Collection and transfusion of blood and blood components in the United States, 1989

A rapid and accurate closed-tube immunoassay for platelets on an automated hematology analyzer

Accurate and precise platelet counts are important for patients with severe thrombocytopenia or who are receiving chemotherapy. We developed a novel flow cytometric analysis of platelets that may be particularly valuable for assessing the necessity for platelet transfusions. This ImmunoPlt (CD61) assay is based in part on CD61 monoclonal antibody labeling and has been automated and implemented on the CELL-DYN 4000 hematology analyzer. It is well suited for thrombocytopenic specimens, since it reduces interference by nonplatelet particles. It takes less than 5 minutes from closed-tube aspiration to report. Data for more than 350 thrombocytopenic specimens demonstrate that the ImmunoPlt (CD61) assay is more accurate than the optical scatter or the impedance count for specimens with platelet counts between 1 and 60 x 10(3)/microL (1 and 60 x 10(9)/L). The ImmunoPlt (CD61) assay is more precise than the optical scatter or the impedance count for specimens with platelet counts between 1 and 50 x 10(3)/microL (1 and 50 x 10(9)/L).

Institutional variability in red blood cell conservation practices for coronary artery bypass graft surgery. Institutions of the MultiCenter Study of Perioperative Ischemia Research Group

OBJECTIVE

To assess whether substantial institutional variability exists in red blood cell conservation practices associated with coronary artery bypass graft (CABG) surgery.

DESIGN

Prospective, randomized patient enrollment and data collection.

SETTING

Twenty-four U.S. academic institutions participating in the Multicenter Study of Perioperative Ischemia.

PARTICIPANTS

A well-defined subset of primary CABG surgery patients (n = 713) expected to be at low risk for bleeding and exposure to allogeneic transfusion.

INTERVENTIONS

None (observational study).

MEASUREMENTS AND MAIN RESULTS

Frequency of use of red blood cell conservation techniques was determined among institutions. Correlation was determined between use of each technique and transfusion of allogeneic red blood cells and between use of each technique and median institutional blood loss. Significant variability (p < 0.01) was detected in institutional transfusion practice with respect to the use of predonated autologous whole blood, normovolemic hemodilution, red cell salvage, and reinfusion of shed mediastinal blood. The frequency of institutional use of these techniques was not associated with allogeneic transfusion (r2 < 0.15) or blood loss (r2 < 0.10) in the low-risk population of patients examined.

CONCLUSIONS

Institutions vary significantly in perioperative blood conservation practices for CABG surgery. Further study to determine the appropriate use of these techniques is warranted.

Platelet-rich plasma sequestration, with therapeutic platelet yields, reduces allogeneic transfusion in complex cardiac surgery

Platelet dysfunction is the most common cause of nonsurgical bleeding after cardiopulmonary bypass (CPB). We hypothesized that reinfusion of a therapeutic quantity of platelets sequestered before CPB would decrease the need for allogeneic platelet transfusion, as well as decrease bleeding and total allogeneic transfusion, in cardiac surgery patients at moderately high risk for bleeding. Fifty-five patients undergoing either reoperative coronary artery bypass (CABG) or combined CABG and valve replacement were randomized to control or platelet-rich plasma sequestration (pheresis) groups. All patients received intraoperative epsilon-aminocaproic acid infusions. There was no significant difference between groups with respect to preoperative characteristics, duration of CPB, or target postoperative hematocrit. Mean platelet yields were 6.2 +/- 2.1 units (3.1 x 10(11) platelets). Mean pheresis time was 44 min. Allogeneic platelets (range = 6-12 units) were transfused to 28% of control patients, compared with 0% of pheresis patients (P < 0.01). Allogeneic packed red blood cells were transfused to 45% of control patients (1.2 units per patient) versus 31% of pheresis patients (0. 7 unit per patient) (P = 0.35). Total allogeneic units transfused were significantly reduced in the pheresis group (P < 0.02). Mediastinal chest tube drainage was not significantly decreased in the pheresis group. In this prospective, randomized study, therapeutic platelet yields were obtained before CPB. In contrast with recent studies with low platelet yields, these data support the conclusion that platelet-rich plasma sequestration is effective in reducing allogeneic platelet transfusions and total allogeneic units transfused in cardiac surgery patients at moderately high risk for post-CPB coagulopathy and bleeding.

IMPLICATIONS

Transfusion of allogeneic blood products, including platelets, is common during complex cardiac surgical procedures. In the present prospective, randomized study, a significant reduction in allogeneic platelet transfusion and total allogeneic units transfused was observed after the reinfusion of a therapeutic quantity of autologous platelets sequestered before cardiopulmonary bypass.

The influence of citrate concentration on the quality of plasma obtained by automated plasmapheresis: a prospective study

BACKGROUND

There is a need for more comprehensive work dealing with the quality of plasma collected by automated plasmapheresis using different final concentrations of citrate anticoagulant. A prospective study was performed to examine the influence of three concentrations of sodium citrate on the levels of clotting factors and markers of activated hemostasis and fibrinolysis.

STUDY DESIGN AND METHODS

Fifty-one experienced plasma donors were recruited for subsequent 750-mL plasmapheresis procedures using 4-percent (wt/vol) sodium citrate. Anticoagulant-to-blood ratios of 1:16.6, 1:14.2, and 1:12.5 were used, corresponding to sodium citrate concentrations of 6 percent, 7 percent, and 8 percent (vol/vol), respectively. Between two plasmapheresis procedures, there was a washout period of 7 days. Determinations were made of the plasma levels of fibrinogen and factors V, VII, VIII, and IX, as well as antithrombin, tissue-type plasminogen activator, and several markers of activated hemostasis and fibrinolysis: activated factor VII, prothrombin splits products, D-dimers, and beta-thromboglobulin.

RESULTS

The plasma samples anticoagulated with 6-percent citrate contained significantly higher levels of factors V, VIII, and IX than the samples anticoagulated with 8-percent citrate (p<0.0001, p< or =0.0001 and p = 0.009, respectively). The citrate concentration had no influence on the levels of fibrinogen, factor VII, antithrombin, or tissue-type plasminogen activator. There was no evidence that the plasma samples containing lower citrate concentrations were more prone to activation of hemostasis or fibrinolysis.

CONCLUSION

A reduction in the final citrate concentration of plasma collected by automated plasmapheresis results in higher yields of factors V, VIII, and IX without activation of hemostasis. More comprehensive studies should confirm previous work dealing with the establishment of the lowest citrate concentration acceptable in plasma used as therapeutic fresh-frozen plasma or as starting material for the manufacture of plasma derivatives.

Risks, costs, and alternatives to platelet transfusions

The use of platelet transfusions has increased greatly in the past decade and is likely to continue to escalate because of the risks of thrombocytopenia in patients receiving dose-intensive cancer chemotherapy, the increased use of hematopoietic progenitor cell transplantation, and the prevalence of human immunodeficiency virus infection. Despite marked advances in procedures for ensuring the safety of platelets, including intensive donor screening, infectious disease marker testing, and increased use of leukodepletion techniques, platelet transfusions carry a significant risk for immunologic disorders and transmission of bacterial, viral, and perhaps other diseases and can entail a very high cost. In addition, thrombocytopenia has the potential to interfere with delivery of chemotherapy on schedule and at the planned doses, thus potentially compromising treatment outcome. The limitations of platelet transfusions have prompted the development of agents with the potential to stimulate platelet production and thus reduce or eliminate the need for transfusions. Two such agents, interleukin-11 (IL-11) and thrombopoietin (TPO), have demonstrated promise in clinical trials. In November, 1997, IL-11 received FDA approval for the prevention of severe thrombocytopenia in high risk patients receiving myelosuppressive chemotherapy. Thrombopoietic growth factors have the potential to greatly simplify and increase the safety of transfusion medicine.

An analysis of blood management in patients having a total hip or knee arthroplasty

Three hundred and thirty orthopaedic surgeons in the United States participated in a study of transfusion requirements associated with total joint arthroplasty. A total of 9482 patients (3920 patients who had a total hip replacement and 5562 patients who had a total knee replacement) were evaluated prospectively from September 1996 through June 1997. Of those patients, 4409 (46 percent [57 percent of the patients who had a hip replacement and 39 percent of the patients who had a knee replacement]) had a blood transfusion. Two thousand eight hundred and ninety patients (66 percent) received autologous blood, and 1519 patients (34 percent) received allogenic blood. Ordered logistic regression analysis showed the most important predictors of the transfusion of allogenic blood to be a low baseline hemoglobin level and a lack of predonated autologous blood. Preoperative donation of autologous blood decreases the risk of transfusion of allogenic blood; however, inefficiencies in the procedures for obtaining autologous blood were identified. Sixty-one percent (5741) of the patients had predonated blood for autologous transfusion, but 4464 (45 percent) of the 9920 units of the predonated autologous blood were not used. Primary procedures and revision total knee arthroplasty were associated with the greatest number of wasted autologous units. Of the 5741 patients who had predonated blood, 503 (9 percent) needed a transfusion of allogenic blood. The frequency of allogenic blood transfusion varied with respect to the type of operative procedure (revision total hip arthroplasty and bilateral total knee arthroplasty were associated with the highest prevalence of such transfusions) and with a baseline hemoglobin level of 130 grams per liter or less. Transfusion of allogenic blood was also associated with infection (p < or = 0.001), fluid overload (p < or = 0.001), and increased duration of hospitalization (p < or = 0.01). These latter findings warrant further evaluation in controlled studies.

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.

The impact of risk information on patients' willingness to pay for autologous blood donation

OBJECTIVES

For contingent valuation to provide valid values for policy making, it is important that respondents be well informed about the goods they are asked to value. Few studies, however, have tested the impact of providing this information This study assessed the impact of risk information on patients' willingness to pay for autologous blood donation and derived the willingness to pay in a sample of informed patients.

METHODS

Patients were randomized either to receive information about the risks of complications from allogeneic (volunteer) blood transfusions or to base their willingness to pay responses on their own prior knowledge. Four hundred twelve autologous blood donors were recruited from three study sites. Self-administered questionnaires collected information on willingness to pay, risk perceptions, and socioeconomic information.

RESULTS

As predicted by our theoretical model, providing risk information reduced the variance in the willingness to pay for autologous blood donation. A tendency for information to reduce the willingness to pay was also found, suggesting that uninformed patients, on average, overestimate the risks of allogeneic blood transfusions. The median willingness to pay in the informed sample was approximately $750 to $1,100, depending on the estimation method, compared with $800 to $1,900 in the uninformed group. Willingness to pay was significantly related to perceived transfusion risk, personal income, and dread of transfusions.

CONCLUSIONS

Our results are consistent with an economic model where individuals update their prior risk perceptions with new information. The willingness to pay in the informed sample was far higher than the costs of autologous blood donation, suggesting that total benefits outweigh the costs of the procedure.

AUTOLOGOUS TRANSFUSION AFMC EXPERIENCE (1992-1996)

In this era of Acquired Immune Deficiency Syndrome (AIDS) and other infectious diseases - complications of homologous blood transfusion, autologous transfusion is the safest possible blood for transfusion. The present study was conducted from January 1992 to August 1996 to analyse the programme of autologous transfusion. A total of 471 pre-operative autologous collections were undertaken out of a total of 27,542 blood collections during this period. The present study shows a significant increase in autologous collections from 0.44 per cent in 1992 to 3.94 per cent till August 1996. 37.1 per cent autologous donors were from the urosurgery ward. Of the total 471 autologous blood units collected, 171 were transfused to the autologous donors (27.5%).

The use of acute hemodilution in parturients undergoing cesarean section

OBJECTIVE

Concern over transmissible disease has increased interest in methods of minimizing homologous blood transfusion during elective surgery. One method is acute hemodilution, a technique previously unreported in parturients. This study was designed to determine its feasibility and safety in women at risk of hemorrhage during cesarean section.

STUDY DESIGN

This technique was performed on 38 parturients. Collected blood was retransfused at the end of surgery or earlier, if required. Hemoglobin was measured before hemodilution, after hemodilution, before transfusion, after transfusion, and 24 hours postoperatively. Neonatal assessment included umbilical blood gases and Apgar scores.

RESULTS

All patients were hemodynamically stable and no fetal heart rate abnormalities were observed during the procedure. One patient received homologous blood and 14 received previously donated autologous blood. Umbilical blood gases were normal and 5-minute Apgar scores were > or = 7.

CONCLUSION

This study suggests that acute hemodilution is well tolerated in parturients undergoing cesarean section. This may limit exposure to homologous blood transfusion.

Blood substitutes: evolution and future applications

The development of oxygen-carrying blood substitutes has progressed significantly in the last decade with phase I and phase II clinical trials of both hemoglobin-based and perfluorocarbon-based oxygen carriers nearing completion. As these products approach clinical use it is important for the laboratory medicine community to be aware of their effects on routine laboratory testing and the settings in which they might be used. Here we review the forces driving the development of oxygen-carrying blood substitutes, the clinical settings in which they might be used, the major categories of oxygen carriers in clinical trials, and the challenges faced by these products as they approach clinical use.

The Bridgeport Hospital experience with autologous transfusion in orthopedic surgery

The transfusion records of 341 orthopedic patients who donated blood preoperatively in the years 1992 and 1993 were audited to review the transfusion practices associated with the surgical procedures. The study sample underwent 182 total knee (TKA), 123 total hip (THA) arthroplasties, and 33 laminectomies with fusion (LAM) and 3 without. Data used were age, gender, predonation hemoglobin concentration (Hbd), initial (Hbi) and final (Hbf) hemoglobin concentration, surgical procedure, surgical blood order (SBO), and estimated blood loss (EBL). We analyzed for means and associations and differences between covariates. The means of EBL (mL), transfused units, donated units, Hbi, (g/dL), Hbd, and Hbf (g/dL) for the most common procedures were: TKA--272, 1.1, 2.1, 10.4, 13.9, and 10.1; THA--951, 2.3, 2.4, 9.4, 13.8, and 9.9; and LAM--589, 1.5, 2.2, 12.0, 14.6, and 11.2. Phlebotomies for procedures with minimal blood loss, as for total knee arthroplasties, result in wastage. Autodonation under such circumstances takes patients to an unnecessary low hemoglobin concentration prior to either retransfusing the blood taken or discarding part of it. The number of preoperative autologous units donated can be reduced if predonation hemoglobin concentration is > 15 g/dL and expected blood loss is not > 2 g.

A pilot study of continuous ambulatory electrocardiography in patients donating blood for autologous use in elective coronary artery bypass grafting

BACKGROUND

A pilot study was conducted to evaluate the impact of a single autologous blood donation on the presence or absence of myocardial ischemic episodes in patients with coronary artery disease.

STUDY DESIGN AND METHODS

Fifty patients scheduled for elective coronary artery bypass grafting underwent two 24-hour periods of ambulatory electrocardiogram monitoring, one before and one after their first autologous blood donation. The presence or absence and the number, duration, and integral area of episodes of ST segment depression for each 24-hour monitoring period were determined.

RESULTS

Forty-two patients had legible electrocardiogram recordings for both monitoring periods. Of these, 36 patients (86%) had at least one episode of ST segment depression during any monitoring period. The number of patients who had at least one episode of ST segment depression before donation was not significantly different from the number of those who had at least one episode after donation (31 and 33 patients, respectively; p = 0.73).

CONCLUSION

Donating a unit of blood had no demonstrable effect on the presence or absence of myocardial ischemic episodes in this sample of 42 autologous blood donors with coronary artery disease. The results of this study should be validated in further trials.

Patients' willingness to pay for autologous blood donation

Most cost-effectiveness analyses of autologous blood donation show very small health benefits for a substantial increase in resource utilization. However, these analyses do not consider the psychological benefits of peace of mind to patients participating in the program. In order to quantitate these benefits, we employed contingent valuation methodology to measure the willingness of patients undergoing elective surgery, to pay for autologous blood donation. The internal consistency of patient responses was investigated through correlations of willingness-to-pay values with risk perceptions and patient characteristics. Two hundred and thirty-five patients completed the self-administered questionnaire which included demographic, willingness-to-pay and risk perception questions. Median population willingness to pay for autologous blood donation was approximately $900 per patient. In multivariate analysis, willingness to pay varied significantly with dread of allogenic transfusion, perceived risk of requiring a blood transfusion and income. Patients who participate in autologous blood donation programs value the procedure highly and state they are willing to pay significant amounts out of pocket to assure themselves of available autologous blood. Willingness to pay correlated significantly with factors expected to influence value decisions.

Photochemical and photophysical studies of 3-amino-6-iodoacridine and the inactivation of lambda phage

The photochemistry and photophysics of 3-amino-6-iodoacridine (Acr-I) was studied. Photolysis (350 nm) of Acr-I (free base) generates products consistent with a free radical intermediate in methanol, benzene and carbon tetrachloride. The Acr-I hydrochloride is shown to bind to calf thymus DNA and to the self-complementary dinucleotide cytidylyl-(3'-5')-guanosine (CpG) miniduplex in a manner similar to that of proflavine (Acr-NH2), a known DNA intercalator. The Acr-I is shown to more efficiently nick supercoiled plasmid DNA pBR322 upon 350 nm or 420 nm photolysis than Acr-NH2. The efficiency of Acr-I-sensitized DNA nicking is not oxygen dependent. Photolysis of the Acr-I/(CpG)2 complex leads to cleavage of the dinucleotide and to cytidine base release by selective damage to a specific ribose moiety. Dinucleotide cleavage occurs equally well in the presence or absence of oxygen, thereby eliminating a singlet oxygen- or peroxyl radical-mediated process. Photolysis of Acr-I in the presence of a mononucleotide (GMP) or a non-self-complementary dinucleotide (uridylyl-[3'-5']-cytidine-UpC) does not lead to fragmentation and base release. Similarly, photolysis of the Acr-NH2/(CpG)2 complex does not lead to fragmentation and base release. The data indicate that photolysis of an iodinated intercalator bound to CpG or plasmid DNA generates an intercalated aryl radical and that the reactive intermediate initiates a sequence of reactions that efficiently nick nucleic acids. The inactivation of lambda phage sensitized by Acr-I with UV (350 nm) light is oxygen independent but with visible (420 nm) light is strongly oxygen dependent. The Acr-I fluoresces more intensely when excited at 446 than at 376 nm. Thus, UV photolysis may lead to C-I bond homolysis and free radical formation, a process that is not energetically feasible with visible light. The results demonstrate the difficulty of extrapolating model studies involving simple molecules and DNA to understanding the mechanism of viral inactivation with a particular sensitizer.

Improving the efficacy of preoperative autologous blood donation in patients with low hematocrit: a randomized, double-blind, controlled trial of recombinant human erythropoietin

The effects of therapy with recombinant human erythropoietin (Epoetin alfa) on erythropoiesis, preoperative autologous blood donation, and risk of exposure to allogeneic blood were evaluated in 204 patients scheduled to undergo elective orthopedic surgery. Study protocol required patients to have a baseline hematocrit < or = 39% and surgery scheduled 25-35 days in advance. Patients were randomized to two equal groups and were seen at study centers every 3-4 days within the 21-day trial period. At each visit, phlebotomy(< or = 450 mL) was performed if the hematocrit was > or = 33%, and Epoetin alfa (600 U/kg) or placebo was administered intravenously. A total of 173 patients were assessable; 31% of placebo recipients and 20% of Epoetin alfa recipients required allogeneic transfusion (p = 0.09). Logistic regression modeling showed that the risk of allogeneic transfusion was reduced by Epoetin alfa (p = 0.025). When patients receiving > 6 units of blood (necessitating allogeneic units) were excluded from analysis, 29% of placebo recipients and 14% of Epoetin alfa recipients were exposed to allogeneic blood (p = 0.015). Epoetin alfa recipients predonated more autologous units than did placebo recipients (4.5 vs 3.0 units, respectively; p < 0.001), and their production of red blood cells increased significantly more over baseline production values (668 vs 353 mL, respectively; p < 0.05). These results demonstrate that administration of Epoetin alfa stimulates erythropoiesis, allows predonation of more units of autologous blood, and reduces the risk of exposure to allogeneic blood. Optimal dosing regimens and surgical patients most likely to benefit fro Epoetin alfa therapy must be established.

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.

Drugs affecting hemostasis

Most patients admitted to the PACU are closely observed for postoperative bleeding. Although some bleeding is to be expected, some patients may have alterations in the hemostatic process leading to excess blood loss. Hemostasis can be intentionally altered by drugs given preoperatively and/or intraoperatively. The effects of these drugs may contribute to the postoperative blood loss. This article reviews the normal hemostatic process as a foundation for discussing the commonly used drugs affecting hemostasis.

Blood substitutes: fluids, drugs, or miracle solutions?

Oxygen-carrying volume-expanding solutions that can sustain life in the absence of red blood cells have been developed. Concerns about side effects, sources of hemoglobin, and the ultimate demonstration of efficacy will have to be satisfactorily addressed before anesthesiologists routinely administer such solutions in place of red cells during surgery.

Allogeneic transfusion risks in the surgical patient

The risk of blood transfusion-associated complications has been reduced in the past 10 years through technical advances in testing of blood, viral inactivation of noncellular blood components, enforcement of stringent donor selection criteria, and the use of alternatives to allogeneic transfusion. Even so, a zero-risk blood supply is unfeasible. The general public perceives infectious complications to be the most significant risk: although the greatest fear is associated with transmission of human immunodeficiency virus (HIV), at least three hepatitis viruses are transmissible by all blood components. Human immunodeficiency virus accounts for < 20 cases per year of transfusion-related acquired immunodeficiency syndrome in the United States. The three important noninfectious complications are alloimmunization, which is common but clinically insignificant; immunosuppression, the clinical significance of which is controversial; and graft-versus-host disease, a lethal complication most likely to affect patients who are immunosuppressed, have cancer, or are recipients of bone marrow transplants.

Collection and transfusion of blood and blood components in the United States, 1992

BACKGROUND

Studies were conducted to measure the state of the United States' national blood resource in 1992 and changes therein from 1989.

STUDY DESIGN AND METHODS

With data supplied by the American Red Cross and the American Association of Blood Banks, as well as data from a stratified random-sample survey of 3350 non-American Association of Blood Banks hospitals, statistical methods were applied to estimate national blood activities in 1992.

RESULTS

The total US blood supply in 1992 was 13,794,000 units, a decrease of 3.1 percent from 1989. Some 11,307,000 red cell units were transfused to 3,772,000 patients, an average of 3.0 units per transfused patient. Preoperative autologous blood deposits totaled 1,117,000 units, a 70-percent increase over 1989. Of this number, 566,000 units (50.7%) were transfused, 5,000 (4.4%) transferred to the allogeneic supply, and 546,000 (48.9%) discarded. Of 436,000 directed-donation units, 136,000 (31.2%) were transfused, 57,000 (13.1%) transferred to allogeneic supply, and 243,000 (55.7%) discarded. The total allogeneic blood supply, including imports, decreased by 7.4 percent from 1989, and allogeneic blood transfusions, including those to children, decreased by 8.6 percent. Over 8,300,000 platelet units were transfused; of these, some 3,600,000 were apheresis platelets. In addition, 2,255,000 units of plasma and 939,000 units of cryoprecipitate were transfused.

CONCLUSION

While the US blood supply was adequate for transfusion needs in 1992, blood collections and red cell transfusions had decreased substantially since 1989.

A model for predicting transfusion requirements in head and neck surgery

INTRODUCTION

Although allogeneic blood transfusions have allowed surgeons increased latitude in resecting advanced cancers, they can cause significant morbidity or even death in rare instances. Potential side effects may include transmission of infection and immunosuppression leading to an increased risk of cancer recurrence. Because patients have become more reluctant to receive transfusions, they frequently request preoperative autologous blood donation (PABD). In practice, however, only 50% or less of the donated blood is ultimately transfused while the remainder is discarded.

PURPOSE

The purpose of this study was to develop a transfusion prediction and risk assessment (TPRA) model for predicting the need for perioperative blood transfusions in patients undergoing major head and neck oncologic surgical procedures. By knowing the probability for blood transfusion, the physician and patient can make an educated decision regarding the need for PABD.

PATIENTS AND METHODS

Over a 4-year period, 436 patients underwent major head and neck surgical procedures for neoplasms of the upper aerodigestive tract, the thyroid gland, and the salivary glands. Data obtained prospectively on each patient included age and gender, the TNM stage, primary disease site, type of prior treatment, estimated intraoperative blood loss, duration of surgery, transfusion requirements, preoperative and postoperative hemoglobin and hematocrit levels, type of procedure and method of reconstruction. These variables were examined singly and in combination both for descriptive purposes and to evaluate their interrelationships. In order to develop the TPRA model, only the 12 variables available prior to the surgical procedure were examined. Variables associated with transfusion need were evaluated further in a multivariate analysis. The logistic regression model allowed a linear expression of patient characteristics to be related to a function of the probability of transfusion need. Analyses of association between categorical variables and transfusion status were based on chi-squared, Fisher's Exact, and Mann-Whitney U tests.

RESULTS

Overall, 51 (11.7%) patients required blood transfusions. The median number of units transfused was 2.0 (range, 1 to 13 U). Univariate analysis demonstrated a higher probability for blood replacement in patients with oropharyngeal or hypopharyngeal primary tumor sites, a preoperative hemoglobin level below normal, prior chemotherapy, composite resection, flap reconstruction, between 50 and 59 years of age, and T3 or T4 tumor stage. Logistic regression analysis demonstrated that the need for flap reconstruction, a preoperative hemoglobin below the normal level, and T3 or T4 primary stage were the three factors most significantly associated with the need for transfusion (P < .03). Based on eight combinations of these three variables, transfusion risk predictions were obtained. The TPRA model predicted that patients with a normal hemoglobin level who did not require flap reconstruction and did not have either a T3 or T4 primary stage tumor had the lowest probability (.02) for requiring blood transfusion. Patients at highest risk (.65) were those with less than a normal hemoglobin level, who required flap reconstruction, and had T3 or T4 primary tumor stage. Based on the TPRA model, an algorithm was developed which could serve as a guideline for preoperative transfusion planning.

CONCLUSION

By using the TPRA model to change guidelines for preoperative transfusion planning, costs can theoretically be reduced by 50% without significantly increasing the risk of exposing patients to allogeneic blood transfusion. If the TPRA model proves accurate in a follow-up study to test its validity, it may have clinical utility for aiding the surgeon in more cost-effective transfusion planning.

Use of autologous blood in support of orthopaedic surgery using a hospital-based autologous donor programme

The use of autologous blood in support of orthopaedic surgery has been assessed for 296 patients; 150 underwent hip arthroplasty, 69 underwent knee arthroplasty, 37 underwent spinal procedures and 40 underwent miscellaneous operations. Overall, 87% of patients received no allogeneic blood and 23% of the autologous blood collected was not used. For hip and knee arthroplasty, there appears to be an increased willingness to transfuse patients when autologous blood is available, and a decreased proportion of patients receiving more than 3 units for hip arthroplasty and 2 units for knee surgery, when compared with an audit of blood use when almost all blood used was allogeneic. Wastage of autologous blood in support of spinal surgery was 66%, prompting a review of ordering practices. Assessment of avoidance of allogeneic transfusion by the standard schedule of 3 units for hip arthroplasty and 2 units for knee arthroplasty appears justified by the calculation that collection of an additional unit in each case would avoid allogeneic transfusion in 11 (5%) more patients with the unnecessary collection of 208 units.

Transfusion medicine in obstetrics and gynecology

Obstetricians and Gynecologists care for many patients with conditions potentially requiring blood transfusions. Cesarean section and hysterectomy are the two surgeries performed most frequently and both have the potential for blood loss requiring transfusion. Other examples include postpartum hemorrhage, placenta previa, and ruptured ectopic pregnancy. Obstetricians and gynecologists need to become knowledgeable about the ever-changing aspects of blood transfusion and apply it in their clinical practice. This review intends to update obstetricians and gynecologists and other health care professionals about the basic as well as the latest technologies of blood transfusion. The different types of blood components are discussed including their preparation, indications, risks, and benefits. The complications of blood transfusion and their management are reviewed, including infections, noninfectious, and immunological etiologies. HIV and hepatitis are explored, these being the most serious infectious risks of transfusion. Autologous blood transfusion, an underutilized option, is examined. Hemodilution and intraoperative blood salvage, other techniques for using the patient's own blood, are discussed. Finally, synthetic agents such as erythropoietin, granulocyte colony-stimulating factors, factors, desmopressin acetate, gonadotropin-releasing hormone agonists, and new products are introduced as potential replacements to blood transfusion in the future.

The cost effectiveness of preoperative autologous blood donations

BACKGROUND

Since the recognition that human immunodeficiency virus is transmissible by blood transfusion there has been increasing public and professional support for autologous blood donations before elective surgery. Autologous blood donation is, however, a more expensive process than the donation of allogeneic blood by community volunteers. Furthermore, there have been recent improvements in the safety of the volunteer blood supply.

METHODS

We used a decision-analysis model to assess the cost effectiveness of donating autologous blood for four surgical procedures. Cost data were collected from the observation of transfusion practice at the University of California, Los Angeles, in 1992. Estimates of the risks of transfusion-associated diseases and the costs of treating them came from the medical literature. Cost effectiveness was expressed in dollars per quality-adjusted year of life saved. We performed sensitivity analyses of the variables in our model and examined the effect of strategies suggested to reduce costs.

RESULTS

Substituting autologous for allogeneic blood resulted in little expected health benefit (0.0002 to 0.00044 quality-adjusted year of life saved) at considerable additional cost ($68 to $4,783 per unit of blood). The additional cost of autologous blood was primarily a function of the discarding of units that were donated but not transfused and of a more labor-intensive donation process. The cost-effectiveness ratios ranged from $235,000 to over $23 million per quality-adjusted year of life saved.

CONCLUSIONS

Given the improved safety of allogeneic transfusions today, the increased protection afforded by donating autologous blood is limited and may not justify the increased cost.

Transfusion practice in urological surgery: modifications in association with the introduction of an autologous blood donor programme

The transfusion records of 122 urological patients who had deposited one or more units of autologous blood were analysed. The 95 patients undergoing radical prostatectomy were arbitrarily divided into two cohorts (the first 47 patients enrolled, and the last 48 enrolled) to assess changes in use of blood. The avoidance of allogeneic transfusion in radical prostatectomy was 64% in the first cohort studied, and increased to 81% in the second. There was a significant decline in the mean absolute amounts of blood used from 4.47 to 2.54 units per patient from the first to second cohorts. Introduction of an autologous blood donor programme has been associated with a reduction in total blood use for radical prostatectomy, and a decrease in the number of patients exposed to allogeneic blood. The validity of an autologous blood-order schedule of 3 units for radical prostatectomy is supported.

Efficacy and safety of plateletpheresis by donors with low-normal platelet counts

Our practice is to defer donors with blood platelet (PLT) counts of < 180 x 10(9)/L because PLT yields are low, when compared to PLT units collected from donors with higher counts. In an attempt to minimize deferral, we determined whether 33 donors, who repeatedly demonstrated low-normal PLT counts (150-180 x 10(9)/L) on multiple occasions during the prestudy period. might safely donate satisfactory apheresis PLT units simply by extending the apheresis collection time by 20 min (men) and 40 min (women). Repeat plateletpheresis procedures were scheduled at > or = 28-day intervals. The mean PLT yield (N = 92) was 5.8 x 10(11) with 97% of units containing > or = 4.0 x 10(11) PLTs. Although donors entered the study only after they had repeatedly exhibited predonation PLT counts of < 180 x 10(9)/L, PLT counts were not always below this level at the time of study collections. However, analyzing only donations with true predonation PLT counts of < 180 x 10(9)/L (N = 35), the mean PLT yield was excellent-5.4 x 10(11) with 97% of units containing > or = 4.0 x 10(11) PLTs. The average fall in donor blood PLT counts (pre-vs. postdonation) was 36%, with only ten of 99 postdonation counts being < 100 x 10(9)/L; the lowest was 69 x 10(9)/L. Thus, extending the apheresis collection time permitted donors who in the past were routinely deferred because of low PLT counts to safely donate satisfactory PLT units.

Collection of autologous blood before elective hip replacement. A comparison of the results with the collection of two and four units

The need for allogeneic blood can be reduced effectively with the use of preoperatively donated autologous blood. However, this collection also results in the waste of autologous blood in a considerable number of patients. In order to reduce overcollection, we requested that the amount of autologous blood donated before a total hip replacement be decreased from four units to two units. We then compared the amount of allogeneic blood required for fifty patients who had donated two units of autologous blood with that of fifty historical controls who had donated four units. The patients were matched for sex, initial hemoglobin concentration, and blood loss. There was no significant difference in the percentage of autologous donors who received additional allogeneic blood; 20 per cent (ten) of the patients who had donated two units and 16 per cent (eight) of the patients who had donated four units required allogeneic blood (p = 0.12). Eighteen autologous units from the patients who had donated two units and fifty-one units from the patients who had donated four units were discarded. The erythropoietic response, measured by the increase in the reticulocyte count, was comparable for the two groups. Iron stores, measured as the serum ferritin concentration, were lower after the drawing of four units (33 +/- 39 micrograms per liter) compared with after the drawing of two units (49 +/- 29 micrograms per liter) (p = 0.03). The donation of two units of blood does not increase the exposure to allogeneic blood compared with the exposure after the donation of four units by patients who are going to have a total hip replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Two-years' experience with a Canadian hospital-based autologous blood donor programme

Two years' experience with a hospital-based autologous blood donor programme is described. Of 511 patients enrolled, 86% underwent surgery without use of allogeneic blood, and 19% of collected units were not used. For six common procedures, a 'target' autologous blood schedule of 2 or 3 units (depending on the procedure) was set. If an extra unit for each of 407 patients had been collected (i.e. 3 or 4), an additional 20 patients would have been protected from exposure to allogeneic blood at a cost of 387 unnecessary collections. The difference between the mean haemoglobin (Hb) concentration at entry to the programme and the mean pre-operative Hb concentration was not clinically important and only 25 of 511 patients were deferred on account of anaemia after one or more donations. The autologous blood used represents 3.8% of the units of blood or packed red blood cells transfused during the 2 years of study. Adverse (vasovagal) reactions were infrequent (2.2%) in spite of liberal acceptance criteria.

Red blood cell transfusions for total hip replacement in a regional hospital. A six-year analysis

To evaluate changes in the need for homologous blood and to assess the impact of autologous blood transfusion, red cell transfusions in unilateral total hip replacement surgery, performed electively in the period 1986-1991, were studied in a regional hospital. Transfusion data, perioperative blood loss and post-operative haemoglobin concentration of 495 patients were analysed. From 1986 to 1991, the percentage of patients not transfused with homologous blood increased from 18.5 to 45.5%. After the introduction of an autologous blood transfusion programme in 1987, 116 of 430 patients (27.0%) donated autologous blood. No increase in the percentage of autologous donors was observed during the study. Most common reasons for nonparticipation were the patient's age, doctors' underordering and logistic limitations. 81.9% of autologous donors had total hip replacement surgery without homologous transfusions. Mean blood loss reduced significantly from 1,373 +/- 781 ml in 1986 to 958 +/- 582 ml in 1991 (p < 0.001). Transfusion requirement in the nonautologous patients fell from 2.6 +/- 1.8 units in 1986 to 1.4 +/- 1.4 units per patient in 1989 and increased thereafter to 2.2 +/- 2.1 units in 1991 (p < 0.01) and showed a strong correlation with blood loss (r = 0.58; p < 0.001). No changes in postoperative haemoglobin concentration were observed throughout the study. In conclusion, collection of autologous blood is effective, albeit still underutilized, to reduce homologous blood requirement. The close correlation between blood loss and transfusion requirement accentuates the role of surgical practice in the reduction of homologous transfusions.

Determinants of physician ordering of preoperative autologous donations

Preoperative autologous donation (PAD) is frequently utilized to reduce infectious disease transmission risks, but it is an expensive form of hemotherapy that is not always closely matched with the needs of the patients. We compared the use of PAD in an academic medical center with patient needs and then investigated the efficacy of a simple intervention to promote targeting of PAD toward patients most likely to benefit from having PADs available. Over a 3-month period, surgeons whose patients received allogeneic components were asked to complete a questionnaire designed to identify reasons for not ordering PAD. PAD units were used in 14 (11%) of 124 cases, accounting for 6% of perioperative red cell use. The responses (46, 42% of the surveys sent) stated that PAD had not been ordered because of time constraints (39%), medical problems (26%), anemia (15%), and lack of expectation of blood use (24%). Chart review documented the presence of cited conditions in 88% of cases. Logistic and cost concerns were not evident. However, only 8% of the 176 PAD units collected in that period were transfused. Following dissemination of PAD ordering guidelines, this proportion rose to 52% without a reduction in the proportion of elective surgical cases utilizing autologous transfusion. This improvement in ordering practice was maintained over at least in 5-month period. Thus we were able to improve the efficiency of PAD application (reducing over-ordering) through a simple feedback to surgeons that assisted them in targeting PAD toward patients most likely to need transfusion.

Oxygen carriers and transfusion medicine

The US blood supply is once again expanding (14 million units a year) and annual estimated whole blood and red blood cell (RBC) transfusion now exceeds 12 million units. The observed increase in total transfusions and units transfused per surgical procedure may result from more aggressive therapies, an aging population, and improved access to health care. While autologous blood collection has grown 20-fold in the past decade, autologous blood still accounts for < 8% of transfusions and is unlikely to replace much more of the allogeneic transfusion needs. Although safer than ever, allogeneic blood still transmits infectious disease (HIV:1 in 225,000 units, hepatitis:1 in 3300 units, HTLV I/II:1 in 50,000 units) and poses additional immunologic and non-immunologic risks. Allogeneic RBCs are probably underutilized because of safety concerns. While the cost of a unit of RBCs has been estimated at $150, costs are substantially higher in some areas and blood processing (filtration, gamma irradiation, washing) add additional expense. The narrowing margin between supply and demand, and repeated regional blood shortages argue for the value of safe, effective oxygen carriers.

Trauma and military applications of blood substitutes

PURPOSE

To review potential clinical uses of erythrocyte substitutes in treating military battlefield casualties, with specific emphasis on combat injury rates and wounding patterns, resuscitation doctrine and logistic requirements.

METHODS

Review of published medical literature and of unclassified documents from the U.S. Armed Forces Blood Program.

RESULTS

Hemorrhage is the leading cause of death on the battlefield. Early intervention, with definitive treatment, could save up to 30% of soldiers who are killed in action or who die of wounds. Hemorrhage control and rapid volume expansion in appropriate casualties are the main priorities in pre-hospital resuscitation of battlefield casualties. The role for oxygen-carrying fluids in the initial management of military injuries is undefined; however, erythrocyte substitutes could reduce the logistic requirements for blood in field hospitals. In recent wars, outdating of stored blood resulted in 60-95% of units being discarded: 60% of 1.3 million units in Vietnam and 95% of 120,000 units in the Persian Gulf War.

CONCLUSIONS

Safety, long storage life, light unit weight, and tolerance to environmental extremes are all characteristics that are necessary for erythrocyte substitutes to extend or replace the use of stored blood in treating battlefield casualties.