Menopausal status affects the susceptibility of stored RBCs to mechanical stress

The mechanical fragility index (MFI) is an in vitro measure of sublethal injury to RBCs. In our previous experiments, we demonstrated that an increase in sublethal injury (increasing MFI) was a component of the RBC storage lesion, and that the MFI was significantly higher amongst the RBC units from male donors compared to pre-menopausal female donors during storage. It was hypothesized that hormonal or menstrual factors contributed to this difference. In this study, we found that RBC units donated by post-menopausal women demonstrated an MFI that was significantly higher than those donated by pre-menopausal women throughout storage.     

Sex-related aspects of the red blood cell storage lesion

BackgroundSeveral factors contribute to the manifestation of red blood cell (RBC) storage lesions, with one of the most interesting being the “donor variation effect”. Since many haematological characteristics of blood donors are sex-dependent, sex hormones and their age-dependent variation may affect the storage profile of RBCs.Materials and methodsFresh blood from 200 healthy male and female donors underwent haematological, biochemical and physiological analysis. Three selected groups of donors (men, n=8; pre-menopausal women, n=8; and post-menopausal women, n=4) exhibiting as similar as possible baseline values were recruited for blood donation in leukoreduced CPD/SAGM units. RBC indices, haemolysis and propensity for haemolysis, reactive oxygen species (ROS) and plasma antioxidant capacity were measured bi-weekly.ResultsFemale blood was characterised by lower plasma antioxidant capacity and free haemoglobin (Hb) levels in vivo, in spite of the higher RBC osmotic fragility, compared to male blood. Comparatively low Hb concentration was also measured in stored RBCs from female donors, as in vivo. Mean corpuscular Hb (MCH), mean corpuscular Hb concentration (MCHC), and plasma antioxidant capacity were also lower in female donors throughout storage, even though baseline levels were equal to those of the male group. There was no difference in propensity of stored RBCs for haemolysis between male and female units but intracellular ROS levels were significantly lower in female RBCs. Increased end-of-storage extracellular potassium and recruitment of protein stress markers (clusterin, Hb) to the RBC membrane were observed in the units of post- vs pre-menopausal female donors at mid-storage onwards.DiscussionDonor’s sex has an impact on Hb concentration and redox parameters of stored RBCs. In addition, menopause seems to promote RBC membrane remodelling, at least during prolonged storage. Our pilot study provides new insights on the different effects on RBC storage lesion according to sex.     

Modified formulation of CPDA for storage of whole blood, and of SAGM for storage of red blood cells, to maintain the concentration of 2,3-diphosphoglycerate

BACKGROUND AND OBJECTIVES: A dramatic decrease in the level of 2,3-diphosphoglycerate (2,3-DPG) takes place during the storage of whole blood (WB) in CPDA (citrate-phosphate-dextrose-adenine) and a similar decrease occurs during the storage of red blood cells (RBCs) in SAGM (saline-adenine-glucose-mannitol). The aim of the present study was to prevent this decrease by modifying CPDA and SAGM. MATERIALS AND METHODS: The pH of WB anticoagulant or RBC preservative solution was maintained at 7.6 by autoclaving the dextrose solution separately, by incorporating ascorbic acid and nicotinic acid into both CPDA and SAGM (to produce modified CPDA and SAGM solutions), and by reducing the concentration of adenine and adding citrate to the modified SAGM solution. The concentration of 2,3-DPG in WB after 28 days of storage in modified CPDA, and in RBCs stored in modified SAGM, was compared with that in WB or RBCs stored in unmodified solutions. RESULTS: The initial 2,3-DPG levels were maintained after 28 days in the modified formulations [10.63 +/- 2.58 microM/g of haemoglobin (Hb) in the case of modified CPDA and 12.07 +/- 1.47 microM/g of Hb in the case of modified SAGM], whereas in standard CPDA and SAGM solutions, the concentration of 2,3-DPG decreased to very low levels (0.86 +/- 0.97 microM/g Hb for CPDA and 0.12 +/- 0.008 for SAGM). CONCLUSIONS: Our modification in the formulation of CPDA or SAGM is effective in arresting the dramatic decrease in the level of 2,3-DPG that occurs during storage of WB and RBCs in unmodified solutions.     

Erythrocyte storage in hypertonic (SAGM) or isotonic (PAGGSM) conservation medium: influence on cell properties

Background and Objectives Prolonged red blood cell (RBC) storage may be associated with increased post-transfusion morbidity and mortality. A contributing factor is RBC storage lesions. We analysed the role of additive conservation solutions, either hypertonic or isotonic, on such cell properties. Materials and Methods After blood donation in citrate–phosphate–dextrose as an anticoagulant, 10 RBC units were stored with saline–adenine–glucose–mannitol (SAGM; 376 mOsm/l) and 10 units with phosphate–adenine–glucose–guanosin–saline–mannitol (PAGGSM; 285 mOsm/l). Measurements were made on days 1 and 42 of storage. Results The mean cellular volume measured by centrifuged microhaematocrit increased from 87·6 ± 3·1 fl to 100·7 ± 4·3 fl in PAGGSM and to 92·2 ± 2·5 fl in SAGM (P < 0·001) on day 1, after 42 days it was 95·8 ± 4·0 fl and 93·8 ± 3·9 fl, respectively. Spontaneous haemolysis and osmotic fragility were lower after storage in PAGGSM. Both additives showed a similar degree of echinocytosis, decreased RBC aggregability and deformability, and increased RBC suspension viscosity after storage. Conclusions The isotonic PAGGSM prevented the initial RBC swelling caused by citrate–phosphate–dextrose less than hypertonic SAGM, but reduced the spontaneous haemolysis rate and osmotic fragility after 42 days of storage. All other parameters, such as echinocytosis, decreased RBC deformability and aggregability, and increased blood viscosity was similar for both additive solutions and remained a major problem of blood banking.     

Elastic properties of stored red blood cells from sickle trait donor units

BACKGROUND AND OBJECTIVES: Red blood cells (RBCs) from patients with sickle cell disease present reduced deformability. The aim of this study was to analyse the elasticity of stored RBCs from patients with the sickle cell trait (AS). MATERIALS AND METHODS: The cell elasticity was studied, using laser optical tweezers, on storage days 1, 14, 21, 28 and 35. RESULTS: The elasticity of RBC from AS units stored for 1, 14 and 21 days was significantly greater compared with that of control RBC cells stored for the same time-period. More than 30% of the cells from AS units stored for 28 or 35 days were very rigid and escaped from the optical trap. CONCLUSIONS: RBCs became rigid during storage, suggesting that haemoglobin S might compromise the cell elasticity.     

Influence of irradiation on in vitro red-blood-cell (RBC) storage variables of leucoreduced RBCs in additive solution PAGGS-M

Background The effect of gamma irradiation on leucoreduced red‐blood‐cells (RBCs) stored in an additive solution (AS) containing phosphate, adenine, glucose, guanosine, saline and mannitol (PAGGS‐M) has not yet been studied, and there are different recommendations about storage time of leucoreduced RBCs after irradiation. Study Design and Methods We studied 63 leucoreduced RBC units. All RBCs were stored in AS PAGGS‐M and leucoreduced on the collection day. Twenty‐one components were irradiated on Day +14 with 30 Gy and 22 served as non‐irradiated controls. Samples were drawn and analysed from these 43 units on Day +7, +14, +21, +28, +35, +42 and +49 from the collection day. From 20 units, no samples were taken earlier than on Day +49. Of these, 10 components had been irradiated on Day +14 with 30 Gy and 10 served as non‐irradiated controls. Results Gamma irradiation induced an enhanced in vitro haemolysis rate in the irradiated components. One of the irradiated units showed a haemolysis rate over the recommended limit of 0·8% on Day +42 and four on Day +49. The leakage of potassium ions from irradiated RBCs started to increase faster than that of unirradiated RBCs from the day of irradiation. Lactate dehydrogenase levels increased faster in irradiated units 3 weeks after irradiation. We showed that taking samples weekly does not affect the final result. Conclusions Our findings show that the European recommendations should not be changed in regard to the limitation of the storageability after irradiation of leucoreduced RBCs. The damage after irradiation and storage cannot be prevented by using the high‐quality AS PAGGS‐M.     

Concurrent collection of in-line filtered platelets and red blood cells by apheresis

Multicomponent apheresis procedures offer the possibility to collect standardized blood components as compared to whole blood donations. A new program for the concurrent collection of platelets (PLTs) and red blood cells (RBCs) was evaluated in a prospective study. Apheresis donors ( n=18) underwent concurrent collection of PLTs and RBCs using the Haemonetics MCS+ blood cell separator. Aliquots of PLTs and RBCs were collected during five to six passes of the discontinuous flow procedure. The platelet product was in-line filtered during the last pass of the separation procedure. After collection, saline-adenine-glucose-mannitol (SAGM) preservative solution was automatically added to the RBCs. Thereafter, the RBCs were in-line leukodepleted by gravity filtration at room temperature. The PLTs and RBCs were subsequently stored at 22+/-2 degrees C for 5 days and 4+/-2 degrees C for 35 days, respectively. The following in vitro parameters were evaluated over the storage periods: blood cell counts, glucose, lactate, lactate dehydrogenase, pH, plasma hemoglobin, and potassium. Two ready-to-use blood components from one donor were collected in an average procedure time of 86+/-10 min; 2.47+/-0.74 x 10(11) PLTs were collected in a product volume of 232+/-43 ml. The RBC volume averaged 280+/-20 ml and the hemoglobin content was 56.8+/-2.4 g per unit. The leukocyte contamination of the platelet product was 0.44+/-0.56 x 10(5) and the residual leukocyte content of the RBC product was 0.28+/-0.02 x 10(5). Storage data showed no relevant drop in pH. Day 35 results of the RBC products showed that all of the units had less than 0.8% hemolysis. Standardized PLT and RBC products of good quality can be concurrently collected with the MCS+ blood cell separator. In vitro testing of the products collected and stored for 5 and 35 days, respectively, met the Council of Europe criteria for leukodepleted blood products.     

The effect of timing of gamma‐irradiation on hemolysis and potassium release in leukoreduced red cell concentrates stored in SAGM

While irradiation of red cell concentrates (RCC) prevents graft‐versus‐host disease in susceptible transfusion recipients, it also damages red blood cells (RBC). To understand the ability of irradiation regulations to prevent transfusion of inferior units, we irradiated 980 RCC in saline‐adenine‐glucose‐mannitol (SAGM) using various combinations of pre‐irradiation age and post‐irradiation storage times, and measured hemolysis and extracellular potassium levels. We observed unacceptably high hemolysis (>0·8%) in some RCC and elevated extracellular potassium levels in all gamma‐irradiated RCC. This suggests that more restrictive storage times should be considered for RCC in SAGM.     

Processing cord blood from premature infants into autologous red-blood-cell products for transfusion

Background and Objectives The use of umbilical cord blood (UCB) for transfusion purposes has gained interest the past years. UCB transfusion could serve premature infants, who often need transfusions early in life. Material and Methods We investigated the suitability of different storage media. UCB was collected after 25 ⁰/₇–35 ⁶/₇ gestational weeks and centrifuged to concentrate red cells subsequently stored in saline–adenine–glucose–mannitol (SAGM), or in additive solution‐3 (AS‐3), or stored as whole blood in citrate–phosphate–dextrose–adenine‐1. Quality parameters were measured at 7 day intervals during 35 days and compared to the standard RBC product. Results White‐blood‐cell‐ and platelet counts were higher in the UCB products. In the fractionated units, haemolysis remained below 1·0% in 64% after 14 days, and in 30% after 21 days. Storage in SAGM or AS‐3 showed similar quality. Whole blood UCB showed better pH and haemolysis rates after 21 days. Conclusion UCB can be processed into autologous products for premature infants. Shelf‐life is limited to 14–21 days and compares unfavourably to stored whole blood. Considering the early transfusion needs in these infants, a short shelf‐life would not be a practical objection.     

Glucose‐6‐phosphate dehydrogenase deficiency in transfusion medicine: the unknown risks

The hallmark of glucose‐6‐phosphate dehydrogenase (G6PD) deficiency is red blood cell (RBC) destruction in response to oxidative stress. Patients requiring RBC transfusions may simultaneously receive oxidative medications or have concurrent infections, both of which can induce haemolysis in G6PD‐deficient RBCs. Although it is not routine practice to screen healthy blood donors for G6PD deficiency, case reports identified transfusion of G6PD‐deficient RBCs as causing haemolysis and other adverse events. In addition, some patient populations may be more at risk for complications associated with transfusions of G6PD‐deficient RBCs because they receive RBCs from donors who are more likely to have G6PD deficiency. This review discusses G6PD deficiency, its importance in transfusion medicine, changes in the RBC antioxidant system (of which G6PD is essential) during refrigerated storage and mechanisms of haemolysis. In addition, as yet unanswered questions that could be addressed by translational and clinical studies are identified and discussed.     

Early γ‐irradiation and subsequent storage of red cells in SAG‐M additive solution potentiate energy imbalance,microvesiculation and susceptibility to stress‐induced apoptotic cell death

γ‐Irradiation of red blood cell (RBC) concentrates prevents transfusion‐associated graft‐versus‐host disease but may diminish RBC quality. Herein, we show that early γ‐irradiation (25 Gy) of RBC units and their subsequent storage in SAG‐M additive solution altered membrane microvesiculation, supernatant haemoglobin and cytosolic ATP. γ‐Irradiation did not influence phosphatidylserine externalization, a marker of erythrocyte apoptotic cell death (eryptosis), in RBC stored for 42 days. However, shorter periods (4–21 days) of storage accentuated eryptosis in γ‐irradiated RBC versus untreated RBCs following energy depletion, suggesting that γ‐irradiated RBC is primed for stress‐induced eryptosis during storage.     

Deterioration of red blood cell mechanical properties is reduced in anaerobic storage

BackgroundHypothermic storage of red blood cells (RBCs) results in progressive deterioration of the rheological properties of the cells, which may reduce the efficacy of RBC transfusions. Recent studies have suggested that storing RBC units under anaerobic conditions may reduce this storage-induced deterioration.ResultsThe bulk perfusion rates for anaerobically stored RBC were significantly higher than for conventionally stored RBCs over the entire duration of storage for all devices (up to 10% on day 42; up to 14% on day 63). Capillary perfusion rates suggested that anaerobically stored RBC units contained significantly fewer non-deformable RBC capable of transiently plugging microfluidic device capillaries. The number of plugging events caused by these non-deformable RBC increased over the 63 days of hypothermic storage by nearly 16- to 21-fold for conventionally stored units, and by only about 3- to 6-fold for anaerobically stored units.DiscussionThe perfusion measurements suggest that anaerobically stored RBC retain a greater ability to perfuse networks of artificial capillaries compared to conventionally (aerobically) stored RBC. It is likely that anaerobic storage confers this positive effect on the bulk mechanical properties of stored RBC by significantly reducing the number of non-deformable cells present in the overall population of relatively well-preserved RBC.     

Transitory interruption of recommended storage conditions does not cause significant changes in in vitro parameters of leucocyte‐depleted red blood cells

Background and Objectives Conventional quality control studies of the shelf life of RBC units do not consider cold chain interruptions that occur during cross‐matching or between the release of RBCs from the blood bank and their return from the ward. These interruptions may, however, lead to a considerable loss of quality. On the other hand, differences in the quality of RBCs may derive from the different manufacturing processes employed in various blood centres. Materials and Methods One day after the expiry date of the RBC unit, we analysed complete blood count, blood gas, potassium, LDH, hydroxybutyrate dehydrogenase, glucose, lactate, total and free haemoglobin (Hb) and ATP and compared the results with regard to the frequency of storage interruptions and to two manufacturers of these RBCs. Results We could not find any correlations between the frequency of interruptions (0–11) and these parameters in any of the data sets. However, we found significant differences when comparing the two suppliers. RBCs of manufacturer A (‘A’, inline filtration of whole blood) contained 25% more Hb than those of manufacturer B (‘B’, inline filtration after buffy coat reduction). Sixteen percentage of ‘A’‐RBC, but none of ‘B’‐RBC, exceeded a haemolysis of 0·8%. Conclusions Transitory interruptions of cold chain do not measurably impair the quality of RBCs. The effect on storage of RBCs in the blood bank is not as significant a factor as the differences that exist between RBC manufacturing procedures.     

Prolonged storage of red blood cells affects aminophospholipid translocase activity

BACKGROUND AND OBJECTIVES: Loss of phospholipid asymmetry in the membrane of red blood cells (RBC) results in exposure of phosphatidylserine (PS) and to subsequent removal from the circulation. In this study, we investigated the effect of long-term storage of RBCs on two activities affecting phospholipid asymmetry: the ATP-dependent aminophospholipid translocase (or flippase, transporting PS from the outer to the inner leaflet) and phospholipid scrambling (which will move PS from the inner to the outer leaflet). MATERIALS AND METHODS: Standard leukodepleted RBC concentrates were stored in saline-adenine-glucose-mannitol (SAGM) at 4 degrees C for up to 7 weeks. PS exposure was determined by measurement of AnnexinV-FITC binding to the cells, flippase activity by measurement of the inward translocation of NBD-labelled PS. Scrambling activity was determined by following the inward translocation of fluorescent NBD-phosphatidylcholine. In parallel, intracellular ATP levels were determined. RESULTS: PS exposure amounted to only 1.5 +/- 0.3% positive cells (n = 8) after 5 weeks of storage, which slightly increased to 3.5 +/- 0.7% (n = 8) after 7 weeks of storage. Flippase activity started to decrease after 21 days of storage and reached 81 +/- 5% of the control value after 5 weeks of storage (n = 6) and 59 +/- 6% (n = 6) after 7 weeks. Also in RBC obtained by apheresis, flippase activity decreased upon storage. Scrambling activity remained virtually absent during storage, explaining the low PS exposure despite the decrease in flippase activity. Rejuvenation of RBC after 7 weeks to increase ATP levels only partially restored flippase activity, but in combination with a correction of the intracellular pH to that of fresh cells, almost complete restoration was achieved. The decrease in flippase activity after prolonged storage did make the RBCs more prone to PS exposure after activation of phospholipid scrambling. CONCLUSION: This study shows that, although PS exposure remains low, prolonged storage does compromise the RBC membrane by affecting flippase activity. When the metabolic changes induced by storage are corrected, flippase activity can be restored.     

Influence of the Red Blood Cell Preparation Method on the Efficacy of a Leukocyte Reduction Filter

The performance of a leukocyte reduction bedside filter with different types of RBC concentrates was analyzed. Three types of RBCs were prepared: buffy-coat-depleted RBCs suspended in saline-adenine-glucose-mannitol (SAGM)-additive solution (BC-RBCs; n = 20), RBCs suspended in SAGM-additive solution without buffy coat removal (SAGM-RBCs; n = 20), and RBCs drawn in CPDA-1 conservative solution and processed for component preparation by the platelet-rich plasma method (CPDA-RBCs; n = 20). The units were filtered within 8 h of collection. One filter was used for every 2 units. High numbers of residual WBCs were found even in the units filtered first. Filtration of CPDA-RBCs resulted in a higher residual WBC content than SAGM-RBCs or BC-RBCs (p = 0.0032 and p = 0.0002, respectively). The filter performance strikingly decreased when the WBC load per filter exceeded 4 × 10⁹ or the platelet load was less than 100 × 10⁹. We conclude that filter performance varies with the WBC and platelet content of the RBC concentrates. Under the experimental conditions assayed in this study CPDA-RBCs are the least appropriate ones to be used for bedside leukocyte reduction.     

The effects of polyvinyl chloride and polyolefin blood bags on red blood cells stored in a new additive solution.

BACKGROUND AND OBJECTIVES: Red blood cells (RBCs) must be stored in polyvinyl chloride (PVC) bags plasticized with di-2-ethylhexyl phthalate or a similar plasticizer to achieve their full storage life with conventional storage solutions. Improved storage solutions might remove this requirement and allow blood storage in other plastics. Experimental Additive Solution-61 (EAS-61), which maintains RBCs for 9 weeks with reduced haemolysis and satisfactory 51Cr 24-h recovery, is an appropriate candidate improved RBC storage solution. MATERIALS AND METHODS: Twenty-four units of packed RBCs were pooled in groups of four units, each pool was realiquoted into four units and stored, six pooled units per arm, in one of the following: 100 ml of EAS-61 in PVC; 200 ml of EAS-61 in PVC; 100 ml of EAS-61 in polyolefin (PO); and 200 ml of EAS-61 in PO. Haemolysis, RBC morphology indices, RBC ATP concentrations, and other measures of RBC metabolism and function were measured weekly. RESULTS: RBC haemolysis exceeded 1% by 7 weeks in PO bags containing 100 ml or 200 ml of EAS-61. In PVC bags, haemolysis was less than 1% at 11 weeks. RBC ATP concentrations were 1 mol/g of haemoglobin (Hb) higher at 2 weeks in the PVC-stored units. CONCLUSIONS: RBCs stored in PVC had markedly less haemolysis and higher RBC ATP concentrations than those stored in PO. Haemolysis would limit RBC storage in PO bags to a duration of 6 weeks, even with EAS-61.     

A biomimetic microfluidic chip to study the circulation and mechanical retention of red blood cells in the spleen

Red blood cells (RBCs) are deformable and flow through vessels narrower than their own size. Their deformability is most stringently challenged when they cross micrometer‐wide slits in the spleen. In several inherited or acquired RBC disorders, blockade of small vessels by stiff RBCs can trigger organ damage, but a functional spleen is expected to clear these abnormal RBCs from the circulation before they induce such complications. We analyzed flow behavior of RBCs in a microfluidic chip that replicates the mechanical constraints imposed on RBCs as they cross the human spleen. Polymer microchannels obtained by soft lithography with a hydraulic diameter of 25 μm drove flow into mechanical filtering units where RBCs flew either slowly through 5‐ to 2‐μm‐wide slits or rapidly along 10‐μm‐wide channels, these parallel paths mimicking the splenic microcirculation. Stiff heated RBCs accumulated in narrow slits seven times more frequently than normal RBCs infused simultaneously. Stage‐dependent retention of Plasmodium falciparum‐infected RBCs was also observed in these slits. We also analyzed RBCs from patients with hereditary spherocytosis and observed retention for those having the most altered mechanical properties as determined by ektacytometry. Thus, in keeping with previous observations in vivo and ex vivo, the chip successfully discriminated poorly deformable RBCs based on their distinct mechanical properties and on the intensity of the cell alteration. Applications to the exploration of the pathogenesis of malaria, hereditary spherocytosis, sickle cell disease and other RBC disorders are envisioned.Am. J. Hematol. 90:339–345, 2015. © 2015 Wiley Periodicals, Inc.     

Ontogeny of erythrocyte insulin binding in the sheep

The ontogeny of insulin binding in the sheep was studied using the erythrocytes (RBCs) of 31 fetuses, 10 lambs, and 5 adult animals. Six fetuses were studied on three occasions over a 2-week period from 120--135 days of gestation to provide longitudinal data on changes in insulin binding. Maximal percent binding of [125I]iodoinsulin and receptor concentration decreased significantly as the age of the animal increased (r = 0.76, P less than 0.001 and r = --0.49, P less than 0.001, respectively). Total loss of insulin binding to RBCs was estimated to occur in the second postnatal month, and the RBCs from the adult sheep showed no specific insulin binding. The osmotic fragility of RBCs in each developmental group of animals was also studied to assess possible differences in RBC membrane properties. RBC osmotic fragility was significantly lower in fetuses than in adult sheep (osmotic fragility 50 = 0.55% phosphate-buffered saline vs. 0.76% phosphate-buffered saline, respectively; P less than 0.001). The data suggest that fetal RBCs of lower osmotic fragility and high insulin binding capacity are progressively replaced during late prenatal and early postnatal life by adult-type RBCs of increased osmotic fragility and lacking binding capacity for insulin. The timing of the disappearance of insulin binding to RBCs coincides with the final transition in the animals from a monogastric to a ruminant metabolic state, and may reflect a change in the need for insulin with age.     

Rapid bedside rejuvenation of red blood cell with an autologous cell salvage device

Background and Objectives

During storage, red blood cells (RBCs) undergo physicochemical changes which affect the quality, function, and in vivo survival of transfused packed RBCs (pRBC). Changes include decreased 2,3‐diphosphoglycerate (2,3‐DPG) levels, decreased ATP, changes in mechanical properties and oxidative injury. RBC rejuvenation is a method used to increase levels of 2,3‐DPG and ATP in pRBCs. This process requires incubating the pRBCs with a rejuvenation solution and subsequent washing. Standard blood bank protocols using the COBE 2991 Cell Processor require several hours of preparation. The objective of this study was to verify if a bedside protocol for rejuvenating pRBC and washing with the Sorin Xtra autologous cell salvage system could be used.

Materials and Methods

Outdated pRBC units were obtained and rejuvenated in a model operating suite using a dry air incubator for 1 h at 37°C. Six units of pRBCs were pre‐diluted with saline (1000 ml) and six units were not pre‐diluted with saline. All units were washed with normal saline (1000 ml) using an apheresis‐design cell salvage device in manual mode and wash volume set to 3000 ml. Samples were collected and analyzed for standard RBC quality parameters at baseline and post‐wash.

Results

Total pRBC wash efficiency was 94% ± 12% at a final hematocrit of 67.7 ± 5.9% while maintaining post‐wash hemolysis 0.24 ± 0.12 %. Pre‐dilution prior to washing did not confer statistically significant differences in final RBC quality parameters with the notable exceptions of calculated hemolysis and supernatant potassium levels (P < 0.05). The washing process can be completed within 10 min. The post‐wash RBC parameters are appropriate for immediate transfusion to patients.     

Preservation of Red Blood Cells: Content of Microaggregates and Di-2-Ethylhexylphthalate (DEHP) in Red Blood Cells Stored in Saline-Adenine-Glucose-Mannitol (SAGM) Medium

The content of microaggregates was determined in leukocyte-poor red blood cells (RBC) after 5 weeks of storage in citrate-phosphate-dextrose (CPD)-adenine plasma and in saline-adenine-glucose-mannitol (SAGM) medium. The size range was 3,600-200,000 fl, corresponding to a particle diameter of 19-73 micron, presuming a spherical particle shape. In comparison with CPD-adenine whole blood (100%), the total number of particles per unit of RBC was found to be 41.2% (CPD-adenine anticoagulant) and 25.4% (SAGM medium). The corresponding data for total particle volumes were 43.3 and 30.3%. The significant differences between the two categories of RBC could not be explained on the basis of differences concerning pH or cell composition. A majority of particles (50-62%) was observed in the lowest size range (19-29 microns), corresponding to only 18-26% of the total particle volume. The accumulation of di-2-ethylhexylphthalate (DEHP) was determined in two variations of RBC stored in SAGM medium and in RBC stored in CPD-adenine plasma. The quantities of DEHP per unit of RBC after 5 weeks were significantly smaller in SAGM medium (9.0 +/- 3.6 and 22.7 +/- 6.1 mg, respectively) compared to CPD-adenine plasma (30.1 +/- 9.5 mg).