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.     

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.     

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.     

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.     

Collection of platelets with a new cell separator and their storage in a citrate-plasticized container

A new apheresis device using microprocessor control for the collection of a high-purity single-donor platelet concentrate was evaluated, as was the storage of platelets for up to 5 days in a citrate-plasticized polyvinylchloride blood bag. The study was conducted in three phases: collection of platelets for in vitro studies and determination of donor safety; autologous transfusion of platelets in healthy volunteers; and transfusion of platelets in patients requiring platelet transfusion therapy. Donors had mild hypocalcemia and minimal changes in blood counts except for a platelet count reduction from 288 +/- 50 x 10(3) (288 +/- 50 x 10(9)/L) to 217 +/- 43 x 10(3) per microL (217 +/- 43 x 10(9)/L). A mean of 3.36 +/- 1.24 x 10(11) platelets was collected in the mean volume of 214 mL with red cell and white cell contamination in the range of 10(7). Morphology and aggregation were as described previously in stored platelets. Platelet survival data in eight subjects showed a mean recovery of 61 +/- 11 percent and mean survival of 5.03 +/- 1.07 days by a weighted-mean model. Patients transfused with platelets had mean increments of 23,000 immediately and of 8000 at 24 hours; corrected count increments were 6000 at 1 hour and 4000 at 24 hours. The platelets were successful in providing hemostasis to these patients. Clinically useful 5-day-stored platelets are obtained by using this apheresis technology with a functionally closed system and a citrate-plasticized blood bag.     

The effects of irradiation on platelet function

Current medical practice involves the irradiation of blood components, including platelet concentrates, before their administration to patients with severe immunosuppression. The authors studied the effect of irradiation on in vitro platelet function and the leaching of plasticizers from the bag, both immediately and after 5 days of storage. The platelet count, white cell count, pH, glucose, lactate, platelet aggregation and release reaction, and serotonin uptake were not altered by the irradiation of random-donor or apheresis units with 2000 rads carried out at 0 and 24 hours and 5 days after collection. The leaching of di(2-ethylhexyl)phthalate from the plastic bags followed by the conversion to mono(2-ethylhexyl)phthalate was not increased by irradiation. Therefore, it is possible to irradiate platelet concentrates on the day of collection and subsequently store them for at least 5 days while maintaining in vitro function. This procedure could have considerable benefit for blood banks involved in the provision of many platelet products.     

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.     

Platelet storage for 7 days in second-generation blood bags

Plastic storage bags designed to optimize O2 and CO2 transfer to preserve platelets for 7 days prior to transfusion were studied in vivo and in vitro. Platelets stored 7 days in second-generation CLX bags were compared to platelets stored 3 days in standard (CL-3861) 3-day storage bags and platelets transfused within 24 hours of collection. The CLX bags maintained concentrate pH at a mean of 6.85 +/- 0.03 (SEM) after 7 days, while in standard bags after 3 days of storage, the mean pH was 6.46 +/- 0.03. A smaller proportion of platelets stored 7 days in CLX bags were discarded because of a pH less than 6.0 compared to those stored 3 days in CL-3861 bags (10 vs 21%). Poststorage pH showed strong correlation with concentrate platelet count and weak correlation with concentrate white cell count in both bag types. There was no significant difference in the mean corrected platelet count increments between platelets stored 7 days in second generation CLX bags and those stored 3 days in CL-3861 bags (10,000 and 12,200 at 1 hour, and 7000 and 7500 at 24 hours, respectively) following transfusion to 16 thrombocytopenic recipients. However, transfusion of fresh platelets achieved mean corrected increments at both 1 and 24 hours posttransfusion that were higher than seen with either group of stored platelets (20,100 at 1 hour and 10,800 at 24 hours). Platelets can be stored 7 days in second-generation CLX blood bags with results comparable to those of platelets stored 3 days in standard bags.     

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.     

Transfusion experience with platelet concentrates stored for 24 to 72 hours at 22 degrees C. Importance of storage time

We studied the transfusion response from random donor platelet concentrates in 15 stable multitransfused, thrombocytopenic patients by comparing the platelet counts measured before and 20 hours after transfusion. The observed platelet increments were corrected (corrected increment, C.I.) for the number of units of platelet concentrate transfused and the patient's body surface area in square meters (platelets/microliter per unit/m2). Using platelet concentrates stored for less than 24 hours, the patients achieved a median C.I. of 9500 (range: 5000–18,000). When platelet concentrates stored for 24 to 48 hours or 48 to 72 hours were given, the median C.I. markedly decreased to 1000 (range: 0–4800) and 0 (range: 0–5100), respectively (p less than 0.001). These differences could not be explained by further recipient alloimmunization. Transfusion with platelet concentrates less than 24 hours old on a second occasion, bracketing the transfusions of older platelet concentrates, resulted in a median C.I. of 7200 (range: 5400–14,500). Similar results were obtained in three patients when HLA- identical sibling platelet concentrates were employed. In vitro tests, including pH, morphology, and aggregation, demonstrated no statistically significant differences among the platelet concentrates stored for less than 24 hours, 24 to 48 hours, and 48 to 72 hours. These studies suggest that, although platelet concentrates can be stored for 72 hours without loss of in vitro function, the in vivo recovery is significantly diminished after 24 hours of storage, and preferably patients should not be transfused prophylactically with platelet concentrates greater than 24 hours old.     

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.     

The effect of mode of agitation and type of plastic bag on storage characteristics and in vivo kinetics of platelet concentrates

We studied the characteristics of platelet concentrates stored for 5 days at 22 degrees C. Platelets were prepared in three plastic bags (PL 732, PL 1240, and CLX) and stored on one of four platelet agitators, 1- or 6-rpm elliptical and 2- or 6-rpm circular rotators. A total of 76 studies were divided among 12 groups, each group being composed of a different storage bag-rotator combination. In vivo recovery and survival were calculated using Indium-111 oxine-labeled platelets injected into autologous volunteers. Platelet recovery was assessed at 2 hours postinjection or as the y-intercept of the multiple-hit model survival curve. Survival was calculated using linear, exponential, and multiple-hit computer models. Linear T 1/2 also was calculated as an index of platelet survival. At 5 days, the pH of all concentrates was above pH 7.0 and platelet counts were above 5.5 X 10(10) per bag except for the PL 732 with the 6-rpm elliptical rotator, which was 4.6 X 10(10) per bag. This combination also showed a significantly higher poststorage lactic dehydrogenase (LDH) discharge compared to the mean of the other 11 groups (23.6 +/- 5.4% vs. 10.4 +/- 3.0%, p less than 0.05); however, the beta-thromboglobulin (beta-TG) release was not statistically different.(ABSTRACT TRUNCATED AT 250 WORDS)     

Circulation and function of human platelets isolated from units of CPDA- 1, CPDA-2, and CPDA-3 anticoagulated blood and frozen with DMSO

Platelet concentrates (PC) were isolated by serial differential centrifugation from units of blood anticoagulated with one of the citrate-phosphate-dextrose-adenine solutions (CPDA-1, CPDA-2, CPDA-2). The platelet concentrates were frozen with six percent dimethylsulfoxide at 2–3 degrees C per minute and stored in a -80 degrees C mechanical freezer in polyvinyl chloride or polyolefin plastic containers. After frozen storage at -80 degrees C for up to three months, the concentrates were thawed at 42 degrees C within 2.5 to 4.0 minutes, washed with autologous plasma, two percent dimethylsulfoxide and 10 percent acid-citrate-dextrose solution, and then resuspended in plasma. The washed platelets were labeled with 51Cr and transfused back to the donor from whom they had been obtained. In vitro recovery from whole blood to platelet concentrate was 70.5 ± 17 percent (mean ± one SD). In vitro freeze-thaw-wash recovery determined by phase microscopy was 78.5 ± 12.8 percent, in vivo 51Cr platelet recovery two hours after transfusion was 41.3 ± 13.5 percent, and the platelets had a linear lifespan of about eight days. A single unit of previously frozen platelets shortened an aspirin- prolonged bleeding time two and 24 hours after infusion. Results were similar with platelets isolated from all three anticoagulants and stored in both plastics. The results also were comparable to previous findings in this laboratory with platelets isolated from ACD and CPD anticoagulated blood.     

Evaluation of apheresis platelet concentrates stored for 5 days in PL 732 bags

To assess the functional viability of platelets collected by standard apheresis techniques using the Fenwal CS-3000 "closed system" and stored in Fenwal PL 732 plastic bags for 5 days at room temperature with agitation, a number of in vitro parameters (pH, morphology, platelet volume distribution, osmotic recovery, aggregation, and platelet-associated IgG) were examined as a function of storage time. During the first 24 hours of storage, minimal changes were observed in the test parameters with the exception of ADP-induced aggregation (75% decrease [10 uM], 84% decrease [5 microM]). Significant differences were observed between fresh (day 0) and 5-day-old platelet concentrates in all parameters except median platelet volume. These observed changes in in vitro test parameters with storage time are similar to those previously observed for comparably stored random single-donor platelet concentrates. Thus, the "closed-system" PL 732 apheresis platelet concentrates would be expected to be as effective in vivo as random single-donor platelet concentrates, while minimizing recipient exposure to transmissible agents of infectious disease.     

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)     

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.     

Platelet storage in Fresenius/NPBI polyolefin and BTHC-PVC bags: a direct comparison

SUMMARY: New platelet storage systems, such as changes in the plastic of the storage bags, require validation. In this study, pooled buffy coat platelets stored in Fresenius/NPBI polyolefin bags were compared with those stored in Fresenius/NPBI butyryl-trihexyl citrate (BTHC) plasticized polyvinyl chloride (PVC). The CompoSelect thrombocyte polishing filter system (1000 mL polyolefin bag) and the CompoStop F730 system (1300 mL BTHC-PVC bag) were used to prepare paired, plasma-suspended, buffy coat platelet concentrates. Samples were taken up to day 7 for in vitro analysis. In a separate experiment, 12 units were prepared using the CompoStop F730 system and samples taken after leucofiltration for FXIIa assay. By day 7, platelet concentrates stored in BTHC-PVC demonstrated significantly higher pH levels (7.32 +/- 0.05 vs. 7.26 +/- 0.05) and a greater degree of cell lysis as shown by increased lactate dehydrogenase levels (497 +/- 107 vs. 392 +/- 81 U L(-1)). The supernatants contained higher concentrations of soluble P-selectin and the chemokine 'regulated on activation, normal T-cell expressed and presumably secreted', which are released from the alpha-granules during activation. The ATP concentrations were significantly lower in BTHC-PVC. Platelet counts, mean platelet volume and hypotonic shock response were similar for both bags. FXIIa antigen concentrations were 0.6 +/- 0.2 ng mL(-1) indicating that activation of the contact factor pathway had not occurred. Although the CompoStop F730 leucoreduction filter did not activate the contact system, platelets stored in 100% plasma in BTHC-PVC bags demonstrated different in vitro characteristics from those stored in polyolefin. Further work is required to demonstrate whether these differences will affect in vivo recovery and survival.     

Storage of pooled platelet concentrates. In vitro and in vivo analysis

The use of sterile connecting devices will permit up to 5-day storage of pooled platelet concentrates (PCs). However, there are no data evaluating long-term storage of PCs pooled from multiple donors. Four units of ABO-compatible or -incompatible PCs were pooled and stored in single 300-ml PL-732 storage bags for up to 5 days. Results of in vitro assays showed acceptable storage values regardless of the ABO types in the pool. Pool pH on Day 5 was 6.83 +/- 0.3 (mean +/- 1 SD). The in vitro storage characteristics were comparable to those of unpooled age-matched platelets reported previously from our laboratory. For in vivo studies, 4-unit pools of ABO-compatible random-donor PCs stored for up to 96 hours in 1000-ml PL-732 bags were transfused into patients who were thrombocytopenic due to bone marrow failure, and the correct count increments (CCI) were determined. In vivo results showed a mean 1-hour CCI of 11,368 +/- 5824 for the pooled stored platelets and 7819 +/- 5189 for unpooled controls (p greater than 0.05). To evaluate the possibility that passenger lymphocytes in the concentrates would generate mixed lymphocyte reactions (MLR) in the pooling bag during storage, lymphocytes were studied over 5 days of storage by the use of monoclonal antibodies against activated T-cell markers and by 3H thymidine uptake. Results failed to show evidence of either the generation of activated T-cell markers or the uptake of 3H thymidine.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Therapeutic efficacy of platelet transfusion in patients with acute leukemia: an evaluation of methods

BACKGROUND: Clinical effect of platelet (PLT) transfusion is monitored by measures of PLT viability (PLT recovery and survival) and functionality. In this study we evaluate and compare transfusion effect measures in patients with chemotherapy‐induced thrombocytopenia due to treatment of acute leukemia. STUDY DESIGN AND METHODS: Forty transfusions (28 conventional gamma‐irradiated and 12 pathogen‐inactivated photochemical‐treated PLT concentrates [PCs]) were investigated. PC quality was analyzed immediately before transfusion. Samples were collected from thrombocytopenic patients at 1 and 24 hours for PLT increments and thromboelastography (TEG) with assessments of bleeding score and intertransfusion interval (ITI). Data were analyzed by Spearman's correlation. Patient and PC variables influencing the effect of transfusion were analyzed by use of a mixed‐effects model. RESULTS: PLT dose, storage time, and pathogen inactivation correlated with PLT recovery but not with PLT survival (including ITI), TEG, or clinical bleeding. Fever was negatively correlated with PLT survival but did not affect PLT recovery. After 1 and 24 hours, strong correlations were observed within measures of PLT viability and between PLT increment and the TEG value maximal amplitude (MA). Negative correlation was observed between late MA increment and clinical bleeding status after transfusion (r = ?0.494, p = 0.008). PLT count increments did not correlate to clinical bleeding status. CONCLUSIONS: PLT dose and quality of PCs are important for optimal immediate transfusion response, whereas duration of transfusion effect is influenced mainly by patient variables. The TEG value MA correlates with PLT count increments and bleeding, thus reflecting both PLT viability and functionality.