Red blood cell transfusion-induced inflammation: myth or reality

Association between perioperative red blood cell transfusions and postoperative venous thromboembolism: A systematic review and meta-analysis

BACKGROUND

Whether perioperative red blood cell transfusions increases the risk of postoperative venous thromboembolism is controversial and uncertain.We aims to explore the relationship between perioperative red blood cell transfusions and the risk of postoperative venous thromboembolism by conducting a meta-analysis.

OBJECTIVE

To conduct a meta-analysis to systematically evaluate the relationship between perioperative red blood cell transfusions and the risk of postoperative venous thromboembolism.

METHODS

PubMed, Embase, Cochrane, and Web of Science databases were searched to identify studies examining the relationship between perioperative red blood cell transfusions and the risk of postoperative venous thromboembolism. The databases were searched from establishment to August 2023.Two researchers independently screened literature and extracted data according to inclusion and exclusion criteria. Newcastle-ottawa Scale was used for quality assessment. Meta-analysis of data was performed using RevMan 5.4 software.

RESULTS

A total of 15 studies involving 1,880,990 patients were included in this study.Meta-analysis showed that perioperative red blood cell transfusions increased the risk of postoperative venous thromboembolism [OR = 1.61, 95%CI (1.37, 1.89), P < 0.001]. Subgroup analyses showed that the transfusion dose,transfusion timing,study population and follow-up time were closely related to the risk of postoperative venous thromboembolism.

CONCLUSIONS

In summary, this meta-analysis demonstrated a significant positive association between perioperative red blood cell transfusions and postoperative venous thromboembolism.Healthcare professionals should pay attention to the influence of blood transfusions on postoperative venous thromboembolism, strengthen management and prevention.

New frontiers in neonatal red blood cell transfusion research

Red blood cell (RBC) transfusions are common in neonates requiring intensive care. Recent studies have compared restricted versus liberal transfusion guidelines, but limitations exist on evaluations of outcomes in populations that never required a transfusion compared to those receiving any transfusion. Although there are well-established risks associated with RBC transfusions, new data has emerged that suggests additional clinically relevant associations, including adverse neurodevelopmental outcomes, donor sex differences, and inflammation or immunosuppression. Further research is needed to delineate the magnitude of these risks and to further improve the safety of transfusions. The goal of this review is to highlight underappreciated, yet clinically important risks associated with neonatal RBC transfusions and to introduce several areas in which neonates may uniquely benefit from alterations in practice.

Increased Risk of Venous Thromboembolism in Patients with Postoperative Anemia After Total Joint Arthroplasty: Are Transfusions to Blame?

BACKGROUND

The relationship between anemia and the risk of venous thromboembolism (VTE) following total knee arthroplasty (TKA) and total hip arthroplasty (THA) remains unclear. Red blood cell (RBC) transfusions, which have been shown to have thrombogenic effects, may explain conflicting data. This study sought to elucidate the relationship between anemia, RBC transfusions, and VTE following total joint arthroplasty (TJA).

METHODS

Using the International Classification of Diseases, Tenth Revision (ICD-10) and Current Procedural Terminology (CPT) codes, the Premier Healthcare Database was queried for all adults who underwent primary elective THA or TKA from January 2015 to December 2020. Patients were classified into 3 cohorts: those who did not have a diagnosis of anemia and did not receive an RBC transfusion (the control group), those with acute blood loss anemia who did not receive a transfusion (the anemia without transfusion group), and those with acute blood loss anemia who did receive a transfusion (the anemia with transfusion group). The primary outcomes assessed were the 90-day rate and risk of deep vein thrombosis (DVT), pulmonary embolism (PE), and aggregate VTE. Analysis of variance and pairwise comparisons were used to compare groups. Multivariable analyses were performed to account for confounding factors.

RESULTS

The 1,290,815 patients identified as having undergone TJA included 1,078,507 control patients (83.6%), 198,233 patients who had anemia without transfusion (15.4%), and 14,075 patients who had anemia and transfusion (1.1%). Age, sex, race, length of hospital stay, and hospital costs were significantly different between the 3 groups. After adjusting for confounding factors, there was no difference between the anemia without transfusion group and the control group with regard to DVT (adjusted odds ratio [OR], 0.97 [95% confidence interval (CI), 0.89 to 1.06]; p = 0.500), PE (adjusted OR, 1.04 [95% CI, 0.92 to 1.18]; p = 0.543), and VTE (adjusted OR, 0.99 [95% CI, 0.92 to 1.06]; p = 0.697). However, patients with anemia and transfusion had an increased risk of PE (adjusted OR, 1.83 [95% CI, 1.34 to 2.51]; p < 0.001) and VTE (adjusted OR, 1.39 [95% CI, 1.14 to 1.70]; p = 0.001) compared with patients in the control group.

CONCLUSIONS

Patients with acute blood loss anemia who received a transfusion were at increased risk for developing VTE following TJA, whereas patients with anemia who did not receive a transfusion were not. Orthopaedic surgeons need to be aware of the risks of transfusion and individualize the use of transfusions in their patients.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Modifiable Risk Factors and Preventative Strategies for Severe Retinopathy of Prematurity

Severe ROP is characterized by the development of retinal fibrovascular proliferation that may progress to retinal detachment. The purpose of this report is to review five of the most common and well-studied perinatal and neonatal modifiable risk factors for the development of severe ROP. Hyperoxemia, hypoxia, and associated prolonged respiratory support are linked to the development of severe ROP. While there is a well-established association between clinical maternal chorioamnionitis and severe ROP, there is greater variability between histologic chorioamnionitis and severe ROP. Neonatal sepsis, including both bacterial and fungal subtypes, are independent predictors of severe ROP in preterm infants. Although there is limited evidence related to platelet transfusions, the risk of severe ROP increases with the number and volume of red blood cell transfusions. Poor postnatal weight gain within the first six weeks of life is also strongly tied to the development of severe ROP. We also discuss preventative strategies that may reduce the risk of severe ROP. Limited evidence-based studies exist regarding the protective effects of caffeine, human milk, and vitamins A and E.

Effect of intraoperative blood transfusion on inflammatory response in parturients with placenta previa undergoing cesarean section: A prospective observational study

Background

The neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and red cell distribution width (RDW) have been reported as useful biomarkers for evaluating inflammation and a predictor of surgical prognosis. Although there have been recent reports that transfusion may affect inflammatory responses, studies on the post-transfusion inflammatory response in parturients are rare. Therefore, this study aimed to observe changes in inflammatory response after transfusion during cesarean section (C-sec) through NLR, PLR, and RDW.

Methods

Parturients aged 20-50 years who underwent C-sec under general anesthesia due to placenta previa totalis from March 4, 2021, to June 10, 2021 were participated in this prospective observational study. We compared postoperative NLR, PLR, and RDW between the transfusion and non-transfusion groups.

Results

A total of 53 parturients were included in this study, of which 31 parturients received intraoperative transfusions during C-sec. There were no significant difference in preoperative NLR (3.6 vs. 3.4, p = 0.780), PLR (132.8 vs. 111.3, p = 0.108), and RDW (14.2 vs. 13.6, p = 0.062) between the two groups. However, postoperative NLR was significantly higher in the transfusion group than in the non-transfusion group (12.2 vs. 6.8, p < 0.001). Postoperative RDW was significantly higher in the transfusion group than in the non-transfusion group (14.6 vs. 13.9, p = 0.002) whereas postoperative PLR was not significantly different between the two groups (108.0 vs. 117.4, p = 0.885).

Conclusions

Postoperative NLR and RDW, the inflammatory biomarkers, were significantly higher in the transfused C-sec parturients. These results suggest a significant association between postoperative inflammatory response and transfusion in obstetric practice.

Normothermic Machine Perfusion in Renal Transplantation

Purpose of Review

Normothermic machine perfusion (NMP) is a promising new tool in kidney transplantation to improve the outcome of marginal donor kidney transplantation. This review examines the current evidence for NMP in clinical practice and considers how the technology may be used in the future.

Recent Findings and Summary

There is emerging evidence to suggest that NMP has the potential to expand the donor pool of transplantable organs. The safety and feasibility of NMP have been established in a number of clinical studies but more research is needed to optimise the perfusion conditions. NMP shows promise as a viability assessment tool with particular focus on biomarkers and imaging techniques which provide real-time information to facilitate transplantation decision-making. Moreover, the exciting development of new potential therapeutics such as cell and gene-based therapies which are deliverable during NMP may also improve and recondition grafts prior to implantation.

Red Blood Cell Transfusions and Risk of Postoperative Venous Thromboembolism

INTRODUCTION

Postoperative venous thromboembolism (VTE) is a major risk for orthopaedic surgery and associated with notable morbidity and mortality. Knowing a patient's risk for VTE may help guide the choice of perioperative VTE prophylaxis. Recently, red blood cells (RBCs) have been implicated for their role in pathologic thrombosis. Therefore, we examine the association between perioperative RBC transfusion and postoperative VTE after orthopaedic surgery.

METHODS

A retrospective cohort study was done by conducting a secondary analysis of data obtained from the 2016 American College of Surgeons National Surgical Quality Improvement Program database. Our population consisted of 234,608 adults who underwent orthopaedic surgery. The exposure was whether patients received a perioperative RBC transfusion. The primary outcome was postoperative VTE within 30 days of surgery that warranted therapeutic intervention, which was subsequently split into symptomatic deep vein thrombosis (DVT) and pulmonary embolism (PE). Odds ratios (ORs) were estimated using a multivariate logistic regression model.

RESULTS

At baseline, 1,952 patients (0.83%) had postoperative VTE (DVT in 1,299 [0.55%], PE in 801 [0.34%], and both DVT and PE in 148 [0.06%]). Seven hundred ninety-five patients (0.3%) received preoperative RBC transfusions only, 11,587 patients (4.9%) received postoperative RBC transfusions only, and 848 patients (0.4%) received both preoperative and postoperative RBC transfusions. Postoperative RBC transfusion was associated with higher odds of VTE (adjusted OR [aOR], 1.47; 95% confidence interval [CI], 1.19-1.81), DVT (aOR, 1.40; 95% CI, 1.09-1.79), PE (aOR, 1.59; 95% CI, 1.14-2.22), and 30-day mortality (aOR, 1.21; 95% CI, 1.01-1.45) independent of various presumed risk factors. When creating subgroups within orthopaedics by Current Procedural Terminology codes, postoperative transfusions in spine (aOR, 2.03; 95% CI, 1.13-3.67) and trauma (aOR, 1.40; 95% CI, 1.06-1.86) were associated with higher odds of postoperative VTE.

CONCLUSION

Our results suggest that postoperative RBC transfusion may be associated with an increased risk of postoperative VTE, both symptomatic DVT and life-threatening PE, independent of confounders. Additional prospective validation in cohort studies is necessary to confirm these findings. In addition, careful perioperative planning for patients deemed to be at high risk of requiring blood transfusion may reduce these postoperative complications in orthopaedic patients.

LEVEL OF EVIDENCE

III.

Prevalence and risk factor of post-operative lower extremities deep vein thrombosis in patients undergoing gynecologic surgery: a single-institute cross-sectional study

Background and aim

The study of prevalence and risk factors of postoperative lower limb deep vein thrombosis (DVT) in Thai gynecologic patients was limited. The present study was conducted to evaluate this issue.

Methods

The patients were age > 15 years old without a history of DVT or pulmonary emboli (PE) scheduled for laparotomy or vaginal gynecologic surgery between May and November 2020 were invited to participate. All of these patients were scheduled for a complete duplex ultrasound to detect lower limb DVT 72 h before and within 14 days after the operation. The patients without DVT were scheduled for an interview by telephone about DVT symptoms 30 days after the operation. The clinical variables were compared using univariate and multivariate analysis to identify the independent factors related to the development of DVT.

Results

One hundred and twelve patients met the inclusion criteria. Of these patients, 44 cases (39.3%) were diagnosed as malignancy and 102 patients underwent a hysterectomy. Post-operative DVTs were detected in six patients (5.4%) and all except one had a malignancy. Thus, the prevalence of DVT in malignancy cases was five in 44 patients (11.4%). The independent risk factors for postoperative DVT were age > 60-year-old and receiving a perioperative blood transfusion. Five of six DVT patients received low molecular-weight heparin for treatment of DVT and none developed PE. The rest of the participants reported no symptom-related DVTs from the interview 30 days after the operation.

Conclusion

The prevalence of postoperative DVT in gynecologic patients was 5%, and the independent risk factors were elderly patients and receiving a perioperative blood transfusion.

Ex-vivo Kidney Machine Perfusion: Therapeutic Potential

Kidney transplantation remains the gold standard treatment for patients suffering from end-stage kidney disease. To meet the constantly growing organ demands grafts donated after circulatory death (DCD) or retrieved from extended criteria donors (ECD) are increasingly utilized. Not surprisingly, usage of those organs is challenging due to their susceptibility to ischemia-reperfusion injury, high immunogenicity, and demanding immune regulation after implantation. Lately, a lot of effort has been put into improvement of kidney preservation strategies. After demonstrating a definite advantage over static cold storage in reduction of delayed graft function rates in randomized-controlled clinical trials, hypothermic machine perfusion has already found its place in clinical practice of kidney transplantation. Nevertheless, an active investigation of perfusion variables, such as temperature (normothermic or subnormothermic), oxygen supply and perfusate composition, is already bringing evidence that ex-vivo machine perfusion has a potential not only to maintain kidney viability, but also serve as a platform for organ conditioning, targeted treatment and even improve its quality. Many different therapies, including pharmacological agents, gene therapy, mesenchymal stromal cells, or nanoparticles (NPs), have been successfully delivered directly to the kidney during ex-vivo machine perfusion in experimental models, making a big step toward achievement of two main goals in transplant surgery: minimization of graft ischemia-reperfusion injury and reduction of immunogenicity (or even reaching tolerance). In this comprehensive review current state of evidence regarding ex-vivo kidney machine perfusion and its capacity in kidney graft treatment is presented. Moreover, challenges in application of these novel techniques in clinical practice are discussed.

Increased risk of suicide attempt among patients receiving blood transfusion: A propensity matched analysis

To examine whether the association between blood transfusion and suicide attempt exists.Utilizing the national insurance database from Taiwan and propensity score matching analysis, the incidence of suicide attempt in a cohort with blood transfusion versus controls was compared.The key finding is that higher incidence of suicide attempt in blood transfusion than control group (with an adjusted hazard ratio of 1.79 with 95% confidence interval, 1.72-1.88) after adjusted for the covariates.Patients receiving blood transfusion are an increased risk of subsequent suicide attempt.

Blood transfusions increase the risk for venous thromboembolism events following total joint arthroplasty

The association between blood transfusions and thromboembolic events (VTE) following total joint arthroplasty (TJA) remains debatable. Using contemporary institutional data, this study aimed to determine whether blood transfusions increase the risk of VTE following primary and revision TJA. This was a single institution, retrospective cohort study. The clinical records of all patients (n = 34,824) undergoing primary and revision TJA between 2009 and 2020 were reviewed. Demographic variables, co-morbidities, type of chemoprophylaxis and intraoperative factors such as use of tranexamic acid were collected. Clinical notes, hospital orders, and discharge summaries were reviewed to determine if a patient received a blood transfusion. Comprehensive queries utilizing keywords for VTE were conducted in clinical notes, physician dictations, and patient-provider phone-call logs. Propensity score matching as well as adjusted mixed models were performed. After adjusting for various confounders, results from regression analysis showed a significant association between allogenic blood transfusions and risk for developing VTE following primary and revision TJA (OR 4.11, 95% CI 2.53-6.69 and OR 2.15, 95% CI 1.12-4.13, respectively). While this strong association remained significant for PE in both primary (p < 0.001) and revision (p < 0.001) matched cohorts, it was no longer statistically significant for DVT (p = 0.802 and p = 0.65, respectively). These findings suggest that the risk of VTE is increased by approximately three-folds when blood transfusions are prescribed. This association was mainly due to higher symptomatic PE events which makes it even more worrisome. Surgeons should be aware of this association, revisit criteria for blood transfusions and use all means available in the perioperative period to optimize the patients and avoid transfusion.

Impact of small fractions of abnormal erythrocytes on blood rheology

Red blood cell (RBC) populations are inherently heterogeneous, given mature RBC lack the transcriptional machinery to re-synthesize proteins affected during in vivo aging. Clearance of older, less functional cells thus aids in maintaining consistent hemorheological properties. Scenarios occur, however, where portions of mechanically impaired RBC are re-introduced into blood (e.g., damaged from circulatory support, blood transfusion) and may alter whole blood fluid behavior. Given such perturbations are associated with poor clinical outcomes, determining the tolerable level of abnormal RBC in blood is valuable. Thus, the current study aimed to define the critical threshold of blood fluid properties to re-infused physically-impaired RBC. Cell mechanics of RBC were impaired through membrane cross-linking (glutaraldehyde) or intracellular oxidation (phenazine methosulfate). Mechanically impaired RBC were progressively re-introduced into the native cell population. Negative alterations of cellular deformability and high shear blood viscosity were observed following additions of only 1-5% rigidified RBC. Low-shear blood viscosity was conversely decreased following addition of glutaraldehyde-treated cells; high-resolution microscopy of these mixed cell populations revealed decreased capacity to form reversible aggregates and decreased aggregate size. Mixed RBC populations, when exposed to supraphysiological shear, presented with compounded mechanical impairment. Collectively, key determinants of blood flow behavior are sensitive to mechanical perturbations in RBC, even when only 1-5% of the cell population is affected. Given this fraction is well-below the volume of rigidified RBC introduced during circulatory support or transfusion practice, it is plausible that some adverse events following surgery and/or transfusion may be related to impaired blood fluidity.

Normothermic kidney perfusion: An overview of protocols and strategies

Normothermic machine perfusion (NMP) technologies are emerging as an important adjunct in organ preservation and transplantation. NMP can enable the reduction or avoidance of cold ischemia and allows for pretransplant measurement of function and metabolic status to assess the suitability of the organ for transplantation. The key requirement of NMP is to provide an environment that is protective to the organ, ensures optimal oxygen delivery and supports metabolic function. Red blood cell-based solutions, artificial hemoglobin solutions, and acellular solutions have all been utilized in NMP. However, there is no clear consensus on perfusion protocols. A period of NMP after hypothermic preservation is the most commonly used strategy. As an alternative, several groups have developed and tested the feasibility of more prolonged periods of NMP. There are only a few reports of the application of NMP in clinical kidney transplantation and each uses different approach and conditions. This review details the rationale for NMP protocols considering duration of NMP and different perfusate compositions in experimental and clinical models. We also include a discussion on the mechanistic action of NMP, comparison of subnormothermic and hypothermic conditions, the different logistical approaches and future requirements.

Incidence of venous thromboembolism after standard treatment in patients with epithelial ovarian cancer in Korea

Background

Venous thromboembolism (VTE) is a hospital‐associated severe complication that may adversely affect patient prognosis. In this study, we evaluated the incidence of VTE and its risk factors in patients with epithelial ovarian cancer (EOC).

Methods

We retrospectively analyzed the electronic health record data of 1268 patients with EOC who received primary treatment at the National Cancer Center, Korea between January 2007 and December 2017 to identify patients who developed VTE. Demographic, clinical, and surgical characteristics of these patients were ascertained. Competing risks analyses were performed to estimate the cumulative incidence of VTE according to the treatment type. The associations between putative risk factors and the incidence of VTE were evaluated using the Fine–Gray regression models accounting for competing risks of death.

Results

VTE was the most prevalent cardiovascular event, found in 9.6% (n = 122) of all patients. Of these VTE events, 115 (94.3%) occurred within 2 years of EOC diagnosis. Advanced cancer stage at diagnosis (distant vs. localized, hazards ratio [HR])= 14.49, p = 0.015) and extended hospital stay (≥15 days, HR =3.87, p = 0.004) were associated with the incidence of VTE. There was no significant difference in the cumulative incidence of VTE between primary cytoreductive surgery followed by adjuvant chemotherapy and neoadjuvant chemotherapy followed by interval cytoreductive surgery (HR =0.81, p = 0.390).

Conclusions

Approximately 10% of patients with EOC were diagnosed with VTE, which was the most common cardiovascular disease found in this study. The assessment of VTE risks in patients with advanced‐stage EOC with an extended hospital stay is needed to facilitate adequate prophylactic treatment.

Postoperative but not intraoperative transfusions are associated with respiratory failure after pneumonectomy

OBJECTIVES

METHODS

We performed a retrospective cohort study using prospectively collected data on consecutive pneumonectomies between 2005 and 2015. Patient records were reviewed for intraoperative/postoperative exposures. Univariable and multivariable analyses were performed.

RESULTS

Of the 251 pneumonectomies performed during the study period, 24 (9.6%) patients suffered respiratory failure. Ninety-day mortality was 5.6% (n = 14) and was more likely in patients with respiratory failure (7/24 vs 7/227, P &lt; 0.001). Intraoperative and postoperative transfusions occurred in 42.2% (n = 106) and 44.6% (n = 112) of patients, respectively and were predominantly red blood cells. On univariable analysis, both intraoperative (P = 0.03) and postoperative transfusion (P = 0.004) were associated with a higher risk of respiratory failure. The multivariable model significantly predicted respiratory failure with an area under curve (AUC) = 0.88 (P = 0.001). On multivariable analysis, the only independent predictors of respiratory failure were postoperative transfusions [adjusted odds ratio (aOR) 6.54, 95% confidence interval (CI) 1.74–24.59; P = 0.005] and lower preoperative forced expiratory volume (adjusted OR 0.96, 95% CI 0.93–0.99; P = 0.03). Estimated blood loss was not significantly different (P = 0.91) between those with (median 800 ml, interquartile range 300–2000 ml) and without respiratory failure (median 800 ml, interquartile range 300–2000 ml).

CONCLUSIONS

Respiratory failure occurred in 9.6% of patients post-pneumonectomy and confers a higher risk of 90-day mortality. Postoperative (but not intraoperative) transfusion was the strongest independent predictor associated with respiratory failure. Intraoperative transfusion may be in reaction to active/unpredictable blood loss and may not be easily modifiable. However, postoperative transfusion may be modifiable and potentially avoidable. Transfusion thresholds should be assessed in light of potential cost-benefit trade-offs.

Association of Perioperative Red Blood Cell Transfusions With Venous Thromboembolism in a North American Registry

Importance

Increasing evidence supports the role of red blood cells (RBCs) in physiological hemostasis and pathologic thrombosis. Red blood cells are commonly transfused in the perioperative period; however, their association with postoperative thrombotic events remains unclear.

Objective

To examine the association between perioperative RBC transfusions and postoperative venous thromboembolism (VTE) within 30 days of surgery.

Design, Setting, and Participants

This analysis used prospectively collected registry data from the American College of Surgery National Surgical Quality Improvement Program (ACS-NSQIP) database, a validated registry of 525 teaching and nonteaching hospitals in North America. Participants included patients in the ACS-NSQIP registry who underwent a surgical procedure from January 1 through December 31, 2014. Data were analyzed from July 1, 2016, through March 15, 2018.

Main Outcomes and Measures

Risk-adjusted odds ratios (aORs) were estimated using multivariable logistic regression. The primary outcome was the development of postoperative VTE (deep venous thrombosis [DVT] and pulmonary embolism [PE]) within 30 days of surgery that warranted therapeutic intervention; DVT and PE were also examined separately as secondary outcomes. Subgroup analyses were performed by surgical subtypes. Propensity score matching was performed for sensitivity analyses.

Results

Of 750 937 patients (56.8% women; median age, 58 years; interquartile range, 44-69 years), 47 410 (6.3%) received at least 1 perioperative RBC transfusion. Postoperative VTE occurred in 6309 patients (0.8%) (DVT in 4336 [0.6%]; PE in 2514 [0.3%]; both DVT and PE in 541 [0.1%]). Perioperative RBC transfusion was associated with higher odds of VTE (aOR, 2.1; 95% CI, 2.0-2.3), DVT (aOR, 2.2; 95% CI, 2.1-2.4), and PE (aOR, 1.9; 95% CI, 1.7-2.1), independent of various putative risk factors. A significant dose-response effect was observed with increased odds of VTE as the number of intraoperative and/or postoperative RBC transfusion events increased (aOR, 2.1 [95% CI, 2.0-2.3] for 1 event; 3.1 [95% CI, 1.7-5.7] for 2 events; and 4.5 [95% CI, 1.0-19.4] for ≥3 events vs no intraoperative or postoperative RBC transfusion; P < .001 for trend). In subgroup analyses, the association between any perioperative RBC transfusion and postoperative VTE remained statistically significant across all surgical subspecialties analyzed. The association between any perioperative RBC transfusion and the development of postoperative VTE also remained robust after 1:1 propensity score matching (47 142 matched pairs; matched OR, 1.9; 95% CI, 1.8-2.1).

Conclusions and Relevance

The results of this study suggest that perioperative RBC transfusions may be significantly associated with the development of new or progressive postoperative VTE, independent of several putative confounders. These findings, if validated, should reinforce the importance of rigorous perioperative management of blood transfusion practices.

Two-way Interaction Effects of Perioperative Complications on 30-Day Mortality in General Surgery

BACKGROUND

Multiple perioperative complications increase mortality risk, and certain complications synergistically increase this risk to a greater degree than might be expected if the complications were independent, but these effects are not well established.

METHODS

This is a retrospective cohort study of 422,827 intraabdominal general surgery patients (American College of Surgeons National Surgical Quality Improvement Program 2005-2011). Eight complications were evaluated: acute respiratory failure (ARF), acute kidney injury (AKI), sepsis/septic shock, stroke, cardiac arrest (CA), myocardial infarction (MI), deep vein thrombosis/pulmonary embolus, and transfusion. Each combination of two complications (28 total) was modeled using a Cox model for 30-day mortality, with adjustment for preoperative comorbidities and risk factors. Additive interaction was determined with the relative excess risk due to interaction (RERI). A positive RERI indicates that the mortality risk with both complications is greater than the sum of the individual mortality risks. Bonferroni correction was applied (α = 0.05/28 = 0.0018).

RESULTS

Seven combinations demonstrated positive interaction: sepsis-CA (RERI 88.1; p < 0.0001), ARF-AKI (RERI 50.5; p < 0.0001), AKI-sepsis (RERI 33.9; p < 0.0001), sepsis-stroke (RERI 33.9; p < 0.0001), ARF-stroke (RERI 32.3; p < 0.0001), AKI-MI (RERI 24.5; p = 0.0013), and ARF-sepsis (RERI 19.2; p < 0.0001). Two combinations demonstrated negative interaction: ARF-CA (RERI -65.1; p = 0.0017) and CA-transfusion (RERI -52.0, p < 0.0001).

CONCLUSIONS

Interaction effects exist between certain complications to increase the risk of short-term mortality. ARF, AKI, sepsis, and stroke were most likely to be involved in positive interactions. Further research into the mechanisms for these effects will be necessary to develop strategies to minimize the compounding effects of multiple complications in the perioperative period.

Red cell transfusion in paediatric patients with thalassaemia and sickle cell disease: Current status, challenges and perspectives

Notwithstanding the high safety level of the currently available blood for transfusion and the decreasing frequency of transfusion-related complications, administration of labile blood products to paediatric patients still poses unique challenges and considerations. The incidence of thalassaemia and sickle cell disease in the paediatric population may be high enough under specific racial and geographical contexts. Red cell transfusion is the cornerstone of β-thalassaemia treatment and one of the most effective ways to prevent or correct specific acute and chronic complications of sickle cell disease. However, this life-saving strategy comes with its own complications, such as additional iron overload, alloimmunization and haemolytic reactions, among others. In paediatrics, the dependency of the transfusion outcome upon disease and other recipient characteristics is more prominent compared with the adults, owing to differences in developmental maturity and physiology that render them more susceptible to common risks, exacerbate the host response to transfused cells, and modify the type or the clinical severity of the transfusion-related morbidity. The adverse branch of red cell transfusion is likely the overall effect of several factors acting synergistically to shape the clinical phenotype of this therapy, including inherent donor/blood unit variables, like antigenicity, red cell deformability and extracellular vesicles, as well as recipient variables, such as history of alloimmunization and inflammation level at time of transfusion. This review focuses on paediatric patients with β-thalassaemia and sickle cell disease as a recipient group with distinct transfusion-related characteristics, and introduces new concepts for consideration, not adequately studied and elucidated so far.

Red blood cell transfusion in surgical cancer patients: Targets, risks, mechanistic understanding and further therapeutic opportunities

Anemia is present in more than half of cancer patients and appears to be an independent prognostic factor of short- and long-term adverse outcomes. It increases in the advanced period of cancer and perioperatively, in patients with solid tumors who undergo surgery. As a result, allogeneic red blood cell (RBC) transfusion is an indispensable treatment in cancer. However, its safety remains controversial, based on several laboratory and clinical data reporting a linkage with increased risk for cancer recurrence, infection and cancer-related mortality. Immunological, inflammatory and thrombotic reactions mediated by the residual leukocytes and platelets, the stored RBCs per se, the biological response modifiers and the plasticizer of the unit may underlie infection and tumor-promoting effects. Although the causality between transfusion and infection has been established, the effects of transfusion on cancer recurrence remain confusing; this is mainly due to the extreme biological heterogeneity that characterizes RBC donations and cancer context. In fact, the functional interplay between donation-associated factors and recipient characteristics, including tumor biology per se, inflammation, infection, coagulation and immune activation state and competence may synergistically and individually define the clinical impact of each transfusion in any given cancer patient. Our understanding of how the potential risk is mediated is important to make RBC transfusion safer and to pave the way for novel, promising and highly personalized strategies for the treatment of anemia in surgical cancer patients.

Duration of red blood cell storage and inflammatory marker generation

Red blood cell (RBC) transfusion is a life-saving treatment for several pathologies. RBCs for transfusion are stored refrigerated in a preservative solution, which extends their shelf-life for up to 42 days. During storage, the RBCs endure abundant physicochemical changes, named RBC storage lesions, which affect the overall quality standard, the functional integrity and in vivo survival of the transfused RBCs. Some of the changes occurring in the early stages of the storage period (for approximately two weeks) are reversible but become irreversible later on as the storage is extended. In this review, we aim to decipher the duration of RBC storage and inflammatory marker generation. This phenomenon is included as one of the causes of transfusion-related immunomodulation (TRIM), an emerging concept developed to potentially elucidate numerous clinical observations that suggest that RBC transfusion is associated with increased inflammatory events or effects with clinical consequence.

Addition of Sodium Pyruvate to Stored Red Blood Cells Attenuates Liver Injury in a Murine Transfusion Model

RBCs undergo numerous changes during storage and stored RBCs may induce adverse effects, ultimately resulting in organ injury in transfusion recipients. We tested the hypothesis that the addition of SP to stored RBCs would improve the quality of the stored RBCs and mitigate liver injury after transfusion in a murine model. RBCs were harvested from C57BL/6J mice and stored for 14 days in CPDA-1 containing either a solution of SP in saline or saline alone. Haemolysis, the 24-hour posttransfusion recovery, the oxygen-carrying capacity, and the SOD activity of stored RBCs were evaluated. The plasma biochemistry, hepatic MDA level, MPO activity, IL-6, TNF-α concentrations, and histopathology were measured two hours after the transfusion of stored RBCs. Compared with RBCs stored in CPDA-1 and saline, the addition of SP to stored RBCs restored their oxygen-carrying capacity and SOD activity, reduced the AST activity, BUN concentrations, and LDH activity in the plasma, and decreased the MDA level, MPO activity, and concentrations of IL-6 and TNF-α in the liver. These data indicate that the addition of SP to RBCs during storage has a beneficial effect on storage lesions in vitro and subsequently alleviates liver injury after the transfusion of stored RBCs in vivo.

The outsider adverse event in transfusion: Inflammation

In order to maintain adequate inventories of red blood cells (RBCs) for transfusion, RBC units are refrigerator-stored for variable amounts of time prior to transfusion. A subset of RBCs is damaged during prolonged storage. Clearance of these damaged RBCs is hypothesized to induce an inflammatory response in the transfusion recipient. However, there is controversy over whether RBC transfusions are in fact associated with inflammation, and more generally, whether current standards for maximal RBC storage times are safe. We will explore the evidence for and against this outsider adverse event in transfusion: whether certain RBC transfusions do or do not cause inflammation.

Hepcidin as a new biomarker for detecting autologous blood transfusion

Autologous blood transfusion (ABT) is an efficient way to increase sport performance. It is also the most challenging doping method to detect. At present, individual follow-up of haematological variables via the athlete biological passport (ABP) is used to detect it. Quantification of a novel hepatic peptide called hepcidin may be a new alternative to detect ABT. In this prospective clinical trial, healthy subjects received a saline injection for the control phase, after which they donated blood that was stored and then transfused 36 days later. The impact of ABT on hepcidin as well as haematological parameters, iron metabolism, and inflammation markers was investigated. Blood transfusion had a particularly marked effect on hepcidin concentrations compared to the other biomarkers, which included haematological variables. Hepcidin concentrations increased significantly: 12 hr and 1 day after blood reinfusion, these concentrations rose by seven- and fourfold, respectively. No significant change was observed in the control phase. Hepcidin quantification is a cost-effective strategy that could be used in an "ironomics" strategy to improve the detection of ABT.