Room Temperature Storage of Platelets S. MURPHYAND F. H. GARDNER From the Hematology Research Laboratory, Presbyterian- University of Pennsylvania Medical Center, Philadelphia, Pennsylvania
ALTHOUGH OUR GROUP has had a long interest in the techniques for liquid storage of platelets, we have confined our efforts in recent years to an evaluation of the factors which effect the viability of platelets stored at 22 C or room temperature. The modern management of acute leukemia and aplastic anemia requires a platelet preparation which provides not only immediate hemostatic effect but also hemostatic protection for the patient for 48 to 72 hours after infusion. Studies indicate that platelet survival, as measured by 51Chromium, is compromised if platelets are stored at any temperature below 20 C. Such platelets may provide immediate hemostatic benefit but their efficacy beyond the first few hours after infusion is doubtful. On the other hand, storage at temperatures above 24 C is also suboptimal. The major limiting factor in storage a t 22 C is a fall in pH which results from a generation of lactic acid by platelet glycolysis and, to a lesser degree, from the retention of CO, arising from the oxidation of glucose and fatty acids. Viability of platelets is lost if pH falls to 6.0 or below. Since metabolic rate is enhanced at higher temperatures, the range of storage temperature should be 20 to 24 C. Since ambient temperatures in many blood banks may vary outside of this range, it is important to be aware of the narrow range which assures optimal results. Even within this optimal temperature range, other technical factors require careful monitoring. First of all, the concentrates must be agitated. In our experience, failure to agitate leads not only to a more rapid pH fall but also to a reduction in viability of
platelets which results from a factor which has not yet been defined but which is independent of pH. No data is available to define the optimal method or rate of agitation. Secondly, the plastics from which containers are constructed vary in their suitability. Some are clearly not suitable. We have found Fenwal plastic PL-146 the best of those which we have examined. Finally, concentrate volume and platelet concentration govern the rate at which pH falls. This follows from the dependence of rate of pH fall on rate of lactic acid and CO, production. These facts suggest that concentrate volume should be the largest that one can afford considering the volume which will eventually be infused into the patient and the necessity to retain adequate volumes of platelet-poor plasma for protein fractionation. We have settled on a volume of 50 ml. Unfortunately, with this volume and the technique of agitation which we use, some concentrates will have pH
ALTHOUGH OUR GROUP has had a long interest in the techniques for liquid storage of platelets, we have confined our efforts in recent years to an evaluation of the factors which effect the viability of platelets stored at 22 C or room temperature. The modern management of acute leukemia and aplastic anemia requires a platelet preparation which provides not only immediate hemostatic effect but also hemostatic protection for the patient for 48 to 72 hours after infusion. Studies indicate that platelet survival, as measured by 51Chromium, is compromised if platelets are stored at any temperature below 20 C. Such platelets may provide immediate hemostatic benefit but their efficacy beyond the first few hours after infusion is doubtful. On the other hand, storage at temperatures above 24 C is also suboptimal. The major limiting factor in storage a t 22 C is a fall in pH which results from a generation of lactic acid by platelet glycolysis and, to a lesser degree, from the retention of CO, arising from the oxidation of glucose and fatty acids. Viability of platelets is lost if pH falls to 6.0 or below. Since metabolic rate is enhanced at higher temperatures, the range of storage temperature should be 20 to 24 C. Since ambient temperatures in many blood banks may vary outside of this range, it is important to be aware of the narrow range which assures optimal results. Even within this optimal temperature range, other technical factors require careful monitoring. First of all, the concentrates must be agitated. In our experience, failure to agitate leads not only to a more rapid pH fall but also to a reduction in viability of
platelets which results from a factor which has not yet been defined but which is independent of pH. No data is available to define the optimal method or rate of agitation. Secondly, the plastics from which containers are constructed vary in their suitability. Some are clearly not suitable. We have found Fenwal plastic PL-146 the best of those which we have examined. Finally, concentrate volume and platelet concentration govern the rate at which pH falls. This follows from the dependence of rate of pH fall on rate of lactic acid and CO, production. These facts suggest that concentrate volume should be the largest that one can afford considering the volume which will eventually be infused into the patient and the necessity to retain adequate volumes of platelet-poor plasma for protein fractionation. We have settled on a volume of 50 ml. Unfortunately, with this volume and the technique of agitation which we use, some concentrates will have pH
