Cost-effectiveness of epoetin and autologous blood donationin reducing allogeneic blood transfusions incoronary artery bypass graft surgery

Lack of Cost-Effectiveness of Preoperative Erythropoiesis-Stimulating Agents and/or Iron Therapy in Anaemic, Elective Surgery Patients: A Systematic Review and Updated Analysis

OBJECTIVES

For anaemic elective surgery patients, current clinical practice guidelines weakly recommend the routine use of iron, but not erythrocyte-stimulating agents (ESAs), except for short-acting ESAs in major orthopaedic surgery. This recommendation is, however, not based on any cost-effectiveness studies. The aim of this research was to (1) systematically review the literature regarding cost effectiveness of preoperative iron and/or ESAs in anaemic, elective surgery patients and (2) update existing economic evaluations (EEs) with recent data.

METHODS

Eight databases and registries were searched for EEs and randomized controlled trials (RCTs) reporting cost-effectiveness data on November 11, 2020. Data were extracted, narratively synthesized and critically appraised using the Philips reporting checklist. Pre-existing full EEs were updated with effectiveness data from a recent systematic review and current cost data. Incremental cost-effectiveness ratios were expressed as cost per (quality-adjusted) life-year [(QA)LY] gained.

RESULTS

Only five studies (4 EEs and 1 RCT) were included, one on intravenous iron and four on ESAs + oral iron. The EE on intravenous iron only had an in-hospital time horizon. Therefore, cost effectiveness of preoperative iron remains uncertain. The three EEs on ESAs had a lifetime time horizon, but reported cost per (QA)LY gained of 20-65 million (GBP or CAD). Updating these analyses with current data confirmed ESAs to have a cost per (QA)LY gained of 3.5-120 million (GBP or CAD).

CONCLUSIONS

Cost effectiveness of preoperative iron is unproven, whereas routine preoperative ESA therapy cannot be considered cost effective in elective surgery, based on the limited available data. Future guidelines should reflect these findings.

Cost-Effectiveness Research in Anesthesiology

Perioperative interventions aimed at decreasing costs and improving outcomes have become increasingly popular in recent years. Anesthesiologists are often faced with a choice among different treatment strategies with little data available on the comparative cost-effectiveness. We performed a systematic review of the English language literature between 1980 and 2014 to identify cost-effectiveness analyses of anesthesiology and perioperative medicine interventions. We excluded interventions related to critical care or pediatric anesthesiology, and articles on interventions not normally ordered or performed by anesthesiologists. Of the >5000 cost-effectiveness analyses published to date, only 28 were applicable to anesthesiology and perioperative medicine and met inclusion criteria. Multidisciplinary interventions were the most cost-effective overall; 8 of 8 interventions were "dominant" (improved outcomes, reduced cost) or cost-effective, including accelerated, standardized perioperative recovery pathways, and perioperative delirium prevention bundles. Intraoperative measures were dominant in 3 of 5 cases, including spinal anesthesia for benign abdominal hysterectomy. With regard to prevention of perioperative infection, methicillin-resistant Staphylococcus aureus (MRSA) decolonization was dominant or cost-effective in 2 of 2 studies. Three studies assessing various antibiotic prophylaxis regimens had mixed results. Autologous blood donation was not found to be cost-effective in 5 of 7 studies, and intraoperative cell salvage therapy was also not cost-effective in 2 of 2 reports. Overall, there remains a paucity of cost-effectiveness literature in anesthesiology, particularly relating to intraoperative interventions and multidisciplinary perioperative interventions. Based on the available studies, multidisciplinary perioperative optimization interventions such as accelerated, standardized perioperative recovery pathways, and perioperative delirium prevention bundles tended to be most cost-effective. Our review demonstrates that there is a need for more rigorous cost-effective analyses in many areas of anesthesiology and that anesthesiologists should continue to lead collaborative, multidisciplinary efforts in perioperative medicine.

Investigating the Generalizability of Economic Evaluations Conducted in Italy: A Critical Review

OBJECTIVES

To assess the methodological quality of Italian health economic evaluations and their generalizability or transferability to different settings.

METHODS

A literature search was performed on the PubMed search engine to identify trial-based, nonexperimental prospective studies or model-based full economic evaluations carried out in Italy from 1995 to 2013. The studies were randomly assigned to four reviewers who applied a detailed checklist to assess the generalizability and quality of reporting. The review process followed a three-step blinded procedure. The reviewers who carried out the data extraction were blind as to the name of the author(s) of each study. Second, after the first review, articles were reassigned through a second blind randomization to a second reviewer. Finally, any disagreement between the first two reviewers was solved by a senior researcher.

RESULTS

One hundred fifty-one economic evaluations eventually met the inclusion criteria. Over time, we observed an increasing transparency in methods and a greater generalizability of results, along with a wider and more representative sample in trials and a larger adoption of transition-Markov models. However, often context-specific economic evaluations are carried out and not enough effort is made to ensure the transferability of their results to other contexts. In recent studies, cost-effectiveness analyses and the use of incremental cost-effectiveness ratio were preferred.

CONCLUSIONS

Despite a quite positive temporal trend, generalizability of results still appears as an unsolved question, even if some indication of improvement within Italian studies has been observed.

Role of quality improvement in prevention of inappropriate transfusions

PURPOSE

Many different methods are used to manage surgical bleeding and reduce transfusion. Techniques vary by institution, resulting in inconsistent outcomes. We reviewed the current literature on the quality and costs of transfusions, focusing on prevention and management of transfusions during surgery, and provide recommendations on future directions for quality improvement (QI).

DATA SOURCES

Ovid, PubMed, and Scopus.

STUDY SELECTION

Key words included QI, blood loss, transfusion, hemostasis, and costs. Inclusion criteria were English language, publication between 1999 and 2010, and primary end points of blood loss, transfusion, or hemostasis.

DATA EXTRACTION

A total of 1331 abstracts were reviewed; 43 met the inclusion criteria.

RESULTS

A variety of bleeding management (BM) techniques were identified, with multiple studies suggesting that algorithms combining pre-, peri-, and postoperative interventions have the greatest potential to minimize transfusions. Most studies assessing the economic impact of BM interventions excluded resources beyond blood acquisition cost and longer-term complications, which may underestimate transfusion costs and bias estimates of the cost-effectiveness of interventions. Despite consensus on avoiding inappropriate transfusions, little agreement exists on optimal use of interventions.

CONCLUSIONS

Multifaceted algorithms show promising results. Future QI should focus on reducing practice variation via evidence-based guidelines for effective use of BM interventions.

Strategy of transfusion in cardiac surgery: limits of hematocrit and how much is too low?

The use of blood and blood products in cardiac surgery is higher than necessary and a reduction is imperative due to complications and costs. Hemodilution is unavoidable in cardiopulmonary bypass and is the most likely pitfall when evaluating transfusion needs. Even patients with coexisting cardiovascular diseases tolerate perioperative hemodilution better than most anticipate. Hemodynamic monitoring is important to evaluate the association between hemoglobin level and organ function. Use of both mechanical and medical blood conservation strategies is required to reduce blood transfusion, and most of the methods have a positive cost-effectiveness and cost-benefit. By using the right strategy and policy, transfusion of blood and blood products can be reduced to less than 5% of cardiac patients.

Coagulation and fibrinolytic protein kinetics in cardiopulmonary bypass

The development of Cardiopulmonary Bypass (CPB) catopulted the field of cardiothoracic surgery into a new dimension--one that changed the lives of individuals with congenital and acquired heart disease worldwide. Despite its contributions, CPB has clear limitations and creates unique challenges for clinicians and patients alike, stemming from profound hemostatic pertubations and accompanying risk for bleeding and possibly thrombotic complications.

Preoperative use of recombinant human erythropoietin in pediatric orthopedics: a decision model for long-term outcomes

BACKGROUND CONTEXT

Spine surgery for scoliosis is associated with significant blood loss and may require blood transfusion. The risks inherent in blood transfusion have inspired interventions, including human recombinant erythropoietin (rHuEPO), which has emerged as a safe and effective adjunct in minimizing exposure to allogenic blood in children undergoing scoliosis surgery. However, there is little information in the literature on their economic impact on the health-care system.

PURPOSE

The purpose of this study was to evaluate the cost-effectiveness of rHuEPO in adolescent idiopathic scoliosis.

STUDY DESIGN/SETTING

We designed a decision analytic model capturing costs and potential long-term outcomes of transfusion-related complications to compare the cost-effectiveness of preoperative rHuEPO with a control group and a common alternative, preoperative autologous donation (PAD).

PATIENT SAMPLE

This is a decision analytic model. Decision modeling relies on a summation of the probability of different clinical studies; no patients were specifically studied.

OUTCOME MEASURES

The standard cost-effectiveness ratio (C/E) of $50,000 per quality-adjusted life year (QALY) was used as the threshold value for determining the cost-effectiveness of these two preoperative intervention strategies.

METHODS

From the model we calculated the probability that a patient would experience transfusion-related complications based on the mean number of allogenic units transferred as a result of scoliosis surgery. The standard C/E of $50,000 per QALY was used as the threshold value for determining the cost-effectiveness. Some aspects of the model were derived from retrospective data from the literature. Sensitivity analyses were also conducted to discover which variables, when changed within the accepted range, caused the final result of the model to change significantly.

RESULTS

Results indicated a cost per year-of-life-saved exceeding $1 million for the PAD arm and over $1.5 million for the rHuEPO arm. The low rates of transfusion in adolescent idiopathic scoliosis surgery and the relative safety of the blood supply create a scenario where even inexpensive interventions are not cost-effective. However, rHuEPO would become cost-effective if decreased transfusion rates or higher postoperative hematocrit resulted in decreased length of stay.

CONCLUSION

The use of rHuEPO preoperatively and the use of PAD are not cost-effective although both techniques remain clinically effective tools.

Does the Use of Erythropoietin Reduce the Risk of Exposure to Allogeneic Blood Transfusion in Cardiac Surgery? A Systematic Review and Meta-Analysis

BACKGROUND

The use of blood conservation techniques is important in cardiac surgery as postoperative bleeding is common and allogeneic blood transfusion carries the risk of transfusion reactions and infection transmission. Erythropoietin with and without preoperative autologous blood donation is one of the modalities to avoid allogeneic blood transfusion. The objective of this review was to assess the effectiveness of erythropoietin in reducing the risk of exposure to allogeneic blood transfusion during or after cardiac surgery.

METHODS

A meta-analysis of 11 identified randomized controlled trials, reporting comparisons between erythropoietin and control, was undertaken. The primary outcome was the number of patients exposed to allogeneic blood transfusion during or after cardiac surgery.

RESULTS

Eleven studies, involving 708 patients, met the inclusion criteria for this review. In total, 471 patients were given erythropoietin, and 237 patients formed the control group. The administration of erythropoietin with and without preoperative autologous blood transfusion prior to cardiac surgery is associated with a significant risk reduction: RR = 0.28 (95% CI 0.18-0.44, P < 0.001) and RR = 0.53 (95% CI 0.32-0.88, P < 0.01), respectively.

CONCLUSION

The administration of erythropoietin before cardiac surgery is associated with a significant reduction in the risk of exposure to allogeneic blood transfusion. Further studies are warranted to define the patients' subgroups that may benefit the most from EPO administration.

Autologous Blood Donation in Cardiac Surgery: Reduction of Allogeneic Blood Transfusion and Cost-Effectiveness

OBJECTIVE

The purpose of this study was to assess transfusion requirements in patients undergoing cardiac surgery with and without autologous blood donation and to calculate the costs of predonation from the hospital perspective.

DESIGN

Observational study.

SETTING

Single university hospital.

PARTICIPANTS

Four thousand three hundred twenty-five patients undergoing elective cardiac surgery with and without autologous blood donation.

INTERVENTIONS

Eight hundred forty-nine patients (20%) underwent autologous blood donation, whereas 3,476 (80%) did not. Perioperative allogeneic blood transfusion was recorded as the primary endpoint. To avoid selection bias, patients were stratified according to their preoperative risk score. A decision model was derived from acquired data for the optimization of autologous blood donation.

MEASUREMENTS AND MAIN RESULTS

Allogeneic blood transfusion rate was 13% in patients with predonation versus 48% without predonation (p < 0.05). This difference remained statistically significant even after risk stratification. The predonation of 1, 2, or 3 units reduced the probability of receiving allogeneic blood to 24%, 14%, and 9%, respectively. An efficient program of predonation within the department of anesthesiology allowed keeping the costs of predonation low. Decision-tree analysis revealed that predonation of 2 autologous units of blood saved the most allogeneic blood for the smallest increase in costs. Incremental cost for male patients predonating 2 units was dollars 33 (US), whereas for females predonation could be done at no extra cost in comparison to patients without predonation.

CONCLUSION

Autologous blood donation significantly reduces allogeneic blood requirement in cardiac surgery. If adjusted for diagnosis and gender, autologous blood donation is a cost-effective alternative to reduce allogeneic blood consumption.

Cost-effectiveness of recombinant human erythropoietin for reducing red blood cells transfusions in critically ill patients

OBJECTIVE

To examine the cost-effectiveness of using recombinant human erythropoietin (rHuEPO) to reduce red blood cells (RBC) transfusions in intensive care unit (ICU) patients.

METHODS

Decision analysis examining costs and effectiveness of using rHuEPO versus not using rHuEPO in a simulated adult medical/surgical/trauma (mixed) ICU. Two independent cost-effectiveness models were created based on the results of two multicenter studies that investigated the use of rHuEPO. Base case assumptions and estimates of effectiveness were obtained from these two studies. Mean cumulative doses of rHuEPO were 190,900 units and 102,400 units for studies 1 and 2, respectively. The models accounted for the deferral rate for allogeneic RBC transfusions, rHuEPO efficacy (the reduction in allogeneic RBC use), and adverse effects of rHuEPO and allogeneic RBC transfusions. Model estimates were obtained from published sources. Costs were expressed in 2002 US dollar (dollars) and effectiveness was measured using discounted quality-adjusted life-years (QALYs). A 3% discount rate was used. Probabilistic sensitivity analysis was conducted using second-order Monte Carlo simulation.

RESULTS

Incremental costs of using rHuEPO to reduce RBC transfusions amounted to 1918 dollars and 1439 dollars; incremental effectiveness values were 0.0563 QALYs and 0.0305 QALYs; and the cost-effectiveness ratios were 34,088 dollars and 47,149 dollars per QALY for studies 1 and 2, respectively. The model was most sensitive to the attributable risk of nosocomial bacterial infections per RBC unit. rHuEPO was cost-effective in 52.0% of the Monte Carlo simulations for a willingness to pay of 50,000 dollars/QALY.

CONCLUSION

rHuEPO appears to be cost-effective for reducing RBC transfusions in heterogeneous ICU populations, assuming RBC transfusions increase the risk of nosocomial bacterial infections.

Predicting Allogeneic Blood Transfusion Use in Total Joint Arthroplasty

Total joint arthroplasty (TJA) patients often receive allogeneic blood transfusion. In this study we sought to create and validate a clinical prediction rule for transfusion in TJA using data that are easily available when scheduling the procedure. Logistic regression modeling was applied to retrospective data from all TJA procedures performed in Edmonton, Alberta in 2000 (n = 1875). The area under the receiver operating curve for the resulting model in the training and validation data sets was 0.80 and 0.76 respectively. By assigning a simple score based on six independent predictors (age, gender, weight, hemoglobin, ASA operative risk classification and whether revision surgery was planned), it was possible to classify a given subject's risk of receiving allogeneic transfusion. We conclude that accurate prediction of transfusion risk in TJA is possible using a rule based on simple preoperative clinical and laboratory data. Such prediction could allow transfusion prevention strategies to be applied selectively to those at greatest risk.

Management of Jehovah’s Witness patients with haematological problems

The management of practising Jehovah's Witnesses who have haematological problems presents many different challenges both at the level of treatment strategy and ethics. This article focuses on the beliefs of Jehovah's Witnesses and addresses treatment modalities available for and acceptable to these individuals. Recent advances in the development of novel therapeutic agents have aided the management of Jehovah's Witnesses. Finally, the background to the ethical dilemmas raised by these issues is discussed.

Clinical and economic impact of epoetins in cancer care

Anaemia develops in most patients undergoing cancer therapy and invariably induces fatigue, which is a major determinant of QOL. Blood transfusions are reserved for patients with severe anaemia, since blood is a scarce resource and provides a short-lived benefit. Epoetins are recombinant proteins capable of alleviating therapy-related anaemia in 40-60% of cancer patients. The number of patients needed to be treated with epoetins to avoid the transfusion of one unit of blood ranges from 2.6 to 5.2; however, the absolute risk reduction depends on patients' characteristics and dose-escalation. The ratio between acquisition costs of epoetins and blood transfusion requirement is very high; thus, many thousands of dollars needs to be spent on epoetins to save 1 blood unit. Despite this, epoetins have been widely adopted by industrialised countries, where cancer patients are about 2% of the total population. The resulting budget impact of epoetins can be calculated at about 10% of the overall direct cost for cancer care, and it is expected to continue growing by about 20% each year, due to the expanding cancer population and the intensification of cancer therapies. The economic burden of epoetins needs to be weighed against the improvement of patients' QOL and society's willingness to pay for a non-life-saving therapy. All published economic evaluations of epoetins invariably report that this supportive therapy is not cost effective. Society should be made aware of the opportunity cost of treatments and should be allowed to elicit preferences for healthcare interventions and prioritisation criteria. In the near future we expect that a wider range of epoetins, drug patent expiry, a more appropriate patient selection criteria and an improved dosage schedule may help increase the efficiency of cancer-related anaemia management.

Post-operative course of coronary artery bypass surgery patients who pre-donate autologous blood

BACKGROUND

Pre-operative autologous blood donation is used to reduce the need of allogeneic blood in patients undergoing coronary bypass surgery operations, but it is not clear what impact the blood donation has on the post-operative course of these patients.

METHODS

We studied the post-operative course of 210 patients who pre-donated autologous blood before their coronary bypass operation (donors) and of 67 patients who were eligible to pre-donate but did not (controls).

RESULTS

The clinical variables and the technical operative parameters of the patients in the two groups were similar. There was no significant difference between the duration of assisted ventilation post-operatively (756 +/- 197 vs. 802 +/- 395 min; P=0.54) or length of stay in the intensive care unit (1.8 +/- 1.1 vs. 1.7 +/- 0.9 days; P=0.52) of the two groups. The number of autologous units of packed red cells and of fresh frozen plasma (FFP) received by the donors was significantly higher than the number of units of allogeneic packed red cells (1.5 +/- 0.9 vs. 0.3 +/- 0.9; P=0.001) and the units of homologous FFP received by the controls (2.3 +/- 0.8 vs. 0.6 +/- 1; P=0.001).

CONCLUSIONS

We found no evidence that autologous blood donation exerted a negative influence on the post-operative course of patients undergoing coronary bypass surgery. Patients who pre-donated blood received no allogeneic blood products, but the number of autologous blood products received by donors was higher than the number of blood products received by patients who did not pre-donate.

Cost comparisons of pharmacological strategies in open-heart surgery

Open-heart surgery (OHS) is performed to bypass occluded arteries, replace malfunctioning cardiac valves or correct congenital abnormalities. The average cost of OHS varies from $US25 057-$US79 795 (1997 values). The objective of this paper was to review economic studies of pharmacological strategies in open-heart surgery. Pharmacological strategies studied include the prevention of postoperative complications such as atrial fibrillation (AF), bleeding and infection. Modifications in anaesthetic technique have been attempted by using agents that promote early extubation. In addition, strategies for postoperative management of sedation, analgesia and AF and use of neuromuscular blockers have also been compared. The majority of studies in this area have been cost analyses with few cost-effectiveness studies performed. Prophylaxis against AF with amiodarone is associated with a reduction in AF and was cost-neutral compared with placebo. Compared with placebo, prevention of bleeding with antifibrinolytics reduces transfusion costs. In direct comparative studies, lysine analogues, due to lower drug acquisition costs, offset transfusion costs to a greater extent than aprotinin. However, safety concerns with the lysine analogues remain. Erythropoietin decreases transfusion requirements and is cost effective compared with no intervention when the cost of postoperative bacterial complications is included. First- and second-generation cephalosporins prevent postoperative infections. Based on drug acquisition cost, the first-generation agents are less expensive although when administration costs are included, both classes have similar costs. Modifications in anaesthetic technique with short-acting anaesthetic agents, results in higher drug costs although nursing and total hospital costs are typically reduced. For neuromuscular blockers, drug acquisition costs are lowest with pancuronium but administration costs and the cost of adverse events have not been included in existing analyses. Midazolam provides an equivalent level of postoperative sedation to propofol but the acquisition cost is lower. The combined use of propofol and midazolam warrants further investigation, as its use is associated with lower sedative agent costs compared with either agent alone. There is limited data on the economics of postoperative analgesia and the management of AF. As the majority of studies to date are partial cost analyses, additional studies that include length of stay and other hospitalisation data are warranted. In future, cost-effectiveness and cost-utility studies, which incorporate quality of life and the cost of adverse effects and other longer term costs, should be undertaken.

Perioperative use of erythropoietin

Erythropoietin (EPO) is the primary regulator of red blood cell (RBC) production, and hypoxia is the main stimulus for EPO secretion. Increases in circulating levels of EPO are proportionate to the levels of tissue hypoxia, which are influenced by hematocrit (HCT). Small decreases in HCT as would be typical after presurgical autologous blood donation often do not result in increased EPO levels or in compensatory erythropoiesis. Erythropoiesis may also be limited by deficiencies of vitamin B(12), folate, and, most commonly, iron. The preoperative administration of EPO is effective in increasing erythrocyte mass and autologous donation volumes while maintaining higher HCT levels. In some surgical populations, particularly those individuals who experience surgical blood losses in excess of 2 L, EPO treatment also reduces allogeneic blood exposure. This effect is prominent in patients with a low initial HCT. Current assessments of the cost-effectiveness of EPO suggest that it achieves little overall improvement in patient health and that what improvement it does offer, it does at enormous cost.

Practical management of anticoagulation, bleeding and blood product support for cardiac surgery part two: Transfusion issues

We summarise recent advances in transfusion medicine applicable to cardiac surgery and cardiac transplantation. It is important that clinicians know the risks of blood transfusion in Australia. They should also be aware of the different types of transfusion reaction so that there is early recognition and investigation. Blood conservation strategies including acceptance of normovolaemic anaemia in clinically stable patients are important in reducing the requirement for red cell transfusion. Cytomegalovirus (CMV) seronegative blood products are recommended for heart transplant recipients with no evidence of prior CMV infection. Leucodepletion of units of unknown CMV status reduces the risk of CMV infection and are an acceptable alternative when seronegative units are unavailable. Leucodepletion of cellular blood products has been shown to reduce infection rates postoperatively in a large trial involving cardiac surgical patients. Further studies are needed to confirm this promising finding. Irradiation of blood products eliminates the risk of transfusion-associated graft versus host disease. Routine preoperative screening for cold agglutinins is no longer recommended.

Erythropoietin therapy versus red cell transfusion

Erythropoietin therapy was approved for use as a blood conservation intervention beginning in 1989 for patients with medical anemia and in 1997 for surgical patients. The adoption of this strategy has been rapid in some settings (such as renal failure patients), progressive in others ( eg, cancer patients), and slow in others (surgery patients, for instance). At the same time, the risks of blood transfusion have declined substantially whereas the costs of blood transfusion have increased significantly. The evolution of new techniques such as acute normovolemic hemodilution (ANH) and the novel erythropoiesis-stimulating protein (NESP) bring new options to allogeneic blood transfusion. Erythropoietin therapy, with or without autologous blood procurement, is undergoing new scrutiny as an alternative to blood transfusion. This is not only because of traditional concerns regarding blood risks but because of new blood inventory and cost considerations.

Erythropoietin therapy and preoperative autologous blood donation in children undergoing open heart surgery

We assessed the feasibility and efficacy of subcutaneous erythropoietin alpha (EPO) therapy and preoperative autologous blood donation (ABD) in children undergoing open heart surgery. Thirty-nine children were treated consecutively with EPO (100 U x kg(-1) s.c. three times a week in the 3 weeks preceding the operation and i.v. on the day of surgery) and two ABDs were made (Group 1). As controls to compare transfusion requirements, 39 consecutive age-matched patients who had undergone open heart surgery during the two preceding years were selected (Group 2). In a mean time of 20 (SD 5) days, 96% of scheduled ABDs were performed and only three mild vasovagal reactions were observed. The mean volume of autologous red blood cells (RBC) collected was 6 (1) ml x kg(-1) and the mean volume of autologous RBC produced as a result of EPO therapy before surgery was 7 (3) ml x kg(-1), corresponding to a 28 (11)% increase in circulating RBC volume. The mean volume of autologous RBC collected was not different from that produced [6 (1) vs 7 (3) ml x kg(-1), P=0.4]. Allogenic blood was administered to three out of 39 children in Group 1 (7.7%) and to 24 out of 39 (61.5%) in Group 2. Treatment with subcutaneous EPO increases the amount of autologous blood that can be collected and minimizes allogenic blood exposure in children undergoing open heart surgery.

Transfusion medicine : support of patients undergoing cardiac surgery

There is still no alternative that is as effective or as well tolerated as blood; nevertheless, the search for ways to conserve, and even eliminate blood transfusion, continues. Based on hemoglobin levels, practice guidelines for the use of perioperative transfusion of red blood cells in patients undergoing coronary artery bypass grafting have been formulated by the National Institutes of Health and the American Society of Anesthesiologists. However, it has been argued that more physiologic indicators of adequacy of oxygen delivery should be used to assess the need for blood transfusion. Methods used for conserving blood during surgery include autologous blood donation, acute normovolemic hemodilution and intra- and postoperative blood recovery and reinfusion. The guidelines for the use of autologous blood transfusion are controversial and it does not appear to be cost effective compared with allogeneic blood transfusion in patients undergoing cardiac surgery. Similarly, the cost effectiveness of intra- and postoperative blood recovery and reinfusion need further evaluation. Treatment with recombinant human erythropoietin (rhEPO) remains unapproved in the US for patients undergoing cardiac or vascular surgery, but it is a valuable adjunct in Jehovah's Witness patients, for whom blood is unacceptable. The characterization of darbepoetin alfa, a novel erythropoiesis stimulating protein with a 3-fold greater plasma elimination half-life compared with rhEPO, is an important advance in this field. Darbepoetin alfa appears to be effective in treating the anemia in patients with renal failure or cancer and trials in patients with surgical anemia are planned. Desmopressin has been used to effectively reduce intraoperative blood loss. Topical agents to prevent blood loss, such as fibrin glue and fibrin gel, and agents that alter platelet function, such as aspirin (acetylsalicylic acid) or dipyridamole, need further evaluation in patients undergoing cardiac surgery. Aprotinin has been shown to preserve hemostasis and reduce allogeneic blood exposure to a greater extent than the antifibrinolytic agents tranexamic acid and aminocaproic acid. Controlled clinical trials comparing the costs of these agents with clinical outcomes, along with tolerability profiles in patients at risk for substantial perioperative bleeding are needed.