Influence of a 12-hour, 22 degrees C holding period for buffy coats on the preparation of platelet concentrates stored in plasma

Comparative analysis of platelet concentrates prepared after two hours and overnight storage of buffy coat at room temperature

INTRODUCTION

The overnight storage of the buffy coat (BC) at room temperature has logistic and operational advantages for the blood centre. The present study aimed to evaluate the impact of an overnight hold (stored) of BC at room temperature in comparison with the 2-hour hold (fresh) of buffy coats on the platelet concentrate (PC) characteristics.

METHODS

A total of 60 BCs were included in the study, 30 PCs (fresh) were prepared after two hours holding time of the BCs and the other 30 PCs (stored) were prepared after the overnight BC storage at room temperature. The primary endpoint of PCs evaluation was the platelet yield, volume, pH, WBC count, RBC count, and platelet swirling in the PC and the secondary endpoints were glucose concentration, lactate, LDH, and sterility of the PCs. All the tests were performed on the day+1 of the blood collection.

RESULTS

There was no difference concerning the volume, RBC count, and swirling between the two groups (P>0.05). The PCs from the fresh BC had higher pH and glucose concentration (P<0.05). On the other hand, the overnight hold of BC produced higher platelet counts, WBC counts, lactate, and LDH levels (P<0.05). All the 60 PCs did not record any bacterial growth on the culture media for the sterility results.

CONCLUSION

The overnight hold of BC produces a higher platelet yield with higher storage lesions. This may also allow better supervision, ensuring better quality control.

Storage of platelet concentrates from pooled buffy coats made of fresh and overnight-stored whole blood processed on the novel Atreus 2C+ system: in vitro study

BACKGROUND

The Atreus 2C+ system (Gambro BCT) automatically separates whole blood (WB) into buffy coat (BC), red blood cells (RBC), and plasma and transfers the components into separate containers. After processing with the Atreus, 4 to 6 BC units can be pooled and processed into leukoreduced platelets (PLTs) by use of the automated OrbiSac BC system (Gambro BCT). The aim of our in vitro study was to investigate the effects of holding either WB or BC overnight before preparation of PLTs by use of the Atreus 2C+ system for BC preparation. A standard routine procedure involving conventional blood containers for the preparation of BC combined with the OrbiSac process (top-and-top system; Terumo) was used as a reference.

STUDY DESIGN AND METHODS

WB was either processed within 8 hours after collection ("fresh blood") or stored overnight before processing. WB units were separated into BC, RBC, and plasma units and transferred into individual containers. Either the BC or the WB units rested overnight at 22 +/- 2 degrees C. Six ABO-identical BCs, obtained from either fresh or overnight-stored WB, were pooled and processed with the OrbiSac BC system to obtain leukoreduced PLTs. In total, 20 Atreus and 10 reference (leukoreduced PLTs) samples were analyzed for various in vitro variables during the 7-day storage period.

RESULTS

No significant difference in glucose consumption, lactate production, mean PLT volume, LDH activity, bicarbonate, ATP, RANTES, and the expression of CD62p and CD42b between groups was detected. pH was maintained at greater than 7.0 (Day 7). Swirling remained at the highest levels (score, 2) for all units throughout storage.

CONCLUSION

PLTs derived from BCs, obtained from either fresh or overnight-stored WB processed on the novel automated Atreus 2C+ system, were equivalent to control PLTs with regard to PLT in vitro characteristics during 7 days of storage. Stable recovery of PLTs and satisfactory PLT content according to current standards were also found.

[New container of sample: role in the reduction of bacterial contamination of standard platelet units]

BACKGROUND

Bacterial contamination of unstable blood products constitutes today the most frequent infectious risk transmitted by blood transfusion. Platelet concentrates are often incrimineted. As responsible germs are in general of cutaneous origin, a sample procedure with diversion of the first 20 ml during blood donation is studied. The aim of this study is to evaluate the results of this technique on bacterial contamination rate of standard platelet units prepared at the regional blood transfusion center in Casablanca.

STUDY DESIGN AND METHODS

A comparative study of two types of sample pockets is made: 500 Standard Platelet concentrates (CPS) are prepared after collection using standard triple bags (Baxter) (group 1) and 560 pockets of CPS were prepared after collection using triple bags with Sample Diversion Pouch sampling system for elimination of the first 20 ml of donation (Macopharma and Terumo) (group 2). The skin was disinfected in two times with alcohol 70%. The bacteriological study was made in the two groups at the third day of conservation.

RESULTS

Six CPS of group 1 were contaminated, of which five were staphylococci coagulase negative and one bacillus sp. Six CPS of group 2 were contaminated, of which five were staphylococci coagulase negative and one staphylococcus aureus. The bacteria isolated were those of cutaneous flora at 100%. Diversion of first 20 ml of blood donation results in a 16.6% reduction in bacterial contamination of CPS (P>0.05).

CONCLUSION

The non-significant reduction in the prevalence of the bacterial infection of CP formulates the problem of the indication of the sampling devices with derivation of first 20 ml during blood collection.

Elimination and multiplication of bacteria during preparation and storage of buffy coat-derived platelet concentrates

BACKGROUND

The prevalence of bacterial contamination of random-donor platelet concentrates (PCs) is considerably lower than that of blood donations. Which key steps of the preparation procedure contribute to the elimination of bacteria was investigated.

STUDY DESIGN AND METHODS

Ten bacteria species were used. Blood donations were spiked with bacteria and stored at 22 degrees C for 8 hours. The buffy coats were kept for 6 hours. PCs were prepared from pools of 4 buffy coats. At each preparation step and during PC storage, bacteria contents were measured. In additional experiments, the titers of spiked blood and buffy coats were determined after storage at 20, 22, or 24 degrees C for 8 and up to 24 hours, respectively.

RESULTS

Enterobacter cloacae, Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, and Yersinia enterocolitica were completely inactivated during storage in blood or buffy coats. Titer reduction was between 3.32 and 4.62 log. Bacillus cereus, Propionibacterium acnes, Staphylococcus aureus, and Staphylococcus epidermidis did not multiply. Compared with their values in spiked blood the titers in the PCs were reduced by 1.7 to 2.8 log. Klebsiella pneumoniae was the only species that grew in blood. With the exception of P. acnes, those species that were not removed by the preparation process multiplied in the PCs. Remarkable donor-to-donor variations of the bactericidal activities of buffy coats were detected when the storage time was prolonged to 24 hours.

CONCLUSIONS

Bacteria are significantly eliminated by the preparation procedure for random donor PCs. Also, blood and buffy coats are bactericidal for most species. When buffy-coat storage is prolonged, it cannot, however, be predicted whether specific strains vanish or multiply.

Effect of holding buffy coats 4 or 18 hours before preparing pooled filtered PLT concentrates in plasma

BACKGROUND

Filtered PLT concentrates (PCs) were prepared in plasma pooling three (for children) or six buffy coats (BCs; for adults) after holding them a maximum of 4 hours (blood bags collected in the afternoon) or 18 hours (blood bags collected in the morning).

STUDY DESIGN AND METHODS

With flow cytometry, PCs prepared after holding BCs 4 or 18 hours were compared. BCs removed from whole-blood donations in quadruple bag packs ("top-top") were held 4 or 18 hours before pooling them with a sterile connecting device. After the BCs were centrifuged, the supernatant was transferred through a BC filter (Autostop, Pall Medical) to a CLX bag. Samples for analysis were collected from the whole-blood bag, BCs, and PCs immediately after preparation and after 1, 3, 5, and 7 days of storage on a flat-bed agitator at 22 +/- 2 degrees C. The main PLT membrane glycoproteins (GPs, IIb-IIIa, IV, and Ibalpha), some of their ligands (fibrinogen, fibronectin, and VWF), activation-dependent antigens (CD62P and CD63), and procoagulant activity markers (annexin V and bound coagulation FV-Va) have been studied.

RESULTS

In the 12 PCs (six pools of 3 units each group) studied, a minor increase in activation markers during preparation was observed. During the storage, a significant increase in the expression of GPIIb-IIIa, CD62P, CD63, annexin V, and FVa was measured. After 5 days of storage, only the percentage of PLTs with bound fibrinogen was significantly greater in PCs prepared after holding BCs for 4 hours.

CONCLUSION

In PCs prepared after holding BCs 4 or 18 hours before pooling and filtering, only a minor significant difference in the percentage of PLTs with bound fibrinogen was found after 5 days of storage. This difference is probably of little, if any, transfusional significance.

[Blood transfusion and bacterial risk]

Initial hemovigilance data confirm the incidence and severity of transfusion reactions due to the bacterial contamination of blood components (TRBC). With 18 deaths reported through the French hemovigilance network over the past 5 years, bacterial risks represent one of the major immediate complications of blood components (BC) transfusion. BC contamination may lead to more or less severe TRBC, depending on their origin: bacteria growth, the BC itself or unknown origin. Although the rate of donated blood or BC contamination is known (0.5% and 0.05%, respectively) it is still difficult to assess the actual incidence of TRBC, as it is difficult to identify them and relate them to transfusion. Likewise, better knowledge of bacteria, symptoms and outcome is required to improve prevention methods. Better prevention can reduce BC contamination and proliferation of bacteria at each stage of blood transfusion. Methods to detect BC contamination are still under investigation. Through continuous education of hemovigilance actors in identifying and dealing with TRBC, as well as drawing up procedures to perform inquiries and specific bacterial analyses, case reporting can be further improved in order to achieve more efficient prevention.

[Blood transfusion and bacterial risk]

Initial hemovigilance data confirm the incidence and severity of transfusion reactions due to the bacterial contamination of blood components (TRBCs). With 18 deaths reported through the French hemovigilance network over the past five years, bacterial risks represent one of the major immediate complications of BC transfusion. BC contamination may lead to more or less severe TRBCs, depending on their origin: bacteria growth, the BC itself or unknown origin. Although the rate of donated blood or BC contamination is known (0.5% and 0.05%, respectively), it is still difficult to assess the actual incidence of TRBCs, as it is difficult to identify and relate them to transfusion. Likewise, a better knowledge of bacteria, symptoms, and outcome is required to improve prevention methods. Better prevention can reduce BC contamination and proliferation of bacteria at each stage of blood transfusion. Methods of detecting BC contamination are still under investigation. Through continuous education of hemovigilance participants in identifying and dealing with TRBCs, as well as drawing up procedures to perform inquiries and specific bacterial analyses, case reporting can be further improved, in order to achieve more efficient prevention.

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 x 10(11)/U showed a pH above 6.8 and optimal swirling scores. 29 of 39 PCs (74%) with yields above 3.1 x 10(11)/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 x 10(11)/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.

[Quality of platelet products: current methods of in vitro assessment]

Efficiency of platelet transfusion is closely related to the quality of the preparation and also to the optimization of storage conditions at 20 degrees C. During this last years, processes for obtaining platelet suspensions became different (platelet rich plasma platelet, pooled or single buffy coat platelet, apheresis platelet), process for purification were developed (filtration, gamma or UV-irradiation, synthetic media for storage, virus inactivation), duration of storage was extended to 5 or 7 days and clinical applications were intensified. According to this advance, noted in some European countries, multicenter consensus on methods of quality control must be defined by different study groups. In the recent past, many publications have described a lot of in vitro tests for estimating functions, morphology, metabolic activity, lysis and activation of platelets. Current available methods for routine quality control or for development of new procedures, such as pH measurement inspection of swirling, percent of discoid shape, mean platelet volume, hypotonic shock response or total ATP level should be considered, in accordance with the in vivo viability.