Allogeneic Red Blood Cell Research Articles

Cell salvage in obstetrics-Background and practical implementation

Postpartum hemorrhage (PPH) remains aleading cause of maternal mortality worldwide, with an increasing incidence in western countries over the past decades. During this period the numbers of PPH-related allogeneic red blood cell (RBC) transfusions have also significantly increased. Given the increasing scarcity and risks of allogeneic RBC transfusions, which are also associated with adverse maternal outcomes, optimized blood management strategies are urgently needed in obstetrics. In recent years, patient blood management (PBM) has been increasingly integrated into medical care, resulting in asignificant improvement in patient outcomes. Cell salvage (CS) is one of the PBM blood-sparing techniques that enables the collection, processing and retransfusion of the patient's own blood during major bleeding events. Although recent evidence indicates that CS can significantly reduce the demand for allogeneic RBC transfusions and improve patient outcomes, the utilization in obstetrics in German hospitals remains low, with ausage rate of only 0.07% of births with peripartum hemorrhage. It must be assumed that concerns about patient-related complications, such as amniotic fluid embolism and maternal alloimmunization contribute to this hesitancy, alongside alack of familiarity with the technique. This article provides an overview of the current evidence on the use and safety of CS in obstetrics. To facilitate a practical implementation, fundamental considerations and organizational precautions were prepared based on the experiences of the University Hospitals in Würzburg and Frankfurt and presented in the form of graphics and checklists for the perioperative use of CS during cesarean sections.

Transfusion Risk in Open, Laparoscopic, and Robotic-Assisted Surgery: A Propensity Score Matched Case-Control Study across Surgical Disciplines

Introduction: Robotic-assisted surgery is increasingly performed in various surgical disciplines demonstrating improved oncological and functional outcomes compared to conventional surgery. Objective: Unclear is how robotic-assisted surgery affects perioperative anemia and the need for blood products. Methods: In this case-control study, 15,009 matched patient pairs undergoing urological, visceral, or thoracic surgery were included. Pairwise comparisons between robotic-assisted surgery, laparoscopic surgery, and open surgery were performed with propensity score matching. Results: Robotic-assisted surgery compared to open surgery was associated with a risk reduction of allogeneic red blood cell transfusion by RR: 0.32 (95% CI: 0.27–0.37) and a limited reduction of perioperative hemoglobin (perioperative hemoglobin difference of 0.40 g/dL, 95% CI: 0.31–0.49). Robotic-assisted surgery was associated with a shorter length of hospital stay by 4.29 days (95% CI: 3.74–4.84). Compared to laparoscopic surgery, robotic-assisted surgery had no significant effect on red blood cell transfusions (RR: 0.94, 95% CI: 0.75–1.18), perioperative hemoglobin (0.27 g/dL, 95% CI: 0.16–0.38), or length of hospital stay 0.53 days (95% CI: −0.14–1.19). Conclusions: Robotic-assisted and laparoscopic procedures are associated with reduced blood transfusions compared to open surgery and, thus the advancement of minimally invasive procedures constitutes an important measure to improve patient outcomes.

Is it useful to wash stored red blood cells in cardiopulmonary bypass priming fluid for neonatal cardiac surgery? A single-centre retrospective study.

Neonatal cardiac surgery requires careful consideration of cardiopulmonary bypass (CPB) priming fluid composition due to small blood volume and immature physiology. This study investigated the impact of allogeneic stored red blood cells (RBCs) processed using an autotransfusion system in CPB priming fluid for neonates. We compared perioperative parameters, inflammatory mediators, coagulation indicators, vasoactive-inotropic score (VIS) and clinical outcomes between neonates receiving unwashed (n = 56) and washed (n = 45) RBCs in CPB priming fluid. Regression models were used to assess the independent association between RBC washing and patient outcomes. The autotransfusion system improved stored RBC quality. The washed group showed higher peak haematocrit (p < 0.01) and haemoglobin levels (p = 0.04) during CPB, an increased oxygen delivery index during rewarming (p < 0.05) and lower postoperative lactate levels and VIS (p < 0.05). Inflammatory (IL-6, IL-8 and IL-10) and coagulation parameters (D-dimer, fibrinogen and fibrin degradation product) fluctuated compared with baseline but did not significantly differ between groups. The washed group had a lower incidence of hyperlactacidaemia and delayed sternal closure at CPB weaning. Adding washed allogeneic stored RBCs to neonatal CPB priming fluid reduced postoperative lactate elevation and VIS without early improvement in the inflammatory and coagulation systems.

Immune cell kinetics after allogeneic red blood cell transfusion in patients undergoing cardiovascular surgery

Background and ObjectivesRecent reports have highlighted that allogeneic blood transfusions decrease immune responses and affect patient outcomes. However, the effects of allogeneic red blood cell transfusions on the composition of immune cells are unclear. We aimed to clarify the alterations in host immune cells in patients who received allogeneic red blood cell transfusions during the perioperative period of cardiovascular surgery. Materials and MethodsEight non-transfused, 22 intraoperative autotransfusions, and 36 allogeneic red blood cell-transfused patients undergoing surgery were grouped, and lymphocyte subsets were analyzed using flow cytometry. Blood samples collected before surgery, approximately 1-week, and 1-month after surgery were used for analysis. Surgical parameters, operation time, blood loss, and length of hospital stay were also assessed. ResultsThe group receiving transfusions showed statistical significance compared to non-transfused in the above-mentioned surgical parameters. When comparing the autologous and allogeneic transfusion groups, only the allogeneic red blood transfusion group had a longer hospital stay. In comparing preoperative and 1-week and 1-month postoperative samples, there were almost no differences in CD4, CD20, or NK counts between the autotransfusions and the allogenic red blood cell transfusion groups. In contrast, a significant decrease in lymphocyte count was observed in the allogenic red blood cell transfused group 1-week postoperatively compared to preoperatively. Moreover, the number of CD8 + cells was statistically lowest in the allogeneic transfusion group 1 week after the operation. ConclusionOur results suggest that allogeneic red blood cell transfusion could alter immune cell composition especially CD8 + cells, potentially impacting immune function.

Intraoperative cell salvage reduces postoperative allogeneic blood transfusion and shortens off-bed time in simultaneous bilateral total hip arthroplasty: a single-center retrospective study

BackgroundSimultaneous bilateral total hip arthroplasty (SI-THA) results in more blood loss and a greater need for postoperative allogeneic blood transfusion (ABT). Previous studies have reported that multimodal patient blood management (PBM) strategies were associated with a smaller effect of intraoperative cell salvage (ICS) in unilateral total hip arthroplasty. However, there are few studies on the role of ICS in SI-THA. This study aims to explore the effect of ICS with multimodal PBM strategies on SI-THA and to identify risk factors associated with ABT.MethodsThis retrospective matched cohort study included 72 patients in the ICS group and 72 patients in the control group who were matched according to age, sex, and year of hospitalization. Demographic data, hematological indicators, blood loss, and ABT were compared between the two groups. Logistic regression analysis was performed to identify independent risk factors for postoperative ABT. Postoperative outcomes were also recorded.ResultsIn the cohort of 144 patients, 27 patients (37.5%) in the ICS group while 45 patients (62.5%) in the control group received postoperative ABT after SI-THA. Compared with the control group, the ICS group showed significant differences in terms of blood loss, postoperative hemoglobin and hematocrit. The transfused volume of allogeneic red blood cells per ABT patient was also lower in the ICS group. Multivariate logistic regression analysis indicated that sex, the utilization of ICS, and preoperative hematocrit level were identified as independent factors associated with postoperative ABT. The utilization of ICS significantly shortened off-bed time and length of hospital stay, but had no effect on early pain and functional outcomes.ConclusionThe utilization of ICS can significantly affect postoperative ABT in SI-THA patients with multimodal PBM strategies. Sex, the utilization of ICS and preoperative hematocrit level were identified as independent factors associated with postoperative ABT. The utilization of ICS promoted weight-bearing functional exercises, but had no effect on early outcomes.

Providing red blood cells to facilitate organ transplant via normothermic perfusion techniques: A single-center experience.

Normothermic regional perfusion (NRP) and normothermic machine perfusion (NMP) are organ procurement and transport techniques that can improve organ quality, facilitate longer transport, and reduce postoperative complications, increasing organ availability and improving outcomes. NRP and NMP often require allogeneic red blood cells (RBCs). Our academic transfusion service began providing RBCs to support NRP and NMP for adult heart transplant (HT), orthotopic liver transplant (OLT), and multiorgan transplant (MOT) in August 2020. This single-center, retrospective study describes the implementation process and analyzes the characteristics of RBC support during the first 3 years of the perfusion programs. Timing and quantity of units issued and used, organ recipient demographics, and transplant outcomes were obtained from transfusion service and electronic medical records. From 2020 to 2023, the transfusion service received 233 requests to support NRP and NMP perfusion cases. Of these, 105 cases resulted in RBC use, and units were returned or discarded in 112 cases. A total of 131 patients received perfusion-facilitated transplants (92 HT, 27 OLT, and 12 MOT). The majority of perfusion-facilitated HTs utilized NRP (81/92, 88%), whereas most perfusion-facilitated OLTs utilized NMP (21/27, 78%). Across all 233 requests, a total of 381 RBC units were used to facilitate 131 transplants, averaging 2.91 units/transplant. Provision of RBCs for NRP and NMP techniques represents a novel method for transfusion services to support and facilitate life-saving organ transplants with only modest product use, about three RBC units per organ transplant in this single-center study.

Risk factors for allogeneic red blood cell transfusion in adult spinal deformity surgery.

Retrospective study. To investigate the risk factors for allogeneic red blood cell (RBC) transfusion in adult spinal deformity (ASD) surgery. Studies have not thoroughly explored the roles of intraoperative hypothermia, autologous blood donation, and hemostatic agent administration, which would provide a better understanding of the risk for perioperative RBC transfusion in ASD surgery. The medical records of 151 patients with ASD who underwent correction surgery between 2012 and 2021 were retrospectively reviewed. Estimated blood loss and perioperative allogeneic transfusion were examined. Patients were categorized into two groups based on whether they received perioperative allogeneic blood transfusion. Logistic regression analysis was employed to investigate the effect of age, sex, blood type, body mass index, American Society of Anesthesiologists' physical status, preoperative hemoglobin level, autologous blood donation, global spine alignment parameters, preoperative use of anticoagulants or antiplatelet medicine and nonsteroidal anti-inflammatory drugs, number of instrumented fusion levels, total operative duration, three-column osteotomy, lateral interbody fusion, pelvic fixation, intraoperative hypothermia, use of gelatin-thrombin based hemostatic agents, and intraoperative tranexamic acid (TXA) with simultaneous exposure by two attending surgeons. The estimated blood loss was 994.2±754.5 mL, and 71 patients (47.0%) received allogeneic blood transfusion. In the logistic regression analysis, the absence of intraoperative TXA use and simultaneous exposure (odds ratio [OR], 26.3; 95% confidence interval [CI], 7.6-90.9; p<0.001), lack of autologous blood donation (OR, 21.2; 95% CI, 4.4-100.0; p<0.001), and prolonged operative duration (OR, 1.6; 95% CI, 1.3-1.9; p<0.001) were significant independent factors for perioperative allogeneic blood transfusion in ASD surgery. Autologous blood storage, intraoperative TXA administration, and simultaneous exposure should be considered to minimize perioperative allogeneic blood transfusion in ASD surgery, particularly in patients with anticipated lengthy surgeries.

Evaluation of staged autologous blood transfusion during extracorporeal membrane oxygenation decannulation: A retrospective study

BackgroundClinical blood resources are scarce and autologous blood transfusion for extracorporeal membrane oxygenation (ECMO) withdrawal is less studied. ObjectivesTo assess the use of staged autotransfusion during ECMO decannulation. MethodsThe study included ECMO withdrawal patients. Patients in the autologous transfusion group underwent staged transfusion during ECMO withdrawal, while those in the control group received 2.0 units of allogeneic packed red blood cells (RBCs) to increase hemoglobin (Hb). Parameters such as Hb, hematocrit (Hct), adverse events, decannulation success rate, volume of allogeneic RBC transfusions, and transfusion costs were compared. ResultsA total of 82 Chinese patients were enrolled, with a mean age of 46 years, 27 were female, and the top three primary diagnoses were cardiac arrest, acute myocarditis, and severe pneumonia. There were 41 individuals in the autologous blood transfusion group and 41 in the control group. No significant differences were observed in Hb, Hct, adverse events, and the success rate for decannulation between the two groups (all P > 0.05). Compared with the control group, the volume of allogeneic RBC transfusions [0 (0∼1.50) U vs. 3.5 (1.88∼40) U, P < 0.001] and the total cost [130 (130∼390) Chinese Yuan (CNY) vs. 910 (487.50, 1040) CNY, P = 0.002] were lower in the autologous transfusion group. ConclusionIn comparison with allogeneic RBC transfusion, staged autotransfusion during ECMO decannulation not only effectively maintained Hb levels but also reduced the requirement for allogeneic RBC transfusions. In addition, this approach decreased the associated costs and did not increase the risk of clinical adverse events.

Interference of Monoclonal Antibody Therapy in Transfusion: An Update

Monoclonal antibody (MoAb) therapy has been increasingly used in recent years for hematologic malignancies. The MoAbs anti-CD38 and anti-CD47 are immunoglobulins directed against epitopes that are highly expressed not only on cancer cells, but also on red blood cells (RBCs), as well as platelets. Additionally, producing an off-target effect interferes in pre-transfusion testing, having the potential to unchain hemolytic anemia. Blood banks must assure the availability and safety of blood products for patients in need. Thus, MoAbs have become a challenge for blood banks, since methods to overcome interferences must be adopted. Several strategies have been proposed to mitigate pan-reactivity in pre-transfusion indirect antiglobulin tests, such as the treatment of reagent RBCs with enzymes or reducing agents, allogeneic RBC adsorptions, and drug-specific neutralization assays. All of these have some kind of limitation. This review summarizes the interferences of MoAbs in pre-transfusion testing, focusing on the available strategies to mitigate them in order to provide a safe transfusion.

Red Blood Cell Transfusion Strategies in Cardiovascular Interventions.

Acute coronary syndrome, cardiac surgery, and cardiac structural interventions are among the most common situations leading to allogeneic red blood cell consumption due to the prevalence of bleeding and anemia. The wide variability in the use of transfusions derives from the current lack of data, and the absence of strong evidence and clear guideline recommendations. The current approach is to avoid unnecessary blood transfusions and limit their use to life-saving conditions; this conservative strategy derives from often controversial and inconclusive results of observational and randomized studies where liberal and restricted red blood transfusion strategies seemed to have similar outcomes. The pivotal question for future research lies in elucidating whether blood transfusions function as an active participant or merely a catalyst in amplifying adverse events. The present review aims to summarize the current literature data and critically analyze the available evidence for red blood transfusions in cardiac interventions.

Post-transfusion biotin-labeled red blood cell survival studies in pediatric sickle cell disease with antibodies of uncertain significance.

Red blood cell (RBC) antibodies are common in multiply transfused patients with sickle cell disease (SCD). Unlike RBC alloantibodies, the potential of autoantibodies to cause post-transfusion hemolysis may be uncertain. Biotin-labeling provides a direct measurement of red cell survival (RCS) over time, thus can be used to assess the clinical significance of RBC antibodies. Antibodies to biotinylated RBC (B-RBC) occasionally are detected after exposure, which may impact B-RBC survival in subsequent RCS studies. Pediatric patients with SCD receiving monthly chronic transfusions underwent RCS studies, receiving aliquots of allogeneic RBC labeled at distinct densities of biotin (2-18 μg/mL). B-RBC survival was followed for 4 months post-transfusion, and B-RBC antibody screening for 6 months. Patients with warm autoantibodies (WAA) or B-RBC antibodies are reported here. RBC antibodies were detected during RCS in four patients: one with WAA, one with WAA followed by B-RBC-specific antibodies, and two with transient B-RBC antibodies within the first 5 weeks of exposure. B-RBC half-lives (T50) ranged 37.6-61.7 days (mean 47.8 days). There was no evidence of increased hemolysis or accelerated B-RBC clearance in the presence of WAA or B-RBC antibodies. Biotinylation of allogenic RBC can be used to assess the possible effects of RBC antibodies on transfusion survival in individual cases, particularly when it is uncertain if the detected antibodies may result in hemolysis. In the cases presented here, neither WAA nor B-RBC antibodies were associated with significant shortening of B-RBC survival in individuals with SCD.

O145: Autologous blood transfusion reduces the requirement for perioperative allogeneic blood transfusion in patients undergoing major hepatopancreatobiliary surgery: a retrospective cohort study.

Abstract Introduction Major hepatopancreatobiliary surgery is associated with a risk of major blood loss. We aimed to assess whether autologous transfusion of blood salvaged intraoperatively reduced postoperative allogenic transfusion in this patient cohort. Materials and Methods In this single-centre study, information from a prospective database of 501 patients undergoing major hepatopancreatobiliary resection (2015–2022) was analysed. Patients who received cell salvage (n=264) were compared with those who did not (n=237). Nonautologous (allogenic) transfusion was assessed from the time of surgery to 5 days postsurgery, and blood loss tolerance was calculated using the Lemmens–Bernstein–Brodosky formula. Multivariate analysis was used to identify factors associated with allogenic blood transfusion avoidance. Results 32% of lost blood volume was replaced through autologous transfusion in patients receiving cell salvage. Although the cell salvage group experienced significantly higher intraoperative blood loss compared with the noncell salvage group (1360 vs. 971 ml, P=0.0005), they received significantly fewer allogenic red blood cell units (0.92 vs. 1.5 units/patient, P=0.03). Correction of blood loss tolerance in patients undergoing cell salvage was independently associated with avoidance of allogenic transfusion (Odds ratio 0.05 (0.006–0.38) P=0.005). In a subgroup analysis, cell salvage was associated with significant reduction in 30-day mortality in patients undergoing major hepatectomy (1 vs. 6%, P=0.04). Conclusion Cell salvage use was associated with reduction in allogenic blood transfusion and a reduction in 30-day mortality in patients undergoing major hepatectomy. Prospective trials are warranted to understand whether the use of cell salvage should be routinely utilised for major hepatectomy.

Efficacy of intraoperative blood salvage and autotransfusion in living-donor liver transplantation: a retrospective cohort study.

Liver transplantation (LT) may be associated with massive blood loss and the need for allogeneic blood transfusion. Intraoperative blood salvage autotransfusion (IBSA) can reduce the need for allogeneic blood transfusion. This study aimed to investigate the effectiveness of blood salvage in LT. Among 355 adult patients who underwent elective living-donor LT between January 1, 2019, and December 31, 2022, 59 recipients without advanced hepatocellular carcinoma received IBSA using Cell Saver (CS group). Based on sex, age, model for end-stage liver disease (MELD) score, preoperative laboratory results, and other factors, 118 of the 296 recipients who did not undergo IBSA were matched using propensity score (non-CS group). The primary outcome was the amount of intraoperative allogenic red blood cell (RBC) transfusion. Comparisons were made between the two groups regarding the amount of other blood components transfused and postoperative laboratory findings. The transfused allogeneic RBC for the CS group was significantly lower than that of the non-CS group (1,506.0 vs. 1,957.5 ml, P = 0.026). No significant differences in the transfused total fresh frozen plasma, platelets, cryoprecipitate, and estimated blood loss were observed between the two groups. The postoperative allogeneic RBC transfusion was significantly lower in the CS group than in the non-CS group (1,500.0 vs. 2,100.0 ml, P = 0.039). No significant differences in postoperative laboratory findings were observed at postoperative day 1 and discharge. Using IBSA during LT can effectively reduce the need for perioperative allogeneic blood transfusions without causing subsequent coagulopathy.

Current concepts in the use of cell salvage in obstetrics.

The worldwide leading cause of maternal death is severe maternal hemorrhage. Maternal hemorrhage can be profound leading to an entire loss of blood volume. In the past two decades, Patient Blood Management has evolved to improve patient's care and safety. In surgeries with increased blood loss exceeding 500 ml, the use of cell salvage is strongly recommended in order to preserve the patient's own blood volume and to minimize the need for allogeneic red blood cell (RBC) transfusion. In this review, recent evidence and controversies of the use of cell salvage in obstetrics are discussed. Numerous medical societies as well as national and international guidelines recommend the use of cell salvage during maternal hemorrhage. Intraoperative cell salvage is a strategy to maintain the patient's own blood volume and decrease the need for allogeneic RBC transfusion. Historically, cell salvage has been avoided in the obstetric population due to concerns of iatrogenic amniotic fluid embolism (AFE) or induction of maternal alloimmunization. However, no definite case of AFE has been reported so far. Cell salvage is strongly recommended and cost-effective in patients with predictably high rates of blood loss and RBC transfusion, such as women with placenta accreta spectrum disorder. However, in order to ensure sufficient practical experience in a multiprofessional obstetric setting, liberal use of cell salvage appears advisable.

Obstetric blood transfusion in placenta previa patients with prenatal anemia: a retrospective study

BackgroundThe appropriate use of obstetric blood transfusion is crucial for patients with placenta previa and prenatal anemia. This retrospective study aims to explore the correlation between prenatal anemia and blood transfusion-related parameters in this population.MethodsWe retrieved the medical records of consecutive participants who were diagnosed with placenta previa and underwent cesarean section in our hospital. We compared the baseline demographics and clinical characteristics of patients with and without anemia. The correlation between prenatal anemia and obstetric blood transfusion-related parameters was evaluated using multivariate regression analysis.ResultsA total of 749 patients were enrolled, with a mean prenatal hemoglobin level of 10.87 ± 1.37 g/dL. Among them, 54.87% (391/749) were diagnosed with anemia. The rate of obstetric blood transfusion was significantly higher in the anemia group (79.54%) compared to the normal group (44.41%). The median allogeneic red blood cell transfusion volume in the anemia group was 4.00 U (IQR 2.00–6.00), while in the normal group, it was 0.00 U (IQR 0.00–4.00). The prenatal hemoglobin levels had a non-linear relationship with intraoperative allogeneic blood transfusion rate, massive blood transfusion rate, red blood cell transfusion units, and fresh plasma transfusion volume in patients with placenta previa, with a threshold of 12 g/dL.ConclusionsOur findings suggest that prenatal anemia is associated with a higher rate of blood transfusion-related parameters in women with placenta previa when the hemoglobin level is < 12 g/dL. These results highlight the importance of promoting prenatal care in placenta previa patients with a high requirement for blood transfusion.

Effects of ferric derisomaltose on postoperative anaemia in adult spinal deformity surgery: a study protocol for a randomised controlled trial

IntroductionPostoperative anaemia is prevalent in adult spinal deformity (ASD) surgery in association with unfavourable outcomes. Ferric derisomaltose, a novel iron supplement, offers a promising solution in rapidly treating postoperative anaemia....

Correlation Between 6 Characteristics of Perioperative Hypothermia and Allogeneic Red Blood Cell Transfusion in Abdominal Surgery Patients

To explore the correlation between six characteristics of perioperative hypothermia and allogeneic red blood cell (RBC) transfusions in patients who underwent abdominal surgeries. Patients who underwent abdominal surgeries at West China Hospital, Sichuan University between October 2019 and July 2021 were retrospectively enrolled. A wearable wireless temperature sensor was used to continuously monitor the core body temperature of patients throughout the perioperative period. The perioperative temperature nadir, maximum temperature loss, percentage of time with hypothermia, time-weighted average temperature, area under the curve (AUC) at 36 ℃, and AUC at 37 ℃ were calculated for the period from entering the operation room to 24 hours after the end of anesthesia. The restricted cubic spline (RCS) and multiple logistic regression models were used to explore the correlation between these temperature characteristics and perioperative allogeneic RBC transfusions. A total of 3119 patients were included in the study, with an allogeneic RBC transfusion rate of 2.8%. The RCS model showed that allogeneic RBC transfusion was associated with the perioperative temperature nadir (Poverall=0.048) and AUC at 36 ℃ (Poverall=0.026) and no statistical significance was found in the nonlinear test. The association between allogeneic RBC transfusions and other temperature characteristics was not statistically significant. According to the RCS model results, cut-off points were taken to form groups based on the body temperature characteristics. Multivariate logistic regression showed that the perioperative temperature nadir<35.5 ℃ (odds ratio [OR]=2.47, 95% confidence interval [CI]: 1.21-5.03) and AUC at 36 ℃≥100 ℃·min (OR=2.24, 95% CI:1.09-4.58) were associated with increased demand for allogeneic RBC transfusion. Hypothermia is associated with an increased need for perioperative allogeneic RBC transfusions and has a cumulative effect over time. For patients at high risk of bleeding, attention should be paid to the prevention of perioperative hypothermia and reduction in the cumulative exposure to hypothermia, thereby reducing the need for blood transfusion.

Association Between Storage Time of Transfused Red Blood Cells and Infection After Clean-contaminated Surgery: A Retrospective Cohort Study.

To investigate the association between the storage time of transfused red blood cells (RBCs) and risks of infections after clean-contaminated surgery. Storage lesions of RBCs can aggravate transfusion-related immunomodulation. Very few randomized controlled trials have investigated the impacts of storage time on postoperative outcomes in noncardiac patients. We included adult patients who had undergone clean-contaminated surgery from 2014 to 2018 and received allogeneic RBC transfusion. In transfusion episode-level analysis, the exposure was the storage time of each transfusion episode. In patient-level analysis, the exposures were the mean, weighted mean, maximum storage time, and Scalar Age of Blood Index of RBCs transfused into each patient. The primary outcome was infections that developed after transfusions within postoperative day 30. The 4046 patients were included who received 11604 transfusion episodes. Of these, 1025 (25.3%) patients developed postoperative infections. An increased storage time of transfused RBCs was not associated with increased odds of postoperative infections in either transfusion episode-level analysis [odds ratio (OR), 1.03 per 5 days, 95% CI, 0.95-1.11] or patient-level analysis (mean: OR, 1.02, 95% CI, 0.95-1.10; weighted mean: OR, 1.02, 95% CI, 0.95-1.10; maximum: OR, 1.06, 95% CI, 0.98-1.14; Scalar Age of Blood Index: OR, 0.99, 95% CI, 0.96-1.03), after adjusting 17 confounders. Prolonged storage time of transfused RBCs was not associated with increased risks of infections after clean-contaminated surgery.

HPB O02 Autologous blood transfusion reduces the requirement for peri-operative allogenic blood transfusion in patients undergoing major hepatopancreatobiliary surgery

Abstract Background Major hepatopancreatobiliary surgery is associated with a risk of major blood loss. We aimed to assess whether autologous transfusion of blood salvaged intra-operatively reduces the requirement for post-operative allogenic transfusion in this patient cohort. Methods In this single centre study, information from a prospective database of 501 patients undergoing major HPB resection (2015–2022) was analysed. Patients who received cell salvage (n=264) were compared with those who did not (n=237). Non-autologous (allogenic) transfusion was assessed from the time of surgery to 5 days post-surgery, and blood loss tolerance was calculated using the Lemmens-Bernstein-Brodosky formula. Multivariate analysis was used to identify factors associated with allogenic blood transfusion avoidance. Results 32% of lost blood volume was replaced through autologous transfusion in patients receiving cell salvage. Although the cell salvage group experienced significantly higher intra-operative blood loss compared with the non-cell salvage group (1360ml vs 971ml, p=0.0005), they received significantly less allogenic red blood cell units (1.5 vs 0.92 units/patient, p=0.03). Correction of blood loss tolerance in patients who underwent cell salvage was independently associated with avoidance of allogenic transfusion (OR 0.05 (0.006-0.38) p=0.005). In a subgroup analysis, cell salvage use was associated with a significant reduction in 30-day mortality in patients undergoing major hepatectomy (6% vs 1%, P=0.04). Conclusions Cell salvage use was associated with a reduction in allogenic blood transfusion and a reduction in 30-day mortality in patients undergoing major hepatectomy. Prospective trials are warranted to understand whether the use of cell salvage should be routinely utilised for major hepatectomy.

Low-Volume Acute Normovolemic Hemodilution Does Not Reduce Allogeneic Red Blood Cell Transfusion in Cardiac Surgery in the Modern Era of Patient Blood Management: A Propensity Score-Matched Cohort Study

Patients undergoing cardiac surgery often require blood transfusions, which are associated with increased morbidity and mortality. Patient blood management (PBM) strategies, including acute normovolemic hemodilution (ANH), have been implemented to minimize allogeneic transfusion requirements. Older studies suggested that ANH is associated with reduced transfusions; however, its effectiveness in the modern era of PBM remains unclear. This was a retrospective cohort study. The study was held at a single university hospital. 542 patients who underwent elective cardiac surgery with cardiopulmonary bypass (CPB) using low-priming-volume circuits between January 2017 and March 2022. Patients who received ANH were matched with those who did not receive ANH, using propensity scores. The primary outcome was the proportion of patients who received perioperative red blood cell (RBC) transfusion. Of the 542 eligible patients, 49 ANH cases were propensity-score matched to 97 controls. The median ANH volume was 450 mL (IQR, 400-800 mL). There was no significant difference in perioperative RBC transfusion rates between the 2 groups (24.5% in the ANH group vs 30.9% in the control group, p=0.42). The odds ratio for perioperative RBC transfusion in the ANH group versus the control group was 0.72 (95% CI, 0.32-1.55, p=0.42). Low-volume ANH was not associated with a significant reduction in perioperative allogeneic RBC transfusion during cardiac surgery with CPB using low-priming-volume circuits. The benefits of low-volume ANH in reducing the requirement for RBC transfusion in the modern era of PBM may be smaller than reported previously.