Systemic blood activation with open and closed venous reservoirs

In 20 patients undergoing coronary artery bypass grafting, we studied prospectively systemic blood activation, blood loss, and the need for donor blood when using an extracorporeal circuit equipped at random with one of two different venous reservoirs. In 10 patients we used an open venous reservoir system (ORS) consisting of a hard shell venous reservoir with an integral cardiotomy filter, and in 10 patients we used a closed reservoir system consisting of a collapsible venous reservoir and separate cardiotomy reservoir. Concentrations of complement 3a, elastase, thromboxane B2, and fibrin degradation products showed a biphasic course, especially in ORS patients. During bypass, we observed a first peak of levels of complement 3a, thromboxane B2, fibrin degradation products, and elastase, which was higher in ORS patients than in patients with the closed system, because their blood continuously contacted the foreign materials of the filter and air in the open reservoir, which was avoided in the closed reservoir. Intensive blood—foreign material contact also caused the highest (p < 0.05) hemolysis in ORS patients. The larger amount of hemolytic products in ORS patients theoretically resulted in a temporary decrease in capacity of their Kupffer cells to clear endotoxin released after aortic declamping. This theory might explain the significantly (p < 0.01) higher second peak of activated products after declamping that was observed in ORS patients. Due to increased blood activation, the largest (p < 0.001) amount of shed blood loss, greatest (p < 0.05) need for colloid-crystalloid infusion, and largest (not significant) need for donor blood were found in ORS patients (0.8 ± 0.4 versus 0.2 ± 0.2 units of packed cells). For these reasons, we do not recommend the routine use of an open venous reservoir.