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Biomedical subjects

E L Wallace

Publications and source records attributed to E L Wallace.

At least 19 recordsLinked to original sources

Computer-assisted audiovisual health history self-interviewing. Results of the pilot study of the Hoxworth Quality Donor System.

BACKGROUND: The safety of blood for transfusion depends, in part, on the reliability of the health history given by volunteer blood donors. To improve reliability, a pilot study evaluated the use of an interactive computer-based audiovisual donor interviewing system at a typical midwestern blood center in the United States. STUDY DESIGN AND METHODS: An interactive video screening system was tested in a community donor center environment on 395 volunteer blood donors. Of the donors using the system, 277 completed surveys regarding their acceptance of and opinions about the system. RESULTS: The study showed that an interactive computer-based audiovisual donor screening system was an effective means of conducting the donor health history. The majority of donors found the system understandable and favored the system over a face-to-face interview. Further, most donors indicated that they would be more likely to return if they were to be screened by such a system. CONCLUSION: Interactive computer-based audiovisual blood donor screening is useful and well accepted by donors; it may prevent a majority of errors and accidents that are reportable to the FDA; and it may contribute to increased safety and availability of the blood supply.

Attitude to Computers↗

The specific hospital significantly affects red cell and component transfusion practice in coronary artery bypass graft surgery: a study of five hospitals.

BACKGROUND: Interhospital differences in blood transfusion practice during coronary artery bypass graft (CABG) surgery have been noted, but the underlying issues have not been identified. STUDY DESIGN AND METHODS: Records of 3217 consecutive CABG cases in five university teaching hospitals in 1992 and 1993 were stratified by hospital, type of revascularization conduit, patients' sex, and other factors. Statistical methods were used to compare patient characteristics, transfusion outcomes, and hospital outcomes. RESULTS: Forward two-step logistic regression using patient likelihood of red cell transfusion factors in the first step and the specific hospital in the second step revealed a significant effect of hospital on the delta odds ratios for red cell transfusion. This finding was confirmed by analyses of a highly stratified subset of cases, males in diagnosis-related group 107 (primary cases of coronary bypass without coronary catheterization) who underwent revascularization with venous and internal mammary artery grafts, revealing variations among hospitals from 109 to 457 units of red cells transfused per hundred cases. Corresponding variations in transfusions of all blood components were from 324 to 1019 units by hospital. Variation in red cell transfusion practice among surgeons in the same hospital was not responsible for these interhospital differences. CONCLUSION: The effect of the specific hospital on transfusion practice is attributed to institutional differences that, through reasons of training or hierarchy, become ingrained in hospitals.

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The Collaborative Hospital Transfusion Study: variations in use of autologous blood account for hospital differences in red cell use during primary hip and knee surgery.

BACKGROUND: Red cell use in patients undergoing Diagnosis Related Group (DRG) 209 procedures (major joint and limb reconstruction procedures of the lower extremities) has been shown to have large, unexplained interhospital variations. STUDY DESIGN AND METHODS: Abstracted records of 2590 consecutive DRG 209 patients at five university hospitals from January 1992 to December 1993 were stratified by procedure and preoperative blood deposit status. Patient characteristics and transfusion and in-hospital outcomes were compared across hospitals. RESULTS: Blood use among patients who did not preoperatively deposit blood was similar across hospitals. Significant differences were found across hospitals for total hip replacement patients in the percentage of patients preoperatively depositing blood (59-80%), percentage of patients receiving transfusion(s) (51 to > 99%), the mean number of units collected per patient (1.6-2.9), and the mean number of unused autologous units per 100 patients (1-185). No significant differences were found in the percentage of those who deposited blood and then required allogeneic units. There was little variability in length of hospital stay or in last hematocrits. Findings were similar for total knee replacement patients. CONCLUSIONS: Interhospital variations in red cell use for primary total hip and knee reconstruction are primarily due to hospital-specific differences in autologous blood collection and transfusion.

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Collection and transfusion of blood and blood components in the United States, 1994.

BACKGROUND: Collections and transfusions of blood in the United States in 1994 were measured and compared with those in 1992. STUDY DESIGN AND METHODS: Completed survey questionnaires were returned by all 147 regional blood centers, 1340 American Association of Blood Banks (AABB) member hospitals, and 523 non-AABB hospitals. Statistical tests verified the representativeness of the sample. RESULTS: The United States domestic blood supply in 1994 (13,340,000 units) was 3.3 percent less than in 1992. It included allogeneic blood (11,773,000 units), autologous blood (1,013,000 units), and directed donations (334,000 units). Of these, 432,000 units were rejected on testing, 11,107,000 units were transfused to 3,398,000 patients, and 1,801,000 units were discarded or unaccounted for. Platelet transfusions amounted to 7,866,000 units. Compared with the totals for 1992, transfusions of single-donor platelets (714,000 packs or 4,284,000 units) increased by 17.6 percent, while transfusions of platelet concentrates (3,582,000 units) fell by 23.6 percent. Fresh-frozen plasma transfusions (2,621,000 units) increased by 16.2 percent over the number for 1992. CONCLUSIONS: The US blood collection rate in 1994 was 74.6 units per 1000 population of donor age, the lowest recorded level since 1971. The US RBC transfusion rate in 1994 was 42.8 units per 1000 population, about the same as 1979. Transfusions of single-donor platelets, 16.5 units per 1000 population, exceeded transfusions of platelet concentrate (13.8/1000) for the first time. Plasma transfusions were 10.1 units per 1000 population. The US blood supply in 1994 was adequate to meet patient demands.

Blood Banks↗

Determinants of red cell, platelet, plasma, and cryoprecipitate transfusions during coronary artery bypass graft surgery: the Collaborative Hospital Transfusion Study.

BACKGROUND: Very little is known about the determinants of blood transfusions in patients undergoing coronary artery bypass graft surgery. STUDY DESIGN AND METHODS: To identify factors that influenced the transfusion of red cells, platelets, plasma, and cryoprecipitate, statistical methods were used to study 2476 consecutive diagnosis-related group 106 and 107 patients in five teaching hospitals who underwent coronary artery bypass surgery between January 1, 1992, and June 30, 1993. RESULTS: The likelihood of red cell transfusion was significantly associated with 10 preoperative factors: 1) admission hematocrit, 2) the patient's age, 3) the patient's gender, 4) previous coronary artery bypass surgery, 5) active tobacco use, 6) catheterization during the same admission, 7) coagulation defects, 8) insulin-dependent diabetes with renal or circulatory manifestations, 9) first treatment of new episode of transmural myocardial infarction, and 10) severe clinical complications. Platelet and/or plasma transfusions were strongly associated with the dose of red cells transfused. Transfusion requirements and other in-hospital outcomes were associated with patient characteristics, surgical procedure (reoperation vs. primary procedure), and the conduits used for revascularization (venous graft only, venous and internal mammary artery graft, or internal mammary artery graft only). Blood resource use and donor exposures were evaluated with respect to the risk to patients of contracting hepatitis C virus and human immunodeficiency virus infections. CONCLUSION: The classification of coronary artery bypass graft patients on the basis of attributes known preoperatively and by conduits used yields subsets of patients with distinctly different transfusion requirements and in-hospital outcomes.

Age Factors↗

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.

Blood Banks↗

Blood product utilization in hip and knee arthroplasty: effect of gender and autologous blood on transfusion practice.

Analysis of total blood product support for a 1-year cohort of patients undergoing hip or knee total joint arthroplasty showed significant differences in transfusion therapy between patients who predeposited autologous blood and those who did not. In primary joint arthroplasty, 51% of nonpredepositing patients undergoing hip replacement and 28% of nonpredepositing patients undergoing knee replacement required red cell transfusions. In revision procedures, 58-61% were transfused. Predepositors requiring only autologous blood received less blood per patient than nonpredepositors; however, 73-87% of primary and 86-88% of revision arthroplasty patients were transfused. Predepositors receiving supplemental allogeneic blood used a volume of red cells comparable to nonpredepositing patients, which was significantly greater than the red cell requirement of predepositors using only autologous blood. Moreover, regardless of predeposit status, the extent of red cell replacement differed between men and women. Male patients presented with significantly higher hematocrits and were less likely to be transfused than females undergoing the same procedure. However, once the transfusion-decision was made, the average amount of red cells given for each procedure did not show gender-related variation. Despite differences in admission and lowest observed hematocrits, all patients were discharged with hematocrits in the same range, suggesting that men were replaced with relatively less blood than women. These differences in transfusion practice relating to gender and predeposit status could not be associated with identifiable changes in clinical outcome which might provide rationale for the observed differences in practice.

Blood Transfusion↗

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

To probe recent trends in transfusion practice and their effect on the adequacy of the national blood resource, transfusions and collections in the United States in 1989 were studied, by using data shared by the American Association of Blood Banks, the American Red Cross, and the Council of Community Blood Centers, together with results from a sample survey of the 3600 hospitals that were not members of the national organizations. Statistical methods were used to estimate national activities. The total US supply of blood in 1989 was 14,229,000 units, an increase of 1.2 percent over the supply in 1987. Red cell transfusions were 12,059,000 units. A total of 3,159,000 patients underwent transfusion with whole blood and/or red cells (mean, 3.8 units/patient). Preoperative autologous deposits of 655,000 units by 310,000 patients represented an increase of 65 percent over the level in 1987. However, only 356,000 units (54%) were transfused to the patients who preoperatively deposited them; of the remainder, 13,000 units were crossed over for transfusion to other patients, while 286,000 units were never used. Directed donations, 350,000 units, were provided for 130,000 intended recipients, but only 97,000 units (28%) were transfused to their intended recipients; of the balance, 59,000 units (17%) were crossed over and 194,000 units (55%) were never transfused. Total platelet transfusions were equivalent to 7,258,000 units in 1989, for an increase of 13.7 percent over totals in 1987.

Blood Component Transfusion↗

Red cell transfusions in coronary artery bypass surgery (DRGs 106 and 107)

To study red cell transfusion practice in 3216 coronary artery bypass graft (CABG) cases in 11 hospitals in 1988, abstracted patient records were stratified by diagnosis related group (DRG) (that is, DRG 106, coronary artery bypass without catheterization, or DRG 107, coronary artery bypass with catheterization) and International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM) surgical procedure code. Means of units per transfused patient, age and length of stay, and in-hospital mortality rates were significantly greater for patients in DRG 106 than DRG 107. Gender was a significant factor for transfusion outcomes; female patients were more likely to undergo transfusion, and, when transfused, they received more units of red cells than male patients. For a given DRG/ICD-9-CM surgical procedure class, significant differences were found between hospitals in the percentage of patients transfused, but not in mean units of red cells per transfused patient. However, within individual hospitals, the proportion of patients transfused and the number of units per transfused patient did not vary significantly across DRG/ICD-9-CM procedure classes. These results suggest that circumstances operating within a hospital, still to be identified, had more influence on transfusion decisions than the nature of the surgical intervention.

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Costing blood products and services.

At present, blood centers and transfusion services have limited alternatives for offsetting the ever-rising costs of health care inputs. In the face of current revenue constraints, cost reduction or cost containment through efficiency improvements or service reduction is the principal available means. Such methods ought to be pursued vigorously by blood bankers with the aid of well-designed costing and other physical measurements systems. Experience indicates, however, that blood bankers, in their attempts to reduce or contain costs, are likely to place undue reliance on cost accounting systems as the means of capturing sought-for benefits. Management must learn enough about methods of costing to judge directly the uses and limitations of the information produced. Such understanding begins with recognition that all costs and cost comparisons should be specific to the purpose for which they are developed. No costing procedure is capable of producing measures generally applicable to all management decisions. A measure relevant to a planning decision is unlikely to be appropriate for performance evaluation. Useful comparisons among sets of organizations of costs, or of measures of physical inputs and outputs, require assurance that the methods of measurement employed are the same and that the sets of organizations from which the measures are drawn are reasonably comparable.

Blood Banks↗

Collection and transfusion of blood in the United States, 1982-1988.

Widespread concern about the safety of the national blood supply, particularly with respect to the human immunodeficiency virus (HIV), has reportedly affected the use of blood products to support patients. To examine these changes, we conducted national surveys of blood collection and transfusion in the United States in 1982, 1984, 1986, and 1987 and made a limited survey of these activities in 1988. Transfusions of whole blood and red cells reached a peak of 12.2 million units in 1986, then declined to 11.6 million units in 1987 and continued to decline in 1988. Transfusions of plasma declined from a peak of 2.3 million units in 1984 to 2.1 million units in 1987. Growth in the use of platelet transfusions (6.4 million units in 1987) also slowed; however, the proportion of platelets transfused as platelets from single donors grew from 11 percent in 1980 to 25 percent in 1987. Donations of autologous blood increased sharply, from less than 30,000 units in 1982 to 397,000 units in 1987, equivalent to 3 percent of the homologous-blood collections. The growth in collections of homologous blood slowed after 1982. The supply of homologous blood reached a peak of 13.4 million units in 1986 and did not grow between 1986 and 1988. These trends in red-cell, plasma, and platelet transfusions appear to have continued through 1988. We conclude that the unprecedented decline in transfusions of whole blood and red cells, coupled with the continued importation of packed red cells from Western Europe and the offsetting effect of autologous predeposits, forestalled serious shortages of blood that could have resulted from the decline in collections of homologous blood. We attribute these changes in blood collection and blood transfusion to the effects of the epidemic of HIV infection.

Blood Banks↗

Exposure of patients to human immunodeficiency virus through the transfusion of blood components that test antibody-negative.

The risk of transmission of the human immunodeficiency virus to recipients of blood transfusions exists chiefly during the period between the time a donor is infected and the time he or she has a positive blood test for HIV antibodies. Estimating the chance that blood will be donated during this period is an effective way to define the risk of HIV infection from transfusion. Using this approach, and employing data from over 17 million American Red Cross blood donations, we estimate that during 1987 the most likely number of units of blood infected with undetected HIV that were transfused was 131 (range, 67 to 227). For a patient, the odds of contracting HIV infection were 1:153,000 per unit transfused. A patient who received the average transfusion (5.4 units) had odds of 1:28,000. The risk has been decreasing by more than 30 percent a year. We estimate that donor-recruitment practices plus careful education and screening are eliminating 49 of every 50 donors likely to be HIV-positive and that testing is 92 to 97 percent effective, for a combined effectiveness of 99.9 percent. The risk of undetected infectious units can probably be further reduced by transfusing fewer units and units from fewer donors, recruiting more women and fewer men as new donors, and encouraging more frequent donations from donors who have been tested repeatedly.

AIDS Serodiagnosis↗

Effects of donor recruitment methods on population responses.

It is important to know the preferences of blood donors and nondonors as to 1) the method of contact of the prospective donor by the recruiter, 2) the character of the relationship between the recruiter and the recruit, 3) the recruitment message used by the recruiter, and 4) the logistics of the collection. Interviews with almost 2,000 blood donors and nondonors in the Buffalo region were done to provide information on these preferences. Results of the studies include evidence that face-to-face recruiting is over three times as effective as is recruiting by the telephone. the relationship between recruiter and recruit is important primarily to first-time donors. The recruitment message should include all of the reasons for donating. Replacement donors are a good source of future volunteers, and the logistics of blood collection, particularly selection of donor sites and overall time required to donate, are crucial in determining donor responses.

Blood Donors↗