In vitro analysis of volume-reduced washed platelet concentrates stored in bicarbonated Ringer's solution containing less than 5% residual plasma.

Background and Objectives Volume-reduced washed platelet (PLT) concentrates (PCs) can prevent circulatory overload and allergic reactions in patients undergoing PLT transfusions. For these reasons, they are in demand for paediatric settings and for patients at risk of circulatory overload. Here, we evaluated the quality of volume-reduced washed PCs stored for 5 days in a novel acetate-free PLT additive solution (PAS) containing glucose and bicarbonate (BRS-A) with <5% residual plasma protein. Materials and Methods PCs from two apheresis donations were mixed and divided equally into control and test units. For the test unit (volume-reduced washed PCs), PLTs were washed and stored in 90 ml BRS-A with <5% plasma protein. PLTs in the control unit were stored in 200 ml 100% plasma without any washing manipulations. The in vitro properties of PLTs in both units were compared over a 5-day storage period. Results The procedure for volume-reduced washed PCs effectively removed >98% plasma protein in 100% plasma PCs and yielded an approximately twofold lower mean volume (91 ml) compared to that observed with the control units. Immediately after washing, the mean PLT concentration of the test units was 20.5 x 10(11)/l, twofold higher than that of the control units. The pH (37 degrees C) levels in the test unit remained above 7.0 for 5 days. Glucose consumption and lactate production rates of the test units on days 1-3 were higher than those of the control units, leading to glucose exhaustion in the test unit by Day 3. Hypotonic shock responses and CD62P and CD42b expression levels in both units were comparable during 5-day storage. Conclusion Considering the pH buffering capacity of BRS-A, a 90-ml volume may be acceptable for maintaining the in vitro quality of washed PLTs for at least 2 days.