Liberal or restrictive transfusion after cardiac surgery

The impact of organisational change on transfusion practices in perioperative care: an analysis of blood product use following the merger of three London cardiac surgery units to form the Barts Heart Centre

Objectives

In 2015, three London cardiac centres, with different transfusion infrastructure support, merged to form the Barts Heart Centre. We describe the impact on transfusion rate, blood usage and interoperator variation.

Design

Data was collected on all adult patients undergoing cardiac surgery during 2014 as well as 2016, using the National Institute Cardiovascular Outcomes Research (NICOR) data set.

Measurements and main results

Over the two time periods, a total of 3,647 cardiac procedures were performed (1,930 in 2014 and 1,717 in 2016). There were no significant differences in type of surgery or patient comorbidity between the two epochs of time. Overall, red blood cell transfusion at 24 hours and until hospital discharge reduced significantly in 2016 (odds ratio 0.77; 95% confidence interval 0.68-0.89; p=0.0002). Interoperator variability (adjusted for comorbidities) reduced after merger from standard deviation 0.394 (standard error (SE) 0.096) to 0.269 (SE 0.082), p=0.001.

Conclusion

Clinical and organisational factors can improve transfusion service.

Liberal Versus Restrictive Red Blood Cell Transfusion Thresholds in Hematopoietic Cell Transplantation: A Randomized, Open Label, Phase III, Noninferiority Trial

PURPOSE

Evidence regarding red blood cell (RBC) transfusion practices and their impact on hematopoietic cell transplantation (HCT) outcomes are poorly understood.

PATIENTS AND METHODS

We performed a noninferiority randomized controlled trial in four different centers that evaluated patients with hematologic malignancies requiring HCT who were randomly assigned to either a restrictive (hemoglobin [Hb] threshold < 70 g/L) or liberal (Hb threshold < 90 g/L) RBC transfusion strategy between day 0 and day 100. The noninferiority margin corresponds to a 12% absolute difference between groups in Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT) score relative to baseline. The primary outcome was health-related quality of life (HRQOL) measured by FACT-BMT score at day 100. Additional end points were collected: HRQOL by FACT-BMT score at baseline and at days 7, 14, 28, 60, and 100; transplantation-related mortality; length of hospital stay; intensive care unit admissions; acute graft-versus-host disease; Bearman toxicity score; sinusoidal obstruction syndrome; serious infections; WHO Bleeding Scale; transfusion requirements; and reactions to therapy.

RESULTS

A total of 300 patients were randomly assigned to either restrictive-strategy or liberal-strategy treatment groups between 2011 and 2016 at four Canadian adult HCT centers. After HCT, mean pre-transfusion Hb levels were 70.9 g/L in the restrictive-strategy group and 84.6 g/L in the liberal-strategy group (P < .0001). The number of RBC units transfused was lower in the restrictive-strategy group than in the liberal-strategy group (mean, 2.73 units [standard deviation, 4.81 units] v 5.02 units [standard deviation, 6.13 units]; P = .0004). After adjusting for transfusion type and baseline FACT-BMT score, the restrictive-strategy group had a higher FACT-BMT score at day 100 (difference of 1.6 points; 95% CI, -2.5 to 5.6 points), which was noninferior compared with that of the liberal-strategy group. There were no significant differences in clinical outcomes between the transfusion strategies.

CONCLUSION

In patients undergoing HCT, the use of a restrictive RBC transfusion strategy threshold of 70 g/L was as effective as a threshold of 90 g/L and resulted in similar HRQOL and HCT outcomes with fewer transfusions.

Transfusion of Red Blood Cells, Fresh Frozen Plasma, or Platelets Is Associated With Mortality and Infection After Cardiac Surgery in a Dose-Dependent Manner

BACKGROUND

It is unclear whether transfusion of platelets or fresh frozen plasma, in addition to red blood cells, is associated with an increased risk of mortality and infection after cardiac surgery.

METHODS

Patients who underwent valve surgery and/or coronary artery bypass grafting from January 1, 2011 to June 30, 2017 and September 1, 2013 to June 30, 2017 at 2 centers performing cardiac surgery were included in this retrospective study. After stratifying patients based on propensity score matching, we compared rates of mortality and infection between patients who transfused red blood cells, fresh frozen plasma, or platelets with those who did not receive such transfusions. We also compared outcomes between patients who received any of the 3 blood products and patients who received no transfusions at all. Multivariable logistic regression was used to assess associations between transfusion and outcomes.

RESULTS

Of 8238 patients in this study, 109 (1.3%) died, 812 (9.9%) experienced infection, and 4937 (59.9%) received at least 1 type of blood product. Transfusion of any blood type was associated with higher rates of mortality (2.0% vs 0.18%; P < .01) and infection (13.3% vs 4.8%; P < .01). Each of the 3 blood products was independently associated with an increase in mortality per unit transfused (red blood cells, odds ratio 1.18, 95% confidence interval [CI], 1.14-1.22; fresh frozen plasma, odds ratio 1.24, 95% CI, 1.18-1.30; platelets, odds ratio 1.12, 95% CI, 1.07-1.18). Transfusing 3 units of any of the 3 blood products was associated with a dose-dependent increase in the incidence of mortality (odds ratio 1.88, 95% CI, 1.70-2.08) and infection (odds ratio 1.50, 95% CI, 1.43-1.57).

CONCLUSIONS

Transfusion of red blood cells, fresh frozen plasma, or platelets is an independent risk factor of mortality and infection, and combination of the 3 blood products is associated with adverse outcomes after cardiac surgery in a dose-dependent manner.

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.

Sublingual microcirculation does not reflect red blood cell transfusion thresholds in the intensive care unit-a prospective observational study in the intensive care unit

Purpose

Hemoglobin (Hb) transfusion thresholds are established in intensive care units. A restrictive transfusion threshold (Hb 70–75 g/l) is recommended in septic patients, and a liberal transfusion threshold (Hb 90 g/l) for cardiogenic shock. It is unclear whether these historically adopted transfusion thresholds meet the challenges of individual patients.

Methods

We evaluated microvascular flow index (MFI) and proportion of perfused vessels (PPV) in the sublingual microcirculation with CytoCam-IDF microscopy and near-infrared spectroscopy (NIRS). A study team-independent, treating intensivist assigned a total of 64 patients to 1 of 2 two transfusion thresholds, 43 patients to the Hb 75 g/l threshold and 21 patients to the Hb 90 g/l threshold, at a surgical intensive care unit. We performed microcirculatory measurements 1 h before and 1 h after transfusion of 1 unit of red blood cells.

Results

Microcirculatory flow variables correlated negatively with pre-transfusion flow variables (ΔMFI: ρ = − 0.821, p <  0.001; ΔPPV: ρ = − 0.778, p <  0.001). Patients with good initial microcirculation (cutoffs: MFI > 2.84, PPV > 88%) showed a deteriorated microcirculation after red blood cell transfusion. An impaired microcirculation improved after transfusion. At both transfusion thresholds, approximately one third of the patients showed an initially impaired microcirculation. In contrast, one third in every group had good microcirculation above the cutoff variables and did not profit from the transfusion.

Conclusion

The data suggest that the established transfusion thresholds and other hemodynamic variables do not reflect microcirculatory perfusion of patients. Blood transfusion at both thresholds 75 g/l and 90 g/l hemoglobin can either improve or harm the microcirculatory blood flow, questioning the concept of arbitrary transfusion thresholds.

Blood consumption in total arterial coronary artery bypass grafting

Background

Accumulating evidence consistently demonstrates that blood transfusion in cardiac surgery is related to decreased short- and long-term survival. We aimed to evaluate periprocedural blood loss and transfusion rates in elective, isolated total arterial coronary artery bypass grafting (CABG) using exclusively skeletonized bilateral internal mammary arteries (IMAs).

Methods

We identified 1011 consecutive patients with coronary artery disease who underwent CABG between 1/2007 and 12/2014. Of them, 595 patients who presented preoperative hemoglobin levels >9md/dl and underwent elective, isolated CABG for multi-vessel coronary artery disease were included in the study population. 419 patients (70.4%) received total arterial CABG using skeletonized bilateral IMAs, in 176 patients (29.6%) mixed CABG (single IMA & saphenous vein) was performed. Propensity score adjustment using 16 variables was applied to control for treatment effect.

Results

In patients undergoing total arterial CABG, heterologous blood transfusion could be avoided in 87.8% of all cases. Propensity score adjusted results showed a significantly lower incidence of erythrocyte concentrate transfusion in patients undergoing total arterial CABG compared to mixed CABG (odds ratio 2.74, 95% confidence interval 1.38–5.43, P = 0.004). There were no statistically significant differences in the rates of thrombocyte concentrate (P = 0.39) and fresh frozen plasma transfusions (P = 0.07).

Conclusions

In this study, patients who underwent elective, isolated total arterial CABG using exclusively skeletonized bilateral IMAs showed reduced transfusion rates of erythrocyte concentrates compared to mixed CABG using a combination of single IMA and saphenous vein grafts. No evidence for a higher incidence of complications was found with a total arterial approach.

Die traumatische Aortenruptur

Verkehrsunfälle sind für den größten Teil der traumatischen Aortenrupturen verantwortlich, meist zusammen mit weiteren schweren Begleitverletzungen. Die prähospitale Sterblichkeit ist hoch. Bei Verdacht auf eine beteiligte Aortenverletzung, aufgrund eines hohen traumatic aortic injury scores, ist eine Computertomographie durchzuführen. Es erfolgt eine Triage der Verletzungen, und die Versorgungspriorität der Aorta richtet sich nach dem Schweregrad der Aorten- und Begleitverletzungen sowie dem Zustand des Patienten. Bis zur definitiven Versorgung der aortalen Läsion muss der Blutdruck konsequent gesenkt werden. Grad I und II können in Einzelfällen unter enger Kontrolle inital konservativ gemanagt werden. Grad III (gedeckte Ruptur) und Grad IV (freie Ruptur) benötigen eine raschestmögliche Versorgung (interventionell, chirurgisch). In ausgesuchten Fällen kann auch eine verzögerte Versorgung günstig sein.

Als bevorzugte Versorgungsform hat sich die interventionelle Stentgrafttherapie etabliert.

Anemia and red blood cell transfusion practice in prolonged mechanically ventilated patients admitted to a specialized weaning center: an observational study

Background

The impact of anemia and red blood cell (RBC) transfusion on weaning from mechanical ventilation is not known. In theory, transfusions could facilitate liberation from the ventilator by improving oxygen transport capacity. In contrast, retrospective studies of critically ill patients showed a positive correlation of transfusions with prolonged mechanical ventilation, increased mortality rates, and increased risk of nosocomial infections, which in turn could adversely affect weaning outcome.

Methods

Retrospective, observational study on prolonged mechanically ventilated, tracheotomized patients (n = 378), admitted to a national weaning center over a 5 year period. Medical records were reviewed to obtain data on patients’ demographics, comorbidities, blood counts, transfusions, weaning outcome, and nosocomial infections, defined according to the criteria of the U.S. Centers for Disease Control and Prevention. The impact of RBC transfusion on outcome measures was assessed using regression models.

Results

Ninety-eight percent of all patients showed anemia on admission to the weaning center. Transfused and non-transfused patients differed significantly regarding disease severity and comorbidities. In multivariate analyses, RBC transfusion, but not mean hemoglobin concentration in the course of weaning, was independently correlated with weaning duration (adjusted β 12.386, 95% CI 9.335–15.436; p <  0.001) and hospital length of stay (adjusted β 16.116, 95% CI 8.925–23.306; p <  0.001); there was also a trend toward increased hospital mortality (adjusted odds ratio [OR] 2.050, 95% CI 0.995–4.224; p = 0.052), but there was no independent correlation with weaning outcome or nosocomial infections. In contrast, hemoglobin level on the day of admission to the weaning center was independently associated with hospital mortality (adjusted OR 0.956, 95% CI 0.924–0.989; p = 0.010), appearing significantly elevated at values below 8.5 g/dl (AUC 0.670, 95% CI 0.593–0.747; p <  0.001).

Conclusions

A high percentage of prolonged mechanically ventilated patients showed anemia on admission to the weaning center. RBC transfusion was independently correlated with worse outcomes. Since transfused patients differed significantly regarding their clinical characteristics and comorbidities, RBC transfusion might be an indicator of disease severity rather than directly impacting patient prognosis.

Preoperative atorvastatin reduces bleeding and blood transfusions in patients undergoing elective isolated aortic valve replacement

OBJECTIVES

Minimization of bleeding to reduce the use of blood products is of utmost importance in cardiac surgery. Statins are known for their pleiotropic effects beyond lipid-lowering properties, and the use of atorvastatin preoperatively is associated with reduced risk of bleeding and blood product use after coronary surgery. However, no studies have investigated if this beneficial effect also extends to aortic valve surgery.

METHODS

In this retrospective cohort study, 1145 consecutive patients undergoing elective primary isolated aortic valve replacement meeting the inclusion and exclusion criteria were selected from January 2009 to December 2017 (547 in the atorvastatin group, 598 in the control group). Postoperative bleeding, blood product use, and complications were monitored during hospitalization.

RESULTS

Postoperative bleeding was significantly lower in the atorvastatin group compared with the controls in the first 12 h after surgery (372 ± 137 vs 561 ± 219 ml; P = 0.001) and considering overall bleeding (678 ± 387 vs 981 ± 345 ml, P = 0.001). A total of 32.3% of controls and 26.3% of atorvastatin users received packed red blood cells (P = 0.027), and major surgical complications were similar between the groups. Postoperative length of stay was shorter in the atorvastatin group with an average reduction of 1 day of hospitalization (6.0 ± 1.4 vs 6.9 ± 2.1 days; P = 0.001). Postoperative bleeding among the atorvastatin-treated patients was significantly greater in those taking lower doses compared to those taking higher doses of atorvastatin with a 20% between-group difference (P = 0.001).

CONCLUSIONS

Preoperative treatment with atorvastatin might reduce postoperative bleeding and transfusion of packed red blood cells in patients undergoing elective isolated aortic valve replacement. This result might translate into faster recovery after surgery and reduced hospitalization costs.

Clinical decision support and improved blood use in patient blood management

Despite many years of published medical society guidelines for red blood cell (RBC) transfusion therapy, along with clinical trials that provide Level 1 evidence that restrictive transfusion practices can be used safely and are equivalent to transfusions given more liberally, annualized blood transfusion activity did not begin to decline in the United States until 2010. Adoption of electronic medical records has subsequently allowed implementation of clinical decision support (CDS): best practice alerts that can be initiated to improve the use of blood components. We describe our own institutional experience using a targeted CDS to promote restrictive blood transfusion practice and to improve RBC use. A 42% reduction in RBC transfusions was demonstrated at our institution from a baseline in 2008 through 2015, and the rate remained stable through 2018. Although the data cannot be used to infer causality, this decreased RBC use was accompanied by improved clinical outcomes.

Optimizing Perioperative Blood and Coagulation Management During Cardiac Surgery

Bleeding and transfusion are common in cardiac surgery and associated with poorer outcome. Bleeding is frequently due to coagulopathy caused by the complex interaction between cardiopulmonary bypass, major surgical trauma, anticoagulation management, and perioperative factors. Patient blood management has emerged to improve outcome by the prediction, prevention, monitoring, and treatment of bleeding and transfusion. Each part of this chain has several individual modalities and when combined leads to result in a better outcome. This article reviews the hemostasis disturbances in cardiac surgery with cardiopulmonary bypass and gives an overview of the most important patient blood management strategies.

Prospective Evaluation of a Blood Transfusion Protocol for Patients Undergoing Cardiac Operations

BACKGROUND

The Society of Thoracic Surgeons clinical practice guidelines recommend the creation of an interdisciplinary blood management team to implement protocols for improved blood transfusion practices. We report our center's prospective evaluation of a blood transfusion protocol.

METHODS

An interdisciplinary blood management team developed protocols for transfusion of packed red blood cells, fresh frozen plasma, platelets, and cryoprecipitate. The protocols were prospectively evaluated by tracking transfusions administered to consecutive patients undergoing cardiac operations, and the primary outcome of interest was the mean number of adjusted units of blood product transfused per patient. Protocol implementation phases were separated by washout phases to control for a potential Hawthorne effect associated with protocol implementation. Protocol compliance was also assessed.

RESULTS

A total of 1441 patients underwent cardiac operations during the 16-month study period. Although there was no statistically significant reduction in transfusions with an unadjusted analysis, there was a significant trend toward a reduction of the mean adjusted total units transfused per patient over the course of the study period (P < .001). The mean adjusted total units transfused per patient were significantly less during the second washout phase (2.8 units; 95% confidence interval [CI], 2.3-3.3) and second protocol phase (2.8 units; 95% CI, 2.32-3.27) compared with the initial baseline survey phase (3.6 units, 95% CI, 3.1-4.1; P < .05 for both comparisons). Only 55.2% of all units were transfused in compliance to the implemented protocols: platelets, 46.8%; cryoprecipitate, 32.1%; packed red blood cells, 60.7%; and fresh frozen plasma, 53.6%.

CONCLUSIONS

During a prospective evaluation of blood transfusion protocols, a risk-adjusted analysis demonstrated a reduction in transfusions despite poor protocol compliance.

Effect of anemia on muscle oxygen saturation during submaximal exercise

BACKGROUND

Objective measures to assess the need for transfusion in chronic anemia are lacking. Near-infrared spectroscopy may be used, but there is wide variability. Assessment of muscle oxygen saturation (SmO₂ ) during exercise could be used to measure the impact of anemia on performance of everyday activities.

STUDY DESIGN AND METHODS

Hematology patients and controls were recruited to undertake a 6-minute walk test (6MWT) and a 20-second isometric handgrip exercise. Muscle oxygen saturation in the exercising muscles was measured before and during exercise. Changes in saturation during exercise were described. Correlations between identified variables, hemoglobin concentration, and 6MWT distance were undertaken. The effect of transfusion was assessed on a transfused subset.

RESULTS

There were 95 sets of exercises conducted in 74 participants. Baseline SmO₂ correlated with hemoglobin concentration and negatively with 6MWT distance. Paradoxically, a higher hemoglobin was associated with a greater SmO₂ fall during the 6MWT, likely due to greater consumption from improved walk distances. The fall in SmO₂ was independent of hemoglobin during isometric contraction, although levels were lower during contraction due to the lower starting SmO₂ . There was a longer time to peak SmO₂ during recovery following isometric exercise in anemia. There were 17 paired tests following a change in hemoglobin, with SmO₂ not predicting improvement in those who had improved exercise capacity.

CONCLUSION

While baseline SmO₂ correlated with hemoglobin concentration, the correlation was not strong enough to predict transfusion requirements. Recovery after isometric forearm contraction correlated with hemoglobin and warrants further investigation.

Discharge Hemoglobin Level and 30-Day Readmission Rates After Coronary Artery Bypass Surgery

BACKGROUND

Restrictive transfusion strategies supported by large randomized trials are resulting in decreased blood utilization in cardiac surgery. What remains to be determined, however, is the impact of lower discharge hemoglobin (Hb) levels on readmission rates. We assessed patients with higher versus lower Hb levels on discharge to compare 30-day readmission rates after coronary artery bypass grafting (CABG).

METHODS

We retrospectively evaluated 1552 patients undergoing isolated CABG at our institution from January 2013 to May 2016. We evaluated 2 Hb cohorts: "high" (above) and "low" (below) the mean discharge Hb level of 9.4 g/dL, comparing patient characteristics, blood utilization, and clinical outcomes including 30-day readmission rates. We further evaluated the effects of the lowest (<8 g/dL) discharge Hb levels on 30-day readmission rates by dividing the patients into 4 anemia cohorts based on discharge Hb levels: "no anemia" (>12 g/dL), "mild anemia" (10-11.9 g/dL), "moderate anemia" (8-9.9 g/dL), and "severe anemia" (<8 g/dL). Risk adjustment accounted for age, sex, Charlson comorbidity index, preoperative comorbidities, revision sternotomy, and patient blood management program implementation.

RESULTS

The "high" and "low" groups had similar patient characteristics except for Hb levels (mean discharge Hb was 10.4 ± 0.9 vs 8.5 ± 0.6 g/dL, respectively). Notably, no evidence for a difference in 30-day readmission rates was noted between the "high" (76/746; 10.2%) and "low" (97/806; 12.0%) (P = .25) Hb cohorts. The 4 anemia cohorts had differences in age, revision sternotomy incidence, Hb levels, certain patient comorbidities, and time to readmission. On multivariable analysis, the risk-adjusted odds of readmission in the "low" Hb cohort (odds ratio, 1.16; 95% confidence interval, 0.84-1.61; P = .36) was not significant compared to the "high" Hb cohort. Compared to patients with discharge Hb ≥8 g/dL, patients with Hb <8 g/dL had a higher incidence of readmission (22/129; 17.1% vs 151/1423; 10.6%; P = .036). On multivariable analysis, Hb <8 g/dL on discharge was predictive of readmission (odds ratio, 1.77; 95% confidence interval, 1.05-2.88; P = .03). The most common reason for readmission was volume overload, followed by infection and arrhythmias.

CONCLUSIONS

A discharge Hb level below the institution mean for CABG patients does not provide evidence for an association with an increased 30-day readmission rate. In the small number of patients discharged with Hb <8 g/dL, there is a suggestion of increased risk for readmission and larger more controlled studies are needed to verify or refute this finding.

Use of red blood cells in Danish intensive care units: A population-based register study

BACKGROUND

Red blood cell (RBC) transfusion is common in the intensive care unit (ICU). Recent trials have shown that a restrictive transfusion strategy is safe in most patients, and recent guidelines recommend such a strategy in most ICU patients. It is unknown if this has translated into a change in clinical practice.

METHODS

We conducted a population-based register study of RBC transfusions in ICUs in the Danish Capital Region between 1st of January 2011 and 31st of December 2016 by linking data from the regional blood bank and the Danish Intensive Care Database. We used crude data and run- and control-charts to analyse changes in the number of RBC transfusions.

RESULTS

We included 27 835 ICU admissions of which 6936 received 40 889 RBC units. The crude use was 36.2 RBC units per one-hundred patient bed-days in 2011 vs 29.8 in 2016. The run-chart analysis did not confirm a change in the total use of RBC units in all ICUs combined, and we observed no change in the proportion of transfused patients or in the use of RBCs among transfused patients. Sensitivity analyses showed decreased use of RBC units in two general ICUs, and a reduced use of RBC units among medical ICU patients.

CONCLUSIONS

In this population-based register study, we did not with certainty observe changes over time in the use of RBC transfusions in all patients in all ICUs in the Danish Capital Region. A reduction in RBC use may have occurred in some general ICUs and in medical ICU patients.

Review of current transfusion therapy and blood banking practices

Transfusion Medicine is a dynamically evolving field. Recent high-quality research has reshaped the paradigms guiding blood transfusion. As increasing evidence supports the benefit of limiting transfusion, guidelines have been developed and disseminated into clinical practice governing optimal transfusion of red cells, platelets, plasma and cryoprecipitate. Concepts ranging from transfusion thresholds to prophylactic use to maximal storage time are addressed in guidelines. Patient blood management programs have developed to implement principles of patient safety through limiting transfusion in clinical practice. Data from National Hemovigilance Surveys showing dramatic declines in blood utilization over the past decade demonstrate the practical uptake of current principles guiding patient safety. In parallel with decreasing use of traditional blood products, the development of new technologies for blood transfusion such as freeze drying and cold storage has accelerated. Approaches to policy decision making to augment blood safety have also changed. Drivers of these changes include a deeper understanding of emerging threats and adverse events based on hemovigilance, and an increasing healthcare system expectation to align blood safety decision making with approaches used in other healthcare disciplines.

Society of Cardiovascular Anesthesiologists Clinical Practice Improvement Advisory for Management of Perioperative Bleeding and Hemostasis in Cardiac Surgery Patients

Bleeding after cardiac surgery is a common and serious complication leading to transfusion of multiple blood products and resulting in increased morbidity and mortality. Despite the publication of numerous guidelines and consensus statements for patient blood management in cardiac surgery, research has revealed that adherence to these guidelines is poor, and as a result, a significant variability in patient transfusion practices among practitioners still remains. In addition, although utilization of point-of-care (POC) coagulation monitors and the use of novel therapeutic strategies for perioperative hemostasis, such as the use of coagulation factor concentrates, have increased significantly over the last decade, they are still not widely available in every institution. Therefore, despite continuous efforts, blood transfusion in cardiac surgery has only modestly declined over the last decade, remaining at ≥50% in high-risk patients. Given these limitations, and in response to new regulatory and legislature requirements, the Society of Cardiovascular Anesthesiologists (SCA) has formed the Blood Conservation in Cardiac Surgery Working Group to organize, summarize, and disseminate the available best-practice knowledge in patient blood management in cardiac surgery. The current publication includes the summary statements and algorithms designed by the working group, after collection and review of the existing guidelines, consensus statements, and recommendations for patient blood management practices in cardiac surgery patients. The overall goal is creating a dynamic resource of easily accessible educational material that will help to increase and improve compliance with the existing evidence-based best practices of patient blood management by cardiac surgery care teams.

Cost-effectiveness comparison of routine transfusion with restrictive and liberal transfusion strategies for surgical patients in China

BACKGROUND AND OBJECTIVES

A health industry standard recommending restrictive transfusion is to be in effect in China in April 2019. We aim to explore its potential economic and clinical impacts among surgical patients.

MATERIALS AND METHODS

A decision tree model was applied to compare cost-effectiveness of current routine transfusion in China, a restrictive (transfusion at Hb < 8 g/dl or ischaemic symptoms) and a liberal (transfusion at Hb < 10 g/dl) strategy. Parameters were estimated from empirical data of 25 227 surgical inpatients aged ≥30 years in a multicenter study and supplemented by meta-analysis when necessary. Results are shown for cardio-cerebral-vascular (CCV) surgery and non-CCV (orthopaedics, general, thoracic) surgery separately.

RESULTS

Per 10 000 patients in routine, restrictive, liberal transfusion scenarios, total spending (transfusion and length of stay related) was 7·67, 7·58 and 9·39 million CNY (1 CNY × 0.157 = 1 US dollar) for CCV surgery and 6·35, 6·70 and 8·09 million CNY for non-CCV surgery; infectious and severe complications numbered 354, 290, and 290 (CCV) and 315, 286, and 330 (non-CCV), respectively. Acceptability curves showed high probabilities for restrictive strategy to be cost-effective across a wide range of willingness-to-pay values. Such findings were mostly consistent in sensitivity and subgroup analyses except for patients with cardiac problems.

CONCLUSION

We showed strong rationale, succeeding previous findings only in cardiac or joint procedures, to comply with the new standard as restrictive transfusion has high potential to save blood, secure safety, and is cost-effective for a wide spectrum of surgical patients. Experiences should be further summarized to pave the way towards individualized transfusion.

Lower vs higher transfusion threshold in septic shock patients of different ages: A study protocol

BACKGROUND

Current evidence indicates that it is safe to use a lower haemoglobin (Hb) threshold for red blood cell (RBC) transfusion as compared to a higher Hb-threshold. However, the recent Transfusion Requirements in Cardiac Surgery (TRICS-3) trial reported a significant interaction between patient age and the effect of lower vs higher Hb-thresholds for RBC transfusion. The interaction between patient age and transfusion strategy appears to differ between trials.

METHODS

This is the protocol and statistical analysis plan for a post hoc analysis of the Transfusion Requirements in Septic Shock (TRISS) trial. We will assess the effect of a lower vs a higher Hb-threshold for RBC transfusion in patients of different ages with septic shock. The primary and secondary outcomes are 1-year mortality and 90-day mortality respectively. We will assess age divided into six age groups and as a continuous variable and present baseline characteristics and odds ratios derived from both simple and adjusted (for the Sequential Organ Failure Assessment score, haematological malignancy, age and trial site) logistic regression models and P-values for the test-of-interaction. Furthermore, we will compare outcomes according to Hb-threshold in each age group using Kaplan-Meier curves and log-rank tests.

DISCUSSION

The outlined study will make a detailed assessment of potential interaction of patient age with transfusion strategy in patients with septic shock. This may inform future trials on the benefits and harms of RBC transfusion.

Low hematocrit levels: a risk factor for long-term outcomes in patients requiring prolonged mechanical ventilation after cardiovascular surgery. A retrospective study

While low-risk patients who undergo elective surgery can tolerate low hematocrit levels, the benefits of higher hematocrit levels might outweigh the risk of transfusion in high-risk patients. Therefore, this study aimed to evaluate the effects of perioperative hematocrit levels on mortality in patients requiring prolonged mechanical ventilation (PMV) after a cardiovascular surgery. This single-center retrospective cohort study was conducted on 172 patients who underwent cardiovascular surgery with cardiopulmonary bypass or off-pump coronary artery bypass grafting and required PMV for ≥72 hours in the intensive care unit (ICU) from 2008 to 2012 at the Yokohama City University Medical Center in Yokohama, Japan. Patients were classified according to hematocrit levels on ICU admission: high (≥30%) and low (<30%) groups. Of 172 patients, 86 were included to each of the low-hematocrit and high-hematocrit groups, with median hematocrit levels (first to third quartiles) of 27.4% (25.4%–28.7%) and 33.0% (31.3%–35.5%), respectively. The difference in survival rates was significant between the two groups using the log-rank test (HR 0.55, 95% CI 0.32 to 0.95, p=0.033). Cox regression analysis revealed that ≥30% increase in hematocrit levels on ICU admission was significantly associated with decreased long-term mortality (HR 0.40, 95% CI 0.20 to 0.80, p=0.0095). Lower hematocrit levels on ICU admission was a risk factor for increased long-term mortality, and higher hematocrit levels might outweigh the risk of transfusion in patients requiring PMV after a cardiovascular surgery.

Prevention of Cardiac Surgery-Associated Acute Kidney Injury: A Review of Current Strategies

Acute kidney injury is a common and often severe postoperative complication after cardiac surgery, and is associated with poor short-term and long-term outcomes. Numerous randomized controlled trials have been conducted to investigate various strategies for prevention of cardiac surgery-associated acute kidney injury. Unfortunately, most trials that have been conducted to date have been negative. However, encouraging results have been demonstrated with preoperative administration of corticosteroids, leukocyte filtration, and administration of inhaled nitric oxide intraoperatively, and implementation of a Kidney Disease: Improving Global Outcomes bundle of care approach postoperatively. These findings require validation in large, multicenter trials.

From the ICU to the operating room: how to manage the patient?

PURPOSE OF REVIEW

To outline key points for perioperative ICU optimization of nutrition, airway management, blood product preparation and transfusion, antibiotic prophylaxis and transport.

RECENT FINDINGS

Optimization entails glycemic control for all, with specific attention to type-1 diabetic patients. Transport-related adverse events may be averted with surgery in the ICU. If moving the patient is unavoidable, transport guidelines should be followed and hemodynamic optimization, airway control, and stabilization of mechanical ventilation ensured before transport. Preinduction preparation includes assessment of the airway and the provision of high-flow oxygen to prolong apneic oxygenation. Postintubation, a protective positive ventilation strategy should be employed. Ideal transfusion thresholds are 7 g/dl for hemodynamically stable adult patients, 8 g/dl in orthopedic or cardiac surgery patients as well as those with underlying cardiovascular disease. Higher transfusions thresholds may be required in specific disease states. Antimicrobial prophylaxis within 120 min of incision prevents most surgical site infections. Antibiotic therapy depends on the antibiotics being received in the ICU, the time elapsed since ICU admission, local epidemiology and the type of surgery. Tailored antimicrobial regimens may be continued periprocedurally. If more than 70% of the nutritional requirement cannot be met enterally, parenteral nutrition should be initiated within 5-7 days of surgery or earlier if the patient is malnourished.

SUMMARY

ICU patients who require surgery may benefit from appropriate perioperative management.

Six-month outcomes after restrictive or liberal transfusion for cardiac surgery (TRICS III trial)

CLINICAL QUESTION

Is transfusing red cell components using a restrictive transfusion threshold (Hb < 75 g L^-1 ) as safe as a liberal transfusion threshold (Hb < 95 g L^-1 in intensive care and < 85 g L^-1 outside intensive care) during and after cardiac surgery for adults at moderate to high risk of death?

EVIDENCE FROM TRIAL

In adults undergoing cardiac surgery who were at moderate to high risk for death, using a restrictive red-cell transfusion threshold was as safe as a liberal red cell transfusion threshold (composite outcome of death from any cause, myocardial infarction, stroke or new-onset renal failure with dialysis at 6 months after surgery).

Patient Blood Management Program Improves Blood Use and Clinical Outcomes in Orthopedic Surgery

WHAT WE ALREADY KNOW ABOUT THIS TOPIC

WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Although randomized trials show that patients do well when given less blood, there remains a persistent impression that orthopedic surgery patients require a higher hemoglobin transfusion threshold than other patient populations (8 g/dl vs. 7 g/dl). The authors tested the hypothesis in orthopedic patients that implementation of a patient blood management program encouraging a hemoglobin threshold less than 7 g/dl results in decreased blood use with no change in clinical outcomes.

METHODS

After launching a multifaceted patient blood management program, the authors retrospectively evaluated all adult orthopedic patients, comparing transfusion practices and clinical outcomes in the pre- and post-blood management cohorts. Risk adjustment accounted for age, sex, surgical procedure, and case mix index.

RESULTS

After patient blood management implementation, the mean hemoglobin threshold decreased from 7.8 ± 1.0 g/dl to 6.8 ± 1.0 g/dl (P < 0.0001). Erythrocyte use decreased by 32.5% (from 338 to 228 erythrocyte units per 1,000 patients; P = 0.0007). Clinical outcomes improved, with decreased morbidity (from 1.3% to 0.54%; P = 0.01), composite morbidity or mortality (from 1.5% to 0.75%; P = 0.035), and 30-day readmissions (from 9.0% to 5.8%; P = 0.0002). Improved outcomes were primarily recognized in patients 65 yr of age and older. After risk adjustment, patient blood management was independently associated with decreased composite morbidity or mortality (odds ratio, 0.44; 95% CI, 0.22 to 0.86; P = 0.016).

CONCLUSIONS

In a retrospective study, patient blood management was associated with reduced blood use with similar or improved clinical outcomes in orthopedic surgery. A hemoglobin threshold of 7 g/dl appears to be safe for many orthopedic patients.

Intensive Care Unit Enhanced Recovery Pathway for Patients Undergoing Orthotopic Liver Transplants Recipients: A Prospective, Observational Study

BACKGROUND

Liver transplant recipients continue to have high perioperative resource utilization and prolonged length of stay despite improvements in perioperative care. Enhanced recovery pathways have been shown in other surgical populations to produce reductions in hospital resource utilization.

METHODS

A prospective, observational study was performed to examine the effect of an enhanced recovery pathway for postoperative care after liver transplantation. Outcomes from patients undergoing liver transplantation from November 1, 2013, to October 31, 2014, managed by the pathway were compared to transplant recipients from the year before pathway implementation. Multivariable regression analysis was used to assess the association of the clinical pathway on clinical outcomes.

RESULTS

The intervention and control groups included 141 and 106 patients, respectively. There were no demographic differences between the control and intervention group including no differences between the length of surgery and cold ischemic time. Median intensive care unit length of stay was reduced from 4.4 to 2.6 days (P < .001). The intervention group had a higher likelihood of earlier discharge (hazard ratio [95% CI], 2.01 [1.55-2.62]; P < .001), and a 69% and 65% lower odds of receiving a plasma (P < .001) or packed red blood cell (P < .001) transfusion. There was no significant effect on hospital mortality (P = .40), intensive care unit readmission rates (P = .75), or postoperative infections (urinary traction infections: P = .09; pneumonia: P = .27).

CONCLUSIONS

An enhanced recovery pathway focused on milestone-based elements of intensive care unit management and predetermined management triggers including hemodynamic goals, fluid therapy, perioperative antibiotics, glycemic control, and standardized transfusion triggers led to reductions in intensive care unit length of stay without an increase in perioperative complications.

Should Transfusion Trigger Thresholds Differ for Critical Care Versus Perioperative Patients? A Meta-Analysis of Randomized Trials

Supplemental Digital Content is available in the text.

Objective:

To address the significant uncertainty as to whether transfusion thresholds for critical care versus surgical patients should differ.

Design:

Meta-analysis of randomized controlled trials.

Setting:

Medline, EMBASE, and Cochrane Library searches were performed up to 15 June 2016.

Patients:

Trials had to enroll adult surgical or critically ill patients for inclusion.

Interventions:

Studies had to compare a liberal versus restrictive threshold for the transfusion of allogeneic packed RBCs.

Measurements and Main Results:

The primary outcome was 30-day all-cause mortality, sub-grouped by surgical and critical care patients. Secondary outcomes included myocardial infarction, stroke, renal failure, allogeneic blood exposure, and length of stay. Odds ratios and weighted mean differences were calculated using random effects meta-analysis. To assess whether subgroups were significantly different, tests for subgroup interaction were used. Subgroup analysis by trials enrolling critically ill versus surgical patients was performed. Twenty-seven randomized controlled trials (10,797 patients) were included. In critical care patients, restrictive transfusion resulted in significantly reduced 30-day mortality compared with liberal transfusion (odds ratio, 0.82; 95% CI, 0.70–0.97). In surgical patients, a restrictive transfusion strategy led to the opposite direction of effect for mortality (odds ratio, 1.31; 95% CI, 0.94–1.82). The subgroup interaction test was significant (p = 0.04), suggesting that the effect of restrictive transfusion on mortality is statistically different for critical care (decreased risk) versus surgical patients (potentially increased risk or no difference). Regarding secondary outcomes, for critically ill patients, a restrictive strategy resulted in reduced risk of stroke/transient ischemic attack, packed RBC exposure, transfusion reactions, and hospital length of stay. In surgical patients, restrictive transfusion resulted in reduced packed RBC exposure.

Conclusions:

The safety of restrictive transfusion strategies likely differs for critically ill patients versus perioperative patients. Further trials investigating transfusion strategies in the perioperative setting are necessary.

Audit of transfusion among the oldest old: treading the fine line between undertransfusion and optimum trigger

BACKGROUND

Recent research has questioned restrictive transfusion policies in vulnerable elderly populations. Our audit assesses the prevalence and postoperative outcomes of extremely elderly patients undergoing the stress of surgery with perioperative hemoglobin (Hb) less than 9 g/dL.

STUDY DESIGN AND METHODS

This retrospective analysis of prospectively collected data addressed patients aged 85+ undergoing elective surgery. Demographic data and baseline characteristics were recorded, as well as Hb and transfused red blood cell (RBC) units. The main endpoint was the prevalence of perioperative Hb less than 9 g/dL, that is, patients with baseline Hb <9 g/dL without preoperative transfusions (defined as Group A). Patients with perioperative Hb of 9 g/dL or greater (with or without transfusion) were designated as Group B. Secondary outcomes included morbidity, length of hospital stay, and mortality 30 days and 6 months after surgery. A bivariate analysis was performed followed by logistic regression to determine whether undergoing the stress of surgery with perioperative Hb less than 9 g/dL was an independent risk factor for postoperative outcomes.

RESULTS

A total of 148 patients were included. The prevalence of perioperative Hb less than 9 g/dL was 25%. It was associated with increased morbidity and mortality -both 30 days and 6 months after surgery- and a prolonged length of hospital stay. Anemia-associated complications were higher among patients from Group A, whereas transfusion-associated ones were evenly distributed. In all the regression models, perioperative Hb less than 9 g/dL was an independent risk factor for worse postoperative outcomes.

CONCLUSION

Perioperative Hb less than 9 g/dL was common among patients aged 85+, and it was associated with increased risk of adverse postoperative outcomes. The tolerance to anemia might decrease perioperatively when Hb is less than 9 g/dL. Thus, less restrictive thresholds deserve further evaluation.

Acute kidney injury after cardiac surgery: prevalence, impact and management challenges

Acute kidney injury (AKI) is a major medical problem that is of particular concern after cardiac surgery. Perioperative AKI is independently associated with an increase in short-term morbidity, costs of treatment, and long-term mortality. In this review, we explore the definition of cardiac surgery-associated acute kidney injury (CSA-AKI) and identify diverse mechanisms and risk factors contributing to the renal insult. Current theories of the pathophysiology of CSA-AKI and description of its clinical course will be addressed in this review. Data on the most promising renal protective strategies in cardiac surgery, from well-designed studies, will be scrutinized. Furthermore, diagnostic tools such as novel biomarkers of AKI and their potential utility will be discussed.

Anemia at Discharge in Elderly Trauma Patients is Not Associated with Six-Month Mortality

Few studies have evaluated outcomes in geriatric trauma patients discharged with anemia. Our hypothesis was that anemia at discharge was not associated with six-month mortality. A 22-month retrospective study of trauma patients ≥ 65 years was conducted from 2015 to 2016. The end point was six-month mortality. The degree of anemia at admission (admission hemoglobin [AHb]) and discharge (discharge hemoglobin [DHb]) was categorized as follows based on hemoglobin (Hb) (g/dL): I (>10), II (>9 and ≤10), III (>8 and ≤9), and IV (≤8). Univariate analysis and multivariate analysis were performed to determine the association of AHb and DHb with the end point. Nine hundred forty-nine patients were analyzed (median age, 82 years). Six-month mortality was 11 per cent. Mortality was associated with AHb by univariate analysis (I:10% [84/831]; II: 13% [9/67]; III: 22% [7/32]; and IV: 26% [5/19]) ( P = 0.003). DHb was not associated with mortality (I:11% [65/613]; II: 12% [21/183]; III: 10% [12/116]; and IV: 18% [7/39]) ( P = 0.37). Logistic regression found that AHb category IV, age, and chronic kidney disease were independently associated with the end point. In geriatric patients, the severity of anemia at admission and not at discharge predicted six-month mortality. Discharging patients with an Hb of ≤8 g/dL was not adversely associated with mortality.

Safety of a Restrictive versus Liberal Approach to Red Blood Cell Transfusion on the Outcome of AKI in Patients Undergoing Cardiac Surgery: A Randomized Clinical Trial

BACKGROUND

Safely reducing red blood cell transfusions can prevent transfusion-related adverse effects, conserve the blood supply, and reduce health care costs. Both anemia and red blood cell transfusion are independently associated with AKI, but observational data are insufficient to determine whether a restrictive approach to transfusion can be used without increasing AKI risk.

METHODS

In a prespecified kidney substudy of a randomized noninferiority trial, we compared a restrictive threshold for red blood cell transfusion (transfuse if hemoglobin<7.5 g/dl, intraoperatively and postoperatively) with a liberal threshold (transfuse if hemoglobin<9.5 g/dl in the operating room or intensive care unit, or if hemoglobin<8.5 g/dl on the nonintensive care ward). We studied 4531 patients undergoing cardiac surgery with cardiopulmonary bypass who had a moderate-to-high risk of perioperative death. The substudy's primary outcome was AKI, defined as a postoperative increase in serum creatinine of ≥0.3 mg/dl within 48 hours of surgery, or ≥50% within 7 days of surgery.

RESULTS

Patients in the restrictive-threshold group received significantly fewer transfusions than patients in the liberal-threshold group (1.8 versus 2.9 on average, or 38% fewer transfusions in the restricted-threshold group compared with the liberal-threshold group; P<0.001). AKI occurred in 27.7% of patients in the restrictive-threshold group (624 of 2251) and in 27.9% of patients in the liberal-threshold group (636 of 2280). Similarly, among patients with preoperative CKD, AKI occurred in 33.6% of patients in the restrictive-threshold group (258 of 767) and in 32.5% of patients in the liberal-threshold group (252 of 775).

CONCLUSIONS

Among patients undergoing cardiac surgery, a restrictive transfusion approach resulted in fewer red blood cell transfusions without increasing the risk of AKI.

Low vs high hemoglobin trigger for transfusion in vascular surgery: a randomized clinical feasibility trial

Current guidelines advocate to limit red blood cell (RBC) transfusion during surgery, but the feasibility and safety of such a strategy remain unclear, as the majority of evidence is based on postoperatively stable patients. We assessed the effects of a protocol aiming to restrict RBC transfusion throughout hospitalization for vascular surgery. Fifty-eight patients scheduled for lower limb bypass or open abdominal aortic aneurysm repair were randomly assigned, on hemoglobin drop below 9.7 g/dL, to either a low-trigger (hemoglobin &lt; 8.0 g/dL) or a high-trigger (hemoglobin &lt; 9.7 g/dL) group for RBC transfusion. Near-infrared spectroscopy assessed intraoperative oxygen desaturation in brain and muscle. Explorative outcomes included nationwide registry data on death and major vascular complications. The primary outcome, mean hemoglobin within 15 days of surgery, was significantly lower in the low-trigger group, at 9.46 vs 10.33 g/dL in the high-trigger group (mean difference, −0.87 g/dL; P = .022), as were units of RBCs transfused (median [interquartile range (IQR)], 1 [0-2] vs 3 [2-6]; P = .0015). Although the duration and magnitude of cerebral oxygen desaturation increased in the low-trigger group (median [IQR], 421 [42-888] vs 127 [11-331] minutes × %; P = .0036), muscle oxygenation was unaffected. The low-trigger group associated to a higher rate of death or major vascular complications (19/29 vs 8/29; hazard ratio, 3.20; P = .006) and fewer days alive outside the hospital within 90 days (median [IQR], 76 [67-82] vs 82 [76-84] days; P = .049). In conclusion, a perioperative protocol restricting RBC transfusion successfully separated hemoglobin levels and RBC units transfused. Exploratory outcomes suggested potential harm with the low-trigger group and warrant further trials before such a strategy is universally adopted. This trial was registered at www.clinicaltrials.gov as #NCT02465125.

Can venous cannula design influence venous return and negative pressure with a minimally invasive extracorporeal circulation?

INTRODUCTION

Recent advances to make cardiopulmonary bypass more physiological include the use of kinetic-assisted venous drainage but without a venous reservoir. Despite manipulation of intravascular volume and patient positioning, arterial flow is frequently reduced. Negative venous line pressures can be generated, which may elicit gaseous microemboli. We investigated the influence of venous cannula design on venous return and negative venous line pressures.

METHODS

In a single-centre, single-surgeon, prospective, randomized, double-blind trial, 48 patients undergoing isolated coronary artery, aortic valve or combined coronary artery and aortic valve surgery, with a minimally invasive circuit, were randomized to a conventional two-stage (2S) or three-stage venous cannula (3S), or to a three-stage venous cannula with additional 'fenestrated' ridges (F3S). Blood flow, venous line pressures and gaseous microemboli number and size were measured.

RESULTS

The pump flow achieved was the same between groups, but in each case fell below the target range of 2.2-2.4 L min^-1 m^-2. The three-stage cannula recorded significantly lower negative pressure than the other cannulae. The total count and volume of gaseous emboli detected with the F3S cannulae was very high in some cases, with wide heterogeneity.

DISCUSSION

The low negative pressures recorded with three-stage cannula, despite having a larger drainage orifice area, suggest that negative pressure may be more influenced by lumen diameter and vena cava collapse rather than drainage hole size. The additional fenestrations resulted in flow characteristics and negative pressures similar to the larger two-stage cannula but are associated with generation of gaseous microemboli.