A standardized multidisciplinary approach reduces the use of allogeneic blood products in patients undergoing cardiac surgery

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.

The Safety and Efficacy of “Bloodless” Cardiac Surgery

Nearly 20% of blood transfusions in the United States are associated with cardiac surgery. Despite the many blood conservation techniques that are available, safe, and efficacious for patients undergoing cardiac surgery, many of these operations continue to be associated with significant amounts of blood transfusion. Although surgical bleeding after cardiopulmonary bypass is a common problem as reflected by the substantial use of blood products, it is the individual physician and institutional behavior that have been identified as reasons for transfusion and not necessarily patient comorbidity or blood loss. Transfusion rates in cardiac surgery remain high despite major advances in perioperative blood conservation, with large variations among individual centers. The adoption of available blood conservation techniques, either alone or in combination in patients undergoing cardiac surgery, could result in an estimated 75% reduction of unnecessary transfusions. The success of previously reported blood conservations programs in cardiac surgery should call for a reevaluation of allogeneic transfusion practices in patients undergoing cardiac surgery. By applying the numerous reported blood conservation strategies for the management of patients presenting for cardiac surgery, we can preserve our dwindling blood resources and help alleviate some of the direct costs of blood as well as the indirect costs of treating noninfectious and infectious complications of transfusion.

Therapeutic options to minimize allogeneic blood transfusions and their adverse effects in cardiac surgery: a systematic review

INTRODUCTION

Allogeneic blood is an exhaustible therapeutic resource. New evidence indicates that blood consumption is excessive and that donations have decreased, resulting in reduced blood supplies worldwide. Blood transfusions are associated with increased morbidity and mortality, as well as higher hospital costs. This makes it necessary to seek out new treatment options. Such options exist but are still virtually unknown and are rarely utilized.

OBJECTIVE

To gather and describe in a systematic, objective, and practical way all clinical and surgical strategies as effective therapeutic options to minimize or avoid allogeneic blood transfusions and their adverse effects in surgical cardiac patients.

METHODS

A bibliographic search was conducted using the MeSH term "Blood Transfusion" and the terms "Cardiac Surgery" and "Blood Management." Studies with titles not directly related to this research or that did not contain information related to it in their abstracts as well as older studies reporting on the same strategies were not included.

RESULTS

Treating anemia and thrombocytopenia, suspending anticoagulants and antiplatelet agents, reducing routine phlebotomies, utilizing less traumatic surgical techniques with moderate hypothermia and hypotension, meticulous hemostasis, use of topical and systemic hemostatic agents, acute normovolemic hemodilution, cell salvage, anemia tolerance (supplementary oxygen and normothermia), as well as various other therapeutic options have proved to be effective strategies for reducing allogeneic blood transfusions.

CONCLUSION

There are a number of clinical and surgical strategies that can be used to optimize erythrocyte mass and coagulation status, minimize blood loss, and improve anemia tolerance. In order to decrease the consumption of blood components, diminish morbidity and mortality, and reduce hospital costs, these treatment strategies should be incorporated into medical practice worldwide.

Drug, Devices, Technologies, and Techniques for Blood Management in Minimally Invasive and Conventional Cardiothoracic Surgery a Consensus Statement from the International Society for Minimally Invasive Cardiothoracic Surgery (ISMICS) 2011

Objective

The objectives of this consensus conference were to evaluate the evidence for the efficacy and safety of perioperative drugs, technologies, and techniques in reducing allogeneic blood transfusion for adults undergoing cardiac surgery and to develop evidence-based recommendations for comprehensive perioperative blood management in cardiac surgery, with emphasis on minimally invasive cardiac surgery.

Methods

The consensus panel short-listed the potential topics for review from a comprehensive list of potential drugs, devices, technologies, and techniques. The process of short-listing was based on the need to prioritize and focus on the areas of highest importance to surgeons, anesthesiologists, perfusionists, hematologists, and allied health care involved in the management of patients who undergo cardiac surgery whether through the conventional or minimally invasive approach. MEDLINE, Cochrane Library, and Embase databases were searched from their date of inception to May 2011, and supplemental hand searches were also performed. Detailed methodology and search strategies are outlined in each of the subsequently published systematic reviews. In general, all relevant synonyms for drugs (antifibrinolytic, aprotinin, ∊-aminocaproic acid, tranexamic acid [TA], desmopressin, anticoagulants, heparin, antiplatelets, anti-Xa agents, adenosine diphosphate inhibitors, acetylsalicylic acid [ASA], factor VIIa [FVIIa]), technologies (cell salvage, miniaturized cardiopulmonary bypass (CPB) circuits, biocompatible circuits, ultrafiltration), and techniques (transfusion thresholds, minimally invasive cardiac or aortic surgery) were searched and combined with terms for blood, red blood cells, fresh-frozen plasma, platelets, transfusion, and allogeneic exposure. The American Heart Association/American College of Cardiology system was used to label the level of evidence and class of each recommendation.

Results and Recommendations

Database search identified more than 6900 articles, with 4423 full-text randomized controlled trials assessed for eligibility, and the final 125 systematic reviews and meta-analyses were used in the consensus conference. The results of the consensus conference, including the evidence-based statements and the recommendations, are outlined in the text, with references given for the relevant evidence that formed the basis for the statements and recommendations.

Bleeding in a Jehovah's Witness patient undergoing a redo aortic valve replacement controlled with cryoprecipitate and a prothrombin complex concentrate

PURPOSE

This is a case report involving a middle-aged Jehovah's Witness patient who underwent a redo aortic valve replacement, coronary artery bypass graft, and Maze procedure facilitated by cardiopulmonary bypass. The consent process included a discussion of the management of bleeding and hemostasis in the perioperative period in the context of the patients' religious choice and the possible consequences of avoiding transfusion in massive bleeding. The medical team agreed to abide by the patient's wishes with respect to the blood and blood products deemed unacceptable by the patient irrespective of the consequences. The consent included a discussion of manufactured hemostatic agents that are designated by the Hospital Liaison Committee Network for Jehovah's Witnesses as subject to personal decision. There was also a discussion of recombinant agents available, all of which are acceptable to Jehovah's Witness patients. The patient accepted the use of cryoprecipitate, prothrombin complex concentrate, and recombinant factor VIIa.

CLINICAL FEATURES

After separation from cardiopulmonary bypass and protamine administration, blood loss was 350 mL over a ten-minute period. The international normalized ratio (INR) was 3.5 at that time. Cryoprecipitate 15 U, 1-deamino-8-D-arginine vasopressin 16 U, and a prothrombin complex concentrate, Octaplex®, 60 mL were administered. Blood loss improved significantly. The INR in the cardiac surgical intensive care unit was 1.3. The sample was taken approximately one hour following the administration of the hemostatic agents. The patient's chest was closed, and chest tube drainage was 310 mL over the next 12 hr.

CONCLUSION

This is a novel case involving the use of prothrombin complex concentrate in the setting of a Jehovah's Witness patient undergoing a complex operative procedure.

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.

Cardiac surgery with cardiopulmonary bypass: does aprotinin affect outcome?

BACKGROUND

Aprotinin, a non-specific serine protease inhibitor, has been used for two decades to reduce perioperative blood loss and the risk for allogeneic transfusion in cardiac surgery. This study evaluated the effects of aprotinin on outcome (mortality, cardiac events, renal failure, and cerebrovascular events) in such patients undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

Data were obtained in patients who received a strict blood conservation protocol: no antifibrinolytic therapy when at low risk (n = 854) and aprotinin (n = 1210) when at high risk for blood transfusion. Relative risk of different pre- and intra-operative variables was calculated for the different outcome variables. Backward stepwise logistic regression analysis was used to identify the independent risk factors associated with the different outcome variables. Statistical significance was accepted at P < 0.01.

RESULTS

Postoperative mortality and morbidity were higher in the aprotinin group but this was related to an increased incidence of perioperative risk factors. Mortality was similar to that predicted by the Euroscore. Complex surgery was the only independent variable associated with postoperative cardiac events. Preoperative heart failure, preoperative creatinine > 1.5 mg dl(-1), urgent, and redo surgery were the independent variables associated with postoperative haemodialysis. Age > 70 yr was identified as the only independent variable associated with neurologic dysfunction.

CONCLUSIONS

In the present study, patients receiving aprotinin as part of a strict blood conservation strategy represent a population at high risk for postoperative complications. For the outcome variables studied, aprotinin administration was not identified as an independent risk factor.

Blood management

CONTEXT

We provide an overview of the principles of blood management: the appropriate use of blood and blood components, with a goal of minimizing their use.

OBJECTIVE

To review the strategies that exploit combinations of surgical and medical techniques, technologic devices, and pharmaceuticals, along with an interdisciplinary team approach that combines specialists who are expert at minimizing allogeneic blood transfusion.

DATA SOURCES

A search on Medline and PubMed for the terms English and humans used in articles published within the last 20 years.

CONCLUSIONS

Blood management is most successful when multidisciplinary, proactive programs are in place so that these strategies can be individualized to specific patients.

The Effects of Levosimendan in Cardiac Surgery Patients with Poor Left Ventricular Function

BACKGROUND

Patients with poor left ventricular function often require inotropic drug support immediately after cardiopulmonary bypass. Levosimendan improves cardiac function by a novel mechanism of action compared to currently available drugs. We hypothesized that, in patients with severely compromised ventricular function, the use of levosimendan would be associated with better postoperative cardiac function than with inotropic drugs that increase myocardial oxygen consumption.

METHODS

Thirty patients with a preoperative ejection fraction < or =30% scheduled for elective cardiac surgery with cardiopulmonary bypass were randomized to two different inotropic protocols: milrinone 0.5 microg [corrected] x kg(-1) x min(-1) or levosimendan 0.1 microg [corrected] x kg(-1) x min(-1), started immediately after the release of the aortic crossclamp. The treatment was masked to the observers. All patients received dobutamine 5 microg [corrected] x kg(-1) x min(-1).

RESULTS

Stroke volume was similar between groups initially after surgery, but it declined 12 h after surgery in the milrinone group but not in the levosimendan group (P < 0.05 between groups) despite similar filling pressures. Total dose, duration of inotropic drug administration and norepinephrine dose were lower in the levosimendan group than in the milrinone group (P < 0.05). The duration of tracheal intubation was shorter in the former group compared with the milrinone group (P = 0008). Three patients in the milrinone group but none in the levosimendan group died within 30 days of surgery.

CONCLUSION

In cardiac surgery patients with a low preoperative ejection fraction, stroke volume was better maintained with the combination of dobutamine with levosimendan than with the combination of dobutamine with milrinone.

Blood conservation strategies in cardiac surgery

Despite the continuous efforts to increase the safety of blood components, red blood cell transfusions remain associated with some risks and side effects. Therefore, numerous techniques have been developed to decrease blood use, but they also carry risks and bear costs. Most of them are frequently used in cardiac surgery, which still consumes a large part of the available blood supply. Among western countries the use of alternative techniques, but also transfusion practice, has been shown to vary markedly. 'Blood conservation' is a global concept engulfing all possible strategies aimed at reducing patients' exposure to allogeneic blood components. The development of the 'best strategy' consists of the selection of those techniques that are most appropriate to the local specific situation. It implies the establishment of a reliable system, collecting data both at the surgical team and at the medical level.

Perioperative Management of a Heterozygous Carrier of Glanzmann’s Thrombasthenia Submitted to Coronary Artery Bypass Grafting With Cardiopulmonary Bypass

Glanzmann's thrombasthenia is a congenital hemorrhagic disorder transmitted as an autosomal recessive trait and characterized by altered production and/or assembly of the platelet membrane glycoprotein IIb/IIIa receptor. We describe the perioperative management of a heterozygous carrier of Glanzmann's thrombasthenia submitted to cardiac surgery with cardiopulmonary bypass and the case was complicated by early excessive postoperative bleeding.

Hemodynamic management of patients in the first 24 hours after cardiac surgery

OBJECTIVE

To describe the physiologic alterations, evaluation, and hemodynamic management of patients in the first 24 hrs after cardiac surgery.

DESIGN

A brief review of preoperative and intraoperative events, postoperative physiology, and a discussion of the evaluation and hemodynamic management of cardiac surgery patients postoperatively based on a review of the literature, known physiology, and clinical experience.

RESULTS

After cardiac surgery, patients undergo alterations in cardiac performance related to co-morbid conditions, preoperative myocardial insults and interventions, the surgical procedure, and intraoperative management. Predictable responses evolve rapidly in the first 24 hrs after surgery. Monitoring, diagnostic regimens, and therapeutic regimens exist to address the patterns of response and occasional complications.

CONCLUSION

By understanding preoperative and intraoperative events and their evolution in the intensive care unit, clinicians can effectively manage patients who experience cardiac surgery.

Hydroxyethyl starch 130/0.4 versus modified fluid gelatin for volume expansion in cardiac surgery patients: the effects on perioperative bleeding and transfusion needs

In this prospective, randomized, open controlled study we compared the effects on net red blood cell loss of 6% hydroxyethyl starch 130/0.4 (HES: n = 64) and 3% modified fluid gelatin (GEL: n = 68) administered for intravascular volume management in patients undergoing coronary surgery. Blood losses were calculated from determination of circulating blood volume and measurement of preoperative and postoperative hematocrit. Amount of colloids that could be administered was limited to 50 mL/kg. If additional fluids were required, balanced crystalloid solution was used. Anesthetic and surgical techniques were standardized. Both groups were similar with regard to demographic and intraoperative variables. Total study drug was 48.9 +/- 17.2 mL/kg in the HES group and 48.9 +/- 14.6 mL/kg in the GEL group. Total red blood cell loss was 544 +/- 305 mL in the HES group and 504 +/- 327 mL the GEL group. Measured blood losses were also similar in both groups (HES, 19.4 +/- 12.3 mL/kg; GEL, 19.2 +/- 14.5 mL/kg). Exposure to allogeneic blood product was comparable in both groups. In the conditions of the present study, HES 130/0.4 up to 50 mL/kg is a valuable alternative to modified fluid gelatin for plasma volume expansion during and after cardiac surgery.

Rationale for blood conservation

BACKGROUND

Exposure of patients to allogeneic blood transfusion can be minimized or avoided by the systematic use of multiple blood conservation techniques. Current use of these technologies is variable.

METHODS

Review of pertinent English language literature.

RESULTS

Enthusiasm for preoperative autologous blood donation (PAD) has declined considerably, perhaps due to increased cost and inconvenience to patients. Acute normovolemic hemodilution (ANH) has several practical advantages over PAD, but has not become generally accepted as a blood conservation strategy. Erythropoietin, iron, and artificial oxygen carriers are pharmacologic alternatives.

CONCLUSIONS

Pharmacologic stimulation of erythropoiesis offers substantial potential to progress toward a goal of bloodless medicine. The potential of artificial blood substitutes is still being defined.

Clinical Outcomes in Cardiac Surgery: Conventional Surgery versus Bloodless Surgery

Bleeding during and after cardiac operations and the effects of cardiopulmonary bypass hemodilution commonly result in blood transfusions. Excessive microvascular bleeding can result in re-exploration and prolonged hospitalization. Nearly 20% of all blood transfusions in the United States are associated with cardiac surgery. The risks associated with the use of allogeneic blood product transfusion include mistransfusion, immunologic complications, and transmission of infectious diseases. The large demand for blood products places significant pressure on the national blood supply, resulting in frequent shortages. The variability in transfusion practice of cardiac surgery patients suggests that sound blood management and a conservative approach to this population can result in reduced transfusions without increasing morbidity or mortality and avoiding complications associated with allogeneic blood transfusion.

Cardiovascular response to acute normovolemic hemodilution in patients with coronary artery diseases: Assessment with transesophageal echocardiography

OBJECTIVE

Preoperative acute normovolemic hemodilution induces an increase in circulatory output that is thought to be limited in patients with cardiac diseases. Using multiple-plane transesophageal echocardiography, we investigated the mechanisms of cardiovascular adaptation during acute normovolemic hemodilution in patients with severe coronary artery disease.

DESIGN

Prospective case-control study.

SETTING

Operating theater in a university hospital.

PATIENTS

Consecutive patients treated with beta-blockers, scheduled to undergo coronary artery bypass (n = 50).

INTERVENTIONS

After anesthesia induction, blood withdrawal and isovolemic exchange with iso-oncotic starch (1:1.15 ratio) to achieve a hematocrit value of 28%.

MEASUREMENTS AND MAIN RESULTS

In addition to heart rate and intravascular pressures, echocardiographic recordings were obtained before and after acute normovolemic hemodilution to assess cardiac preload, afterload, and contractility. In a control group, not subjected to acute normovolemic hemodilution, hemodynamic variables remained stable during a 20-min anesthesia period. Following acute normovolemic hemodilution, increases in cardiac stroke volume (+28 +/- 4%; mean +/- sd) were correlated with increases in central venous pressure (+2.0 +/- 1.3 mm Hg; R = .56) and in left ventricular end-diastolic area (+18 +/- 5%, R = .39). The unchanged left ventricular end-systolic wall stress and preload-adjusted maximal power indicated that neither left ventricular afterload nor contractility was affected by acute normovolemic hemodilution. Diastolic left ventricular filling abnormalities (15 of 22 cases) improved in 11 patients and were stable in the remaining four patients. Despite reduction in systemic oxygen delivery (-20.5 +/- 7%, p < .05), there was no evidence for myocardial ischemia (electrocardiogram, left ventricular wall motion abnormalities).

CONCLUSIONS

In anesthetized patients with coronary artery disease, moderate acute normovolemic hemodilution did not compromise left ventricular systolic and diastolic function. Lowering blood viscosity resulted in increased stroke volume that was mainly related to increased venous return and higher cardiac preload.

Blood component transfusion in primary coronary artery bypass surgery in Kuwait

OBJECTIVE

The aims of this study were to determine the rate of blood product transfusion, associated perioperative factors and cost of such blood product transfusion in primary coronary artery bypass surgery (CABG).

SUBJECTS AND METHODS

The medical records of 159 consecutive primary CABG patients (142 male, 17 female) from January 1, 2003 to June 30, 2003 at Chest Diseases Hospital, Kuwait, were reviewed. Urgent and emergency cases were included.

RESULTS

The mean age of the patients was 57.2 (range 36-77 years). Overall, 128 (80.5%) patients received blood product transfusion during primary CABG: 113 (70.5%) packed red blood cells (RBC), 54 (33.9%) fresh frozen plasma, and 13 (8%) platelets. Overall, 23 patients (12.6%) received more than two RBC transfusions intraoperatively. Significant factors for intraoperative RBC transfusion were: age >60 years, female gender, preoperative hemoglobin <12 g/dl, and 3 or more coronary bypass grafts constructed. One hundred and fifty-nine patients consumed 342 units of RBC at an average of 2.1 RBC units per patient. The cost per patient was 80 Kuwaiti dinar (KD; USD 240).

CONCLUSION

The findings indicate a high rate of blood component transfusion in primary CABG patients in Kuwait that could expose the patients to the possible adverse effects, and such transfusions have high economic impact.

Meeting the clinical challenge of care for Jehovah’s Witnesses1 1Editor’s Note: This article represents the current position of the Watch Tower Society on the use of blood components and fractions in the care of patients who are Jehovah’s Witnesses

Quality patient care entails more than simply biomedical interventions. Respect for the wishes, values, and preferences of patients are important elements of quality care. Unique aspects of the beliefs of Jehovah's Witnesses may present physicians with ethical and clinical conflicts. Witnesses believe that allogeneic blood transfusion (ie, whole blood, red blood cells, white cells, platelets, and plasma) and preoperative autologous blood deposit (PAD) are prohibited by several Biblical passages. This article reviews the Witness position on medical care, blood components, and fractions, placing these and related interventions into categories that may help physicians to individualize clinical management plans and meet the challenge of caring for patients who are Jehovah's Witnesses. It includes an overview of cost, safety, efficacy, and medicolegal issues related to patient care using transfusion-alternative strategies.

3.5% urea-linked gelatin is as effective as 6% HES 200/0.5 for volume management in cardiac surgery patients

PURPOSE

To compare the efficacy of volume expansion with 3.5% gelatin and 6% hydroxyethyl starch 200/0.5 in patients undergoing cardiac surgery. The second objective was to compare the two colloids in terms of blood losses and allogeneic blood transfusion exposure rate.

METHODS

In this open-label controlled study, patients were randomly allocated to receive either 3.5% urea-linked gelatin (GEL group: n = 55) or 6% hydroxyethyl starch 200/0.5/5.1 (HES group: n = 55) for per- (including priming of the bypass machine) and postoperative volume management with a maximum dosage of 30 +/- 3 mL.kg(-1).day(-1). Volume replacement was guided according to routine per- and postoperative care based on cardiac index, mixed venous oxygen saturation, and diuresis. If additional colloid was required, 4.5% albumin had to be given. The study period comprised per- and postoperative investigations up to 18 hr after surgery.

RESULTS

All hemodynamic variables were comparable in both groups. Total study drug was 25.8 +/- 4.8 mL.kg(-1) in the GEL group and 24.5 +/- 6.0 mL.kg(-1) in the HES group. There was no difference in the number of patients receiving albumin solution or in the amount of albumin administered. Total blood loss was higher in the HES than in the GEL group (11.0 +/- 7.8 mL.kg(-1) vs 8.7 +/- 4.0 mL.kg(-1); P < 0.05) resulting in a higher need for allogeneic blood transfusion (HES: nine patients received 12 units, GEL two patients received 3 units; P = 0.026).

CONCLUSION

In the conditions of the present study, HES was not associated with a better plasma expansion effect than GEL. HES could result in a higher need for allogeneic blood transfusion.

Blood management in intensive care medicine: CRIT and ABC--what can we learn?

In 284 US intensive care units the CRIT study (Anemia and blood transfusion in the critically ill – Current clinical practice in the United States) assessed allogeneic red blood cell (RBC) transfusion and outcome in 4892 patients. As in the former European ABC study (Anemia and blood transfusion in the critically ill), the mean pretransfusion hemoglobin was approximately 8.5 g/dl and RBC transfusions were independently associated with an increased mortality. These studies were purely observational and, therefore, despite the finest statistical models indicating that RBC transfusions were independently associated with a higher mortality, it remains possible that this adverse outcome is not due to a harmful effect of RBC transfusion in itself, but merely reflects the fact that transfused patients were sicker to start with. The definitive call is still out, but one mechanism by which RBC transfusion might be harmful now appears less likely; namely, storage lesion. In the CRIT study, mortality was not increased in patients receiving 'old' RBCs (>14 days stored) versus 'fresh' RBCs. The effect of leukoreduction could not be assessed since mainly nonleukoreduced RBCs were transfused. The evidence is mounting, however, that RBC transfusions are efficacious only when oxygen delivery is compromised. What can be done to diminish the use of RBC transfusions, its costs and side effects in intensive care medicine? There are two important options available today: decreasing blood loss for diagnostic purposes using pediatric sampling tubes, and establishing restrictive multidisciplinary transfusion guidelines and implementing them in daily clinical practice.

Pharmacological approaches to reducing allogeneic blood exposure

This article discusses evidence for the role of pharmacological interventions such as the protease inhibitor aprotinin (Trasylol), lysine analogue anti-fibrinolytics [tranexamic acid (Cyclokapron) and epsilon aminocaproic acid (Amicar)], DDAVP (Desmopressin) and recombinant Factor VIIa (NovoSeven), in preventing the need for blood and blood-component therapies after major (cardiac, hepatic and orthopaedic/trauma) surgery. The data show that aprotinin is consistently effective in reducing globally the transfusion burden in cardiac and hepatic surgical procedures. However, there are little data to support its use in routine elective orthopaedic surgery. Multiple studies have failed to show an increased risk for myocardial ischaemia or infarction with aprotinin, and there may even be a reduced incidence of perioperative stroke in patients undergoing cardiac surgery. An increased probability of a hypersensitivity reaction when the drug is readministered within a 6-month period remains a significant issue. The data for the lysine analogue anti-fibrinolytics show no evidence of efficacy in reducing the transfusion burden for epsilon aminocaproic acid and inconsistent results with tranexamic acid in cardiac and hepatic surgery. As with aprotinin therapy, there is a paucity of data to support their use in routine elective orthopaedic surgery. There are no data to support the routine use of DDAVP to reduce the transfusion burden. Limited data suggest that this drug may be effective when a defect in platelet function is demonstrated. This aspect deserves further investigation. Recombinant activated Factor VII (rFVIIa) has proven benefit for its licensed indication to reduce bleeding in haemophiliacs with inhibitors to Factors VIII and IX. Reports of benefit in other instances are largely anecdotal. Hence, at this time it is therefore speculative and premature to suggest whether there is a place for this agent in routine clinical practice. No adequately powered, placebo-controlled prospective studies are available to investigate the safety of the lysine analogues, DDAVP or rFVIIa in cardiac, hepatic or orthopaedic surgery.