The impact of donor biological variation on the quality and function of cold-stored platelets.

BACKGROUND AND OBJECTIVES: Room temperature-stored platelets (RTPs) maximize platelet viability but limit shelf life. The aims of this study were to investigate the impact of donor variability on cold-stored platelets (CSPs) and RTP, to determine whether RTP quality markers are appropriate for CSP. MATERIALS AND METHODS: Double platelet donations (n = 10) were collected from consented regular male donors stored in 100% plasma. A full blood count, donor age, weight, height and body mass index (BMI) were collected at the time of donation. Platelet donations were split equally into two bags, and assigned to non-agitated CSP or agitated RTP. The quality and function of platelets were assessed throughout the standard 7 days of storage and at expiry (day 8). Non-parametric statistical analyses were used to analyse results given the small sample size. RESULTS: As expected, there were significant differences between CSP and RTP throughout storage including a reduction in CSP concentration as well as a loss of swirling. Furthermore, a significant increase in CSP exhibiting activation and apoptotic markers was observed. Platelet concentrations were further impacted by donor BMI, and donors with the highest BMI (>29) had the lowest platelet concentration and activation response at the end of CSP storage. CONCLUSION: Platelet quality and functionality play a vital role in transfusion outcomes; however, blood components are inherently variable. This study demonstrated, for the first time, the specific impact of donor BMI on CSP quality and function and highlights the requirement for novel quality markers for assessing CSPs.

The oxygen saturation of red blood cell concentrates: The basis for a novel index of red cell oxidative stress.

BACKGROUND: Oxidative stress is a major driving force in the development of storage lesions in red cell concentrates (RCCs). Unlike manufactured pharmaceuticals, differences in component preparation methods and genetic/physiological status of donors result in nonuniform biochemical characteristics of RCCs. Various characteristics of donated blood on oxygen saturation (SO2 ) distribution were investigated, and a model to estimate potential oxidative stress burden of stored RCC at transfusion is proposed. STUDY DESIGN AND METHODS: The oxygen content of freshly prepared RCCs (770) was quantified noninvasively as fractional hemoglobin saturation (SO2 ) with visible reflectance spectrometry. Using separate RCCs and mimicking typical handling of RCCs during routine storage, evolution of SO2 was followed for construction of an empirical model. Based on this model, the oxygen exposure index (OEI) was formulated to estimate the accumulated oxygen exposure burden of RCC at the time of transfusion. RESULTS: The SO2 of RCCs varied widely at donation (mean 43% ± 1.3%; range 20%-93%). Multivariate regression model showed that sex and processing method had small effects on SO2 (R2  = 0.12), indicating that variability was mainly attributed to other individual donor characteristics. Storage simulation model indicated that median SO2 increased gradually over 6 weeks (approx. 1.3 fold), while OEI increased at a faster rate (approx. eight-fold). CONCLUSION: In addition to storage age, the OEI provides a potential new metric to assess the quality of RCCs at the time of transfusion in terms of their oxidative stress. In future studies, a single noninvasive measurement during storage could link OEI to clinical outcomes in transfusion recipients.

Residual red cells in blood components: A multisite study of fully automated enumeration using a hematology analyzer.

BACKGROUND: Manufacture of platelet concentrates (PCs) and plasma may fail to remove all residual red blood cells (rRBCs). Measuring rRBCs for compliance to guidelines has proven challenging, leading to an absence of a consensus methodology. Sysmex hematology analyzers with the Blood Bank mode (BB mode) analysis option offer the potential for automated rRBC counting. We therefore performed a two-site appraisal of the system. STUDY DESIGN AND METHODS: Performance characteristics were determined using platelet and plasma samples spiked with RBCs. Sample stability (n = 47) and the impact of sample type were also assessed. Components (platelets, n = 1474; plasma, n = 77) prepared using different routine manufacturing methods were tested to assess variation in rRBC concentration. RESULTS: Linearity studies up to 19 000 RBCs/µL demonstrated good correlation between expected and observed results (R2 ≥ 0.9731), and flow cytometric results also correlated well with BB mode (R2 = 0.9400). Precision analysis gave a limit of quantitation of 6 to 7 RBCs/µL, and carryover was 0.03%. Ethylenediaminetetraacetic acid and plain tube results were not significantly different (P ≥ 0.10), and samples were stable up to 24 hours. Apheresis PCs produced at two sites had lower rRBC concentrations (medians, 17 and 13 RBCs/µL) than those produced with the buffy coat method either manually (median, 681 RBCs/µL) or with the automated Terumo Automated Centrifuge and Separator Integration process (median, 81 RBCs/µL). All PCs failing visual inspection as having RBCs ≥4000 RBCs/µL were also detected by the BB mode. CONCLUSION: The BB mode had acceptable performance characteristics and has the potential for integration into a fully automated process control system for rRBC enumeration in plasma and PCs.

Changes in plasma unit distributions to hospitals over a 10-year period.

BACKGROUND: There are many influences on a hospital's demand for plasma. Pharmaceuticals are now being administered for many indications instead of plasma, although trauma resuscitation now emphasizes increased and early intervention with plasma. This multinational study evaluated changes in blood center plasma unit distributions over a 10-year period. STUDY DESIGN AND METHODS: Data on the total number and the ABO groups of plasma unit distributions were obtained from nine American blood collectors (ABCs) and nine national or provincial blood services (NPBS) from 2007 through 2016. Plasma distributions to trauma hospitals by five ABCs and four NPBS were also analyzed. RESULTS: The overall number of plasma unit distributions from ABCs decreased by 23.1% from 2007 to 2016, but the relative proportion of distributed AB plasma units increased during the same period. The NPBS (excluding the Japanese Red Cross [JRC]) also had a 35.4% decrease in the overall number of plasma unit distributions with an increase in the relative proportion of AB plasma distributions between 2007 and 2016. The JRC, however, reported an increase in the overall number of plasma distributions by 13.5% in 2016 compared to 2007. The proportion of low-titer A plasma distributions increased to 1.6% of total plasma distributions by ABCs in 2016. There was a trend of distributing increasing proportions of group AB plasma units to trauma hospitals over the 10-year period. CONCLUSION: Although the number of plasma unit distributions has decreased at many blood collectors over time, the proportion of AB units has increased at both ABCs and NPBS.

Safety and feasibility of platelet transfusion through long catheters in the neonatal intensive care unit: an in vitro study.

OBJECTIVE: To assess the safety and feasibility of platelet transfusion through small-bore long lines used in the neonatal intensive care unit (NICU), including double-lumen umbilical venous catheters (UVCs) and 24 G and 28 G peripherally inserted central catheters (PICCs). DESIGN: Prospective in vitro controlled study. SETTING: Blood transfusion service laboratory. METHODS: In vitro platelet transfusions were set up as per NICU practice. Transfusion line pressure was monitored. Post-transfusion swirling, presence of aggregates, pH analysis and automated cell count in vitro activation response by flow cytometry assessing CD62P expression were assessed. MAIN OUTCOME MEASURES: All transfusions completed successfully. The rate of infusion was reduced in 5 of 16 transfusions through 28 G lines due to 'pressure high' alarms. There was no difference in swirling values or transfusion aggregate formation, CD62P expression levels, platelet count, platelet distribution width, mean platelet volume, plateletcrit or platelet to large cell ratio across transfusions post-transfusion. CONCLUSIONS: This study showed that in vitro platelet transfusion performed through 24 G and 28 G neonatal PICC lines and double-lumen UVCs is non-inferior to 24 G short cannulas, using outcome measures of platelet clumping, platelet activation and line occlusion. This suggests that where available these lines can be used if necessary for platelet transfusion.