Comparison of haemostatic function of PAS-C-platelets vs. plasma-platelets in reconstituted whole blood using impedance aggregometry and thromboelastography.

BACKGROUND AND OBJECTIVES: There are concerns about the haemostatic function of platelets stored in platelet additive solution (PAS). Aim of this study was to compare the haemostatic function of PAS-C-platelets to plasma-platelets in reconstituted whole blood. MATERIALS AND METHODS: In our experiment, whole blood was reconstituted with red blood cells, solvent-detergent (SD) plasma and either PAS-C-platelets or plasma-platelets (n = 7) in a physiological ratio. On storage days 2, 5, 8 and 13, the agonist-induced aggregation (multiple electrode aggregometry), clot formation (thromboelastography) and agonist-induced CD62P responsiveness (flow cytometry) were measured. RESULTS: Samples with PAS-C-platelets showed significantly lower aggregation than plasma-platelets when induced with adenosine diphosphate, -6 U (95% confidence interval: -8; -4) or thrombin receptor-activating protein, -15 U (-19; -10). Also when activated with collagen and ristocetin, the PAS-C-platelets showed less aggregation, although not statistically significant. All samples with PAS-C-platelets showed significantly lower agonist-induced CD62P responsiveness than samples with plasma-platelets. However, there was no difference regarding all TEG parameters. CONCLUSION: Our findings demonstrate that the function - aggregation and CD62P responsiveness - of PAS-C-platelets in reconstituted whole blood is inferior to that of plasma-platelets, which may have implications in the setting of massive transfusions.

Critical re-appraisal of blood component quality after overnight hold of whole blood outside current room temperature limits.

BACKGROUND AND OBJECTIVES: According to European guidelines, the temperature of whole blood (WB) has to be maintained at 20-24°C until processing within 24 h, but in blood bank practice, WB is frequently held at temperatures between 18-25°C. We aimed to assess the impact of these small temperature deviations on the quality of the blood components. MATERIALS AND METHODS: After rapid cooling, 7 WB units were held overnight at 18°C and 8 units at 25°C, reflecting worst case holding conditions, and separated into a red cell concentrate (RCC), plasma and buffy coat (BC). RCCs were filtered at test temperature and stored for 42 days at 2-6°C. BCs were processed to single-BC platelet concentrates (sPC) and stored up to Day 8 at 20-24°C. RESULTS: After overnight hold at 18°C, 2,3-DPG in WB decreased by 34 ± 9%, while at 25°C the decrease was 82 ± 6%. Accordingly, the 2,3-DPG levels in the RCCs in the 25°C group were significantly lower than in the 18°C group (2·2 ± 1·4 vs. 10·4 ± 2·9 µmol/g Hb). RCCs and sPCs in the 25°C group showed higher initial lactate levels and lower pH compared to the 18°C group, but these differences levelled off at the end of storage. RCCs showed small differences in ATP levels and haemolysis. Plasma in both groups showed comparable Factor VIII:C levels. CONCLUSION: The temperature of WB during overnight hold strongly affects initial 2,3-DPG levels of RCCs and supports the maintenance of temperature limits between 20 and 24°C. Other in vitro effects of the temperature deviations were small and of no practical relevance.

Evaluation of the role of the GPIb-IX-V receptor complex in development of the platelet storage lesion.

BACKGROUND AND OBJECTIVES: In mice, loss of sialic acid resulting in shedding of glycoprotein (GP) Ibα and GPV has been linked to platelet survival. The aim of this study was to determine whether loss of sialic acid and the GPIb-IX-V complex contributes to development of the platelet storage lesion (PSL) in human platelet concentrates (PCs). MATERIALS AND METHODS: PCs (stored in plasma (with or without Mirasol treatment); PAS-C or PAS-E) were stored at room temperature. Flow cytometry was used to monitor membrane expression of the GPIb-IX-V complex, CD62P, surface glycans and PS exposure. The functionality of stored platelets was determined employing aggregometry and ristocetin-induced VWF binding. RESULTS: Storage time of PCs in blood banks is limited to 7 days. During this time period, a minor but gradually increasing subpopulation of GPIbα-negative platelets was observed. Also, ristocetin-induced VWF binding was impaired in a small population of platelets. Mean surface expression of GPIbα and GPV remained stable until day 9, whereas CD62P expression increased; also a rapid decrease in ADP-induced aggregation was observed for PAS-C, PAS-E and Mirasol-treated PCs. Upon prolonged storage (>9 days), a slow decline in surface expression of GPIbα and GPV was observed; no major changes were observed in surface sialylation with the exception of Mirasol-treated platelets. CONCLUSION: In a small population of stored platelets, changes in GPIbα occur from day 2 onwards. Loss of sialic acid and subsequent shedding of GPIbα and GPV is not an early event during the development of the PSL.

Separation of centrifuged whole blood and pooled buffy coats using the new CompoMat G5: 3 years experience.

BACKGROUND AND OBJECTIVES: Semi-automatic separation devices can be used for the separation of centrifuged whole blood into leucoreduced red cell concentrate (LR-RCC), plasma and buffy coat (BC) and to make platelet concentrates (PC) from pooled BCs. To improve and to obtain a more uniform and standardized process, the CompoMat G5 (Fresenius) was implemented, a new-generation semi-automated device. MATERIALS AND METHODS: Uniform programs for WB separation and preparation of PCs were validated, using collection and pooling systems with CompoFlow (CF) closures, which can be automatically opened by the G5. Cell counts were performed and compared with historic data of blood components obtained with the formerly used Compomat G4 and Optipress II. After implementation, different adjustments were made to improve product quality. RESULTS: Leucoreduced red cell concentrates (280 ± 15 ml, 53 ± 5 g haemoglobin) and plasma (317 ± 16 ml) met European guidelines. BCs (48 ± 2 ml, 0·42 ± 0·05 l/l, 93 ± 25 × 10(9) platelets) contained a similar platelet (PLT) content as BC prepared before with the Compomat G4. A relatively high percentage (4-6%) of PCs (330 ± 17 ml, 330 ± 50 × 10(9) PLT, 0·12 ± 0·21 × 10(6) leucocytes) contained <250 × 10(9) PLT which was the subject of improvement studies. After implementation, RCC and BC discard decreased and workload was less. Operator complaints were also less frequent. CONCLUSION: The same high-quality blood components can be prepared by using the CompoMat G5 as previously with other semi-automated devices. Improvement was realized by automation of the opening process by the use of collection systems with CF closures, which led to a decrease in discarded units and workload.

Effect of rate and delay of cooling during initial cooling process: in vitro effect on red cells.

BACKGROUND: Whole blood is stored at room temperature (RT) until processing into components. After separation and filtration, the RCC has to be cooled from RT to +2 - 6°C. Different start times of the cooling process and different cooling rates can be encountered in daily routine. The effect of these parameters of the initial cooling of leucoreduced red cell concentrates (LR-RCC) on in vitro quality is not known. METHODS: In paired experiments (n=12), LR-RCCs in SAGM were cooled immediately after preparation from RT to +2 to +6°C either 'fast' (within 2½ h) or 'slow' (within 10-24 h) or 'slow' after a holding period of 6, 12, 18 or 24 h. Units were then stored at +2-6°C for 42 days and sampled at regular intervals for in vitro analysis. RESULTS: Irrespective of the start time and cooling rate during the initial cooling process, all units maintained good in vitro quality up to Day 42 with haemolysis <0·8%. Adenosine triphosphate (ATP) levels remained >2·7 µmol/g Hb in 99% of all units up to Day 35. Differences in pH, ATP content and 2,3-DPG content between the groups were largest at Day 2 or 3 but generally disappeared during storage. CONCLUSION: Start time and cooling rate of the initial cooling process had minor effects on in vitro quality of red cells. LR-RCCs can be stored up to 24 h before cooling down to +2-6°C without deleterious effects on in vitro parameters during 42-day storage.