Effect of methods of platelet resuspension on stored platelets

Platelets are prepared from whole blood by differential centrifugation. Following their isolation as a platelet button, platelets are allowed to rest for a short period in the residual plasma before resuspension. In this study, the feasibility of resuspending platelets without this rest period is studied. A total of 35 platelet concentrates (PC) were prepared from blood collected in CPDA-1 and resuspended by one of the following four methods: (1) no resting period, PC placed on a rotator immediately after preparation, (2) a 1.5 hour rest period and gentle shaking prior to rotation, (3) no rest period and immediate gentle shaking prior to rotation, and (4) a 1.5 hour resting phase and no shaking prior to rotation. Following the previous processing, all platelet concentrates were stored for 72 hours on an elliptical platelet rotator at 20 to 24 degrees C to provide continuous agitation. A number of in vitro tests were used as indicators of platelet viability during storage. These included platelet morphology, pO2, pCO2, pH, osmotic recovery, number of platelets in the concentrate, and platelet volume distribution. Our findings demonstrate that platelets are of similar quality after storage in all of the four groups described. Our studies suggest that the resting phase is unnecessary for platelet preparation. The elimination of the resting phase would allow platelet concentrates to be available sooner and improve cost-effectiveness of platelet preparation.