Increased mortality, postoperative morbidity, and cost after red blood cell transfusion in patients having cardiac surgery

Gastrointestinal hemorrhage: should we transfuse less?

Although blood transfusion has an established place in the conventional management of acute upper gastrointestinal (GI) hemorrhage, there is growing evidence of adverse side effects of transfusion, both acute and later. An Ovid Medline literature search was performed to evaluate the significance and importance of these effects. Evidence of impaired hemostasis with repletion of blood volume in the acute phase was found in multiple studies and in uncontrolled studies in combat casualties. There are multiple large studies of a so-called immunosuppressive effect of transfused blood leading to increased infection rates and mortality dependent both on dose and on the age of the stored blood. In view of evidence of increased bleeding with early blood volume restoration and the growing evidence of so-called immunosuppressive effects of stored blood, there is a need to consider trials using a conservative utilization of blood in acute GI bleeding.

Does blood transfusion harm cardiac surgery patients?

Over recent years there has been a substantial body of evidence demonstrating strong associations between transfusion and adverse outcomes, including myocardial, neurological and renal injury, in a range of clinical settings where transfusion is administered for reasons other than life-threatening bleeding. The strength of these associations across a range of clinical settings suggests that confounding and bias, the chief limitations of all observational studies, are unlikely to account for all of these observations. Given the wide range in transfusion rates in cardiac centres, with up to 100% of patients in some centres exposed to allogenic blood components, this evidence, albeit circumstantial, presents a strong argument for prospective randomised trials to attempt to determine, firstly, if transfusion causes adverse outcomes, and secondly, in which patient groups does the benefit of transfusion outweigh these risks? These issues are discussed in the context of an article published this month in BMC Medicine.

Hospital variation in transfusion and infection after cardiac surgery: a cohort study

BACKGROUND

Transfusion practices in hospitalised patients are being re-evaluated, in part due to studies indicating adverse effects in patients receiving large quantities of stored blood. Concomitant with this re-examination have been reports showing variability in the use of specific blood components. This investigation was designed to assess hospital variation in blood use and outcomes in cardiac surgery patients.

METHODS

We evaluated outcomes in 24,789 Medicare beneficiaries in the state of Michigan, USA who received coronary artery bypass graft surgery from 2003 to 2006. Using a cohort design, patients were followed from hospital admission to assess transfusions, in-hospital infection and mortality, as well as hospital readmission and mortality 30 days after discharge. Multilevel mixed-effects logistic regression was used to calculate the intrahospital correlation coefficient (for 40 hospitals) and compare outcomes by transfusion status.

RESULTS

Overall, 30% (95 CI, 20% to 42%) of the variance in transfusion practices was attributable to hospital site. Allogeneic blood use by hospital ranged from 72.5% to 100% in women and 49.7% to 100% in men. Allogeneic, but not autologous, blood transfusion increased the odds of in-hospital infection 2.0-fold (95% CI 1.6 to 2.5), in-hospital mortality 4.7-fold (95% CI 2.4 to 9.2), 30-day readmission 1.4-fold (95% CI 1.2 to 1.6), and 30-day mortality 2.9-fold (95% CI 1.4 to 6.0) in elective surgeries. Allogeneic transfusion was associated with infections of the genitourinary system, respiratory tract, bloodstream, digestive tract and skin, as well as infection with Clostridium difficile. For each 1% increase in hospital transfusion rates, there was a 0.13% increase in predicted infection rates.

CONCLUSION

Allogeneic blood transfusion was associated with an increased risk of infection at multiple sites, suggesting a system-wide immune response. Hospital variation in transfusion practices after coronary artery bypass grafting was considerable, indicating that quality efforts may be able to influence practice and improve outcomes.

The efficacy of an intraoperative cell saver during cardiac surgery: a meta-analysis of randomized trials

BACKGROUND

Cell salvage may be used during cardiac surgery to avoid allogeneic blood transfusion. It has also been claimed to improve patient outcomes by removing debris from shed blood, which may increase the risk of stroke or neurocognitive dysfunction. In this study, we sought to determine the overall safety and efficacy of cell salvage in cardiac surgery by performing a systematic review and meta-analysis of published randomized controlled trials.

METHODS

A comprehensive search was undertaken to identify all randomized trials of cell saver use during cardiac surgery. MEDLINE, Cochrane Library, EMBASE, and abstract databases were searched up to November 2008. All randomized trials comparing cell saver use and no cell saver use in cardiac surgery and reporting at least one predefined clinical outcome were included. The random effects model was used to calculate the odds ratios (OR, 95% confidence intervals [CI]) and the weighted mean differences (WMD, 95% CI) for dichotomous and continuous variables, respectively.

RESULTS

Thirty-one randomized trials involving 2282 patients were included in the meta-analysis. During cardiac surgery, the use of an intraoperative cell saver reduced the rate of exposure to any allogeneic blood product (OR 0.63, 95% CI: 0.43-0.94, P = 0.02) and red blood cells (OR 0.60, 95% CI: 0.39-0.92, P = 0.02) and decreased the mean volume of total allogeneic blood products transfused per patient (WMD -256 mL, 95% CI: -416 to -95 mL, P = 0.002). There was no difference in hospital mortality (OR 0.65, 95% CI: 0.25-1.68, P = 0.37), postoperative stroke or transient ischemia attack (OR 0.59, 95% CI: 0.20-1.76, P = 0.34), atrial fibrillation (OR 0.92, 95% CI: 0.69-1.23, P = 0.56), renal dysfunction (OR 0.86, 95% CI: 0.41-1.80, P = 0.70), infection (OR 1.25, 95% CI: 0.75-2.10, P = 0.39), patients requiring fresh frozen plasma (OR 1.16, 95% CI: 0.82-1.66, P = 0.40), and patients requiring platelet transfusions (OR 0.90, 95% CI: 0.63-1.28, P = 0.55) between cell saver and noncell saver groups.

CONCLUSIONS

Current evidence suggests that the use of a cell saver reduces exposure to allogeneic blood products or red blood cell transfusion for patients undergoing cardiac surgery. Subanalyses suggest that a cell saver may be beneficial only when it is used for shed blood and/or residual blood or during the entire operative period. Processing cardiotomy suction blood with a cell saver only during cardiopulmonary bypass has no significant effect on blood conservation and increases fresh frozen plasma transfusion.

The association of hemodilution and transfusion of red blood cells with biochemical markers of splanchnic and renal injury during cardiopulmonary bypass

BACKGROUND

Hemodilution is the main cause of a low hematocrit concentration during cardiopulmonary bypass. This low hematocrit may be insufficient for optimal tissue oxygen delivery and often results in packed cell transfusion. Our objective in this study was to find a relationship between intraoperative hematocrit and allogeneic blood transfusion on release of postoperative injury markers from the kidneys and the splanchnic area.

METHODS

Fifty consecutive patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were included. Systemic tissue hypoxia was assessed by lactate concentrations. Kidney and splanchnic ischemia were assessed by the measurement of N-acetyl-beta-D-glucosaminidase (NAG) and intestinal fatty acid binding protein (IFABP) in urine. Patients were retrospectively placed into groups according to their lowest hematocrit concentration on bypass (<24% or >or=24%).

RESULTS

The intraoperative lactate and the postoperative NAG and IFABP concentrations were higher in the low hematocrit group (<24%) than in the high hematocrit group (>or=24%; P < 0.05). Low hematocrit correlated with higher lactate concentrations (R(2) = 0.150, P < 0.01) and with higher NAG concentrations (R(2) = 0.138, P < 0.01) and IFABP concentrations (R(2) = 0.107, P < 0.01) postoperatively. Transfusion of packed cells during cardiopulmonary bypass correlated with higher lactate (R(2) = 0.089, P < 0.05), NAG (R(2) = 0.431, P < 0.01), and IFABP concentrations (R(2) = 0.189, P < 0.01).

CONCLUSIONS

The results support the concept that hemodilution below an intraoperative hematocrit of 24% and consequently transfusion of red blood cells is related to release of injury markers of the kidneys and splanchnic area.

Why an alternative to blood transfusion?

Allogeneic blood transfusions have been associated with several risks and complications and with worse outcomes in a substantial number of patient populations and clinical scenarios. Allogeneic blood is costly and difficult to procure, transport, and store. Global and local shortages are imminent. Alternatives to transfusion provide many advantages, and their use is likely to improve outcomes as safer and more effective agents are developed.

Iron homoeostasis in rheumatic disease

Iron is critical in nearly all cell functions and the ability of a cell, tissue and organism to procure this metal is obligatory for survival. Iron is necessary for normal immune function, and relative iron deficiency is associated with mild immunosuppression. Concentrations of this metal in excess of those required for function can present both an oxidative stress and elevate risks for infection. As a result, the human has evolved to have a complex mechanism of regulating iron and limiting its availability. This homoeostasis can be disrupted. Autoimmune diseases and gout often present with abnormal iron homoeostasis, thus supporting a participation of the metal in these injuries. We review the role of iron in normal immune function and discuss both clinical evidence of altered iron homoeostasis in autoimmune diseases and gout as well as possible implications of both depletion and supplementation of this metal in this patient population. We conclude that altered iron homoeostasis may represent a purposeful response to inflammation that could have theoretical anti-inflammatory benefits. We encourage physicians to avoid routine iron supplementation in those without depleted iron stores.

State-of-the-Art Blood Management in Cardiac Surgery

Blood has been described as the most precious and personal substance in the world. Current directions in cardiac surgery are moving away from transfusing donor “Allogeneic” blood products, and towards improving methods of saving and preserving the patient's own “autologous” blood. Nothing else comes close to the natural healing abilities and homeostasis that one's own whole blood offers. No substitute, whether it is human or artificial, will ever work as well with fluid shifts, hemostasis and homeostasis. News reports today commonly feature severe blood shortages and research documenting recognized transfusion risks such as how older stored blood can put heart surgery patients at increased risk and others that point to the morbidity and mortality associated with its use. Therefore the medical community is moving towards more effective blood utilization by minimizing the exposure to donated blood. Current techniques are saving as much as possible of the patient's own blood that might otherwise be mismanaged or lost during surgery. Techniques, such as Ultrafiltration, that quickly concentrate and reinfuse whole blood back to the patient are the best choice. Admission to discharge hemovigilance requires a concerted multidisciplinary team effort with multimodal tools available in the coagulation armamentarium to effectively avoid this form of organ transplant. Improving outcomes and reducing morbidity and mortality in cardiac surgery takes place at the microcirculatory capillary level and with control of Hemostasis. Cardiac teams need to effectively communicate and minimize blood loss and hemodilution and reverse it, for state of the art blood management in Cardiac surgery.

Effect of oxygen affinity on systemic perfusion and brain tissue oxygen tension after extreme hemodilution with hemoglobin-starch conjugates in rats

PURPOSE

To determine the oxygen affinity for optimal tissue oxygen delivery with a hemoglobin-hydroxyethyl starch conjugate (HRC 101).

METHODS

Anesthetized rats were hemodiluted (180 ml kg(-1)) with low (P(50) approximately 70 mmHg) or high affinity (P(50) approximately 14 mmHg) HRC 101 at hemoglobin (Hb) concentrations near 100 or 70 g l(-1) (n = 6-8). Hippocampal tissue oxygen tension (P(Br)O(2)), blood flow, arterial blood gases, Hb, hematocrit (Hct) and lactate were measured. Data (mean +/- SD) were analyzed by two-way ANOVA.

RESULTS

Hemodilution reduced the hematocrit to 1 +/- 1% in all groups. P(Br)O(2) was best maintained after hemodilution with low affinity HRC 101 at Hb 100 and 70 g l(-1) (25.2 +/- 7.6 and 16.6 +/- 8.3 torr, respectively). P(Br)O(2) decreased (9.5 +/- 9.3 torr, P < 0.05) and serum lactate levels increased (5.0 +/- 1.7 mmol l(-1), P < 0.05) following hemodilution with the high affinity HRC 101 (Hb 100 g l(-1)).

CONCLUSIONS

HRC 101 with a lower oxygen affinity favored tissue perfusion and maintained P(Br)O(2) after near complete blood volume exchange in rats.

Pharmacological and clinical profile of bivalirudin in the treatment of patients with acute coronary syndrome

BACKGROUND

Bivalirudin is a direct thrombin inhibitor with several pharmacological advantages over heparin. It has been studied extensively in non-ST elevation acute 60 coronary syndromes (NSTE-ACS) and in percutaneous coronary intervention. Bivalirudin has also recently been investigated in patients with ST-elevation myocardial infarction (STEMI) treated with primary angioplasty and stenting. More than 27,000 patients were randomized in these trials.

OBJECTIVE

To provide an overview of the pharmacological properties of bivalirudin and its efficacy and safety profile in patients across the spectrum of acute coronary syndromes (ACS).

METHODS

All published, peer-reviewed clinical trials were reviewed and as relevant were included.

RESULTS AND CONCLUSIONS

Bivalirudin with provisional IIb/IIIa antagonists provides consistent results across the full spectrum of ACS, with similar or non-inferior protection from ischemic events and significantly reduces bleeding complications compared with heparin and IIb/IIIa antagonists. In STEMI, mortality at 30 days and 1 year is significantly reduced. The unique pharmacokinetic profile of bivalirudin allows for simultaneous reductions in both ischemic and hemorrhagic events and makes it an appropriate alternative to heparin.

Safety and Efficacy of Recombinant Activated Factor VII

Background— Blood loss is a common complication of cardiac surgery. Evidence suggests that recombinant activated factor VII (rFVIIa) can decrease intractable bleeding in patients after cardiac surgery. Our objective was to investigate the safety and possible benefits of rFVIIa in patients who bleed after cardiac surgery.

Methods and Results— In this phase II dose-escalation study, patients who had undergone cardiac surgery and were bleeding were randomized to receive placebo (n=68), 40 μg/kg rFVIIa (n=35), or 80 μg/kg rFVIIa (n=69). The primary end points were the number of patients suffering critical serious adverse events. Secondary end points included rates of reoperation, amount of blood loss, and transfusion of allogeneic blood. There were more critical serious adverse events in the rFVIIa groups. These differences did not reach statistical significance (placebo, 7%; 40 μg/kg, 14%; P =0.25; 80 μg/kg, 12%; P =0.43). After randomization, significantly fewer patients in the rFVIIa group underwent a reoperation as a result of bleeding ( P =0.03) or required allogeneic transfusions ( P =0.01).

Conclusions— On the basis of this preliminary evidence, rFVIIa may be beneficial for treating bleeding after cardiac surgery, but caution should be applied and further clinical trials are required because there is an increase in the number of critical serious adverse events, including stroke, in those patients randomized to receive rFVIIa.

Relationships among haemoglobin level, packed red cell transfusion and clinical outcomes in patients after cardiac surgery

OBJECTIVE

To identify associations among haemoglobin (Hb) concentrations, blood transfusions, and clinical outcomes in patients after cardiac surgery, especially in those who undergo valve replacement or bypass surgery.

DESIGN

Prospective observational trial.

SETTING

Surgical intensive care unit in a tertiary-level university hospital.

PATIENTS

1216 Consecutive patients.

MEASUREMENTS

Haemoglobin at admission and 6, 12, 24, and 48 h later, and then, every 24 h while patients remained in the intensive care unit (ICU); number of transfusions and clinical events.

RESULTS

Patients were divided into quartiles according to minimal haemoglobin, the first and second of which (Hb <8.10 and <8.91 g/dL, respectively) differed significantly (P < 0.001) from the other two quartiles in terms of more organ failure, longer ICU stay, and higher mortality. We found associations between being transfused >or=4 packed red cells (PRCs) and a worse clinical outcome and higher mortality. The associated mortality rate was higher for patients who underwent bypass surgery when they had Hb <or=8.9 g/dL and for those who underwent valve replacement when they had Hb >8.9 g/dL and were transfused >or=4 PRCs.

CONCLUSIONS

Low haemoglobin concentrations and transfusions in patients undergoing cardiac surgery are associated with increased morbidity and mortality. Also, anemia and transfusions are associated with poor outcome. Therefore, intra- and postoperative bleeding seem to be a risk factor in patients undergoing cardiac surgery.

Anemia and red blood cell transfusion in neurocritical care

INTRODUCTION

Anemia is one of the most common medical complications to be encountered in critically ill patients. Based on the results of clinical trials, transfusion practices across the world have generally become more restrictive. However, because reduced oxygen delivery contributes to 'secondary' cerebral injury, anemia may not be as well tolerated among neurocritical care patients.

METHODS

The first portion of this paper is a narrative review of the physiologic implications of anemia, hemodilution, and transfusion in the setting of brain-injury and stroke. The second portion is a systematic review to identify studies assessing the association between anemia or the use of red blood cell transfusions and relevant clinical outcomes in various neurocritical care populations.

RESULTS

There have been no randomized controlled trials that have adequately assessed optimal transfusion thresholds specifically among brain-injured patients. The importance of ischemia and the implications of anemia are not necessarily the same for all neurocritical care conditions. Nevertheless, there exists an extensive body of experimental work, as well as human observational and physiologic studies, which have advanced knowledge in this area and provide some guidance to clinicians. Lower hemoglobin concentrations are consistently associated with worse physiologic parameters and clinical outcomes; however, this relationship may not be altered by more aggressive use of red blood cell transfusions.

CONCLUSIONS

Although hemoglobin concentrations as low as 7 g/dl are well tolerated in most critical care patients, such a severe degree of anemia could be harmful in brain-injured patients. Randomized controlled trials of different transfusion thresholds, specifically in neurocritical care settings, are required. The impact of the duration of blood storage on the neurologic implications of transfusion also requires further investigation.

2008 Emily Cooley Memorial Lecture: lessons learned from pediatric transfusion medicine clinical trials . . . a little child shall lead them

BACKGROUND

Many clinical practices in transfusion medicine are controversial and/or lack definitive guidelines established by sound clinical trials. Although recommendations based on results of clinical trials performed using infants and children may not always be applied directly to adults--and vice versa--lessons learned from pediatric trials can be useful when critically assessing the design/results/conclusions of adult trials.

STUDY DESIGN AND METHODS

Four randomized clinical trials (RCTs) studying pediatric patients were critically reviewed. They addressed two red blood cell (RBC) transfusion issues: 1) transfusion guidelines by which RBC transfusions are "triggered" by liberal (LIB; high pretransfusion patient hematocrit [Hct] levels) versus being "triggered" by restricted (RES; low pretransfusion Hct levels) and 2) transfusion of fresh RBCs (<or=7 days' storage) versus RBCs (up to 42 days' storage).

RESULTS

Findings established by primary outcomes generally were firm (e.g., fewer RBC transfusions were given to infants/children managed by RES guidelines; transfusing small volumes of RBCs stored up to 42 days to preterm infants diminished allogeneic donor exposures and were equally efficacious and safe as fresh RBCs stored <or=7 days). Findings based on secondary outcomes, subset, and post hoc analyses were inconsistent (e.g., clinical outcomes were equivalent after LIB or RES transfusions in only two of three RCTs; in the third, more neurologic problems were found in neonates given RES transfusions).

CONCLUSIONS

Clinical practices should be based on data pertaining to the primary outcomes of RCTs, because trials are designed and statistically powered to address these issues. Clinical practices suggested by analysis of secondary outcomes, subsets of patients, and post hoc analyses should be applied cautiously until studied further-ideally, as primary outcomes in subsequent RCTs.

Massive transfusion--evaluation of current clinical practice and outcome in two large teaching hospital trusts in Northern England

BACKGROUND AND OBJECTIVES

Although numerous guidelines exist for the management of massive blood loss, there have been few data confirming whether these guidelines are observed in practice or whether compliance results in improved outcome. We have performed a retrospective audit of cases of massive transfusion in two major teaching hospital trusts in Northern England to investigate the use of blood components and patient outcome.

MATERIALS AND METHODS

The massive transfusion population was electronically derived from a list of all blood component transfusions in 2006. Data from the intensive care and patient administration databases established hospital outcome. Factors independently predictive of survival were identified by logistic regression. Data are presented as medians and interquartile ranges. Odds ratios (OR) are given with 95% confidence intervals.

RESULTS

Two hundred and four patients had a massive transfusion. Although only 1.3% of all transfused patients, the massive transfusion group used 10% of the total blood products. Their mortality rate was 34%. Factors independently predictive of survival were: a ratio of fresh frozen plasma: red blood cells > 1.1, OR 7.22 (1.95-26.68), and elective surgery, OR 4.56 (1.88-11.05). Factors independently predictive of death were: age (per year), OR 0.97 (0.95-0.99), liver disease, OR 0.25 (0.09-0.70), male gender, OR 0.41 (0.19-0.89), vascular surgery, OR 0.34 (0.12-0.96) and number of adult packs of platelets transfused, OR 0.69 (0.57-0.83).

CONCLUSION

Massive transfusion occurs rarely but has a high mortality and requires a disproportionate amount of blood products. An increased ratio of fresh frozen plasma to red blood cells was associated with improved outcome.

Incidence, prevalence, and analysis of risk factors for surgical site infection following adult spinal surgery

STUDY DESIGN

A retrospective cohort study to identify rates and analyze the risk factors for postoperative spinal wound infection.

OBJECTIVE

To determine significant risk factors for postoperative spinal wound infection by comparing those patients who developed a postoperative wound infection with the rest of the cohort.

SUMMARY OF BACKGROUND DATA

A surgical site infection (SSI) is a common complication after spinal surgery. SSI leads to higher morbidity, mortality, and healthcare costs. To develop strategies to reduce the risk for SSI, independent risk factors for SSI should be identified.

METHODS

The electronic patient record of all 3174 patients who underwent orthopedic spinal surgery at out institution were abstracted. Individual patient and perioperative characteristics were stored in an electronic database.

RESULTS

In total, 132 (4.2%) patients were found to have an SSI with 84 having deep based infection. Estimated blood loss over 1 liter (P = 0.017), previous SSI (P = 0.012) and diabetes (P = 0.050) were found to be independent statistically significant risk factors for SSI. Obesity (P = 0.009) was found to significantly increase the risk of superficial infection, whereas anterior spinal approach decreased the risk (P = 0.010). Diabetes (P = 0.033), obesity (P = 0.047), previous SSI (P = 0.009), and longer surgeries (2-5 hours [P = 0.023] and 5 or more hours [P = 0.009]) were found to be independent significant risk factors for deep SSI.

CONCLUSION

SSI is commonly seen after spinal surgery. In our study, we identified independent risk factors for both deep and superficial SSI. Identification of these risk factors should allow us to design protocols to decrease the risk of SSE in future patients.

The association of preoperative anemia and perioperative allogeneic blood transfusion with the risk of surgical site infection

BACKGROUND

The purpose of the study was to investigate allogeneic blood transfusion (ABT) and preoperative anemia as risk factors for surgical site infection (SSI).

STUDY DESIGN AND METHODS

A prospective, observational cohort of 5873 consecutive general surgical procedures at Basel University Hospital was analyzed to determine the relationship between perioperative ABT and preoperative anemia and the incidence of SSI. ABT was defined as transfusion of leukoreduced red blood cells during surgery and anemia as hemoglobin concentration of less than 120 g/L before surgery. Surgical wounds and resulting infections were assessed to Centers for Disease Control standards.

RESULTS

The overall SSI rate was 4.8% (284 of 5873). In univariable logistic regression analyses, perioperative ABT (crude odds ratio [OR], 2.93; 95% confidence interval [CI], 2.1 to 4.0; p < 0.001) and preoperative anemia (crude OR, 1.32; 95% CI, 1.0 to 1.7; p = 0.037) were significantly associated with an increased odds of SSI. After adjusting for 13 characteristics of the patient and the procedure in multivariable analyses, associations were substantially reduced for ABT (OR, 1.25; 95% CI, 0.8 to 1.9; p = 0.310; OR, 1.07; 95% CI, 0.6 to 2.0; p = 0.817 for 1-2 blood units and >or=3 blood units, respectively) and anemia (OR, 0.91; 95% CI, 0.7 to 1.2; p = 0.530). Duration of surgery was the main confounding variable.

CONCLUSION

Our findings point to important confounding factors and strengthen existing doubts on leukoreduced ABT during general surgery and preoperative anemia as risk factors for SSIs.

A critical appraisal of "transfusion strategies for patients in pediatric intensive care units" by Lacroix J, Hebert PC, Hutchison, et al (N Engl J Med 2007; 356:1609-1619)

OBJECTIVE

To review the findings and discuss the implications of transfusion strategies in stable critically ill children.

DESIGN

A critical appraisal of the article "Transfusion strategies for patients in pediatric intensive care units" by Lacroix J, Hebert PC, Hutchison, et al, published in the N Engl J Med in 2007 with literature review.

FINDINGS

In this prospective, randomized, controlled, noninferiority trial the authors compared a liberal transfusion strategy, using a transfusion threshold of 9 g/dL, to a conservative transfusion strategy, using a transfusion threshold of 7 g/dL. The primary end point was multiple organ dysfunction syndrome (MODS) or progression of MODS. The authors found that when comparing the restrictive transfusion strategy to the liberal strategy, the absolute risk reduction for developing new or progressive MODS was only 0.4% (95% confidence interval, -4.6 -5.5). Using the restrictive protocol, the number needed to treat to prevent one red blood cell (RBC) transfusion was only two. The number of RBC units per patient in the restrictive group was 0.9, and in the liberal group was 1.7 (p < 0.001). When comparing the two strategies there was a relative reduction of 96% in the number of patients who had any transfusion exposure and a relative decrease of 44% in the number of transfusions administered in the restrictive strategy.

CONCLUSIONS

Using a restrictive transfusion protocol with a transfusion threshold of 7 g/dL in stable critically ill children is as safe as using a liberal protocol and can decrease the number of patients exposed to RBC transfusions.

Increased mortality, morbidity, and cost associated with red blood cell transfusion after cardiac surgery

PURPOSE OF REVIEW

Literature since 2006 was reviewed to identify the harms and costs of red blood cell (RBC) transfusion.

RECENT FINDINGS

Several studies, in people having various cardiac surgery operations, found strong associations of RBC transfusion with mortality and postoperative morbidity. The effect on mortality was strongest close to the time of operation but extended to 5 years. Morbidity outcomes included serious wound and systemic infections, renal failure, prolonged ventilation, low cardiac index, myocardial infarction, and stroke. RBC transfusion was also strongly associated with increased cardiac intensive care unit and ward postoperative stay, and hence, increased cost of admission; available studies did not consider all resources used and the associated costs.

SUMMARY

The harms of RBC transfusion have potentially serious and long-term consequences for patients and are costly for health services. This evidence should shift clinicians' equipoise towards more restrictive transfusion practice. The immediate aim should be to avoid transfusing a small number of RBC units for general malaise attributed to anaemia, a practice that appears to occur in about 50% of transfused patients. Randomized trials comparing restrictive and liberal transfusion triggers are urgently needed to directly compare the benefits and harms from RBC transfusion.

The silent risks of blood transfusion

PURPOSE OF REVIEW

Clinical research has identified blood transfusion as an independent risk factor for immediate and long-term adverse outcomes, including an increased risk of death, myocardial infarction, stroke, renal failure, infection and malignancy. New findings have called into question the traditional assumptions clinicians utilize in evaluating the risks and benefits of blood transfusion. Appreciation of newly recognized risks is important for conserving scarce resources and optimizing patient outcomes.

RECENT FINDINGS

Recent clinical outcomes research has examined the impact of blood transfusion on critically ill patients, trauma patients, patients undergoing cardiac surgery, patients experiencing acute coronary syndromes, oncology patients and others. These studies provide additional evidence of adverse outcomes associated with blood transfusion in a wide variety of clinical contexts.

SUMMARY

The benefits of blood transfusion have never been conclusively demonstrated, but evidence of transfusion-related harm continues to accumulate. Given the transfusion triggers that currently predominate in clinical practice it appears that clinical outcomes could improve significantly with more widespread adoption of restrictive transfusion strategies.

Factors Associated with Sudden Death in Peritoneal Dialysis Patients

Background

Relatively little is known of the epidemiology and predictors of sudden death in peritoneal dialysis (PD) populations. We aimed to identify the risk factors of sudden death among PD subjects.

Methods

To explore clinical correlates of sudden death in PD patients, we conducted a population-based case-control study using data from a single dialysis unit. Cases ( n = 24) were defined as all PD patients that met the criteria for sudden death during January 2003 through December 2006. We also selected 48 control subjects that were selected from the prevalent PD patient name list compiled in alphabetical order. Data on the hemoglobin, potassium, and calcium levels, residual renal function, dialysis adequacy, cardiovascular risks, comorbid conditions, concurrent use of aspirin, beta-blockers, angiotensin-converting enzyme inhibitors, and erythropoietin, electrocardiographic and echocardiographic findings were extracted from case notes and computer records. Confounders were controlled by logistic regression.

Results

Over a period of 4 years, 24 PD patients (mean age 61.4 ± 9.5 years, median duration of dialysis 3.1 years) experienced sudden death. Univariate analyses showed that patients that died suddenly were more likely to be male and to have diabetes mellitus, a history of smoking, and a lower small solute clearance as measured by Kt/V. Cases of sudden death were also more likely to have received blood transfusion within the previous 1 year. There were no significant differences between patients and controls for residual renal function, serum potassium levels, control of blood pressure and mineral metabolism, or hemoglobin levels. Multivariate regression analysis confirmed independent association between recent blood transfusion and increased odds of sudden death [adjusted odds ratio (OR) 5.18, 95% confidence interval (CI) 1.44 – 18.6]. Two other factors significantly associated with risk of sudden death were male gender (adjusted OR 4.16, 95% CI 1.14 – 15.2) and diabetes mellitus (adjusted OR 5.33, 95% CI 1.53 – 18.6).

Conclusion

This study shows that recent blood transfusion is associated with an increased likelihood of sudden death in PD patients. The mechanisms that underlie this observation are unclear.

Neurological complications of cardiac surgery

Neurological injury resulting from cardiac surgery has a range of manifestations from focal neurological deficit to encephalopathy or coma. As the safety of drug-eluting stents comes into question, more patients will likely undergo coronary artery bypass graft surgery. These projections, along with the growing proportions of elderly patients and those with comorbidities, portend the potential for rising rates of perioperative neurological complications. The risk for neurological injury may be determined by the type of procedure, by patient-specific characteristics, and by the extent of cerebral embolization and hypoperfusion during and after surgery. Changes in surgical techniques, including the use of off-pump surgery, have not decreased rates of brain injury from cardiac surgery. When appropriate, modern neuroimaging techniques should be used in postoperative patients to confirm diagnosis, to provide information on potential etiology, to direct appropriate therapy, and to help in prognostication. Management of postoperative medications and early use of rehabilitation services is a recommended strategy to optimize the recovery for individuals with neurological injury after cardiac surgery.

Haematological and infectious complications associated with the treatment of patients with congenital cardiac disease: consensus definitions from the Multi-Societal Database Committee for Pediatric and Congenital Heart Disease

A complication is an event or occurrence that is associated with a disease or a healthcare intervention, is a departure from the desired course of events, and may cause, or be associated with, suboptimal outcome. A complication does not necessarily represent a breech in the standard of care that constitutes medical negligence or medical malpractice. An operative or procedural complication is any complication, regardless of cause, occurring (1) within 30 days after surgery or intervention in or out of the hospital, or (2) after 30 days during the same hospitalization subsequent to the operation or intervention. Operative and procedural complications include both intraoperative/intraprocedural complications and postoperative/postprocedural complications in this time interval.The MultiSocietal Database Committee for Pediatric and Congenital Heart Disease has set forth a comprehensive list of complications associated with the treatment of patients with congenital cardiac disease, related to cardiac, pulmonary, renal, haematological, infectious, neurological, gastrointestinal, and endocrinal systems, as well as those related to the management of anaesthesia and perfusion, and the transplantation of thoracic organs. The objective of this manuscript is to examine the definitions of operative morbidity as they relate specifically to the haematological system and to infectious complications. These specific definitions and terms will be used to track morbidity associated with surgical and transcatheter interventions and other forms of therapy in a common language across many separate databases.The MultiSocietal Database Committee for Pediatric and Congenital Heart Disease has prepared and defined a near-exhaustive list of haematological and infectious complications. Within each subgroup, complications are presented in alphabetical order. Clinicians caring for patients with congenital cardiac disease will be able to use this list for databases, quality improvement initiatives, reporting of complications, and comparing strategies for treatment.

Tranexamic acid and aprotinin in primary cardiac operations: an analysis of 220 cardiac surgical patients treated with tranexamic acid or aprotinin

BACKGROUND

Antifibrinolytics are widely used in cardiac surgery to reduce bleeding. Allogeneic blood transfusion, even in primary cardiac operations with low blood loss, is still high. In the present study we evaluated the impact of tranexamic acid compared to aprotinin on the transfusion incidence in cardiac surgical patients with low risk of bleeding.

METHODS

This prospective, randomized, double-blind study included 220 patients undergoing primary coronary artery revascularization (coronary artery bypass grafting [CABG]) or aortic valve replacement (AVR). Randomized in blocks of 20, patients received either tranexamic acid (approximately 6 g) or full-dose aprotinin (approximately 5-6 x 10(6) Kallikrein Inhibiting Units). Transfusion was guided by a strict transfusion algorithm. Molecular markers of hemostasis were determined to assess differences in the mode of action of the two drugs. Primary end-points were the incidence of allogeneic red cell transfusion and 24-h postoperative blood loss. Data were analyzed according to the intention-to-treat principle and compared using the chi(2) and Mann-Whitney U-test.

RESULTS

Two-hundred-twenty patients were enrolled (CABG: 134, AVR: 86). In the aprotinin Group 47% of patients received allogeneic blood during the hospital stay as compared to 61% in the tranexamic acid group (P = 0.036). Aprotinin conferred a 23% reduction in allogeneic transfusion risk (RR 0.77, 95% CI 0.53-0.88). Overall, no significant difference in postoperative bleeding was observed, although 24-h blood loss was reduced in aprotinin-treated CABG patients (500, 350-750 mL vs 650, 475-875 mL (median, 25th-75th percentile); P = 0.039). Despite the lower transfusion rate, the hemoglobin concentration on the first postoperative day was higher in the aprotinin group (11.3, 9.9-12.1 vs 10.6, 9.9-11.6 mg/dL; P = 0.023). The fibrinolytic activity at the end of operation determined by D-Dimer was comparable in both groups. (0.15, 0.11-0.17 mg/L [aprotinin] versus 0.18, 0.12-0.24 mg/L [tranexamic acid]). The activated partial thromboplastin time was prolonged up to 4 h postoperatively in the aprotinin group, while the heparin requirement was reduced: 19% of the patients in the aprotinin group and 45% in the tranexamic acid group received at least one additional bolus heparin during cardiopulmonary bypass (P < 0.001). Troponin T levels postoperatively and on postoperative day 1 were significantly higher in the tranexamic acid group (P = 0.017). No differences in renal, cardiac, or mortality outcomes were observed.

CONCLUSION

Considering the rate of transfusion of red blood cells, tranexamic acid was slightly inferior in patients undergoing CABG, but there was no difference in patients receiving AVR. Tranexamic acid seems to be less effective in operations with increased bleeding such as CABG. Clinical benefit depends on specific patient and institution characteristics (ClinicalTrials.gov NCT00396760).

Minimally invasive mitral valve surgery: a systematic review and meta-analysis

The mitral valve has been traditionally approached through a median sternotomy. However, significant advances in surgical optics, instrumentation, tissue telemanipulation, and perfusion technology have allowed for mitral valve surgery to be performed using progressively smaller incisions including the minithoracotomy and hemisternotomy. Due to reports of excellent results, minimally invasive mitral valve surgery has become a standard of care at certain specialized centers worldwide. This meta-analysis quantifies the effects of minimally invasive mitral valve surgery on morbidity and mortality compared with conventional mitral surgery and demonstrates equivalent perioperative mortality (1641 patients, odds ratio (OR) 0.46, 95% confidence interval 0.15-1.42, p=0.18), reduced need for reoperation for bleeding (1553 patients, OR 0.56, 95% CI 0.35-0.90, p=0.02) and a trend towards shorter hospital stays (350 patients, weighted mean difference (WMD) -0.73, 95% CI -1.52 to 0.05, p=0.07). These benefits were evident despite longer cardiopulmonary bypass (WMD 25.81, 95% CI 13.13-38.50, p<0.0001) and cross-clamp times (WMD 20.91, 95% CI 8.79-33.04, p=0.0007) in the minimally invasive group. Case-control studies show consistently less pain and faster recovery compared to those having a conventional approach. Data for minimally invasive mitral valve surgery after previous cardiac surgery are limited but consistently demonstrate reduced blood loss, fewer transfusions and faster recovery compared to reoperative sternotomy. Long-term follow-up data from multiple cohort studies are also examined revealing equivalent survival and freedom from reoperation. Thus, current clinical data suggest that minimally invasive mitral valve surgery is a safe and a durable alternative to a conventional approach and is associated with less morbidity.

The risk of iatrogenic bleeding in acute coronary syndromes and long-term mortality

PURPOSE OF REVIEW

This review examines the association between bleeding and adverse outcomes in patients with acute coronary syndrome and explores mechanisms behind this association and strategies for reducing bleeding complications in acute coronary syndrome.

RECENT FINDINGS

Bleeding is a common complication of antithrombotic treatment in acute coronary syndrome, and major bleeding occurs in around 5% of patients. Important risk factors for major bleeding include increasing age, female sex, renal impairment, and invasive procedures. Recent studies suggest that major bleeding in patients with acute coronary syndrome is independently associated with an increase of early and long-term morbidity and mortality. This may be due to the direct effects of anaemia and hypovolaemia, the treatment modification or withdrawal, or the adverse effects of transfusion. Bleeding complications may be reduced by use of new antithrombotic agents and by improved attention to dosing with current agents.

SUMMARY

Future studies should examine the effects on overall morbidity and mortality of strategies designed to reduce bleeding complications in patients with acute coronary syndrome. There is a need to apply uniform definitions of bleeding severity. Future trials should report all clinically relevant bleeding outcomes and transfusions. Studies are needed to investigate methods to reduce the risk of bleeding, better understand mechanisms of adverse outcome after bleeding, and establish best practice for the management of bleeding including appropriate use of transfusion in patients with acute coronary syndrome.