The effect of storage on platelet morphology

Platelet concentrates were stored for one, two or three days at 4 degrees C (unagitated) or at room temperature (unagitated and linearly agitated). After washing the concentrates twice at room temperature and then incubating them for 60 minutes at 37 degrees C, the platelet morphology was investigated by scanning and transmission electron microscopy. Platelets in freshly prepared concentrates were slightly activated, indicated by some pseudopod formation. Platelets stored at 4 degrees C rapidly lost the normal discoid shape. After three days of storage their surface membranes showed extensive folding, they were slightly vacuolated, and had lost most of their granules. Incubation of cold-stored platelets at 37 degrees C did not induce return to the discoid shape. Room temperature storage resulted in reversal of the slight initial platelet activation. After three days of unagitated room temperature storage the platelets were slightly more vacuolated than those stored with agitation. Room temperature storage usually resulted in well-preserved discoid platelets; however, some agitated platelet concentrates stored at room temperature contained a high proportion of odd shaped cells. This finding could not be correlated with pH change. The failure of platelets stored at 4 degrees C to return to the discoid shape after incubation at 37 degrees C could explain their short survival following transfusion. These results also provide a morphologic correlation with the reported slightly better recovery and survival of platelets stored at room temperature with agitation compared with those stored without agitation.     

Viability and function of platelet concentrates stored in CPD-adenine (CPDA-1)

The effective use of CPDA-1 as an anticoagulant in routine blood banking practice requires demonstration that platelet concentrates prepared in this solution meet both in vitro quality control standards and maintain posttransfusion viability and function after storage. In this study of 138 units of CPDA-1 platelet concentrates, the average platelet count was 8.0 +/− 0.2 × 10(10) with 81 per cent of the units having greater than 5.5 × 10(10) platelets. The mean poststorage pH was 6.68 +/− 0.03 and only four of the units had a pH of less than 6.0 (3%). Residual plasma volume averaged 75 +/− 1 ml. Platelet viability was determined in 16 normal volunteers by measuring survival of 51Cr- labeled autologous platelets after storage for 72 hours at 22 +/− 2 C. Platelet recovery averaged 50 +/− 4 per cent, while survival was 7.3 +/− 0.4 days for the 15 units with a pH above 6.0. Measurements of posttransfusion platelet viability and function were made in 12 paients with thrombocytopenia secondary to marrow failure. Their mean pretransfusion platelet count was 17,000 +/− 2,000/microliter, and their standardized template bleeding times were all greater than 30 minutes. Platelet recovery averaged 44 +/− 5 per cent and survival 3.3 +/− 0.5 days. In seven of the patients with the best posttransfusion increments, bleeding time was improved. Five patients with poor posttranfusion platelet increments showed no improvement in bleeding time with CPDA-1; two of these patients were also transfused with CPD platelets and had no response. Our studies indicate that platelet concentrates prepared in CPDA-1 meet in vitro quality control standards and after transfusion, maintain viability and function comparable to that of CPD collected platelets.     

Storage of platelets prepared by discontinuous flow centrifugation

Platelet concentrates were prepared by plateletpheresis using discontinuous flow centrifugation. Platelet units were stored in PL-146 bags of 300 ml and 2,000 ml capacity, and in vitro measures helpful in predicting platelet viability were compared. Storage in bags of 300 ml capacity led to significant fall in pH, decreased recovery from osmotic stress, and deterioration of morphology in 24 hours. Storage lesions were significantly decreased by use of 2,000 ml capacity bags.     

Evaluation of two instruments for noninvasive platelet concentrate quality assessment

The Platelet Monitoring System (PMS) and the Non-invasive Assessment of Platelet Shape and Concentration (NAPSAC) instruments which relate light scattering characteristics of platelet concentrates (PC) to platelet concentration and shape, were evaluated to determine their accuracy in assessing platelet quality during storage from 1 to 7 days. The results were correlated with platelet concentration, % discs and pH on 121 PC stored in PL732 containers. NAPSAC output is in the form of platelet concentration and % discs. When NAPSAC and standard method values were compared, correlation coefficients (r) did not exceed 0.76 for counts and 0.62 for % discs. PMS output is in the form of lights with red indicating poor quality and green or amber indicating acceptable quality. Sensitivity of the PMS instrument did not exceed 83% and specificity did not exceed 63%. Mean platelet number, % discs and pH were comparable for units triggering red versus green or amber lights. In a separate study, 13 PL732 PC stored 5 days and transfused autologously were evaluated on the PMS. Three red light units exhibited recovery and survival times similar to those observed with PC triggering green/amber lights. These data indicate that neither instrument adequately assesses the quality of PL732 PC.     

Recovery and survival in vivo of platelet concentrates prepared with prostaglandin E1

In follow-up to previous studies showing that stimulators of adenylate cyclase inhibit the activation of platelets in platelet concentrates (PC), the posttransfusion recovery and survival of autologous platelets prepared and stored after the addition of prostaglandin E1 (PGE1) to platelet-rich plasma at a concentration of 1.3 X 10(-8) M were investigated. Six normal subjects were studied on the two occasions, using PC stored with and without PGE1 and radiolabeling with 51Cr. The mean recovery of platelets prepared with PGE1 (35.2 +/- 8.1%) was significantly lower (p less than 0.013) than that of routinely prepared platelet concentrates (46.3 +/- 9.4%). The mean life-spans of platelets prepared with and without PGE1 were 7.1 +/- 0.4 and 6.2 +/- 1.0 days, respectively (p = NS). Despite its ability to inhibit the activation of platelets during concentration and storage, prostaglandin E1 appears to reduce posttransfusion recovery of platelets significantly in this experimental model and cannot be recommended at this time as an adjunct for PC preparation.     

Circulation of Concentrated One‐day‐old Platelets in Vivo

Platelet concentrates of rat and human origin were stored at 22 C or at 4 C for up to 24 hours without additives. Transfusion of these concentrates into thrombocytopenic recipients demonstrated that: (1) storage of rat or human platelets at 4 C for up to 24 hours did not affect their recovery in vivo ; (2) storage at 22 C resulted in a marked reduction in the viability of rat platelets but only a slight reduction in the viability of human platelets as adjudged by these criteria; (3) at 24 hours posttransfusion, the residual increment of platelets stored at 22 C was significantly higher than that of platelets stored at 4 C. The pH of the concentrates (rat and human) stored at 4 C remained slightly alkaline while the pH of those stored at 22 C., especially rat platelets, was significantly reduced. The deleterious effects of storage of platelets at 4 C are well known. These effects, however, do not preclude their usefulness when a limited objective of arresting or preventing hemorrhage for short periods is pursued. When daily platelet transfusions are feasible, platelets stored for 24 hours at 4 C in the absence of fresh material are adequate for clinical use.     

Ultraviolet-B irradiation of platelets: a preliminary trial of efficacy

Prior studies established that ultraviolet-B light (UVB) irradiation of platelet concentrates (PCs) at appropriate doses can eliminate the mixed lymphocyte culture-stimulating and -responding capacity of lymphocytes in the PCs without adversely affecting in vitro platelet function. The in vivo recovery and survival and in vitro characteristics of UVB-irradiated platelets were investigated in paired studies. PCs were stored for 1 day and then exposed to UVB. Platelet recovery, survival, and function were comparable to those of nonirradiated platelets. Recovery and survival of platelets stored for 5 days before UVB exposure were decreased relative to controls, although they were considered clinically acceptable. Paired transfusion studies were also performed in seven thrombocytopenic patients by using platelets obtained by apheresis. Comparable posttransfusion platelet increments and bleeding time corrections were obtained with both irradiated and control (nonirradiated) platelets. It can be concluded that platelets survive and function relatively normally in vivo after UVB irradiation sufficient to abolish lymphocyte reactivity in mixed lymphocyte culture. Long-term studies of UVB-irradiated PCs are needed to assess their potential in reducing recipient alloimmunization.     

In vitro function and in vivo viability of stored platelet concentrates. Effect of a secondary plasticizer component of PVC storage bags

Previous studies have shown that CL-2399 (Cutter) and PL-130 (Fenwal) polyvinyl chloride (PVC) plastic bags are unsatisfactory for storage of platelet concentrates (PC) at 22 degrees C. In an effort to explain the effects of plastic bags, the chemical make-up of CL-2399 and PL-130 PVC films was determined and compared with that of P1-146 (Fenwal) PVC, which is satisfactory for PC storage at 22 degrees C. The only significant difference between the three materials was the incorporation of tetrahydrofurfuryl oleate (THFO) as a secondary plasticizer in CL-2399 and PL-130. The response of platelets to aggregating agents, uptake of serotonin, recovery from hyptonic stress, and serotonin release during storage following storage in a modified CL- 2399 plastic prepared without THFO and designated CL-3000 (Cutter) was equivalent to PL-146 and far superior to CL-2399. In vivo studies in two laboratories of platelets stored in CL-3000 bags showed satisfactory recovery (56 +/− 4.2% and 46.7 +/− 2.7%) and survival (6.4 +/− 0.4 days and 7.4 +/− 0.6 days). From these studies we conclude that the THFO secondary plasticizer component of PL-130 and CL-2399 is the cause of the poor platelet viability of platelets stored in these plastic bags. The mechanism of impairment is not known. The causative agent(s) may be degradation products of THFO (formed during manufacture of the PVC film) that are leached from the plastic into PC during storage.     

Viability of platelets following storage in the irradiated state. A pair-controlled study

Gamma irradiation of blood products is a standard practice recommended for the prevention of posttransfusion graft-versus-host disease in susceptible hosts. We studied the effects of irradiation on stored platelet concentrates and evaluated whether platelets could be stored for 5 days in the irradiated state without adverse effects on their viability. Using a pair-controlled design in which each of six normal subjects acted as his or her own control, we compared in vitro storage characteristics and in vivo kinetics of platelet concentrates exposed to 30 Gy and stored for 5 days with those of platelet concentrates simply stored for 5 days without irradiation. Irradiation had no significant effects on in vitro storage characteristics (platelet count, mean platelet volume, pH, and white cell count) or on in vivo kinetics, including initial recovery and mean platelet survival. Using the multiple-hit model, initial recovery was 49.6 +/- 10.8 percent, and mean platelet survival was 5.6 +/- 1.05 days for irradiated concentrates, compared with 51.3 +/- 13.0 percent and 5.9 +/- 0.50 days, respectively, for the unirradiated control concentrates. We conclude that irradiation of platelet concentrates with up to 30 Gy has no effect on their in vivo recovery or survival, and that irradiation administered before storage of platelet concentrates does not interfere with their clinical efficacy.     

Studies of the minimum temperature at which human platelets can be stored with full maintenance of viability

Platelet concentrates from normal donors were stored for 3 days under identical conditions except for the temperature of storage, which was maintained at 21 +/- 0.5, 19.5 +/- 0.5, or 18 +/- 0.5 degrees C. Immediate posttransfusion recovery of the stored platelets determined by 51Cr labeling averaged 47, 47, and 48 percent after storage at 21, 19.5, and 18 degrees C, respectively (differences not significant). Mean life span of the transfused platelets, however, was 8.12, 5.21, and 1.85 days at 21, 19.5, and 18 degrees C, respectively. The difference between mean life span following storage at 21 degrees C was significantly different from that after storage at 18 degrees C (p less than 0.03). Reduction in viability after storage at the lower temperature correlated with the reduction in the number of discoid platelets. These findings indicate that platelet viability is compromised after storage for 3 days at 18 degrees C and, possibly, at 19.5 degrees C, and illustrate the need for quality control of temperature in short-term platelet storage.     

Effect of white cells on platelets during storage

White cells (WBCs) present in stored platelet concentrates have adverse effects on platelet function and on posttransfusion recovery. Although these effects have been attributed to the fall in pH that results from active WBC metabolism, platelets stored in gas-permeable storage bags still exhibit abnormalities, despite maintenance of a stable pH of greater than 6.0. The changes in platelet proteins and function brought about by storage with a controlled number of WBCs were studied. Twelve platelet-pheresis specimens were centrifuged at 180 x g to achieve a WBC count of less than 2 x 10(5) per mL (which contained less than 10% granulocytes). These specimens were split into two aliquots and placed in platelet bags for storage at 22 degrees C with constant horizontal agitation. Neutrophils, obtained from the same donor by centrifugation of 50 mL of whole blood through a discontinuous ficoll gradient, were added to one of the two platelet storage bags to achieve a final neutrophil count of 1 x 10(6) per mL. Platelet aliquots were removed and studied on Days 3 and 5. In platelets stored without neutrophils, the average response to ristocetin, using the mean slope as an index of platelet responsiveness, was 10.3 (n = 9, SD = 11) on Day 3, whereas for the platelets stored with neutrophils, it was 1.25 (n = 12, SD = 0.9, p less than 0.01). Significant differences were also seen on Day 5 (slope = 4.5 for platelets stored without neutrophils, slope = 0.3 for platelets stored with neutrophils, p less than 0.01). Platelet aggregation with 8 microM ADP and 1.5 mg per mL of collagen did not differ significantly.(ABSTRACT TRUNCATED AT 250 WORDS)     

Platelet concentrates stored for 5 days in a reduced volume of plasma maintain hemostatic function and viability

BACKGROUND: Platelet concentrates prepared from whole blood are generally suspended in a standard volume of 50 to 60 mL of plasma and can be stored thus at 20 to 24 degrees C for up to 5 days. In vitro studies suggested that this plasma volume could be reduced to 30 to 35 mL without impairing platelet function. STUDY DESIGN AND METHODS: This study evaluated whether platelets stored for 5 days in a reduced volume (30-35 mL) of plasma maintained their in vivo viability, hemostatic function, and recovery in recipients. Paired autologous platelet survival studies were done in 20 adult volunteers to assess platelet viability. A rabbit ear bleeding-time model was used to compare the hemostatic effectiveness of human platelet concentrates stored for 5 days in the standard or reduced volume of plasma. Platelet recovery was compared in thrombocytopenic hospital patients. RESULTS: Paired platelet survival studies indicated no significant difference between the values in platelet concentrates stored for 5 days in the reduced volume of plasma and the values in those stored in the standard volume. In the animal model, there was no significant difference in the bleeding times achieved by either set of platelet concentrates. The platelet count increments in thrombocytopenic patients were measured. The platelet count increments in patients who received reduced-volume platelet concentrates were as good as the increments achieved in patients given standard-volume concentrates. CONCLUSION: The in vivo viability, recovery, and hemostatic function of platelets collected in polyvinylchloride plastic containers and stored in 30 to 35 mL of plasma for 5 days are maintained as well as those of platelets stored in 50 to 60 mL of plasma.     

Paired comparison of the in vivo and in vitro results of storage of platelet concentrates in two containers

Both in vitro and in vivo methods are used to test the validity of techniques for storing platelet concentrates for transfusion. In this study, the characteristics of platelet concentrates stored for 5 days at 22 degrees C in two different containers were evaluated by paired comparison using two in vitro measurements and two in vivo measurements. On two occasions, 10 normal subjects donated concentrates that were stored in containers of either the CLX system or the PL-146 system. The first plastic used was chosen at random. If necessary, a concentrate platelet count was reduced to 1,200,000 per microliters by addition of plasma to avoid pH fall. Mean recoveries were 48.2 +/- 10.6 percent (mean +/- 1 SD) and 42.4 +/- 7.8 percent for platelets stored in containers of the CLX and PL-146 systems, respectively. Similarly, survivals (T 1/2 in days) were 3.4 +/- 0.8 and 3.0 +/- 0.7, respectively. Since a paired design was used, the superiority of the CLX system was demonstrable with a one-tailed paired t test. If a paired design had not been used, a pooled t test would have been appropriate and the differences would not have been significant. This result emphasizes the value of the paired design. Furthermore, two in vitro measurements that reflect platelet morphology, dispersion of the size distribution and extent of shape change with adenosine diphosphate, were superior for platelets stored in CLX containers as well, suggesting a relationship between these measurements and in vivo viability.(ABSTRACT TRUNCATED AT 250 WORDS)     

Recovery, lifespan, and function of CPD-Adenine (CPDA-1) platelet concentrates stored for up to 72 hours at 4 C

We studied the in vivo recovery, lifespan, and hemostatic effectiveness of CPDA-1 platelet concentrates stored for up to 72 hours at 4 C. A total of 120 CPDA-1 concentrates containing an average (+/− 1 S.D.) of 6.6 +/− 2.0 × 10(10) platelets were prepared. The pH of the units following storage at 4 C was 6.8 +/− 0.2; no unit had a pH below 6.3. Autologous transfusion of six normal volunteers showed that platelets stored at 4 C for 72 hours had an in vivo recovery of 40 +/− 18 per cent and a lifespan of 5.1 +/− 1.5 days. The hemostatic effectiveness of CPDA-1 platelets was determined by platelet counts and template bleeding time measurements in 10 thrombocytopenic patients. Patients receiving 48-hour-stored platelets had a four- to six-hour posttranfusion corrected platelet increment averaging 15,300 +/− 3,200/microliter which was 67 +/− 34 per cent of expected recovery. Four of the five patients transfused with this preparation showed an improved bleeding time. In contrast, three patients receiving 72-hour- stored platelets had a four- to six-hour posttransfusion increment of 5,800 +/− 2,400/microliter that was only 26 +/− 13 per cent of the expected recovery; furthermore, only one of these patients showed any correction of the bleeding time. These data indicate that CPDA-1 platelets are hemostatically effective when stored at 4 C for up to 48 hours.     

Preparation and storage of platelet concentrates

A technique of platelet concentrate preparation and storage is presented which permits the maximum number of viable and functional platelets to be preserved for periods of 72 hours. Although the storage conditions must be followed precisely, the method is nevertheless simple to perform and does not require specialized expensive equipment. Critical factors include: 1) preparation of the platelet concentrates with an initial centrifugation of 1000 × g for 9 minutes and a second centrifugation of 3000 × g for 20 minutes (86%+/− 1 platelet yield), 2) a storage bag composed of either Fenwal's PL-146 or McGaw plastic, 3) constant gentle mixing, 4) a 70 ml residual plasma volume, and 5) room temperature storage (22 C +/− 2). In Vivo platelet recovery after 72 hours of storage at room temperature averaged 46 per cent +/− 3 and survival was 7.9 days +/− 0.3 (81% of fresh platelet viability). The function of these platelets as measured by the correlation between bleeding time and platelet count after transfusion of pooled platelets into unimmunized, aplastic thrombocytopenic recipients was as good as that of fresh platelets. Both viability and function of concentrated platelets stored at 4 C are severely compromised.     

In vitro characteristics and in vivo viability of platelets contained in granulocyte-platelet apheresis concentrate

A paired prospective study was performed to compare the in vitro storage characteristics and in vivo kinetics of platelets stored in granulocyte-platelet concentrates prepared by apheresis with platelets prepared from whole blood. Platelet and granulocyte-platelet concentrates were collected from five healthy volunteer autologous donors and stored for 16 to 18 hours at 20 to 24 degrees C with and without agitation, respectively. After storage, pH, platelet count, percent release of beta-thromboglobulin, morphologic score, and percent osmotic recovery were measured. In addition, the granulocyte-platelet concentrates were assayed for total leukocyte count, release of lysozyme, and by several in vitro tests of granulocyte function. The platelets in both products were labeled with 111In oxine and infused into the donors. The pH of both products was above 6.0 at the end of storage. The units stored as platelet concentrates compared with those stored as granulocyte-platelet concentrates showed a higher percent release of beta-thromboglobulin, 18.4 +/- 4.0 percent versus 5.9 +/- 3.2 percent (mean +/- SD), but significantly better morphologic scores, 676 +/- 21 versus 525 +/- 56, and better osmotic recovery scores, 72 +/- 10 percent versus 40 +/- 7 percent, respectively (all p less than 0.05). The platelet concentrates (compared with the granulocyte-platelet product) had significantly better in vivo recovery, 49.5 +/- 15.8 percent versus 38.9 +/- 11.5 percent, and survival, 6.1 +/- 1.3 days versus 2.4 +/- 0.4 days, respectively (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Reduction of the volume of stored platelet concentrates for use in neonatal patients

Premature infants and neonatal patients who require platelet transfusions may develop circulatory overload when administered a 50-ml unit of platelet concentrate. We evaluated the influence of centrifugation and resuspension steps used to reduce the volume of stored platelet concentrates on platelet properties by in vitro methods and by determining post-transfusion increments in neonatal patients. In vitro studies were conducted with platelet concentrates stored at 20 to 24 degrees C for 1 and 5 days in CLX (Cutter) and PL732 (Fenwal) containers and for 1 and 2 days in PL146 containers (Fenwal). With platelets stored in any of the three containers, platelet morphology, mean platelet volume, hypotonic stress response, synergistic aggregation, and platelet factor 3 activity were not affected by the processing steps. The centrifugation and resuspension steps did not cause an enhanced discharge of lactate dehydrogenase from platelets. Similar results were obtained when the platelet concentrates were stored on either a flatbed or an end-over-end tumbler agitator. The in vitro platelet recovery following volume reduction was at least 85 percent. In vivo studies were conducted with platelets stored in the PL732 and PL146 containers. Infusion of platelet concentrates after volume reduction produced a mean corrected increment of 18,947 +/− 14,824 when platelets were stored in the PL146 container and 16,178 +/− 15,699 when platelets were stored in the PL732 container. These results indicate that the volume of stored platelet concentrates can be reduced in a manner which maintains platelet properties.     

Extension of platelet concentrate storage

Extension of the storage time of platelet concentrates in a satellite bag which is part of a new blood bag system was studied by reinfusing autologous 51Cr-labeled platelets into normal volunteers, and measuring postinfusion platelet counts and bleeding times in patients requiring platelet transfusions. This satellite bag, made of polyvinylchloride plasticized with a new agent, was found to protect platelet concentrates against fall of pH better than other containers studied. This protection was felt to be due to the greater gas permeability of the new plastic. Mean in vivo recovery and half-life (greater than 31% and 3.3 days, respectively) of autologous reinfused platelets were satisfactory following 5 days of storage. Following 7 days of storage, mean recovery was 41 percent and half-life was 2.8 days. Peripheral platelet count increments in patients following platelet transfusions with concentrates stored 4 to 7 days in the new plastic were comparable to increments following transfusion of platelets stored 2 to 3 days in the other plastics studied. Bleeding times shortened in three of four patients receiving platelet concentrates stored from 4 to 6 days in the new plastic. Platelet concentrates stored in the new bag at 20 to 24 degrees C with flat-bed or elliptical agitation could be transfused for up to 5 days following phlebotomy with acceptable clinical results. The new plastic container is promising for storage of platelet concentrates for up to 7 days. Due to the higher pH of 50-ml platelet concentrates stored in bags made with the new plastic, the concentrates were superior at any storage interval to those stored in bags made of the other plastics studied.     

Improvement of platelet storage conditions by using new polyolefin containers

BACKGROUND : Storage of pooled platelet concentrates (PCs) with yields above 3.0 × 10¹¹ platelets per unit in a 1-L PL-732 polyolefin container for 5 days often results in a drop in pH to below 6.0. Recently, new oxygen-permeable platelet containers (1-L PL-2410, 1-L and 1.5-L Compoflex) have been developed. The maximal platelet storage capacities of the new containers and the PL-732 were compared. STUDY DESIGN AND METHODS : Large platelet pools (n = 27) with platelet concentrations between 1.2 and 1.4 × 10¹¹ per L were made from 3 to 5 PCs prepared from buffy coats. The pools were divided in equal volumes among the PL-732 and the three new platelet containers. Platelet counts in the PCs ranged from 1.0 to 5.0 × 10¹¹ per unit. All PCs were stored on a flatbed shaker at 22 ± 2°C and evaluated on Days 1, 3, 5, and 7 by measuring platelet count, pH, pO₂, pCO₂, HCO₃-, glucose, lactate, platelet swirling, and soluble p-selectin. RESULTS : Day 7 storage of PCs (n = 6) with yields between 3.0 and 4.0 × 10¹¹ platelets in PL-732 showed mean ± SD pH values of 5.93 ± 0.05 and lactate values of 32.3 ± 7.9 mmol per L; in 4 of these 6 PCs, pH was below 6.0. In contrast, storage of these PCs in 1-L PL-2410 and 1.5-L Compoflex containers and of 2 of these 6 PCs in 1-L Compoflex containers showed pH values above 6.8. Lactate values were 15.5 ± 1.3, 15.3 ± 1.8, and 19.5 ± 4.7 mmol per L, respectively (p < 0.001 vs. PL-732). The platelet storage capacity of the new containers with platelet yields between 4.0 and 5.0 × 10¹¹ per unit (n = 6) was evaluated. Day 7 storage of these PCs in the 1.5-L Compoflex showed an average pH value of 6.74 ± 0.20; in 2 of 6 PCs, pH was below 6.8. The average pH value in the PL-2410 was 6.38 ± 0.31, and in all PCs, pH was below 6.8. Average lactate values were 17.8 ± 5.7 and 25.8 ± 5.6 mmol per L (p < 0.05), respectively. Soluble p-selectin values on Day 7 of storage increased approximately twofold in all PCs. CONCLUSION : The new oxygen-permeable containers showed platelet quality comparable to that with the PL-732 and for longer storage periods and at higher platelet counts.     

Storage of human platelet concentrates in an artificial medium without dextrose

It was shown previously that human blood platelets stored in an artificial medium (PCD) for up to 5 days remain functional in vitro and have normal survival and recovery in vivo. This report demonstrates that the medium can be simplified further by the removal of dextrose, leaving for study a medium consisting simply of balanced salts and citrate anticoagulant (PC). Some dextrose, 3.2 mM, was present in the fresh PC platelet concentrates due to plasma carryover in the production of platelet concentrates, but this dextrose concentration was considerably less than the 22.6 to 25.5 mM present in platelet concentrates in PCD or plasma. Platelet count, pH, PCO2, and PO2, as well as platelet aggregation and release responses to stimulation, in vitro, were as well preserved in the PCD or PC media as in the plasma controls. In the PC medium, platelets consumed 2.5 mM dextrose over 5 days and left 0.7 mM dextrose. The same consumption of dextrose was noted in PCD platelet concentrates, while platelets in plasma metabolized twice as much dextrose and formed twice as much lactate. Thus, the rate of glycolysis in platelet concentrates was independent of the dextrose concentration in the medium, and the platelet functions were well preserved.