ISSN:1075-2765    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:1075-2765    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Erythropoietin (EPO) is the primary regulator of red blood cell (RBC) production, and hypoxia is the main stimulus for EPO secretion. Increases in circulating levels of EPO are proportionate to the levels of tissue hypoxia, which are influenced by hematocrit (HCT). Small decreases in HCT as would be typical after presurgical autologous blood donation often do not result in increased EPO levels or in compensatory erythropoiesis. Erythropoiesis may also be limited by deficiencies of vitamin B12, folate, and, most commonly, iron. The preoperative administration of EPO is effective in increasing erythrocyte mass and autologous donation volumes while maintaining higher HCT levels. In some surgical populations, particularly those individuals who experience surgical blood losses in excess of 2 L, EPO treatment also reduces allogeneic blood exposure. This effect is prominent in patients with a low initial HCT. Current assessments of the cost-effectiveness of EPO suggest that it achieves little overall improvement in patient health and that what improvement it does offer, it does at enormous cost.

ISSN:1075-2765    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

A number of pharmacologic and nonpharmacologic technologies are in current use to minimize perioperative homologous blood use. Clinical trials, many of them randomized controlled trials, have been done evaluating these approaches and have demonstrated their efficacy. However, data on safety has relied mostly on case reports, uncontrolled studies, and, for the pharmacologic agents, extrapolation from the nonsurgical setting. In this review I analyze the data from the randomized trials and the lower-level evidence studies to provide the best estimates in safety with these alternatives. In general, these alternatives are safe with proper dosing and monitoring of effects. With aprotinin, the primary concern is anaphylaxis, and this predominantly with re-exposure. With aprotinin and with the anti-fibrinolytics, increased venous thromboembolic risk has not been a consistent finding. Tranexamic acid use intraoperatively is advantageous, but postoperative use appears to have no advantage and may be associated with renal dysfunction. DDAVP is low-risk, provided it is not overused, which can induce hyponatremia. Autologous predonation probably has similar risks as homologous blood with respect to transfusion errors and bacterial infection. As with most medical interventions, we must be vigilant to prevent human error.

ISSN:1075-2765    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Over the past three decades, evidence from a variety of sources has suggested that allogeneic blood transfusions can induce clinically significant immunosuppression in recipients. This clinical syndrome is referred to in the transfusion medicine literature as transfusion-associated immunomodulation (TRIM) and has been linked to an improved clinical outcome in the setting of renal transplantation. Possible deleterious TRIM-associated effects include increased prevalence of cancer recurrence and postoperative bacterial infections. The recognition that TRIM can increase morbidity and mortality in allogeneically transfused individuals has become a major concern for those involved in transfusion medicine. Whether TRIM predisposes recipients to increased risk for cancer recurrence and/or bacterial infections is still not proven, however. In contrast to the available clinical data, studies in experimental animal models suggest that TRIM is an immunologically mediated biologic effect associated with the infusion of allogeneic leukocytes, which can be ameliorated by prestorage leukoreduction. Although considerable data have been accumulated in an attempt to unravel the clinically adverse effects of TRIM, the precise mechanism of TRIM has yet to be elucidated. Further studies, both basic and applied, to establish the clinically relevant manifestations of TRIM as well as the mechanism(s) are urgently required.

ISSN:1075-2765    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

In general, transfusion guidelines for non-neonatal pediatric patients are similar to those for adults. However, some differences do exist and certain precautions may be necessary particularly in the setting of massive transfusions. We review these differences as they apply to general pediatric surgery outside of the neonatal period, with respect to the transfusion of red blood cells (RBCs), platelets, fresh-frozen plasma (FFP), and cryoprecipitate. We include a discussion of the indications for transfusion and practical considerations such as dosing and administration. Finally, we briefly review the use of directed donations and specialized (irradiated, CMV seronegative) blood components.

ISSN:1075-2765    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Various measures are taken to ensure the safety of the blood supply. Donor selection begins with education of the public about transfusion-transmissible diseases. Potential donors must answer a questionnaire designed to identify specific risk factors for these infections. The questionnaire is the only line of protection against certain infections for which no testing is performed, such as malaria, babesiosis, leishmaniasis, and Chagas disease. All donations are tested for the presence of antibodies to HIV-1 and -2, HCV, HTLV and syphilis, the hepatitis B surface antigen (HbsAg), the p24 antigen (HIV), and also for HIV and HCV nucleic acids. The introduction of new and improved screening tests for transfusion-transmissible diseases has led to remarkable improvement in the safety of the blood supply, with substantial shortening of the window period for HIV, HCV, and HBV infections. The current challenge of the industry is to reduce even further the small but significant risk of bacterial contamination of platelet components. Finally, some safety measures are purely precautionary, such as the deferral of donors who have traveled to certain countries affected by the bovine spongiform encephalopathy (BSE).

ISSN:1075-2765    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Concerns about transfusion-associated complications, in particular viral transmission, have motivated a more restrained pattern of clinical transfusion practice. This change in practice has allowed for an evaluation of the risks of withholding transfusion and the benefits of providing transfusion. The recognized risks of transfusion have declined, and this reduction in risks has been brought about by improved screening, better testing strategies and tests, and leuko-reduction at the time of donation. There are benefits to transfusion, in limiting hypoxic morbidity and mortality. These benefits are clearly evident only at very low levels of serum hemoglobin concentrations in healthy patients who tolerate moderate levels of anemia without morbidity. However, the benefits of transfusion are apparent at higher initial serum level concentrations in patients with cardiovascular disease who are less tolerant of anemia.

ISSN:1075-2765    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

This paper provides a brief history of the evolution of the Jehovah's Witness faith with a short discussion on the biblical justification for followers' refusal of blood transfusions. It also briefly considers the ethical principles leading to potential conflicts between health care workers and Jehovah's Witnesses patients and examines several significant legal rulings in the United States and Canada that caregivers should be aware of. A discussion of what blood products are and are not currently acceptable is also presented. Finally, the impact of the Jehovah's Witness reform movement aimed at allowing blood transfusions and the nature of recent doctrinal shifts in the Jehovah's Witness faith on the matter of blood transfusions are discussed.

ISSN:1075-2765    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The aim of this study was to investigate the changes in circulating blood volume (CBV) after infusions of Hemoglobin glutamer-200 (bovine; Hb-200) in combination with 6% hetastarch in an animal model of acute posthemorrhagic anemia. Fifteen rabbits with a mean body weight of 2.2 ± 0.2 kg were studied. After determination of the circulating plasma volume (CPV) and CBV, one third of the CBV was withdrawn via an arterial catheter. An equal volume of Hb-200 was then infused in the 5 animals in study group 1. In the remaining 10 animals, the same volume of 6% hetastarch solution was infused. Fifteen minutes after completion of the infusion, an additional infusion of 6% hetastarch at a dose equal to one third of the baseline CBV was performed in study group 1 and the control group. In study group 2, equal volumes of Hb-200 were infused. CPV measurements were performed at baseline, after hemorrhage, 5 and 15 minutes after volume replacement, and 1 and 15 minutes after hypervolemic hemodilution using the Evans blue dye dilution technique. The mean baseline CPV value was 53.4 ± 1.1 mL/kg. The mean CBV at baseline was 90.8 ± 4.9 mL/kg. After one third of the CBV was withdrawn, no differences in CBV or CPV were observed between the three groups. Replacement of one third of the CBV with Hb-200 significantly increased the CPV (73.7 ± 1.8 mL/kg) when compared with the baseline level (53.5 ± 1.8 mL/kg; n = 5;P< 0.05). The difference between the groups was first observed 15 minutes after infusion. CPV was significantly higher in study group 1 (87.0 ± 2.2 mL/kg ) compared with the other groups (80.2 ± 2.6 mL/kg in the control group and 79.5 ± 3.6 mL/kg in study group 2). After a second transfusion, the differences between the groups became more prominent. Study group 2 demonstrated the highest CPV and CBV. The two study groups demonstrated a statistically significant increase in circulating volumes compared with the control group. The magnitude of this difference was lower than expected based on in vitro colloid osmotic pressure measurements.

ISSN:1075-2765    

出版商:OVID    

年代:2002

数据来源: OVID