AUTOTRANSFUSION AFTER TOTAL KNEE ARTHROPLASTY - EFFECTS ON BLOOD-CELLS, PLASMA CHEMISTRY, AND WHOLE-BLOOD RHEOLOGY

Postoperative drain blood was collected and reinfused using tile Const aVac system (Stryker, Kalamazoo, MI) in 30 patients after total knee a rthroplasty. Of the total 1.1-L volume of postoperative bleeding, 60% was reinfused. No clinical complications were observed. Differences be tween venous blood and drain blood and between Venous blood and drain blood after separate incubation were studied with respect to acidic an d inflammatory effects on blood cells, plasma chemistry, and whole blo od theology. In drain blood, leukocyte and platelet counts were reduce d (P <.001), probably as a result of consumption in the wound. Acidic incubation occurs in the drain container because of production of lact ate from glucose, with a minimum pH at 5 hours of 7.2. The low pH caus ed slight but significant erythrocyte swelling (P <.01). The complemen t C3d indicated leukocyte activation, although of modest magnitude. De spite incubation and complement activation, maximum erythrocyte hemoly sis after 24 hours of incubation was less than 1%. Drain blood showed a lower resistance against micropore filtration than venous blood (P < .001), mainly because of the reduced number of leukocytes, and remaine d unchanged with incubation. Although the autotransfusion system can b e improved with respect to blood quality, filtered drain blood should be considered acceptable for reinfusion.