Biochemical and cellular changes in leukocyte-depleted red blood cells stored for transfusion

Effect of leukoreduction on the omics phenotypes of canine packed red blood cells during refrigerated storage

BACKGROUND

Red blood cell (RBC) storage promotes biochemical and morphological alterations, collectively referred to as storage lesions (SLs). Studies in humans have identified leukoreduction (LR) as a critical processing step that mitigates SLs. To date no study has evaluated the impact of LR on metabolic SLs in canine blood units using omics technologies.

OBJECTIVE

Compare the lipid and metabolic profiles of canine packed RBC (pRBC) units as a function of LR in fresh and stored refrigerated (up to 42 days) units.

ANIMALS

Packed RBC units were obtained from 8 donor dogs enrolled at 2 different Italian veterinary blood banks.

STUDY DESIGN AND METHODS

Observational study. A volume of 450 mL of whole blood was collected using Citrate-Phosphate-Dextrose-Saline-Adenine-Glucose-Mannitol (CPD-SAGM) transfusion bags with a LR filter to produce 2 pRBC units for each donor, without (nLR-pRBC) and with (LR-pRBC) LR. Units were stored in the blood bank at 4 ± 2°C. Sterile weekly samples were obtained from each unit for omics analyses.

RESULTS

A significant effect of LR on fresh and stored RBC metabolic phenotypes was observed. The nLR-pRBC were characterized by higher concentrations of free short and medium-chain fatty acids, carboxylic acids (pyruvate, lactate), and amino acids (arginine, cystine). The LR-pRBC had higher concentrations of glycolytic metabolites, high energy phosphate compounds (adenosine triphosphate [ATP]), and antioxidant metabolites (pentose phosphate, total glutathione).

CONCLUSION AND CLINICAL IMPORTANCE

Leukoreduction decreases the metabolic SLs of canine pRBC by preserving energy metabolism and preventing oxidative lesions.

Red Blood Cell Storage with Xenon: Safe or Disruption?

Xenon, an inert gas commonly used in medicine, has been considered as a potential option for prolonged preservation of donor packed red blood cells (pRBCs) under hypoxic conditions. This study aimed to investigate how xenon affects erythrocyte parameters under prolonged storage. In vitro model experiments were performed using two methods to create hypoxic conditions. In the first method, xenon was introduced into bags of pRBCs which were then stored for 42 days, while in the second method, xenon was added to samples in glass tubes. The results of our experiment showed that the presence of xenon resulted in notable alterations in erythrocyte morphology, similar to those observed under standard storage conditions. For pRBC bags, hemolysis during storage with xenon exceeded the acceptable limit by a factor of six, whereas the closed-glass-tube experiment showed minimal hemolysis in samples exposed to xenon. Notably, the production of deoxyhemoglobin was specific to xenon exposure in both cell suspension and hemolysate. However, this study did not provide evidence for the purported protective properties of xenon.

A comparative study of stored arterial versus venous blood collected using the acute normovolemic hemodilution method in coronary artery bypass grafting patients in Iran

BACKGROUND

In the present study, arterial and venous blood was collected from patients who were candidates for elective coronary artery bypass grafting (CABG); the blood was stored for 28 days and cellular, biomechanical, and hematological changes in blood were compared to determine whether stored arterial blood is superior to stored venous blood.

METHODS

The present follow-up comparative study included 60 patients >18 years of age, with hemoglobin >14 mg/dl and ejection fraction >40% who were candidates for CABG. After induction of anesthesia, 250 ml of arterial or venous blood was drawn from patients (arterial blood group and venous blood group). Laboratory blood samples were taken at specified times from the collected blood and re-injected into the patients after CABG.

RESULTS

Significant differences were observed in pH, partial pressure of carbon dioxide (PCO2), partial pressure of oxygen (PO2), bicarbonate (HCO3), and glucose values at several time points between the groups. Other parameters such as urea and creatinine did not show any significant differences between the groups.

CONCLUSIONS

Twenty-eight days of storage can have a negative effect on some of the cellular, biochemical, and hematological components of arterial and venous blood; however, the quality of stored arterial blood and venous blood does not differ significantly.

The estimated negative impacts on the red blood cell inventory of reducing shelf-life at two large health authorities in British Columbia, Canada, using a discrete-event simulation model

BACKGROUND AND OBJECTIVES

Reducing the maximum red blood cell (RBC) shelf-life is under consideration due to potential negative effects of older blood. An assessment of the impacts of this change on blood supply chain management is evaluated.

MATERIALS AND METHODS

We performed a simulation study using data from 2017 to 2018 to estimate the outdate rate (ODR), STAT order and non-group-specific RBC transfusion at two Canadian health authorities (HAs).

RESULTS

Shortening shelf-life from 42 to 35 and 28 days led to the following: ODRs (in percentage) in both HAs increased from 0.52% (95% confidence interval [CI] 0.50-0.54) to 1.32% (95% CI 1.26-1.38) and 5.47% (95% CI 5.34-5.60), respectively (p < 0.05). The estimated yearly median of outdated RBCs increased from 220 (interquartile range [IQR] 199-242) to 549 (IQR 530-576) and 2422 (IQR 2308-2470), respectively (p < 0.05). The median number of outdated redistributed units increased from 152 (IQR 136-168) to 356 (IQR 331-369) and 1644 (IQR 1591-1741), respectively (p < 0.05). The majority of outdated RBC units were from redistributed units rather than units ordered from the blood supplier. The estimated weekly mean STAT orders increased from 11.4 (95% CI 11.2-11.5) to 14.1 (95% CI 13.1-14.3) and 20.9 (95% CI 20.6-21.1), respectively (p < 0.001). The non-group-specific RBC transfusion rate increased from 4.7% (95% CI 4.6-4.8) to 8.1% (95% CI 7.9-8.3) and 15.6% (95% CI 15.3-16.4), respectively (p < 0.001). Changes in ordering schedules, decreased inventory levels and fresher blood received simulated minimally mitigated these impacts.

CONCLUSION

Decreasing RBC shelf-life negatively impacted RBC inventory management, including increasing RBC outdating and STAT orders, which supply modifications minimally mitigate.

Postoperative dysnatremia in infants after open-heart surgery occurs frequently and is associated with prolonged intensive care length of stay

BACKGROUND

Dysnatremia after surgery for congenital heart disease (CHD) is well known and has been associated with prolonged pediatric intensive care unit length of stay (PICU-LOS). Fluctuations in plasma sodium levels occur perioperatively. The primary aim of the study was to evaluate the occurrence of dysnatremia during the first 48 h after surgery and whether it was associated with PICU-LOS. The secondary aim was to evaluate if the degree of sodium fluctuations was associated with PICU-LOS.

METHODS

A retrospective observational, single-center study including infants undergoing surgery for CHD. The highest and lowest plasma sodium value was registered for the prespecified time periods. PICU-LOS was analyzed in relation to the occurrence of dysnatremia and the degree of plasma sodium fluctuations. The occurrence of dysnatremia was evaluated in relation to surgical procedure and fluid administration.

RESULTS

Two hundred and thirty infants who underwent 249 surgical procedures were included. Dysnatremia developed in more than 60% within 48 h after surgery. Infants with normonatremia had a 40%-50% shorter PICU-LOS among children in RACHS-1 category 3-6, compared with infants developing either hypo- or hyper-/hyponatremia within 48 h after surgery (p = .006). Infants who had a decline of plasma sodium >11 mmol/L had almost double the PICU-LOS compared to those with a decline of <8 mmol/L.

CONCLUSION

Dysnatremias were common after surgery for CHD and associated with prolonged PICU-LOS. The degree of decline in plasma sodium was significantly associated with PICU-LOS. Fluid administration both in terms of volume and components (blood products and crystalloids) as well as diuresis were related to the occurrence of dysnatremias.

Do We Store Packed Red Blood Cells under "Quasi-Diabetic" Conditions?

Red blood cell (RBC) transfusion is one of the most common therapeutic procedures in modern medicine. Although frequently lifesaving, it often has deleterious side effects. RBC quality is one of the critical factors for transfusion efficacy and safety. The role of various factors in the cells’ ability to maintain their functionality during storage is widely discussed in professional literature. Thus, the extra- and intracellular factors inducing an accelerated RBC aging need to be identified and therapeutically modified. Despite the extensively studied in vivo effect of chronic hyperglycemia on RBC hemodynamic and metabolic properties, as well as on their lifespan, only limited attention has been directed at the high sugar concentration in RBCs storage media, a possible cause of damage to red blood cells. This mini-review aims to compare the biophysical and biochemical changes observed in the red blood cells during cold storage and in patients with non-insulin-dependent diabetes mellitus (NIDDM). Given the well-described corresponding RBC alterations in NIDDM and during cold storage, we may regard the stored (especially long-stored) RBCs as “quasi-diabetic”. Keeping in mind that these RBC modifications may be crucial for the initial steps of microvascular pathogenesis, suitable preventive care for the transfused patients should be considered. We hope that our hypothesis will stimulate targeted experimental research to establish a relationship between a high sugar concentration in a storage medium and a deterioration in cells’ functional properties during storage.

Effect of Leukoreduction on Hematobiochemical Parameters and Storage Hemolysis in Canine Whole Blood Units

Simple Summary

During the storage of blood units, cells undergo many changes, defined as storage lesions; these are biochemical, morphological and immunological modifications and seem to be responsible for adverse post-transfusion effects in recipients. The pre-storage leukoreduction seems to reduce them. The aims of this study are both to evaluate the human filter effectiveness and the effect of pre-storage leukoreduction in stored canine whole blood units. We tested whole blood units, leukoreduced and not, obtained from seven enrolled subjects, until the 42nd day. The white blood cell (WBC) and platelet (PLT) counts are reported to express the leukoreduction effectiveness. As indicators of storage-induced hemolysis, the lactate dehydrogenase activity (LDH) and sodium, potassium, and chlorine electrolytes were measured in plasma, and the red blood cell (RBC) count, hemoglobin concentration (Hgb), and hematocrit (Hct) were obtained with the complete blood count (CBC). The mean corpuscular volume (MCV) values and morphological index obtained from blood smear evaluation were used as indices of morphological changes. We observed that the leukoreduction filter for human use is equally effective on canine whole blood and that leukoreduction has a partially protective role to prevent some storage lesions.

Abstract

Storage lesions (SLs) occur when the red blood cell quality is altered during the preservation of blood units. Pre-storage leukoreduction would limit the number of SLs. The aims of this study were to evaluate the effectiveness of a leukoreduction filter for human use and the effect of pre-storage leukoreduction on some ematobiochemical parameters in stored canine whole blood. Seven canine blood units were tested. Each one was divided into two units—one leukoreduced (LRWB) and one non-leukoreduced (nLRWB). On each unit, we determined the complete blood count (CBC), lactate-dehydrogenase (LDH), electrolytes (Na⁺, K⁺, Cl⁻), morphological index (MI) and hemolysis, on storage days 0, 7, 14, 21, 28, 35, and 42. Leukoreduction allowed a 98.30% recovery of the RBC count, retaining 99.69% and 94.91% of WBCs and PLTs, respectively. We detected a significant increase of LDH and MI with strongly higher values in nLRWB compared to LRWB. A progressive increase in electrolytes and LDH concentrations was observed as indices of stored hemolysis. LDH showed significantly lower values in LRWB units compared to nLRWB, suggesting its release from leukocytes. In the majority of units, hemolysis reached 1% on the 42nd day of storage. We assert the human leukoreduction filter effectiveness on canine whole blood, and we recommend using nLRWB before day 14, especially for critically ill patients. The difference of the basal hemolysis (day 0) percentages observed between subjects suggests that more studies should be performed to confirm a possible inter-individual donor biological variability of RBC membrane resistance, as happens in humans.

Evaluation of cellular changes in blood stored for transfusion at Bungoma County Referral Hospital, Kenya

Introduction

during the storage of transfusion blood, it may undergo a series of cellular changes that in speculation could be the reason behind the risk of using prolonged stored blood. It's important therefore to monitor the cellular changes that may reduce its survival and function. The objective was to assess the cellular changes in whole blood stored for transfusion at Bungoma county referral hospital.

Methods

a single center, prospective and observational study design involving 20 randomly selected donor blood units in citrate phosphate dextrose adenine (CPDA-1) anticoagulant was employed, cellular changes were evaluated for 35 days. The changes were tested using the Celtac F Haematology analyzer. Statistical Analysis of variance was employed in the descriptive statistics. All the investigation was executed using statistical package for social sciences (SPSS V.23). Results were regarded as significant at P<0.05. Results were presented in tables and charts.

Results

at the end of the 35 days blood storage at blood bank conditions, WBC, RBC, platelets counts and MCHC decreased significantly (P<0.0001, =0.0182, <0.0001, =0.0035). The MCV, HCT and MCH increased significantly (P <0.0001, =0.0003, =0.0115) while HGB had insignificant variance (P =0.4185).

Conclusion

platelets, WBC, RBC counts, and indices are significantly altered in stored blood especially when stored over two weeks based on most of the cellular components analyzed in this study. The study, therefore, recommends the utilization of fresh blood to avoid the adverse outcome of cellular changes of reserved blood.

An Insight into the Stages of Ion Leakage during Red Blood Cell Storage

Packed red blood cells (pRBCs), the most commonly transfused blood product, are exposed to environmental disruptions during storage in blood banks. In this study, temporal sequence of changes in the ion exchange in pRBCs was analyzed. Standard techniques commonly used in electrolyte measurements were implemented. The relationship between ion exchange and red blood cells (RBCs) morphology was assessed with use of atomic force microscopy with reference to morphological parameters. Variations observed in the Na⁺, K⁺, Cl⁻, H⁺, HCO₃⁻, and lactate ions concentration show a complete picture of singly-charged ion changes in pRBCs during storage. Correlation between the rate of ion changes and blood group type, regarding the limitations of our research, suggested, that group 0 is the most sensitive to the time-dependent ionic changes. Additionally, the impact of irreversible changes in ion exchange on the RBCs membrane was observed in nanoscale. Results demonstrate that the level of ion leakage that leads to destructive alterations in biochemical and morphological properties of pRBCs depend on the storage timepoint.

Biochemical changes in whole blood stored for transfusion at Bungoma County Referral Hospital, Kenya

Background

During storage, transfusion blood may undergo a series of biochemical changes that could pose risks to patients when used. It is important therefore to monitor biochemical changes that may reduce survival or function of stored blood cells.

Objective

This study assessed biochemical changes in whole blood stored for transfusion at Bungoma County Referral Hospital in the western region of Kenya between February 2019 and August 2019.

Methods

A prospective study design involving 20 randomly selected donor blood units in citrate phosphate dextrose adenine anticoagulant was employed. Biochemical changes were evaluated for 35 days. Potassium and sodium levels were tested using the HumaLyte Plus5 analyser. Blood pH level was estimated using the Hanna pH meter.

Results

At the end of the 35 days of storage under blood bank conditions, the mean potassium level significantly increased from 7.31 mmol/L at baseline to 20.14 mmol/L at week 5 (p < 0.0001), and the mean sodium level significantly decreased from 150.72 mmol/L at baseline to 121.56 mmol/L at week 5 (p < 0.0001). The pH level decreased insignificantly from 7.48 at baseline to 7.38 at the end of week 1 (p = 0.0757) but decreased significantly to 6.15 at the end of week 5 (p < 0.0001).

Conclusion

Potassium increased and sodium concentrations decreased significantly from the first week of blood storage. The pH decreased significantly from the second week of storage. Therefore, aged blood should be avoided to circumvent potential adverse outcomes from biochemical changes and stored blood should be tested before use.

Impact of G6PD status on red cell storage and transfusion outcomes

There are inter-individual differences in the quality of refrigerator-stored red blood cells (RBCs). Possible sources of these variations include nutritional and genetic factors. Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common enzyme deficiency worldwide that affects the ability of RBCs to respond to oxidative stress, has been implicated as a genetic factor that affects the quality of stored RBCs. This review considers the literature concerning G6PD-deficient RBCs. It discusses RBC unit variables such as in vitro storage, 24-hour post-transfusion recovery (PTR), post-transfusion survival, and post-transfusion clinical outcomes.There are several differences in the in vitro storage characteristics between G6PD-deficient and G6PD-normal RBCs. Recent studies identified differences in the pathways related to glycolysis, purine metabolism, glutathione homeostasis, and fatty acid metabolism. In vitro experiments modelling the transfusion of G6PD-deficient RBCs, as well as autologous PTR studies in vivo, demonstrate increased haemolysis and decreased PTR, respectively, both indicators of a decrease in quality as compared to G6PD-normal RBCs. Finally, studies transfusing G6PD-deficient and G6PD-normal RBCs show that, in certain clinical settings, G6PD-deficient RBCs are associated with increased haemolysis.In summary, G6PD deficiency is associated with a decrease in the quality of RBCs after storage and its impact is often under-estimated. Understanding the underlying mechanisms by which G6PD deficiency affects RBC storage and transfusion outcomes may provide important clues to help optimise the future efficacy and safety of transfusions.

[Effect of red blood cell storage duration on the clinical effect of exchange transfusion and internal environment in neonates with hyperbilirubinemia]

OBJECTIVE

To study the effect of red blood cell (RBC) storage duration on the clinical effect of exchange transfusion (ET) and internal environment in neonates with hyperbilirubinemia.

METHODS

A retrospective analysis was performed for the clinical data of 135 neonates with hyperbilirubinemia who received ET between January 2015 and August 2018. According to RBC storage duration, the neonates were divided into short-term storage group (RBCs were stored for ≤7 days) with 56 neonates and long-term storage group (RBCs were stored for >7 days) with 79 neonates. The two groups were compared in terms of serum total bilirubin (TBIL) level and the rate of TBIL reduction at 0 and 12 hours after ET, as well as the duration of continued phototherapy and rate of repeated ET. Routine blood test parameters, electrolytes, blood glucose, and blood gas parameters were measured before ET and at 0 hour after ET.

RESULTS

At 0 hour after ET, there were no significant differences in the TBIL level and the rate of TBIL reduction between the two groups (P>0.05). At 12 hours after ET, the long-term storage group had a significantly higher TBIL level and a significantly lower rate of TBIL reduction than the short-term storage group (P<0.01). The long-term storage group had a significantly longer duration of continued phototherapy after ET than the short-term storage group (P<0.05). Compared with the short-term storage group, the long-term storage group had significantly higher incidence rates of ET-related complications, including hyponatremia, hyperkalemia, and metabolic acidosis (P<0.05).

CONCLUSIONS

The use of RBCs with a storage duration of >7 days in ET for neonates with hyperbilirubinemia does not affect the immediate effect of ET, but these neonates tend to have a poor outcome after continued phototherapy and high risk of hyponatremia, hyperkalemia, and metabolic acidosis.

Red blood cell storage lesion: causes and potential clinical consequences

Red blood cells (RBCs) are a specialised organ that enabled the evolution of multicellular organisms by supplying a sufficient quantity of oxygen to cells that cannot obtain oxygen directly from ambient air via diffusion, thereby fueling oxidative phosphorylation for highly efficient energy production. RBCs have evolved to optimally serve this purpose by packing high concentrations of haemoglobin in their cytosol and shedding nuclei and other organelles. During their circulatory lifetimes in humans of approximately 120 days, RBCs are poised to transport oxygen by metabolic/redox enzymes until they accumulate damage and are promptly removed by the reticuloendothelial system. These elaborate evolutionary adaptions, however, are no longer effective when RBCs are removed from the circulation and stored hypothermically in blood banks, where they develop storage-induced damages ("storage lesions") that accumulate over the shelf life of stored RBCs. This review attempts to provide a comprehensive view of the literature on the subject of RBC storage lesions and their purported clinical consequences by incorporating the recent exponential growth in available data obtained from "omics" technologies in addition to that published in more traditional literature. To summarise this vast amount of information, the subject is organised in figures with four panels: i) root causes; ii) RBC storage lesions; iii) physiological effects; and iv) reported outcomes. The driving forces for the development of the storage lesions can be roughly classified into two root causes: i) metabolite accumulation/depletion, the target of various interventions (additive solutions) developed since the inception of blood banking; and ii) oxidative damages, which have been reported for decades but not addressed systemically until recently. Downstream physiological consequences of these storage lesions, derived mainly by in vitro studies, are described, and further potential links to clinical consequences are discussed. Interventions to postpone the onset and mitigate the extent of the storage lesion development are briefly reviewed. In addition, we briefly discuss the results from recent randomised controlled trials on the age of stored blood and clinical outcomes of transfusion.

Comparative Evaluation of Biochemical and Hematological Parameters of Pre-Storage Leukoreduction during RBC Storage

Background: Some of the red cell storage lesions (RCSLs) take place during red blood cell (RBC) storage and may reduce the function of these cells dramatically, which mostly caused by residual leucocytes in blood components. This study was planned to observe the biochemical and hematological changes in pre-storage leukoreduced RBC (LR-RBC) compared with unfiltered RBC during in vitro storage. Materials and Methods: Ten unit RBCs were collected, processed and stored according to Iranian standard operating procedure (SOP) of Iranian Blood Transfusion Organization (IBTO). Every unit was split into two equal parts, unfiltered RBC and LR-RBC. Samples were collected and tested on weeks of storage. Biochemical parameters such as lactate dehydrogenase (LDH), lactate concentration and glucose-6-phosphate dehydrogenase (G6PD) enzyme activity were measured by auto-analyzer. In addition, hematology analyzer was used to monitor the change of RBC indices such as (MCV), (MCH) and (MCHC). Results: In this study, both groups showed progressive increase of LDH and lactate levels, and also G6PD activity decreased during storage. Mean of LDH and lactate in unfiltered RBC was significantly increased compared with LR-RBC during all days of storage (p< 0.05). There was statically significant decrease in the G6PD enzyme activity between the two groups and weeks of storage (p< 0.05). However, the RBC indices remained within the expected levels in both groups. Conclusion: LR-RBC and RBC both exhibited RCSL during storage, but LR-RBC is effective in reducing Red cell storage lesion (RCSL) and also improves the quality of stored red blood cells.

Long-term in vitro culture of Plasmodium vivax isolates from Madagascar maintained in Saimiri boliviensis blood

Background

Plasmodium vivax is the most prevalent human malaria parasite and is likely to increase proportionally as malaria control efforts more rapidly impact the prevalence of Plasmodium falciparum. Despite the prominence of P. vivax as a major human pathogen, vivax malaria qualifies as a neglected and under-studied tropical disease. Significant challenges bringing P. vivax into the laboratory, particularly the capacity for long-term propagation of well-characterized strains, have limited the study of this parasite’s red blood cell (RBC) invasion mechanism, blood-stage development, gene expression, and genetic manipulation.

Methods and results

Patient isolates of P. vivax have been collected and cryopreserved in the rural community of Ampasimpotsy, located in the Tsiroanomandidy Health District of Madagascar. Periodic, monthly overland transport of these cryopreserved isolates to the country’s National Malaria Control Programme laboratory in Antananarivo preceded onward sample transfer to laboratories at Case Western Reserve University, USA. There, the P. vivax isolates have been cultured through propagation in the RBCs of Saimiri boliviensis. For the four patient isolates studied to-date, the median time interval between sample collection and in vitro culture has been 454 days (range 166–961 days). The median time in culture, continually documented by light microscopy, has been 159 days; isolate AMP2014.01 was continuously propagated for 233 days. Further studies show that the P. vivax parasites propagated in Saimiri RBCs retain their ability to invade human RBCs, and can be cryopreserved, thawed and successfully returned to productive in vitro culture.

Conclusions/significance

Long-term culture of P. vivax is possible in the RBCs of Saimiri boliviensis. These studies provide an alternative to propagation of P. vivax in live animals that are becoming more restricted. In vitro culture of P. vivax in Saimiri RBCs provides an opening to stabilize patient isolates, which would serve as precious resources to apply new strategies for investigating the molecular and cellular biology of this important malaria parasite.

Electronic supplementary material

The online version of this article (10.1186/s12936-017-2090-7) contains supplementary material, which is available to authorized users.

Biochemical evaluation of the effects of storage on feline erythrocytes

OBJECTIVE

To describe the biochemical changes that occur during storage of feline packed red blood cells.

METHODS

Feline packed red blood cells were obtained from the manufacturer via overnight delivery immediately following collection. Bag spikes were placed using aseptic technique and samples were drawn on days 1, 4, 7, 14, 21, 28 and 35. Sodium, potassium, chloride, glucose, lactate, pH and ammonia were measured at each time point. Aerobic and anaerobic bacterial cultures were submitted following collection on day 35.

RESULTS

There were statistically significant increases in the median concentrations of lactate and ammonia within the first 2 weeks of storage to a concentration of 12·38 mmol/L and 447·96 µmol/L, respectively. Glucose concentrations decreased significantly by day 28 to a mean of 1·86 mmol/L. Median sodium and chloride concentrations increased throughout the course of storage to a concentration of 158·20 and 131·00 mmol/L, respectively. Mean potassium concentrations decreased to a concentration of 2·40 mmol/L.

CLINICAL SIGNIFICANCE

These results show that biochemical derangements within feline packed red blood cells are progressive, with some alterations, such as lactate and ammonia, occurring early within the storage periods, while others, including glucose and electrolytes, are slower to develop. Additional prospective research evaluating the clinical effects of these biochemical alterations is required.