Blood transfusion and blood conservation: cost and utilization issues

The effect of surgical time on perioperative complications in adolescent idiopathic scoliosis cases. A propensity score analysis

BACKGROUND

Posterior spinal instrumentation and fusion (PSIF) for adolescent idiopathic scoliosis (AIS) can be lengthy and complication-ridden. The aim of this study was to evaluate the effect of surgical time on perioperative complications in this procedure when controlling for confounding variables with propensity score analysis.

METHODS

This was an IRB-approved review of electronic health records from 2010 to 2019 at a single tertiary care children's hospital. Patients undergoing PSIF were grouped into "short" (< 6 h) or "long" (≥ 6 h) surgical time groups. Outcome measures were estimated blood loss (EBL), cell saver transfusions, packed red blood cell (pRBC) transfusions, length of stay (LOS), intraoperative monitoring (IOM) alerts, hematocrit, ICU transfer, neurologic loss, surgical site infection, and 90-day readmissions. We controlled for age, sex, BMI, curve severity, number of segments fused, and surgeon factors.

RESULTS

After propensity score matching there were 113 patients in each group. The short surgical time group had lower EBL (median 715, IQR 550-900 vs median 875, IQR 650-1100 cc; p < 0.001), received less cell saver blood (median 120, IQR 60-168 vs median 160, IQR 97-225 cc; p = 0.001), received less intraoperative pRBCs (median 0, IQR 0-0 vs median 0, IQR 0-320, p = 0.002), had shorter average LOS (4.8 ± 1.7 vs 5.4 ± 2.5 days; p = 0.039), and fewer IOM alerts (4.3% vs 18%, p = 0.003).

CONCLUSIONS

Patients with shorter surgical times had less blood loss, received less transfused blood, had a shorter LOS, and fewer IOM alerts compared to patients with longer surgical times. Surgical times < 6 h may have safety and efficacy advantages over longer times.

LEVEL OF EVIDENCE

III.

Recent advances in micro-sized oxygen carriers inspired by red blood cells

Supplementing sufficient oxygen to cells is always challenging in biomedical engineering fields such as tissue engineering. Originating from the concept of a 'blood substitute', nano-sized artificial oxygen carriers (AOCs) have been studied for a long time for the optimization of the oxygen supplementation and improvement of hypoxia environments in vitro and in vivo. When circulating in our bodies, micro-sized human red blood cells (hRBCs) feature a high oxygen capacity, a unique biconcave shape, biomechanical and rheological properties, and low frictional surfaces, making them efficient natural oxygen carriers. Inspired by hRBCs, recent studies have focused on evolving different AOCs into microparticles more feasibly able to achieve desired architectures and morphologies and to obtain the corresponding advantages. Recent micro-sized AOCs have been developed into additional categories based on their principal oxygen-carrying or oxygen-releasing materials. Various biomaterials such as lipids, proteins, and polymers have also been used to prepare oxygen carriers owing to their rapid oxygen transfer, high oxygen capacity, excellent colloidal stability, biocompatibility, suitable biodegradability, and long storage. In this review, we concentrated on the fabrication techniques, applied biomaterials, and design considerations of micro-sized AOCs to illustrate the advances in their performances. We also compared certain recent micro-sized AOCs with hRBCs where applicable and appropriate. Furthermore, we discussed existing and potential applications of different types of micro-sized AOCs.

A Population-Based Study of Patients with Sleep-Wake Disorders Undergoing Elective Instrumented Spinal Surgery

BACKGROUND

Sleep-wake disorders are associated with multisystemic pathologies, but the clinical risk that such disorders carry for spinal surgery patients is not well understood. This population-based study comprehensively evaluates the significance of sleep-related risk factors on instrumented spinal surgery outcomes.

METHODS

National Inpatient Sample data for hospitalizations of patients undergoing elective instrumented spine surgery between 2008 and 2014 was analyzed using national estimates. Cohorts were defined as those admissions with or without a coexisting sleep-wake disorder diagnosis identified by ICD-9 codes. Postoperative complications, mortality rate, length of stay, discharge status, and total cost of admission were compared between groups using bivariate and multivariate analyses.

RESULTS

A coexisting sleep-wake disorder existed in 234,640 (10.8%) of 2,171,167 instrumented spinal surgery hospitalizations. Multivariate binary logistic regression accounting for these variables confirmed that a sleep-wake disorder is a significant risk factor for postoperative complication (OR 1.160, 95% CI 1.140-1.179, p<0.0001), length of stay above the 75^th percentile (OR 1.303, 95% CI 1.288-1.320, p<0.0001), non-routine discharge (OR 1.147, 95% CI 1.131-1.163, p<0.0001), and death (OR 1.533, 95% CI 1.131-2.078, p<0.01), but not for total charges above the 75^th percentile (OR 0.975, 95% CI 0.962-0.989, p<0.001).

CONCLUSIONS

Sleep-wake disorders confer increased risk of morbidity and mortality in elective instrumented spine surgery. Understanding the specific contributions of sleep-wake disorders to postoperative morbidity and mortality can help physicians implement prophylactic measures to reduce complications and improve postoperative patient recovery.

The SPOT GRADE: A New Method for Reproducibly Quantifying Surgical Wound Bleeding

STUDY DESIGN

Benchtop model with prospective surgeon video testing.

OBJECTIVE

To create a surface bleeding severity scale, the SPOT GRADE (SG), for quantitative assessment of target bleeding site (TBS) blood loss. This is of particular interest for spinal surgery due to epidural bleeding and an inability to use diathermy and radiofrequency cautery close to nerve roots.

SUMMARY OF BACKGROUND DATA

A novel apparatus perfusable at known flow rates and simulating different sized wounds was used to create movies to educate surgeons on specific degrees of bleeding.

METHODS

Training (36) and testing (108) videos were created using a benchtop apparatus employing different bleeding severities based on the six-level SG (none, minimal, mild, moderate, severe, and extreme) and TBS sizes (1, 10, and 50 cm). Fourteen surgeons in four specialties (cardiothoracic, abdominal, spine, and orthopedic lower extremity) were trained and tested to evaluate SG characteristics including inter-rater and intrarater reliability.

RESULTS

The interclass correlation coefficient was estimated to be 0.89840 (95% confidence interval [CI]: 0.85771, 1), whereas the intraclass correlation coefficient was estimated to be 0.93673 (95% CI: 0.89603, 1). In 98% of cases (95% CI: 0.9736, 0.9927), surgeons correctly identified eligible bleeds for a future clinical trial (scores = 1, 2, or 3) and in 91% of cases (95% CI: 0.8895, 0.9344), surgeons correctly identified noneligible bleeds (scores = 4 or 5). In 98.6% of cases (95% CI: 0.9777, 0.9945), physicians correctly identified true hemostasis (score = 0). Based upon these data the probability of a physician rating a bleed incorrectly as hemostasis (score = 0) is estimated to be 1.51% (95% CI: 0.0061, 0.0363).

CONCLUSION

This SG is reproducible and reliable providing a basis for educating surgeons on TBS blood loss. It appears to be a new standard for evaluating wound blood loss.

LEVEL OF EVIDENCE

2.

Blood wastage reduction: a 10-year observational evaluation in a large teaching institution in France

CONTEXT

Blood transfusion has increased significantly during the last decade and blood wastage reduction is a medical and economic challenge in hospital practice and for institutional quality, particularly in the ICU and operating theatre.

OBJECTIVE

To evaluate the impact of multiple strategies in one hospital to reduce red blood cell wastage.

DESIGN

Multicentre, prospective, comparative, observational study.

SETTING

Over 10 years, the study was conducted over two time periods. During the first period (2000 to 2003), information was given to medical professionals about blood wastage, and audits (reasons for wastage) were performed, in a large teaching institution (more than 4% wastage in 1999). The second period (2004 to 2010) was designed to analyse the impact of seven strategies intended to minimise blood wastage. Blood wastage reduction in the local centre was compared with regional (64 institutions) and national centres (1470 institutions). Reduction was compared using the Mann-Kendall non-parametric trend test.

PATIENTS

Local centre (22,572 transfused patients, Nîmes, France), regional centre (South France, 64 institutions, 208,525 transfused patients) and national centres (France, 1470 institutions).

INTERVENTIONS

Medical and surgical procedures.

MAIN OUTCOME MEASURES

The primary end-point was to describe the percentage of blood wastage for two periods in a local centre. The secondary objective was to compare the percentage of blood wastage in the local centre with wastage at regional and national centres.

RESULTS

Over the 10 year study period the percentage of blood wastage in the local centre decreased, with a significant reduction in the second period, from more than 4% (1999) to less than 1% (2010; P < 0.05). Blood wastage at regional and national centres was never less than 1%. Inadequate containers for transport, absence of a temperature analyser in the ICU and inadequate intraoperative blood strategies (excessive orders of blood) were the main causes of wastage. Correction of these points affected the outcome favourably in the second period, but transfusion information was poor in the first period.

CONCLUSION

Seven simple strategies (including transport containers with an effective temperature analyser and audits) decreased blood wastage, especially in the ICU and operating theatre.

Prospective randomized evaluation of a collagen/thrombin and autologous platelet hemostatic agent during total knee arthroplasty

The purpose of this study was to evaluate the effectiveness of a collagen/thrombin and autologous platelet hemostatic agent in preventing blood loss during primary total knee arthroplasty. This prospective, double-blinded, randomized study was designed to enroll a total of 100 patients. Patients were randomized 1:1 to either the treatment arm (standard hemostasis plus study product) or the control arm (standard hemostasis alone). Transfusion requirements, as determined by a blinded investigator using standardized criteria, were significantly lower in the treatment group (no blood transfusions) compared with the control group (5 transfusions; P = .007). These data support the addition of the study product to prevent blood transfusions after primary total knee arthroplasty.

Prospective randomized evaluation of the need for blood transfusion during primary total hip arthroplasty with use of a bipolar sealer

BACKGROUND

Blood loss during total hip arthroplasty can be substantial and may lead to adverse patient outcomes and increased health-care costs. Many blood-management options are available for these procedures. The purpose of the present study was to test the hemostatic efficacy of a bipolar sealer used during total hip arthroplasty in order to determine whether its use results in significantly lower transfusion requirements and/or improved clinical, functional, and health-related quality-of-life outcomes in healthy patients.

METHODS

This prospective, single-center, randomized, double-blinded study was designed to enroll a total of 140 patients. Patients with a low preoperative hemoglobin level or a history of bleeding abnormalities and other medical conditions were excluded. Patients were randomized to either the treatment arm (radiofrequency energy with use of the Aquamantys 6.0 bipolar sealer) or control arm (standard Bovie electrocautery). The primary outcome measure was the transfusion requirement, and the secondary outcome measures were intraoperative estimated blood loss, postoperative hemoglobin levels, perioperative narcotic usage, length of hospital stay, postoperative pain scores, and postoperative function as measured with the Harris hip score and the Short Form-12 quality-of-life score.

RESULTS

Seventy-one patients were assigned to the treatment arm, and sixty-nine were assigned to the control arm. The mean number of units of blood transfused for all patients in the study and control arms were 0.38 and 0.44, respectively (p = 0.72). The transfusion requirements were similar in the two groups, with fifteen of seventy-one patients in the treatment arm and fourteen of sixty-nine patients in the control arm requiring a transfusion (p = 0.9). No significant differences were detected between the groups in terms of estimated blood loss, postoperative hemoglobin levels, perioperative narcotic usage, length of hospital stay, postoperative pain scores, Harris hip scores, or Short Form-12 scores.

CONCLUSIONS

In this patient population, there were no significant differences between the treatment and control groups in terms of the need for blood transfusions or overall blood loss. Given these findings, we have discontinued the use of this bipolar sealing device in uncomplicated primary total hip arthroplasty patients at our institution.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

Causes and consequences of critical bleeding and mechanisms of blood coagulation

Pharmacists who practice in the critical care setting require a solid background on the causes and consequences of bleeding, as well as the mechanisms of hemostasis. This article provides an overview of these topics. Bleeding and outcomes as a result of surgery and trauma, from medical and pharmacologic causes, and in obstetrics and gynecology are discussed. Patients with brain trauma, those with inherited and acquired bleeding disorders, and patients undergoing therapeutic anticoagulation are addressed, as these are populations at special risk for severe bleeding. Bleeding events as a result of hypothermia, acidosis, and disseminated intravascular coagulation are also discussed, as is the pathophysiology of massive blood loss. Traditional and newer cell-based models of coagulation mechanisms are described and compared. Application of this information in pharmacy practice will help ensure that therapies to manage and arrest blood loss are used appropriately in a wide variety of clinical scenarios.

Estimating the cost of blood: past, present, and future directions

Understanding the costs associated with blood products requires sophisticated knowledge about transfusion medicine and is attracting the attention of clinical and administrative healthcare sectors worldwide. To improve outcomes, blood usage must be optimized and expenditures controlled so that resources may be channeled toward other diagnostic, therapeutic, and technological initiatives. Estimating blood costs, however, is a complex undertaking, surpassing simple supply versus demand economics. Shrinking donor availability and application of a precautionary principle to minimize transfusion risks are factors that continue to drive the cost of blood products upward. Recognizing that historical accounting attempts to determine blood costs have varied in scope, perspective, and methodology, new approaches have been initiated to identify all potential cost elements related to blood and blood product administration. Activities are also under way to tie these elements together in a comprehensive and practical model that will be applicable to all single-donor blood products without regard to practice type (e.g., academic, private, multi- or single-center clinic). These initiatives, their rationale, importance, and future directions are described.

Blood transfusion requirement prediction in patients undergoing primary total hip and knee arthroplasty

The aim of this study was to identify the clinical factors associated with the need for peri-operative blood transfusion in non-anaemic patients undergoing hip or knee arthroplasty. We prospectively evaluated 162 consecutive patients who underwent total hip or knee arthroplasty. Analysis was performed to establish the relationship between all independent variables and the need for postoperative transfusion. Univariate analysis revealed a significant relationship between the need for postoperative blood transfusion and the pre-operative haemoglobin levels (P= 0.001), weight (P= 0.019) and age (P= 0.018). Multivariate analysis identified a significant relationship only between the need for transfusion and the pre-operative haemoglobin level (P= 0.0001). The pre-operative haemoglobin level of the patient was the only variable to independently predict the need for blood transfusion after primary hip or knee arthroplasty.

Blood saving protocol in elective total knee arthroplasty

BACKGROUND

To eliminate the need for allogeneic blood transfusion in patients undergoing elective total knee arthroplasty, we established and tried a protocol of combined methods, which is characterized by effectiveness, ease in application, and safety. It is based on perioperative administration of human recombinant erythropoietin plus iron and folic acid, mild acute normovolemic hemodilution, meticulous surgical technique, postoperative blood salvage through a closed-wound drainage system, and lower transfusion triggers.

DATA SOURCES

Sixty-one patients entered the protocol, and the results were retrospectively compared with the ones obtained from 58 consecutive patients who were operated on in the past before the use of any blood saving technique.

CONCLUSIONS

Only 5 patients of those who entered the protocol finally needed allogeneic blood transfusion, receiving a total number of 7 units, which is remarkable when compared with the 50 patients before the application of the protocol who required 111 units. Consequently, the utilization of allogeneic blood was reduced by 94%, a statistically quite significant result (P <0,001). We believe the protocol should be included in orthopedic surgeons' alternatives for blood saving in elective total knee arthroplasty.

Platelet transfusion therapy

The relative merits of apheresis platelets and platelet concentrates are undergoing debate due to evolving issues of safety, inventory, and cost. The application of photochemical inactivation technology may eliminate any rationale for the use of apheresis platelets rather than pooled platelet concentrates, so that the relative merits of these two alternatives will be debated over costs and inventory. Doses of apheresis platelets are determined by donor platelet count and by platelet yield. The generation of a platelet apheresis inventory has been accompanied by a decline in whole blood inventory; research into the impact of these distinct donor pools on national blood policy is needed.

Autologous blood transfusion in oral and maxillofacial surgery patients with the use of erythropoietin

Background: Autologous blood transfusion presents few infectious or immunologic side effects. The aim of the present study was to determine the impact of autologous blood transfusion with or without recombinant human erythropoietin (rHuEPO) in patients who underwent elective maxillofacial operations. Material: Seventy eight consecutive patients (29 men and 49 women) underwent elective maxillofacial operations during the years 1990-95. Study design and Methods: The patients were randomly assigned to three groups: In group 1, 30 patients preoperatively underwent autologous blood predonation with intravenous injection of erythropoietin 600 IU/kg after each blood predonation and autologous blood transfusion intraoperatively; in group 2, 28 patients underwent the same procedure without erythropoietin and in group 3, 20 patients underwent homologous transfusion serving as control group. All patients received ferrous sulphate daily by mouth, preoperatively until one week postoperatively. Results: Group 1 patients showed higher levels of haematocrit, haemoglobin and red blood cell count pre- and postoperatively than the group 2 patients. It was also shown that the use of rHuEPO contributed to an improvement of the blood parameters of the patients in the group 1 compared with those of the patients in groups 2 and 3. Copyright 2001 European Association for Cranio-Maxillofacial Surgery.

Autotransfusion decreases blood usage following cardiac surgery -- a prospective randomized trial

INTRODUCTION

10% of blood issued by the National Blood Service (220,000) is utilised in cardiac procedures. Transfusion reactions, infection risk and cost should stimulate us to decrease this transfusion rate. We tested the efficacy of autotransfusion of washed postoperative mediastinal fluid in a prospective randomized trial.

PATIENTS AND METHODS

166 patients undergoing coronary artery bypass grafting (CABG), valve or CABG + valve procedures were randomized into three groups. The indication for transfusion was a postoperative haemoglobin (Hb) < 10 g/l or a packed cell volume (PCV) < 30. When applicable, group A patients received washed post-operative drainage fluid. Group B all received blood processed from the cardiopulmonary bypass (CPB) circuit following separation from CPB and if appropriate washed post-operative drainage fluid. Group C were controls. Groups were compared using analysis of variance.

RESULTS

There was no significant difference in age, sex, type of operation, CPB time and preoperative Hb and PCV between the groups. Blood requirements were as shown. [table - see text] Twelve patients in group A and 10 in group B did not require a homologous transfusion following processing of the mediastinal drainage fluid.

CONCLUSION

Autotransfusion of washed postoperative mediastinal fluid can decrease the amount of homologous blood transfused following cardiac surgery. There was no demonstrable benefit in processing blood from the CPB circuit as well as mediastinal drainage fluid.

Blood transfusion costs by diagnosis-related groups in 60 university hospitals in 1995

BACKGROUND

Transfusion services are frequently challenged to initiate efforts to reduce blood transfusion costs. One approach is to analyze blood transfusion costs for individual medical and surgical Diagnosis-Related Groups (DRGs). Rank ordering of DRGs by transfusion costs and interinstitutional comparisons of these costs may lead to the selection of DRGs for further analysis of the process of blood transfusion.

STUDY DESIGN AND METHODS

Common DRGs (n = 486) that were related to discharges in 1995 were analyzed from 60 university hospital members of the University HealthSystems Consortium (UHC). Cost data were tabulated by using cost-to-charge ratios reflecting all aspects of blood transfusion-related costs of participating institutions.

RESULTS

Of these 486 DRGs, 471 had identifiable mean blood costs, and 34 had median blood costs, mostly for surgical conditions. Transfusion costs represented a small proportion (< or = 1%) of total hospitalization costs for most DRGS: Nonetheless, millions of dollars were spent on blood transfusion, and for the most expensive DRGs, the costs ranged from 5.0 to 8.6 percent of total hospitalization costs. Transfusion costs are more variable for the DRGs with the lowest transfusion costs than for those with the highest transfusion costs.

CONCLUSION

Members of the UHC may utilize such analyses to identify surgical or medical diagnoses with transfusion costs at variance with the group norm. These DRGs could then be targeted for further evaluation of components contributing to high costs, for possible alterations in physician or clinical laboratory practices. Considering those conditions with the highest cumulative transfusion costs (e.g., BMT, liver transplant, acute leukemia, and cardiothoracic procedures), changes in transfusion practices that affect these particular patient categories may have a significant impact on global blood transfusion costs.

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.

Are there simple measures to reduce the risk of HIV infection through blood transfusion in a Zambian district hospital?

OBJECTIVE

To quantify the potential impact of simple measures to reduce the risk of iatrogenic HIV infection through blood transfusion in a Zambian district hospital.

METHODS

Three studies were conducted at St. Francis' Hospital, Katete, Zambia: (1) From 1991 to 1995 HIV seroprevalence among all listed blood donors and the impact of proper subgroup selection were studied retrospectively; (2) the sensitivity of locally used rapid antibody assays (HIV-spot/Wellcozyme HIV 1 & 2) for the detection of HIV in donor blood and the influence of the expiration date of the tests on this sensitivity were determined prospectively from June 1993 until March 1994 by screening all consecutive surgical patients and blood donors; (3) the number of unnecessary blood transfusions was determined retrospectively from January 1995 through January 1996 and prospectively from February 1996 through March 1996, and possibilities to reduce the total number of blood transfusions were considered.

RESULTS

(1) Excluding prisoners, who have an HIV seroprevalence of 19-25%, from the donor population significantly reduces the overall HIV seroprevalence from 13-16% to 8-9% (P < 0. 01). (2) Under local circumstances the sensitivity of the used rapid antibody assays was 6.8-17.9% lower than claimed by the manufacturer. Usage of non-expired tests increased the sensitivity significantly from 88.2% to 91.7% (P < 0.05). (3) None of the 294 studied blood transfusions can be classified as inappropriate according to international standards.

CONCLUSIONS

Simple measures such as proper subgroup selection among blood donors and correct use of non-expired tests may decrease the risk of iatrogenic HIV transmission. Stricter indications for blood transfusions will not substantially reduce the number of transfusions.

Apheresis platelets: emerging issues related to donor platelet count, apheresis platelet yield, and platelet transfusion dose

Emerging issues in stimulating apheresis platelet donors with platelet growth factors, the relative costs of apheresis and random donor platelet concentrates, optimal platelet transfusion dose, and leucoreduction of platelet products have caused renewed debate regarding apheresis products vs. random, pooled concentrates. The future role of apheresis products in platelet transfusion therapy will in large part be determined by costs, which are increasingly recognized to be influenced by donor platelet count, apheresis yield, and platelet transfusion dose.

Perioperative autologous blood donation in children

Autologous blood donation in children has become a standard of care. Children have to live with the life-time complications associated with allogeneic blood including the transmission of known and unknown pathogens, and the impact of alloimmunization on future blood transfusions, organ transplants and pregnancies. Donor reaction, allogeneic exposure and utilization rates in pediatric preoperative autologous donation (PAD) programs are as good if not better than reported in adult literature. Children are very resilient when undergoing extreme isovolemic hemodilution (IHD). PAD, IHD and intraoperative blood recovery appear to be useful components of a pediatric blood conservation program. Prospective, randomized studies addressing the specific needs of children are required to properly define their perioperative role.

Autotransfusion of washed shed mediastinal fluid decreases the requirement for autologous blood transfusion following cardiac surgery: a prospective randomized trial

OBJECTIVES

The National Blood Service issues 2.2 million units of blood per year, 10% of these (220000) are utilized in cardiac procedures. Transfusion reactions, infection risk and cost should stimulate us to decrease this transfusion rate. We test the efficacy of autotransfusion following surgery in a prospective randomized trial.

METHODS

One hundred and twelve patients undergoing CABG, valve or CABG + valve procedures were randomized into two groups. Group A received washed postoperative drainage fluid and group C were controls. The indication for transfusion was a postoperative haemoglobin (Hb) < 10 g/l or a PCV < 30. There was no significant difference in preoperative and operative variables between the groups.

RESULTS

Twenty-eight patients in group A and 46 in group C required homologous transfusion (P = 0.0008). Group A patients required 298+/-49 ml of banked blood per patient, group C 508+/-49 ml (P = 0.003). There was no difference in total blood required (volume autotransfused + volume banked blood transfused) between the groups (group A 404+/-50 ml, group C 508+/-50 ml) or in mean total mediastinal fluid drainage (group A 652+/-51 ml, group C 686+/-50ml). The mean Hb concentration was significantly higher in group A on day 1 (11.2 g/dl+/-51 vs. 10.6 g/dl+/-13 (P = 0.002)). No morbidity was associated with autotransfusion.

CONCLUSION

Autotransfusion can decrease the amount of homologous blood transfused following cardiac surgery. This represents a benefit to the patient and a decrease in cost to the health service.

Acute normovolemic hemodilution

Acute normovolemic hemodilution was described to be useful as a blood conservation strategy more than 25 years ago, yet seldom is practiced today. The benefit of acute normovolemic hemodilution is perceived to be modest and the technique is not taught in anesthesia or surgery training programs. Acute normovolemic hemodilution is an autologous blood procurement strategy that is superior to the predeposit of autologous blood for several reasons: Acute normovolemic hemodilution is less costly, with an average cost of $25 per unit compared with $175 per unit predonated; and acute normovolemic hemodilution units are reinfused to patients before the patient leaves the operating room, so that the units need not be tested and there is no possibility of administrative error. Emerging clinical studies now show that acute normovolemic hemodilution is equivalent to predonated autologous blood in reducing allogeneic blood exposure in patients undergoing elective surgery.

Oxygen carriers as blood substitutes. Past, present, and future

Prospects for safe and effective blood substitutes are promising, based on clinical trial results of soluble hemoglobin solutions and emulsion of perfluorocarbins. Advantages of blood substitutes include sterilization of viral and bacterial contaminants, room temperature storage, a long shelf life, and absence of ABO and other red cell antigens. Projected arenas for their use include not only military applications but also trauma medicine and elective surgical settings, coupled with acute normovolemic hemodilution. Applications of perfluorocarbons are limited by the need for 100% FIO2. A significant challenge facing development of hemoglobin solutions is their effect on vascular tone through smooth muscle constriction. Development of second or third generation hemoglobin solutions may be necessary so that hemoglobin solutions more closely mimic cellular hemoglobin's nitric oxide binding properties. Optimizing O2 delivery to ischemic tissues and organs may lead to regulatory approval of these agents in this setting before their approval as blood substitutes.

Erythropoietin therapy in the perioperative setting

Recombinant human erythropoietin has been approved for use in patients undergoing autologous donation in Japan, Europe, and Canada since 1993, 1994, and 1996, respectively, and for perisurgical adjuvant therapy without autologous donation in Canada and the United States since 1996. Early clinical trials of erythropoietin therapy in the setting of autologous donation have provided important information regarding clinical safety, erythropoietin dose, and erythropoietic response. Later trials of perisurgical erythropoietin therapy without autologous donation provided data on efficacy (reduced allogeneic blood exposure) that led to approval of erythropoietin in patients undergoing surgery. However, the erythropoietin doses (300 U/kg subcutaneous x14 days) used in these trials, and their subsequent inclusion in labeling for the use of this product, are costly and tedious to administer. A recent study reported that a weekly regimen of erythropoietin (600 U/kg) for 4 weeks is less costly but just as effective at reducing allogeneic blood exposure in elective orthopaedic surgery. The most cost effective regimen that has been shown to minimize allogeneic exposure is preoperative erythropoietin therapy (600 U/kg subcutaneous weekly x2 and 300 U/kg subcutaneous on day of surgery) coupled with acute normovolemic hemodilution in patients undergoing radical retropubic prostatectomy. A similar regimen of erythropoietin therapy in patients undergoing coronary artery bypass grafting (2500 U/kg subcutaneous in divided doses for 2 weeks preoperatively) coupled with hemodilution also was effective. Low dose erythropoietin therapy coupled with acute normovolemic hemodilution ultimately may be shown to be cost equivalent to the predonation of three autologous blood units before elective surgery.

Shed mediastinal blood transfusion after cardiac operations: a cost-effectiveness analysis

BACKGROUND

Cardiac surgical patients consume a significant fraction of the annual volume of allogeneic blood transfused. Scavenged autologous blood may serve as a cost-effective means of conserving donated blood and avoiding transfusion-related complications.

METHODS

This study examines 834 patients after cardiac operations at the University of Alabama Hospital. Data were collected on patients receiving unwashed, filtered, autologous transfusions from shed mediastinal drainage and those receiving allogeneic transfusions. The data were incorporated into clinical decision models; confidence intervals for parameters were estimated by bootstrapping sample statistics. Costs were estimated for transfusing both allogeneic and autologous blood.

RESULTS

The study found a 54% reduction in transfusion risk or a mean reduction of 1.41 allogeneic units per case (95% confidence interval, 1.04 to 1.79 units). The process saved between $49 and $62 per case.

CONCLUSIONS

The use of autologous blood has the potential to significantly reduce the costs and risks associated with transfusing allogeneic blood after cardiac operations.

Autologous blood procurement in the surgical setting: lessons learned in the last 10 years

The percentage of blood transfused yearly that is autologous has increased substantially over the last 10 years. While autologous blood is regarded as a standard of care in many elective surgical settings, the increasing safety of allogeneic blood and the expense of autologous blood procurement have raised question regarding the appropriate roles of autologous blood in blood conservation strategies. We therefore review current activities and emerging questions that arise from this maturing arena.

A cost comparison of allogeneic and preoperatively or intraoperatively donated autologous blood

We determined the cost of allogeneic packed red blood cells and autologous whole blood donated either preoperatively or in the operating room during hemodilution. Direct and indirect cost estimates were based on patients requiring simple transfusion and included procurement and preparation of the blood including testing performed, materials and time used, waste, and materials for administration. Data were derived from prospective blood bank time studies, material invoice records, and retrospective review of anesthesia times. Viral infection and transfusion reaction costs were accepted from previously published sources. Direct cost of purchasing and indirect costs of preparation resulted in an overall cost of $107.26 for the first unit of allogeneic packed red blood cells transfused. A second unit was slightly less costly ($100.89), as no type and screen was required and the same delivery set and filter can be used. The total cost of acquisition, processing, and transfusion of 1 U of preoperatively donated autologous blood was $97.83. The total cost of a 2-U transfusion of autologous whole blood donated in the operating room during acute normovolemic hemodilution was $83.10. These data suggest that autologous predonation of whole blood is somewhat less expensive than allogeneic packed red blood cells, and that hemodilution may be a cost effective alternative to autologous predonation in selected patients.

A cost comparison of allogeneic and preoperatively or intraoperatively donated autologous blood

We determined the cost of allogeneic packed red blood cells and autologous whole blood donated either preoperatively or in the operating room during hemodilution. Direct and indirect cost estimates were based on patients requiring simple transfusion and included procurement and preparation of the blood including testing performed, materials and time used, waste, and materials for administration. Data were derived from prospective blood bank time studies, material invoice records, and retrospective review of anesthesia times. Viral infection and transfusion reaction costs were accepted from previously published sources. Direct cost of purchasing and indirect costs of preparation resulted in an overall cost of $107.26 for the first unit of allogeneic packed red blood cells transfused. A second unit was slightly less costly ($100.89), as no type and screen was required and the same delivery set and filter can be used. The total cost of acquisition, processing, and transfusion of 1 U of preoperatively donated autologous blood was $97.83. The total cost of a 2-U transfusion of autologous whole blood donated in the operating room during acute normovolemic hemodilution was $83.10. These data suggest that autologous predonation of whole blood is somewhat less expensive than allogeneic packed red blood cells, and that hemodilution may be a cost effective alternative to autologous predonation in selected patients.

Blood conservation strategies to minimize allogeneic blood use in urologic surgery

Analysis of the net costs, efficacy, and cost-effectiveness of preoperative autologous blood donation (PAD), versus acute normovolemic hemodilution (ANH), in patients undergoing radical prostatectomy is presented. Currently, PAD is a standard of care for patients undergoing radical prostatectomy. Comparison of PAD with ANH showed no differences in risks or outcome, but ANH was less expensive. Hemodilution is a simple, safe, convenient, and effective alternative to PAD. The use of recombinant human erthropoietin in conjunction with PAD and ANH has optimized perioperative hematocrits and further minimized exposure to allogeneic blood. Intraoperative blood salvage, lower transfusion triggers, and other blood conservation strategies are discussed. The most cost-effective techniques currently available for decreasing allogeneic blood transfusions appear to be avoidance of blood loss, increased tolerance for decreased HCT levels, and autologous blood procurement via ANH.