2,3-Diphosphoglycerate Concentrations in Autologous Salvaged Versus Stored Red Blood Cells and in Surgical Patients After Transfusion

Impact of cold storage on the oxygenation and oxidation reactions of red blood cells

Introduction: Electrostatic binding of deoxyhemoglobin (Hb) to cytoplasmic domain of band 3 anion transport protein occurs as part of the glycolytic regulation in red blood cells (RBCs). Hb oxidation intermediates not only impact RBC's oxygenation but also RBC's membrane through the interaction with band 3. It is not known however whether these critical pathways undergo changes during the storage of RBCs. Methods and Results: Oxygen parameters of fresh blood showed a sigmoidal and cooperative oxygen dissociation curve (ODC) for the first week of storage. This was followed by a large drop in oxygen affinity (P50) (from 30 to 20 mmHg) which remained nearly unchanged with a slight elevation in Bohr coefficients and a significant drop in extracellular acidification rates (ECAR) at the 42-day storage. Oxidation of Hb increased with time as well as the formation of a highly reactive ferryl Hb under oxidative stress conditions. Ferryl Hb interacted avidly with RBC's membrane's band 3, but to lesser extent with old ghost RBCs. Discussion: The observed alterations in RBC's oxygen binding may have been affected by the alterations in band 3's integrity which are largely driven by the internal iron oxidation of Hb. Restoring oxygen homeostasis in stored blood may require therapeutic interventions that target changes in Hb oxidation and membrane changes.

Association between routine cell salvage use for lower segment caesarean section and post-operative iron infusion and anemia

PURPOSE

Intraoperative cell salvage is central to Patient Blood Management including for lower segment caesarean section. Prior to April 2020, we initiated intraoperative cell salvage during caesarean section based on risk assessment for hemorrhage and patient factors. As the pandemic broadened, we mandated intraoperative cell salvage to prevent peri-partum anemia and potentially reduce blood product usage. We examined the association of routine intraoperative cell salvage on maternal outcomes.

METHODS

We conducted a single-center non-overlapping before-after study of obstetric patients undergoing lower segment caesarean section in the 2 months prior to a change in practice ('usual care = selective intraoperative cell salvage', n = 203) and the 2 months following ('mandated intraoperative cell salvage', n = 228). Recovered blood was processed when a minimal autologous reinfusion volume of 100 ml was expected. Post-operative iron infusion and length of stay were modelled using logistic or linear regression, using inverse probability weighting to account for confounding.

RESULTS

More emergency lower-segment caesarean sections occurred in the Usual Care group. Compared to the Usual Care group, post-operative hemoglobin was higher and anemia cases fewer in the Mandated intraoperative cell salvage group. Rates of post-partum iron infusion were significantly lower in the Mandated intraoperative cell salvage group (OR = 0.31, 95% CI = 0.12 to 0.80, P = 0.016). No difference was found for length of stay.

CONCLUSION

Routine cell salvage provision during lower segment caesarean section was associated with a significant reduction in post-partum iron infusions, increased post-operative hemoglobin and reduced anemia prevalence.

Pathogen reduced red blood cells as an alternative to irradiated and washed components with potential for up to 42 days storage

BACKGROUND

The urgency of maintaining a safe and adequate blood supply is increasing. One approach to ensure a sufficient supply is to limit the outdating frequency of blood components. Pathogen inactivation technology was developed primarily to increase safety by preventing transmission of infectious diseases. The Intercept Blood System for pathogen reduction of red blood cells (RBC) has additional benefits such as inactivation of leucocytes and removal of plasma and storage debris through centrifugation. Irradiation and automated washing are detrimental to the RBC membrane and often implicate shortened shelf-life. We aimed to assess whether pathogen inactivation can replace RBC irradiation and washing to avoid shelf-life reduction.

MATERIALS AND METHODS

RBC concentrates (No.=48) were pooled-and-split into four study arms, which underwent pathogen inactivation treatment, irradiation, automated washing or no treatment (reference). RBC quality was evaluated during 42 days by assessment of storage lesion. Washing efficacy was defined by IgA and albumin reduction.

RESULTS

Pathogen reduced RBCs had similar membrane preservation to reference RBCs (hemolysis, microvesicles and extracellular potassium ions), whereas the RBCs were negatively impacted by irradiation or automated washing. ATP increased substantially post-pathogen inactivation, while 2,3-DPG decreased. Pathogen inactivation considerably reduced albumin and IgA, though slightly less efficiently than automated washing.

DISCUSSION

RBCs exhibit superior membrane preservation after pathogen inactivation treatment, compared to both irradiation and automated washing. This suggests that replacement is possible, even though the plasma reduction protocol could be further optimised.Replacement of irradiated and washed RBC concentrates with pathogen reduced RBC concentrates storable up to 42 days would be advantageous for both the blood supply and patient safety.

Impaired O2 unloading from stored blood results in diffusion-limited O2 release at tissues: evidence from human kidneys

ABSTRACT

The volume of oxygen drawn from systemic capillaries down a partial pressure gradient is determined by the oxygen content of red blood cells (RBCs) and their oxygen-unloading kinetics, although the latter is assumed to be rapid and, therefore, not a meaningful factor. Under this paradigm, oxygen transfer to tissues is perfusion-limited. Consequently, clinical treatments to optimize oxygen delivery aim at improving blood flow and arterial oxygen content, rather than RBC oxygen handling. Although the oxygen-carrying capacity of blood is increased with transfusion, studies have shown that stored blood undergoes kinetic attrition of oxygen release, which may compromise overall oxygen delivery to tissues by causing transport to become diffusion-limited. We sought evidence for diffusion-limited oxygen release in viable human kidneys, normothermically perfused with stored blood. In a cohort of kidneys that went on to be transplanted, renal respiration correlated inversely with the time-constant of oxygen unloading from RBCs used for perfusion. Furthermore, the renal respiratory rate did not correlate with arterial O2 delivery unless this factored the rate of oxygen-release from RBCs, as expected from diffusion-limited transport. To test for a rescue effect, perfusion of kidneys deemed unsuitable for transplantation was alternated between stored and rejuvenated RBCs of the same donation. This experiment controlled oxygen-unloading, without intervening ischemia, holding all non-RBC parameters constant. Rejuvenated oxygen-unloading kinetics improved the kidney's oxygen diffusion capacity and increased cortical oxygen partial pressure by 60%. Thus, oxygen delivery to tissues can become diffusion-limited during perfusion with stored blood, which has implications in scenarios, such as ex vivo organ perfusion, major hemorrhage, and pediatric transfusion. This trial was registered at www.clinicaltrials.gov as #ISRCTN13292277.

Cardiopulmonary bypass in a rat model may shorten the lifespan of stored red blood cells by activating caspase-3

BACKGROUND

Red blood cell transfusion is required for many types of surgery against cardiovascular disease, and the function of transfused cells appears to decline over time. The present study examined whether transfusion also reduces red blood cell lifespan in a rat model.

MATERIAL AND METHODS

Bypass in rats were established by connecting a roll pump to the femoral artery and vein. Then FITC-labeled stored red blood cells from rats were transfused in the animals, and the cells in circulation were counted after transfusion. In separate experiments, stored red blood cells were incubated with bypass plasma in vitro, and the effects of incubation were assessed on cell morphology, redox activity, ATP level, caspase-3 activity, and phosphatidylserine exposure on the cell surface. These in vivo and in vitro experiments were also performed after pretreating the stored red blood cells with the caspase-3 inhibitor Z-DEVD-FMK.

RESULTS

Bypass significantly decreased the number of circulating FITC-labeled stored red blood cells and increased the proportions of monocytes, neutrophils and splenic macrophages that had phagocytosed the red blood cells. In vitro, bypass plasma altered the morphology of red blood cells and increased oxidative stress, caspase-3 activity and phosphatidylserine exposure, while decreasing ATP level. Pretreating stored red blood cells with Z-DEVD-FMK attenuated the effects of bypass on caspase-3 activity, but not oxidative stress, in stored red blood cells.

DISCUSSION

Bypass appears to shorten the lifespan of stored red blood cells, at least in part by activating caspase-3 in the cells.

Red Blood Cell Metabolism In Vivo and In Vitro

Red blood cells (RBC) are the most abundant cell in the human body, with a central role in oxygen transport and its delivery to tissues. However, omics technologies recently revealed the unanticipated complexity of the RBC proteome and metabolome, paving the way for a reinterpretation of the mechanisms by which RBC metabolism regulates systems biology beyond oxygen transport. The new data and analytical tools also informed the dissection of the changes that RBCs undergo during refrigerated storage under blood bank conditions, a logistic necessity that makes >100 million units available for life-saving transfusions every year worldwide. In this narrative review, we summarize the last decade of advances in the field of RBC metabolism in vivo and in the blood bank in vitro, a narrative largely influenced by the authors' own journeys in this field. We hope that this review will stimulate further research in this interesting and medically important area or, at least, serve as a testament to our fascination with this simple, yet complex, cell.

Intraoperative use of cell saver devices decreases the rate of hyperlactatemia in patients undergoing cardiac surgery

Objective

This study was aimed to elucidate the effect of the intraoperative cell saver (CS) on hyperlactatemia of patients who underwent cardiac surgery.

Design

A sub-analysis of the CS was performed, which is a historial control trial of patients undergoing cardiac surgery.

Setting

This was a retrospective single-center and not blinded study.

Participants

We examined the occurrence of hyperlactatemia retrospectively in patients of CS group (n = 78) who were included in prospective trial and received valvular surgery, where CS was used during the procedure. Patients subjected to valvular surgery before February 2021 were adopted in control group (n = 79).

Interventions

Arterial blood was sampled (1) before cardiopulmonary bypass, (2) during bypass (3) immediately after bypass, (4) on ICU admission and (5) every 4 h up to 24 h postoperatively.

Measurements and main results

A lower incidence of hyperlactatemia (32.1% vs. 57.0%; P = 0.001) was observed in patients from the CS group. Furthermore, the blood lactate concentration was higher in control group than in CS group during CPB, post CPB, on ICU admission and lasted until 20 h after the operation. Multivariable analysis revealed that intraoperative use of CS was expected to be a protective factor against hyperlactatemia in this study (OR = 0.31, 95% CI 0.15-0.63, P = 0.001).

Conclusion

Intraoperative use of a CS device was associated with a lower incidence of hyperlactatemia. Whether such device use is valuable to limiting hyperlactatemia in cardiac patients after surgery requires further evaluation in larger prospective studies.

Use of Autotransfusion following Percutaneous Thrombectomy for Cardiogenic Shock Due to Pulmonary Embolism in a Single Session-A Case Report

A 64-year-old male patient was admitted to the catheterization laboratory with a suspected myocardial infarction and in cardiogenic shock. Upon further investigation, a massive bilateral pulmonary embolism with signs of right heart dysfunction was discovered, leading to a decision to perform a direct interventional treatment with a thrombectomy device for thrombus aspiration. The procedure was successful in removing almost the entirety of the thrombotic material from the pulmonary arteries. The patient's hemodynamics stabilized and oxygenation improved instantly. The procedure required a total of 18 aspiration cycles. Each aspiration contained approx. 60 mL blood amounting to a total of approx. 1080 mL of blood. During the procedure, a mechanical blood salvage system was used to resupply 50% of the blood via autotransfusion that would otherwise have been lost. The patient was transferred to the intensive care unit for post-interventional care and monitoring. A CT angiography of the pulmonary arteries after the procedure confirmed the presence of only minor residual thrombotic material. The patient's clinical, ECG, echocardiographic, and laboratory parameters returned to normal or near normal ranges. The patient was discharged shortly after in stable conditions on oral anticoagulation.

Patient Blood Management in Vascular Surgery

Patient blood management (PBM) is an evidence-based, multidisciplinary approach aimed at appropriately allocating blood products to patients requiring transfusion while simultaneously minimizing inappropriate transfusions. The 3 pillars of patient blood management are optimizing erythropoiesis, minimizing blood loss, and optimizing physiological reserve of anemia. Benefits seen from PBM include limiting hospital costs and mitigating harm from numerous risks of transfusion.

Storage of red blood cells in alkaline PAGGGM improves metabolism but has no effect on posttransfusion recovery

Storage of red blood cells in the alkaline storage solution PAGGGM improves metabolism but has no effect on posttransfusion recovery.

Transfused red blood cells can recover from the metabolic storage lesion within a day after transfusion.

Additive solutions are used to limit changes that red blood cells (RBCs) undergo during storage. Several studies have shown better preservation of glucose and redox metabolism using the alkaline additive solution PAGGGM (phosphate-adenine-glucose-guanosine-gluconate-mannitol). In this randomized open-label intervention trial in 20 healthy volunteers, the effect of storage, PAGGGM vs SAGM (saline-adenine-glucose-mannitol), on posttransfusion recovery (PTR) and metabolic restoration after transfusion was assessed. Subjects received an autologous biotinylated RBC concentrate stored for 35 days in SAGM or PAGGGM. As a reference for the PTR, a 2-day stored autologous biotinylated RBC concentrate stored in SAGM was simultaneously transfused. RBC phenotype and PTR were assessed after transfusion. Biotinylated RBCs were isolated from the circulation for metabolomics analysis up to 24 hours after transfusion. The PTR was significantly higher in the 2-day stored RBCs than in 35-day stored RBCs 2 and 7 days after transfusion: 96% (90 to 99) vs 72% (66 to 89) and 96% (90 to 99) vs 72% (66 to 89), respectively. PTR of SAGM- and PAGGGM-stored RBCs did not differ significantly. Glucose and redox metabolism were better preserved in PAGGGM-stored RBCs. The differences measured in the blood bag remained present only until 1 day after transfusion. No differences in RBC phenotype were found besides an increased complement C3 deposition on 35-day RBCs stored in PAGGGM. Our data indicate that despite better metabolic preservation, PAGGGM is not a suitable alternative for SAGM because storage in PAGGGM did not result in an increased PTR. Finally, RBCs recovered from circulation after transfusion showed reversal of the metabolic storage lesion in vivo within a day. This study is registered in the Dutch trial register (NTR6492).

Impact of Intraoperative Salvaged Blood Autotransfusion During Obstetric Hemorrhage on the Coagulation Function: A Retrospective Cohort Analysis

Objective

This study aimed to explore the effect of intraoperative blood salvage (autotransfusion) on coagulation function in the rescue of an obstetric hemorrhage.

Methods

A total of 65 pregnant women who were diagnosed with placenta previa in our Hospital and gave birth in the hospital were enrolled in the study. All the patients underwent thromboelastography, routine blood tests, and blood coagulation series + D-dimer before and within 30 min of the autologous blood transfusion. The differences in various indicators were evaluated.

Results

(1) After the autotransfusion, the hemoglobin and neutrophil counts were significantly higher than beforehand, and the platelet count was significantly reduced; the differences were statistically significant (p < .05). (2) There were no significant differences in prothrombin time (PT), fibrinogen, and D-dimer levels before and after the autotransfusion (p > .05). The activated partial thromboplastin time after autotransfusion was shorter than that beforehand, and the difference was statistically significant (p < .05). (3) There were no significant differences in the R value, K value, α value, and MA value of the thromboelastogram before and after the autotransfusion (p > .05).

Conclusion

After the recovery autotransfusion, the hemoglobin of patients with a massive obstetric hemorrhage increased significantly, while the platelet count decreased, but the coagulation function and thromboelastogram did not change significantly, indicating the autotransfusion did not affect the coagulation function of the obstetric hemorrhage rescue. Thus, it would appear that intraoperative blood salvage can be safely used in the clinical rescue of massive hemorrhaging during cesarean section.

Contribution of Various Types of Transfusion to Acute and Delayed Intracerebral Hemorrhage Injury

Intracerebral hemorrhage (ICH) is the second most prevalent type of stroke, after ischemic stroke, and has exceptionally high morbidity and mortality rates. After spontaneous ICH, one primary goal is to restrict hematoma expansion, and the second is to limit brain edema and secondary injury. Various types of transfusion therapies have been studied as treatment options to alleviate the adverse effects of ICH etiopathology. The objective of this work is to review transfusions with platelets, fresh frozen plasma (FFP), prothrombin complex concentrate (PCC), and red blood cells (RBCs) in patients with ICH. Furthermore, tranexamic acid infusion studies have been included due to its connection to ICH and hematoma expansion. As stated, the first line of therapy is limiting bleeding in the brain and hematoma expansion. Platelet transfusion is used to promote recovery and mitigate brain damage, notably in patients with severe thrombocytopenia. Additionally, tranexamic acid infusion, FFP, and PCC transfusion have been shown to affect hematoma expansion rate and volume. Although there is limited available research, RBC transfusions have been shown to cause higher tissue oxygenation and lower mortality, notably after brain edema, increases in intracranial pressure, and hypoxia. However, these types of transfusion have varied results depending on the patient, hemostasis status/blood thinner, hemolysis, anemia, and complications, among other variables. Inconsistencies in published results on various transfusion therapies led us to review the data and discuss issues that need to be considered when establishing future guidelines for patients with ICH.

Industrially Compatible Transfusable iPSC-Derived RBCs: Progress, Challenges and Prospective Solutions

Amidst the global shortfalls in blood supply, storage limitations of donor blood and the availability of potential blood substitutes for transfusion applications, society has pivoted towards in vitro generation of red blood cells (RBCs) as a means to solve these issues. Many conventional research studies over the past few decades have found success in differentiating hematopoietic stem and progenitor cells (HSPCs) from cord blood, adult bone marrow and peripheral blood sources. More recently, techniques that involve immortalization of erythroblast sources have also gained traction in tackling this problem. However, the RBCs generated from human induced pluripotent stem cells (hiPSCs) still remain as the most favorable solution due to many of its added advantages. In this review, we focus on the breakthroughs for high-density cultures of hiPSC-derived RBCs, and highlight the major challenges and prospective solutions throughout the whole process of erythropoiesis for hiPSC-derived RBCs. Furthermore, we elaborate on the recent advances and techniques used to achieve cost-effective, high-density cultures of GMP-compliant RBCs, and on their relevant novel applications after downstream processing and purification.

Intraoperative blood salvage in proximal femur epiphysiolysis surgical treatment with hip controlled dislocation technique: a case series study

OBJECTIVES

To report a case series of Intraoperative Blood Salvage (IOS) in surgeries during the treatment for Slipped Capital Femoral Epiphysis (SCFE) with controlled dislocation of the hip, identifying its efficacy, complications, and the profile of patients with SCFE.

METHODS

Descriptive study reporting a case series, comprising patients seen between January 2016 and March 2018, diagnosed with SCFE, and treated with controlled surgical dislocation of the hip using IOS.

RESULTS

Sample comprised of 15 patients, with a mean age of 13.1 years. The most affected side was the left with 8 cases. None of the patients required allogeneic blood in the postoperative period. Mean pre- and postoperative hemoglobin were 13.2 and 11.2 g.dL-1, respectively, and mean hemoglobin difference was 1.8 g.dL-1. Mean pre- and postoperative hematocrit were 39.13% and 33.20%, respectively, and mean hematocrit difference was 5.52%. No intraoperative complications were observed. One patient presented vomiting and another one, wound infection in the postoperative period.

CONCLUSION

IOS was an alternative blood salvage approach and prevented allogeneic blood transfusion, enabling reduction of potential complications.

Resuscitation From Hemorrhagic Shock With Fresh and Stored Blood and Polymerized Hemoglobin

BACKGROUND

Hemoglobin (Hb)-based oxygen carriers (HBOCs) have been proposed as alternatives to blood for decades. Previous studies demonstrated that large molecular diameter HBOCs based on polymerized bovine Hb (PolybHb) attenuate Hb side-effects and toxicity. The objective of this study was to test the safety and efficacy of tense state PolybHb after long-term storage.

METHODS AND RESULTS

PolybHb was subjected to diafiltration to remove low molecular weight (< 500 kDa) species and stored for 2 years. PolybHb was studied in parallel with blood, collected from rats and stored leukodepleted under blood bank conditions for 3 weeks. Rats were hemorrhaged and resuscitated to 90% of the blood pressure before the hemorrhage with fresh blood, stored blood, fresh PolybHb, or 2-year-stored PolybHb. Hemorrhagic shock impaired oxygen delivery and cardiac function. Resuscitation restored blood pressure and cardiac function, but stored blood required a significantly larger transfusion volume to recover from shock compared with fresh blood and PolybHb (fresh and stored). Stored blood transfusion elevated markers of organ damage compared with all other groups.

CONCLUSIONS

These studies indicate that large molecular diameter PolybHb is as efficacious as fresh blood in restoring cardiac function and confirm the lack of degradation of PolybHb's safety or efficacy during long-term storage.

The Impact of Intraoperative Donor Blood on Packed Red Blood Cell Transfusion During Deceased Donor Liver Transplantation: A Retrospective Cohort Study

BACKGROUND

Blood from deceased organ donors, also known as donor blood (DB), has the potential to reduce the need for packed red blood cells (PRBCs) during liver transplantation (LT). We hypothesized that DB removed during organ procurement is a viable resource that could reduce the need for PRBCs during LT.

METHODS

We retrospectively examined data on LT recipients aged over 18 y who underwent a deceased donor LT. The primary aim was to compare the incidence of PRBC transfusion in LT patients who received intraoperative DB (the DB group) to those who did not (the nondonor blood [NDB] group).

RESULTS

After a propensity score matching process, 175 patients received DB and 175 did not. The median (first-third quartile) volume of DB transfused was 690.0 mL (500.0-900.0), equivalent to a median of 3.1 units (2.3-4.1). More patients in the NDB group received an intraoperative PRBC transfusion than in the DB group: 74.3% (95% confidence intervals, 67.8-80.8) compared with 60% (95% confidence intervals, 52.7-67.3); P = 0.004. The median number of PRBCs transfused intraoperatively was higher in the NDB group compared with the DB group: 3 units (0-6) compared with 2 units (0-4); P = 0.004. There were no significant differences observed in the secondary outcomes.

CONCLUSIONS

Use of DB removed during organ procurement and reinfused to the recipient is a viable resource for reducing the requirements for PRBCs during LT. Use of DB minimizes the exposure of the recipient to multiple donor sources.

Red blood cell storage duration and peri-operative outcomes in paediatric cardiac surgery

BACKGROUND

Prior research on red blood cell (RBC) storage duration and clinical outcomes in paediatric cardiac surgery has shown conflicting results. The purpose of this study was to evaluate whether blood stored for a longer duration is harmful in these patients.

METHODS

We performed a retrospective cohort study of paediatric patients undergoing cardiac surgery at our institution between January 2011 and June 2015. Patients were stratified based on whether they were transfused RBCs stored for ≤15 days (fresher blood) or >15 days (older blood). The primary outcome was composite morbidity, with prolonged length of stay (LOS) as a secondary outcome. Subgroup analyses were performed after stratification by RBC transfusion volume (≤2 vs. >2 RBC units). Multivariable logistic regression models were used to assess the impact of RBC storage duration on composite morbidity and prolonged LOS.

RESULTS

Of 461 patients, 122 (26·5%) received fresher blood and 339 (73·5%) received older blood. The overall rate of composite morbidity was 18·0% (n = 22) for patients receiving fresher blood and 13·6% (n = 46) for patients receiving older blood (P = 0·24). In the risk-adjusted model, patients receiving older blood did not exhibit an increased risk of composite morbidity (OR: 0·74, 95% CI: 0·37-1·47, P = 0·40) or prolonged LOS (OR: 0·72, 95% CI: 0·38-1·35, P = 0·30) compared to patients receiving fresher blood. Similar results were seen after stratification by RBC transfusion volume.

CONCLUSIONS

Transfusing RBCs stored for a longer duration was not associated with an increased risk of morbidity or prolonged LOS in paediatric cardiac surgery patients.

Influence of blood haemoglobin concentration on renal haemodynamics and oxygenation during experimental cardiopulmonary bypass in sheep

AIM

Blood transfusion may improve renal oxygenation during cardiopulmonary bypass (CPB). In an ovine model of experimental CPB, we tested whether increasing blood haemoglobin concentration [Hb] from ~7 g dL-1 to ~9 g dL-1 improves renal tissue oxygenation.

METHODS

Ten sheep were studied while conscious, under stable isoflurane anaesthesia, and during 3 hours of CPB. In a randomized cross-over design, 5 sheep commenced bypass at a high target [Hb], achieved by adding 600 mL donor blood to the priming solution. After 90 minutes of CPB, PlasmaLyte® was added to the blood reservoir to achieve low target [Hb]. For the other 5 sheep, no blood was added to the prime, but after 90 minutes of CPB, 800-900 mL of donor blood was given to achieve a high target [Hb].

RESULTS

Overall, CPB was associated with marked reductions in renal oxygen delivery (-50 ± 12%, mean ± 95% confidence interval) and medullary tissue oxygen tension (PO2 , -54 ± 29%). Renal fractional oxygen extraction was 17 ± 10% less during CPB at high [Hb] than low [Hb] (P = .04). Nevertheless, no increase in tissue PO2 in either the renal medulla (0 ± 6 mmHg change, P > .99) or cortex (-19 ± 13 mmHg change, P = .08) was detected with high [Hb].

CONCLUSIONS

In experimental CPB blood transfusion to increase Hb concentration from ~7 g dL-1 to ~9 g dL-1 did not improve renal cortical or medullary tissue PO2 even though it decreased whole kidney oxygen extraction.

Mechanism and effects of fructose diphosphate on anti-hypoxia fatigue and learning memory ability

This study aims to investigate the mechanisms through which fructose diphosphate (FDP) causes anti-hypoxia and anti-fatigue effects and improves learning and memory. Mice were divided into three groups: low-dose FDP (FDP-L), high-dose FDP (FDP-H), and a control group. Acute toxic hypoxia induced by carbon monoxide, sodium nitrite, and potassium cyanide and acute cerebral ischemic hypoxia were used to investigate the anti-hypoxia ability of FDP. The tests of rod-rotating, mouse tail suspension, and swimming endurance were used to explore the anti-fatigue effects of FDP. The Morris water maze experiment was used to determine the impact of FDP on learning and memory ability. Poisoning-induced hypoxic tests showed that mouse survival time was significantly prolonged in the FDP-L and FDP-H groups compared with the control group (p < 0.05). In the exhaustive swimming test, FDP significantly shortened struggling time and prolonged the time of mass-loaded swimming; the rod-rotating test showed that endurance time was significantly prolonged by using FDP (p < 0.05). FDP significantly decreased lactate and urea nitrogen levels and increased hepatic and muscle glycogen and glucose transporter-4 and Na⁺-K⁺-ATPase (p < 0.05). To conclude, FDP enhances hypoxia tolerance and fatigue resistance and improves learning and memory ability through regulating glucose and energy metabolism.

Clinical Utility of Autologous Salvaged Blood: a Review

INTRODUCTION

Autologous salvaged blood, commonly referred to as "cell saver" or "cell salvage" blood, is an important method of blood conservation. Understanding the mechanism of action and summarizing the existing evidence regarding the safety, efficiency, and the relative costs of cell salvage may help educate clinicians on how and when to best utilize autotransfusion.

METHODS

This review focuses on issues concerning the quality of red blood cells (RBC), efficiency, and the cost effectiveness relative to autotransfusion. The key considerations of safe use and clinical applicability are described along with the challenges for wider dissemination.

RESULTS

Cell salvage can reduce requirements for allogeneic transfusions, along with the associated risks and costs. Autologous salvaged RBCs provide high-quality transfusion, since the cells have not been subjected to the adverse effects of storage as occurs with banked blood. The risks for RBC alloimmunization and transfusion-related infectious diseases are also avoided. With a careful selection of cases, salvaged blood can be more cost effective than donor blood. Cell salvage may have a role in cardiac, major vascular, orthopedic, transplant, and trauma surgeries. However, there remain theoretical safety concerns in cases with bacterial contamination or in cancer surgery.

CONCLUSION

In addition to other methods of blood conservation used in patient blood management programs, autologous salvaged blood adds value and is cost effective for appropriate surgical cases. Evidence suggests that autologous salvaged blood may be of higher quality and confer a cost reduction compared with the allogeneic banked blood, when used appropriately.

Intraoperative cell salvage use reduces the rate of perioperative allogenic blood transfusion in patients undergoing periacetabular osteotomy

Blood loss during periacetabular osteotomy (PAO) is variable, with losses ranging from 100 to 3900 ml in published series. Perioperative allogenic blood transfusion is frequently utilized although is associated with significant risk of morbidity. Cell salvage (CS) is a common blood conservation tool; however, evidence supporting its use with PAO is lacking. Our aim was to assess whether CS affects perioperative allogenic blood transfusion rate in patients undergoing PAO. The clinical records of 58 consecutive PAOs in 54 patients (median age 24.7 years, interquartile range 17.8-29.4 years) performed by a single surgeon between 1 January 2016 and 30 April 2018 were reviewed. Autologous blood pre-donation and surgical drains were not used. Due to variable technician availability, CS was intermittently used during the study period. PAOs were allocated into a CS group or no cell salvage group (NCS group), according to whether an intraoperative CS system was used. There was no significant difference in patient age, gender, body mass index, dysplasia severity, regional anesthetic technique, tranexamic acid administration, surgical duration or estimated blood loss (all P > 0.05) between the two groups. The CS group had a lower preoperative hemoglobin compared to the NCS group (median, 13.4 g/dl versus 14.4 g/dl, P = 0.006). The incidence of allogenic blood transfusion was significantly lower in the CS group compared to the NCS group (2.5% versus 33.3% patients transfused, P = 0.003). Multivariate modeling showed CS use to be protective against allogenic blood transfusion (P = 0.003), with an associated 80-fold reduction in the odds of transfusion (odds ratio, 0.01; 95th% CI, 0-0.57). To our knowledge, this is the first study to assess the effect of CS use on allogenic transfusion rate in patients undergoing PAO. Our results demonstrate CS to be a mandatory component of blood conservation for all patients undergoing PAO.

[Cell salvage : Scientific evidence, clinical practice and legal framework]

Cell salvage is an efficient method to reduce the transfusion of homologous banked blood, as documented by several meta-analyses detected in a systematic literature search. Cell salvage is widely used in orthopedics, trauma surgery, cardiovascular and abdominal transplantation surgery. The retransfusion of unwashed shed blood from wounds or drainage is not permitted according to German regulations. Following irradiation of wound blood, salvaged blood can also be used in tumor surgery. Cell salvage makes a valuable contribution to providing sufficient compatible blood for transfusions in cases of massive blood loss. Certain surgical procedures for Jehovah's Witnesses are only possible with the use of cell salvage. Another possible use is the washing of homologous banked blood, e. g. to prevent potassium-induced arrhythmia or sequestration of autologous platelets. Other advantages besides a good compatibility are the high vitality and functionality of the unstored autologous red blood cells. These have been declared a pharmaceutical product by the German transfusion task force in 2014, so that the autologous red blood cells are now under the control of the Pharmaceutical Products Act (AMG). The new hemotherapy guidelines, however, tolerate cell salvage only under strict rules, whereby the production of autologous blood during or after surgery is still possible without additional special permits. The new guidelines now require the introduction of a quality management system for cell salvage and regular quality controls. These quality controls include a control of the product hematocrit for every application, monthly controls of the protein and albumin elimination rates and the erythrocyte recovery rate for each cell salvage device. Testing for infection markers is not required. The application of cell salvage has to be reported to the appropriate authorities.

Preventing and managing catastrophic bleeding during extracorporeal circulation

The use of extracorporeal circulation for cardiac surgery and extracorporeal life support poses tremendous challenges to the hemostatic equilibrium given its diametric tendency to trigger hyper- and hypocoagulopathy. The necessity of anticoagulant therapy to counteract the hemostatic activation by the extracorporeal circuitry compounded by unfavorable patient and surgical factors significantly increase the risk of catastrophic bleeding in patients who require extracorporeal circulation. Preoperative measures, such as stratification of high-risk bleeding patients, and optimization of the modifiable variables, including anemia and thrombocytopenia, provide a crude estimation of the likelihood and may modify the risk of catastrophic bleeding. The anticipation for catastrophic bleeding subsequently prompts the appropriate preparation for potential resuscitation and massive transfusion. Equally important is intraoperative prevention with the prophylactic application of tranexamic acid, an antifibrinolytic agent that has promising benefits in reduction of blood loss and transfusion. In the event of uncontrolled catastrophic bleeding despite preemptive strategies, all effort must be centered on regaining hemostasis through surgical control and damage control resuscitation to protect against worsening coagulopathy and end organ failure. When control of bleeding is reinstated, management should shift focus from systemic therapy to targeted hemostatic therapy aimed at the potential culprits of coagulopathy as identified by point of care hemostatic testing. This review article outlines the strategies to appropriately intervene using prediction, prevention, preparation, protection, and promotion of hemostasis in managing catastrophic bleeding in extracorporeal circulation.

Transfusion of Red Blood Cells Stored More Than 28 Days is Associated With Increased Morbidity Following Spine Surgery

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to describe the association between storage duration of packed red blood cells (PRBCs) and perioperative adverse events in patients undergoing spine surgery at a tertiary care center.

SUMMARY OF BACKGROUND DATA

Despite retrospective studies that have shown that longer PRBC storage duration worsens patient outcomes, randomized clinical trials have found no difference in outcomes. However, no studies have examined the impact of giving the oldest blood (28 days old or more) on morbidity within spine surgery.

METHODS

The surgical administrative database at our institution was queried for patients transfused with PRBCs who underwent spine surgery between December 4, 2008, and June 26, 2015. Patients undergoing spinal fusion, tumor-related surgeries, and other identified spine surgeries were included. Patients were divided into two groups on the basis of storage duration of blood transfused: exclusively ≤28 days' storage or exclusively >28 days' storage. The primary outcome was composite in-hospital morbidity, which included (1) infection, (2) thrombotic event, (3) renal injury, (4) respiratory event, and/or (5) ischemic event.

RESULTS

In total, 1141 patients who received a transfusion were included for analysis in this retrospective study; 710 were transfused exclusively with PRBCs ≤28 days' storage and 431 exclusively with PRBCs >28 days' storage. Perioperative complications occurred in 119 patients (10.4%). Patients who received blood stored for >28 days had higher odds of developing any one complication [odds ratio (OR) = 1.82; 95% confidence interval (95% CI), 1.20-2.74; P = 0.005] even after adjusting for competing perioperative risk factors.

CONCLUSION

Blood stored for >28 days is independently associated with higher odds of developing perioperative complications in patients transfused during spinal surgery. Our results suggest that blood storage duration may be an appropriate parameter to consider when developing institutional transfusion guidelines that seek to optimize patient outcomes.

LEVEL OF EVIDENCE

3.

Estimation of Achievable Oxygen Consumption Following Transfusion With Rejuvenated Red Blood Cells

Erythrocyte storage induces a nonphysiological increase in hemoglobin-oxygen affinity (quantified by low p50, the oxygen tension at 50% hemoglobin saturation), which can be restored through biochemical rejuvenation. The objective was to mathematically model the impact of transfusing up to 3 standard allogeneic units or rejuvenated units on oxygen delivery (DO₂) and oxygen consumption (VO₂). Oxygen dissociation curves were generated from additive solution-1 red blood cell (RBC) leukoreduced units (n = 7) before and after rejuvenation following manufacturer's instructions. Two of these units were used to prepare standard or rejuvenated donor RBC and added to samples of fresh whole blood. These admixtures were used to construct an in vitro transfusion model of postoperative anemia and determine a linear equation for calculating the sample p50, which was subsequently used to calculate DO₂ and VO₂ after simulated transfusions. Whole blood-packed red blood cell unit admixture p50s could be predicted from a linear model including the p50 of its components, the mass fraction of the transfused component, and interaction terms (R² = .99, P < 0.001). Transfusion with standard units slightly, but significantly, increased projected DO₂ compared with rejuvenated units (P = 0.03), but rejuvenated units markedly increased projected VO₂ (P = 0.03). Standard units did not significantly change VO₂ relative to pre-transfusion levels (P > 0.1). Using high-p50, rejuvenated RBC in simulated transfusions greatly improved projected VO₂, indicating the potential for increased end-organ oxygen availability compared with standard transfusion. Patient capacity to increase cardiac output after cardiac surgery may be limited. Transfusing high-p50 RBC in this setting may improve the perioperative care of these patients.

Should modulation of p50 be a therapeutic target in the critically ill?

INTRODUCTION

A defining feature of human hemoglobin is its oxygen binding affinity, quantified by the partial pressure of oxygen at which hemoglobin is 50% saturated (p50), and the variability of this parameter over a range of physiological and environmental states. Modulation of this property of hemoglobin can directly affect the degree of peripheral oxygen offloading and tissue oxygenation. Areas covered: This review summarizes the role of hemoglobin oxygen affinity in normal and abnormal physiology and discusses the current state of the literature regarding artificial modulation of p50. Hypoxic tumors, sickle cell disease, heart failure, and transfusion medicine are discussed in the context of recent advances in hemoglobin oxygen affinity manipulation. Expert commentary: Of particular clinical interest is the possibility of maintaining adequate end-organ oxygen availability in patients with anemia or compromised cardiac function via an increase in systemic p50. This increase in systemic p50 can be achieved with small molecule drugs or a packed red blood cell unit processing variant called rejuvenation, and human trials are needed to better understand the potential clinical benefits to modulating p50.

Longer average blood storage duration is associated with increased risk of infection and overall morbidity following radical cystectomy

BACKGROUND

Patients with bladder cancer undergoing radical cystectomy (RC) experience high rates of perioperative blood transfusions (PBTs) and morbidity. The aim of this study was to evaluate the effect of blood storage duration on the risk of adverse perioperative outcomes in this high-risk patient population.

MATERIALS AND METHODS

In a retrospective review of RC patients from 2010 to 2014 who received PBTs, the average storage duration for all units transfused was used to classify patients as receiving older blood using 3 different definitions (≥21 days,≥28 days, and≥35 days). Multivariable Poisson regression models were used to determine the adjusted relative risk of perioperative infections and overall morbidity in those given older blood compared to fresher blood.

RESULTS

Of the 451 patients undergoing RC, 205 (45%) received nonirradiated PBTs. In multivariable modeling, increasing average blood storage duration, as a continuous variable, was associated with an increased risk of infections (risk ratio [RR] = 1.08 per day, 95% CI: 1.01-1.17) and overall morbidity (RR = 1.08 per day, 95% CI: 1.01-1.15). Furthermore, ≥28-day blood storage (vs.<28) was associated with increased infections (RR = 2.69, 95% CI: 1.18-6.14) and morbidity (RR = 2.54, 95% CI: 1.31-4.95), and ≥35-day blood storage (vs.<35) was also associated with increased infections (RR = 2.83, 95% CI: 1.42-5.66) and morbidity (RR = 3.35, 95% CI: 1.95-5.77).

CONCLUSIONS

Although blood is stored up to 42 days, storage≥28 days may expose RC patients to increased perioperative infections and overall morbidity compared with storage<28 days. Prospective cohort studies are warranted in cystectomy and other high-risk surgical oncology patients to better determine the effect of blood storage duration.