The short 72-hour shelf-life of platelet concentrates stored in standard PL146 (Fenwal) plastic bags often results in shortages of platelets. This 3-day limitation is based on the biochemical and physiological changes that occur during storage and that result in decreased viability and survival after transfusion. We assessed both in vitro and in vivo function of platelet concentrates stored for 3 and 5 days in two new plastic packs: PL732 (Fenwal) and CLX (Cutter). The concentrate pH was maintained above 7.0 in both bags and there was little change in platelet count or size following 5 days of storage. Aggregation response to adenosine diphosphate, epinephrine, and collagen was maintained well. The PCO2 values indicated good gas escape with lower values after 5 days of storage than at 0 time. Lactate accumulation and glucose utilization were also lower in these new bags. Autologous survivals of chromium-labeled platelets stored for 5 days were 6.0 days (PL732) and 5.1 days (CLX), which are equal to or better than those found for platelets stored for 3 days in PL146. Posttransfusion increments in thrombocytopenic patients were acceptable; 49 percent after 1 hour and 31 percent after 24 hours for concentrates stored in CLX and 44 percent after 1 hour and 28 percent after 24 hours for concentrates stored in PL732. Both of these new bags, which contain different types of plasticizers, provide an environment that results in an improved product and will permit 5-day storage of platelet concentrates; these two benefits will help to alleviate the difficulties in supply of platelet concentrates.

Platelets from several units of plasma were pooled, and then resuspended either as platelet concentrate (PC) (60 ml) or as platelet rich plasma (PRP) (220 ml) and followed during 72 hours of storage at 22 C. Aggregation, pH, and hypotonic shock response are better maintained in the larger volume of plasma. However the decreased pH and function in the PC is not the result of lactate production. While the relative concentration, expressed in mg/dl, is higher in the PC, the absolute production per platelet and, therefore, the total amount of lactate is higher in PRP. Glucose levels are always sufficiently high to permit glucose to be used as a metabolic substrate even after 72 hours. PC maintained in nitrogen have better in vitro function than do platelets stored either in oxygen or CO2. CO2 can easily diffuse through the plastic bag; the same is not true of oxygen. Less than 15 per cent of the volume of oxygen introduced into the bag passed out through the PVC plastic over a 72-hour period. The data suggest that during storage, anaerobic glycolysis is the preferred metabolic route. The relatively poor performance of the PC maybe the result of limitation of some unidentified substrate or cofactor which is present in plasma and which is necessary for maintaining function.