J. de Wildt-Eggen

Reactions and platelet increments after transfusion of platelet concentrates in plasma or an additive solution: a prospective, randomized study.

BACKGROUND: Reactions after platelet transfusions are rather common and frequently are caused by plasma constituents. In recent developments, the preparation and storage of platelet concentrates (PCs) in a platelet additive solution (PAS‐2) have been shown to result in acceptable storage conditions. A major drawback of the use of these PCs is the progressive increase of P‐selectin‐positive platelets during storage. The clinical benefit of transfusions of PCs in PAS‐2 was studied.

Storage of platelets in additive solutions: a multicentre study of the in vitro effects of potassium and magnesium

Background and Objectives  In a preliminary study, the presence of potassium and magnesium in a modified synthetic medium (PAS‐III) was found to have a significant influence on platelet metabolism (using apheresis‐derived, as well as buffy‐coat‐derived platelets) when compared with standard PAS‐III. The differences included reduced glycolysis, as evidenced by lower consumption of glucose and lower production of lactate, but also better preservation of pH and hypotonic shock response reactivity. The results suggested that storage in modified PAS‐III containing 20% plasma was comparable to storage in standard PAS‐III containing 30% plasma. To confirm the preliminary results and to evaluate the effects of different preparation protocols, an international multicentre study, which included 11 different sites, was conducted.

In vitro comparison of platelet storage in plasma and in four platelet additive solutions, and the effect of pathogen reduction: a proposal for an in vitro rating system.

Background  The introduction of platelet (PLT) additive solutions (PASs) and pathogen reduction (PR) technologies possibly allow extension of PLT shelf life. It was our aim to compare in vitro quality of leucocyte‐reduced PLT concentrates (PCs) stored in various PASs, including PR, with those in plasma during 8 days of storage. The study was performed in four blood centres where each tested four conditions.

Reducing the Variation in Performance of Antibody Titrations

Background  Antibody titration is difficult to standardize. We investigated whether a detailed, uniform procedure for antibody titration would reduce variation in both tube‐based and gel card titres in an international study.

Platelets stored in a new-generation container differences between plasma and platelet additive solution II.

Background and Objectives: In order to preserve platelet concentrates (PCs) with high yields, a new polyolefin platelet storage container (PL 2410, 1.3L, Baxter, La Châtre, France) with increased gas permeability in combination with a larger surface area has been developed. The storage capacity was studied with platelets in plasma and platelets additive solution. Materials and Methods: Platelet concentrate pools (PCs) of different yields suspended in either plasma (PCs-PL; n = 30) or PAS II (PCs-PAS; n = 37) were prepared. For preparation of PCs with a low, intermediate and high number of platelets 3, 5 and 6 buffy coat (BCs) were pooled with different volumes of plasma and 5 and 6 BCs were pooled with different volumes of PAS II, in order to obtain PCs of equal volumes comparable with routine conditions. All PCs were stored on a flatbed shaker at 22±2 °C and evaluated on days 1, 2, 5 and 7 by determining platelet and white cell counts, pH (37 °C), pO2, pCO2 and swirling score. Results: Platelet yields ranged from 1.5 up to 5.5 × 1011 platelets/U. On day 7 all PCs-PL (n = 4) with platelet yields above 4.5 × 1011/U had a pH value below 6.8 (range 5.91–6.79). While 7 of 8 PCs-PAS units with platelet yields above 4.0 × 1011/U showed a pH value below 6.8 (range 6.31–6.70). Conclusion: During 7 days of storage in a new 1.3-liter platelet container, the pH was maintained above 6.8 in PCs in plasma with a yield between 1.5- and 4.5 × 1011/U; when PAS II was used, the maximum platelet yield allowed for comparable pH maintenance was somewhat lower (4.0 × 1011/U).

Interruption of agitation of platelet concentrates: effects on in vitro parameters

Background and Objectives  When platelet concentrates (PCs) are shipped from one centre to another, they may remain unagitated for a considerable period of time. It was therefore our aim to study the effects of interruption of agitation on the in vitro parameters of PCs stored in platelet additive solutions.

In vivo and in vitro comparison of platelets stored in either synthetic media or plasma

Since 1980, several synthetic media have been developed for the storage of platelets for transfusion. At present, platelets suspended in approximately 70% synthetic medium and 30% plasma can be stored for at least 5 days at very stable pH levels, generally pH 6·8–7·2. Present knowledge suggests that synthetic media should contain at least acetate, citrate, phosphate, potassium and magnesium. Future studies will probably result in the inclusion of other components to this list. Glucose for platelet metabolism will generally be supplied by carryover of plasma from the original platelet preparation. In addition, improved plastic containers for the storage of platelets will probably facilitate the introduction of new synthetic media. In six studies comparing synthetic media with plasma as the storage environment, and involving patients with intensive chemotherapy for haematological malignancies, the clinical outcome in terms of corrected count increments (CCI) generally indicated similar results. Three studies suggested significant reduction of the incidence of transfusion reactions of platelets suspended in synthetic media as compared with plasma. For future comparisons of platelet storage in either plasma or new synthetic media, additional platelet survival and recovery studies, as well as patient‐transfusion studies, will be needed as in vitro data may not always reflect the clinical outcome. This will add further knowledge to data from the present few clinical studies available that compare storage of platelets in either synthetic media or plasma.

Coagulation factor content of plasma produced from whole blood stored for 24 hours at ambient temperature: results from an international multicenter BEST Collaborative study

BACKGROUND: There is increasing international interest in producing components from blood that has been stored at room temperature for 24 hours. The lack of comprehensive data on the quality of plasma produced from blood stored in this way led to this international study.

Platelet concentrates from fresh or overnight‐stored blood, an international study

BACKGROUND: Whole blood and also buffy coats (BCs) can be held for a few hours or overnight before processing into blood components or platelet concentrates (PCs). Individual studies have reported a range of outcomes regarding in vitro variables for PCs prepared from fresh and stored whole blood. In this multicenter study, effects of storage of whole blood or BCs on the in vitro quality of PCs were studied.

Evaluation of Storage Conditions of Platelet Concentrates Prepared from Pooled Buffy Coats

Five days storage of pooled platelet concentrates (PCs) with high yields often results in a pH fall and poor platelet morphology despite the use of specific containers. In this study we evaluated two techniques for prolonged storage of PCs with high platelet counts, by measuring pH and platelet swirl. In routine procedures, 90 PCs, prepared from five buffy coats, were stored in a single 1‐litre PL 732 container. After 5 days storage, 51 PCs with platelet counts below 3.1 times 1011/U showed a pH above 6.8 and optimal swirling scores. 29 of 39 PCs (74%) with yields above 3.1 times 1011/U showed pH values below 6.8 and poor swirling scores. These poor results can be prevented by shortening the duration of storage. PCs with high yields can be stored for 5 days either by dividing the concentrate into two containers or by adjusting the platelet count to 3.1 times 1011/U. In the latter procedure, we reduced the volume of the concentrate and found that of 102 PCs, only 9 showed poor values for pH and platelet swirl. The data clearly indicate the importance of measuring the prestorage platelet count to select the optimal procedure for concentrate storage.