Subsequently, “standard” blood cells (with known, significant non-ABO-Rh-antibodies) are added to the patient’s serum. In a type and screen, as in a type and cross, the recipient and donor cells are ABO-Rh typed (risk of transfusion reaction 0.2% after simply doing an ABO-Rh type). In the last phase, ( antiglobulin phase), antiglobulin sera are added, further increasing the ability of the crossmatch to detect incomplete antibodies (ex. In the second phase ( incubation phase, 10-20 minutes), the first phase reactants are heated to 37C in salt solution (or for 30-45 minutes in albumin), additional antibodies (mostly to Rh, but also partial or incomplete Ab) are detected, as the salt solution and/or albumin can facilitate agglutination. In the first phase ( immediate phase, 1-5 mins, room temp), ABO errors antibodies and MN, P, and Lewis system antibodies are sought. In order to further decrease this risk, a small sample of donor blood can be mixed with the recipient’s serum. What does a “type and cross” actually mean? As always, both the recipient and donor cells are ABO-Rh typed – this alone reduces the risk of a transfusion reaction to 0.2%. Is the crossmatch worth this extra 0.01% of risk (i.e. Screening lowers this risk to 99.94%, and crossmatching lowers it to 99.95%. Thus, a simple ABO-Rh type reduces the risk of a transfusion reaction to 99.8%. If anti-Rh(D) is accounted for, only 0.1% of these patients will have reactive (A, B, D) antibodies. Many of these are not reactive at temperatures above 30C. some prior exposure to non-native red blood cell antigens) will have any non-A or non-B antibodies. They cite the following statistics – only 1% of previously transfused or pregnant patients (i.e. Some authors (Miller’s Anesthesia, 6th edition, Chapter 55) have questioned whether or not a cross match is really needed. Complications of Blood Product Transfusion Blood Bank Concepts Furthermore, the median units of blood transferred were 2 and 0 units in the liberal and restricted groups, respectively . Importantly, only 3% of the patients in this study required the provision of critical care in an intensive care unit. 34.7% in liberal and restricted, respectively). The primary outcome (death or an inability to walk 10 ft without human assistance at the 60-day follow-up) was no different between groups (35.2% vs. 40% of patients had known CAD in both groups. randomized 2016 patients considered at “high risk” for cardiac morbidity (either a history of or risk factors for cardiovascular disease) to transfusion thresholds of 8 versus 10 post-operatively. Post-Operative Transfusion in Hip Surgery (Prospective, RCT) Ĭarson JL et al. Like the TRACS trial, there was no apparent difference in mortality or morbidity.
These differences persisted after adjusting for hospital and patients factors.
Researches using the STS database found transfusion practices among 700 US hospitals for 100,000 patients undergoing CBP showed wide variance in the rates of product transfusion (RBC (7.8%-92.8%), plasma (0%-97.5%), and platelet (0.4%-90.4%)). Transfusion in Cardiac Surgery (Retrospective) Morbidity and mortality was the same in both groups. The intervention significantly reduced PRBCs transfusion (78% and 47% receiving, respectively). Indications for Transfusion Indications for TransfusionĮvidence of impaired tissue oxygenation: VO2 0.5 in patients with adequate cardiac outputĬorrection of Hb 30% hematocrit) vs conservative (>24%) transfusion strategy in patients undergoing routine CABG and/or valve surgery requiring bypass. Marino’s data on RBC transfusions into euvolemic anemic post-op patients suggests that there is tremendous variability in the effects of blood on VO2 – it should not be taken for granted that RBCs will increase tissue oxygenation. The efficacy of RBC transfusions does not live up to its theoretical limit, as RBCs can increase blood viscosity and lower cardiac output. In an urgent situation, one can do a partial cross match (in which macroscopic agglutination is looked for) in 0.5 may be an ideal transfusion trigger. Major cross matching occurs when the donor erythrocytes are mixed with the recipient’s plasma (minor cross matching mixes the donor plasma with recipient erythrocytes). Blood Compatibility for Red Cell Transfusions
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