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.     

Accumulation of DI-2-Ethylhexyl Phthalate (DEHP) in Whole Blood, Platelet Concentrates, and Platelet-Poor Plasma

The concentration of the plasticizer, di-2-ethylhexyl phthalate (DEHP), in the plasma was measured after storage of the whole blood in polyvinylchloride plastic bags at 4 C for up to 38 days in either ACD or CPD. The plasma from ACD-stored whole blood contained more DEHP than that from CPD-stored whole blood. The continuous-flow centrifugation washing procedures removed about 98 per cent of the DEHP from ACD whole blood stored for 33 days at 4 C.
DEHP was assayed in the platelet-rich plasma, platelet-poor plasma, supernatant of the platelet concentrate, washed platelets, and washed red blood cells prepared from CPD whole blood. Very little DEHP was found in the washed red blood cells and platelets, a small amount was found in the platelet-poor plasma, and a large amount in the supernatant of the platelet concentrate. A greater amount of DEHP accumulated in the platelet concentrates that were stored at 22 C than in those stored at 4 C. When platelet concentrates from CPD whole blood were stored at 22 C for 72 hours, the amount of DEHP was about four times that observed after 4 C storage for the same length of time.     

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.     

Five-day storage of platelets in a non-diethylhexyl phthalate- plasticized container

A non-diethylhexyl phthalate (DEHP)-plasticized blood bag for 5-day storage of random-donor platelet concentrates has been developed. The plastic bag is composed of polyvinylchloride plastic with a butyryl trihexyl citrate plasticizer. The suitability of this plastic for the storage of platelet concentrates for use in clinical transfusion practice was evaluated. In vitro storage studies showed no significant differences at Day 5 for a series of in vitro assays (test plastic vs. control plastic) including pH (7.31 vs. 7.44), lactate dehydrogenase discharge (21.8 vs. 17.1%), pO2 (103 vs. 120 torr), osmotic recovery (52 vs. 57%), and morphology score (527 vs. 516). For paired radiolabeled recovery and survival data from autologous blood donors, results showed equivalence between the test plastic and two control plastics. A small but significant difference between test and control plastics in regard to survival was found by using a linear computer model, but not with a gamma function (multiple-hit) model. For paired transfusions to thrombocytopenic patients, the corrected count increments at 1 to 4 hours (test vs. control) were 13,534 versus 15,494 (p > 0.05, NS). Similar results were seen for corrected count increments determined at 12 to 24 hours. It can be concluded that platelets stored in the test plastic are acceptable for use in clinical practice.     

An in vivo comparison of CPD and CPDA-2 preserved platelet concentrates after an 8-hour preprocess hold of whole blood

To see if citrate-phosphate-dextrose-adenine-two (CPDA-2) anticoagulant- preservative had an effect on the viability of platelets, we studied autologous in vivo recovery and survival in humans for platelet concentrates prepared from six units of blood drawn into CPDA-2 and compared them to six units drawn into citrate-phosphate-dextrose (CPD). These units were prepared from whole blood held at room temperature for 8 hours after collection and were then stored for 3 days at 22 ± 2 degrees C. The recovery for platelets preserved in CPD was 39.0 +/0 4.8 percent and for platelets preserved in CPDA-2, 32.5 ± 4.4 percent. The difference was not significant (p greater than 0.10). In order to estimate population differences, in vitro effects on in vivo viability were also evaluated. Six in vitro variables were studied but only pH at 72 hours (r = 0.77), platelet count (r = 0.64), and morphology score (r = 0.66) correlated to recovery. Only pH at 72 hours significantly influenced recovery (p = 0.007). By adjusting for individual pH differences, mean recovery for platelets stored in CPD was 37.5 percent, and for platelets stored in CPDA-2, 34.0 percent. The mean lifespan was 6.7 ± 0.7 days for platelets preserved in CPD and 6.1 ± 1.0 days for those preserved in CPDA-2. Although hemostatic function was not studied, these data support in vitro observations that platelets preserved with CPDA-2 are not different from platelets preserved with CPD, even after 8-hours of storage of whole blood at room temperature prior to platelet concentrate preparation.     

A feasibility evaluation of an automated bloodcomponent collection system platelets and red cells

BACKGROUND: The purpose of these studies was to evaluate the functional properties of blood components collected with an automated collection system. STUDY DESIGN AND METHODS: Single-donor platelets (n = 44) and packed red cell (RBC) units (n = 10) were collected. In vitro and in vivo assays were used to assess the function of single-donor platelet components stored for 5 days and of packed RBC units after storage for 42 days at 4 degrees C. RESULTS: Adverse events observed in the 44 study subjects were minor. The mean 24-hour recovery value for the packed RBC units stored for 42 days was 83.6 +/- 5.4 percent, with a mean percentage of hemolysis on Day 42 at 0.46 +/- 0.19 percent. The 25 patients receiving platelet components achieved a mean corrected count increment of 15.1 +/- 10.4 x 10(3). All platelet concentrates had less than 1 x 10(6) total white cells. CONCLUSION: Both in vitro and in vivo testing for the packed RBCs collected and stored for 42 days met the standards for both hemolysis and percentage of 51Cr 24-hour RBC recovery. The in vitro results and transfusion data on white cell-reduced platelet components transfused to thrombocytopenic patients were comparable to those on available platelet components.     

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.     

Comparison of two platelet additive solutions

The use of an additive solution for substitution of plasma for storage of leukodepleted platelet concentrates can have many advantages. In this study, a comparison was made between two platelet additive solutions: one containing citrate and acetate (PAS-II), the other also supplemented with additional salts such as magnesium, and with gluconate (Composol-PS). Donor-dependent differences were avoided by applying a paired experimental design (n = 10). The platelet concentrates were prepared by pooling five buffy coats and the additive solution, and prestorage filtration was utilized to remove leucocytes to well below 1 x 106. Storage of platelet concentrates up to 9 days after blood collection revealed that platelet concentrates in Composol-PS maintained an almost constant pH of on average 6.93 from day 2 through day 7, and at 6.90 at day 9. This was in contrast to PAS-II, which showed a gradually decreasing pH from on average 6.97 at day 1 to 6.86 at day 9. In all units stored in both solutions the swirling effect was present during 9 days of storage. In conclusion, both additive solutions allow storage of platelets, derived from pooled buffy coats, for up to 9 days after collection of the whole blood, with maintenance of good quality in vitro. Composol-PS has a slightly better buffering capacity, reflected as a more constant pH throughout the storage period.     

Evaluation of a new, more oxygen-permeable, polyvinylchloride container

A new container made of polyvinylchloride (PVC) with diethylhexyl phthalate (DEHP) used as the plasticizer was subjected to in vitro and in vivo evaluation for prolonged platelet storage. As compared with the original PVC bag, this bag has increased gas permeability by its reduced film thickness, larger surface area (400 ml capacity), and more porous label. The oxygen permeability coefficient, K(O2), of the new container was measured to be 655 nmol per min per atm. On the basis of previous studies relating the K(O2) to the maximal platelet count, it was predicted that this maximal count would be in the range of 7.9 to 8.9 X 10(10) platelets. This prediction was confirmed by carrying out 58 studies measuring pH, pO2, and platelet count on platelet concentrates (PCs) stored for up to 7 days. After 5 days of storage all PCs with counts above 8.0 x 10(10) had pH less than or equal to 7.0, whereas those with counts below 8.0 x 10(10) had pH greater than or equal to 7.0. Six units (10%) with counts above 9.0 X 10(10) had pH levels of 6.5 or below. Thirteen of the PCs underwent extensive in vitro testing of platelet function during 7 days of storage. No significant differences were found in pH, ATP content, and decrease in platelet count, as compared with studies (n = 22) using PCs stored in polyolefin containers.(ABSTRACT TRUNCATED AT 250 WORDS)     

Five-day storage of platelet concentrates

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.     

Impedance aggregometric analysis of platelet function of apheresis platelet concentrates as a function of storage time

Multiple electrode (impedance) aggregometry (MEA) allows reliable monitoring of platelet function in whole blood. The aims of the present study were to implement MEA for analyzing aggregation in platelet concentrates and to correlate results with storage time and blood gas analysis (BGA). We investigated the influence of platelet counts, calcium concentrations and agonists on platelet aggregation. Samples of apheresis concentrates up to an age of 12 days were investigated by MEA and BGA. For ASPI- and TRAPtest MEA was reproducible for a platelet count of 400 per 10^?9?L and a calcium concentration of 5?mmol L^?1. Platelets at the age of 2–4 days yielded steady aggregation. Platelet concentrates exceeding the storage time for transfusion showed steady aggregation up to 10 days, but a significant decline on day 12. Weak correlation was found regarding pCO₂ and MEA as well as regarding glucose concentration and MEA. Our results indicate that MEA is applicable for evaluation of aggregation in stored apheresis concentrates. Prolonged storage seems not to be prejudicial regarding platelet aggregation. Platelet concentrates showed acceptable BGA throughout storage time. Further studies are required to evaluate the application of MEA for quality controls in platelet concentrates.     

The influence of irradiation on stored platelets

Platelet concentrates intended for transfusion to immunosuppressed patients are irradiated to minimize transfusion-induced graft-versus-host disease. Because few reports describe how irradiation influences stored platelets, the authors studied whether 5000 rad of gamma irradiation, the maximum dose currently used clinically, altered platelets in vitro. Platelet concentrates were stored for either 1 day or 5 days in plastic (PL 732) containers before gamma irradiation. One unit of a pair of identical platelet concentrates was irradiated; the second unit served as a control. Irradiation did not alter platelet morphology, mean platelet volume, expression of platelet-factor-3 activity, response to hypotonic stress, extent of discharge of lactate dehydrogenase, release of beta-thromboglobulin, formation of thromboxane B2, nor the ability to undergo synergistic aggregation. The lack of any substantial change was observed whether the platelet concentrates were stored initially for either 1 day or 5 days. These results suggest that stored platelets are not altered deleteriously by irradiation with 5000 rad.     

In vitro changes in platelet function and metabolism following increasing doses of ultraviolet-B irradiation

Ultraviolet-B (UV-B) irradiation of platelet concentrates (PCs) may prevent the development of posttransfusion HLA alloimmunization. This study evaluated the effect of increasing doses of UV-B radiation on stored PCs. Pooled PCs were irradiated at UV-B doses of 600, 2400 or 10,000 mJ per cm2 and stored up to 96 hours under standard blood bank conditions. Compared to nonirradiated room-temperature and 37 degrees C controls, the irradiated units showed no significant changes in platelet count, white cell count, discharge of lactate dehydrogenase, release of beta-thromboglobulin, metabolism of ATP, ADP, ammonia, glutamine, glutamate, hypoxanthine, pCO2, or pO2 at any time of storage following any of the three UV-B doses. However, after a dose of 10,000 mJ per cm2, there were significant decreases in in vitro assays of platelet function-specifically, osmotic recovery and morphology score. Some metabolic systems were also affected by the 10,000 mJ per cm2 radiation dose, as shown by a decline in pH and bicarbonate and an increase in glucose consumption and lactate production (p < 0.05). The changes in these latter assays appeared only after 96 hours of postirradiation storage. Such changes were not seen in either the room- temperature or 37 degrees C control groups. Thus, heat generated during irradiation, per se, did not appear responsible for the observed in vitro changes in platelet function and metabolism. On the basis of the assays analyzed, it is concluded that UV-B irradiation of PCs at doses up to 10,000 mJ per cm2 does not induce significant metabolic or functional derangements following short-term storage (24-48 hours).(ABSTRACT TRUNCATED AT 250 WORDS)     

Phosphatidylserine exposure in platelet concentrates during the storage period: differences between the platelets collected with different cell separators.

BACKGROUND AND OBJECTIVES: Platelet alterations occur during the production and storage of platelet concentrates, the so called "storage lesion". We studied the platelet alterations during the storage period in apheresis concentrates, employing flow cytometry for phosphatidylserine (PS) detection on platelets during the five days of storage. MATERIAL AND METHODS: Twenty-seven single donor platelet concentrates harvested with the Cobe Trima, Baxter Amicus, or Haemonetics MCS+ were analyzed for PS exposure by flow cytometry on the day of production (day 1) and on days 3 and 5 of storage. Furthermore PS expression was analyzed in platelet donors' blood samples withdrawn before plateletpheresis. RESULTS: PS expression on platelets gave the following median values: in blood donors before apheresis it was 1.12% (0.13-1.78) in platelets concentrates on the first day (2 h after apheresis) 2.06% (0.66-15.2), the third day 6.57% (1.98-51.13) and the fifth day 23.04% (3.86-80.23). All differences between median values of PS expression in blood samples before apheresis, and platelets concentrates on days 1, 3 and 5 of storage, are statistically significant. The expression of PS in platelet concentrates was analyzed in relation to the blood cell separator used for the collection procedure and showed the following results: on day 1 the median values of PS in platelet concentrates collected with the three different blood cell separators, Trima, Cobe and MCS, did not show statistically significant differences. On day 3, the platelets concentrates collected with the Trima and with the MCS showed differences that were statistically significant. Those were respectively 10.59% (4.56-51.13) and 3.53% (1.98-12.61), p = 0.005. The PS expression in platelet concentrates collected with the Trima and MCS showed differences that are also statistically significant on day 5 at respectively 32.4% (9.61-80.23) and 8.57% (3.86-48.42), p = 0.005. CONCLUSIONS: PS exposure in platelet concentrates on days 3 and 5 rise to levels that could compromise the quality of the platelet units. Improvements in standardized platelet quality controls, and in platelet collection systems are required to reduce the storage lesions in platelets concentrates.     

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.     

New methods showing in vitro changes of platelets.

INTRODUCTION: In vitro methods for assessing stored platelets are time consuming and variably correlate with in vivo survival. We used the ADVIA 120 and the Thromboelastogram (TEG) to assess changes during storage to determine a correlation of the results with those of other commonly used measures. METHODS: Platelet concentrates were tested at 1 and 5 days of storage. In vitro test included platelet count, aggregation response, the hypotonic shock response (HSR), The Kunicki morphology score (KMS) and platelet activation using CD62. The ADVIA was used to measure the platelet density and the granule content. The TEG measured the kinetics of clot formation. RESULTS: The platelet count and HRS did not change during storage. Aggregation decreased 50% by day 5. The KMS dropped from 307 at day 2-170. The MPC fell below 200g/l. There was slight platelet activation; the rate of clot formation decreased. CONCLUSIONS: Standard measures of in vitro platelet function indicated alterations during storage. A MPC of less than 200 corresponded to a Kunicki morphology score of less than 200. The TEG results correlated will with the KMS. These measurements may prove useful in predicting platelet survival and recovery.     

Use of an electromechanical infusion pump for transfusion of platelet concentrates

To determine whether platelet concentrates can be administered safely through electromechanical infusion devices, we studied stored platelet concentrates passed through one pump system (Abbott). We measured in vitro changes in platelet count and lactic dehydrogenase (LDH) and beta- thromboglobulin (beta-TG) release which occurred after passing the concentrates through the pump system. To compare in vivo survival, five normal volunteers were given an injection of autologous Indium-111- labeled platelet concentrates at two different times, once using platelets which had been passed through the pump system (test group) and once using platelet concentrates which had not (control group). In vitro studies showed no significant changes (p greater than 0.05) in platelet count, or in LDH or beta-TG release after passage through the pump system. In vivo platelet recovery at 2 hours was 39.8 +/− 4.7 percent (mean +/− 1 SD) for the control platelets and 40.7 +/− 9.3 percent for the platelets passed through the pump system (p greater than 0.05; n = 5). There was no significant difference in platelet survival measured in days between the control group and the test group using a linear (8.0 +/− 0.9 vs. 7.2 +/− 0.3), exponential (3.7 +/− 0.7 vs. 3.1 +/− 0.5), or multiple hit (5.4 +/− 2.3 vs. 4.8 +/− 1.0) (p greater than 0.05; n = 5) model. We conclude that this pump system is acceptable for use in clinical practice when control over volume and rate of platelet transfusion is important.     

Platelet viability following storage for 5 days. Influence of holding whole blood for 8 hours at 20 to 24 degrees C before concentrate preparation

Regional blood centers frequently need to hold units of whole blood at 20 to 24 degrees C for several hours after phlebotomy so that sufficient platelet concentrates can be prepared to meet the increasing need. We have evaluated the in vivo viability and in vitro properties of platelets that were prepared from whole blood drawn into citrate- phosphate-dextrose-adenine (CPDA-1) either immediately after phlebotomy or after an 8-hour hold at 20 to 24 degrees C. Platelet concentrates were stored for 5 days at 20 to 24 degrees C in polyolefin containers (PL 732, Fenwal) with end-over-end tumbler agitation. The autologous in vivo recovery (mean +/− SD) and one-half disappearance of 51Cr-labeled platelets prepared immediately after phlebotomy were 44.4 +/− 9.4 percent and 4.0 +/− 0.5 days, respectively. Platelets prepared after the delay of 8 hours showed a recovery of 44.5 +/− 8.4 percent and a one-half disappearance of 4.1 +/− 0.4 days. After 5 days of storage, platelet concentrates showed a mean pH of 7.21 +/− 0.20 when prepared immediately after phlebotomy, and of 7.22 +/− 0.15 when prepared after an 8-hour delay. Mean morphology scores were 280 +/− 33 and 302 +/− 27 for platelets from units prepared immediately after phlebotomy or after a holding period of 8 hours, respectively. Platelets underwent synergistic aggregation after 5 days of storage, independent of the length of time that the units of whole blood were held prior to centrifugation. These studies indicate that platelet concentrates prepared from units of whole blood held initially for 8 hours can be stored for 5 days at 20 to 24 degrees C and survive satisfactorily in vivo and retain in vitro characteristics.     

Di‐2‐ethylhexyl Phthalate, a Plasticizer Contaminant of Platelet Concentrates

Di‐2‐ethylhexyl phthalate (DEHP), a plasticizer used in polyvinyl chloride plastic blood bags, is extracted by human blood during storage at 4 C. The rate of extraction (0.25 mg/100 ml/day) suggested that after only two days of storage, a concentration of 0.5 mg/100 ml might be found in human blood. In contrast to this, five platelet concentrates that were stored at 22 C for two days had a calculated DEHP concentration of approximately 19 mg/100 ml. The concentration of DEHP in platelet‐poor plasma was 16.7 mg/100 ml while the platelets were found to contain 37.7 mg/100 ml packed platelet volume. This result might suggest that platelets can preferentially accumulate DEHP. It is not known if such concentrations of DEHP are injurious to humans who receive platelet transfusions.     

Storage of platelets on flatbed agitators in polyvinyl chloride blood bags plasticized with tri(2-ethylhexyl) trimellitate

Data are presented showing that platelets in polyvinyl chloride blood bags plasticized with tri(2-ethylhexyl) trimellitate can be stored on flatbed agitators (shakers) without the pH falling below 6.0. The lowest pH seen after 7 days of storage in 46 units with platelet yields ranging from 3.6 to 13.3 X 10(10) per unit was 6.43. These bags have a O2 transmission rate of 13.3 mumol per hour per bag. Platelet bags with a O2 transmission rate of 7.9 mumol per hour per bag experience a pH fall after 5 days of storage on the shaker in units whose platelet yield on average exceeds 10 X 10(10). Platelets can be stored on first-generation shakers (70 cycles/min, stroke = 1 inch) without an attempt at manual resuspension of the platelet button. The count after 30 minutes on the shaker averaged 89 +/- 15 percent of the expected count, indicating that resuspension was nearly complete after a relatively short period. Red cells, but not platelets, settled out during storage on the shaker.