plasma concentrations of tumor necrosis factor alpha, interleukin 6, and complement factor C3a were measured in suction blood. RESULTS: Retransfusion of cardiotomy suction blood induced a transient reduction in systemic vascular resistance in all patients. The peak reduction was significantly less pronounced in the group receiving cell-saver processed blood (-12% +/- 2% vs -28% +/- 3%, P = .001). There was a significant correlation between tumor necrosis factor alpha concentration in retransfused cardiotomy suction blood and peak reduction of systemic vascular resistance (r = 0.60, P = .002). CONCLUSIONS: The results suggest cardiotomy suction blood is vasoactive and might influence vascular resistance and blood pressure during cardiac surgery. The observed vasodilation is proportional to the inflammatory activation of suction blood and can be reduced by processing suction blood with a cell-saving device before retransfusion.