Transfusion
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Randomized Controlled Trial
Cardioprotective effects of acute normovolemic hemodilution in patients with severe aortic stenosis undergoing valve replacement.
After acute normovolemic hemodilution (ANH), improvement of the rheologic conditions may contribute to optimize tissue oxygen delivery and attenuate ischemia-reperfusion injuries. It was hypothesized that ANH would confer additional cardioprotection in patients with ventricular hypertrophy undergoing open heart surgery. ⋯ Besides conventional cardiac preservation techniques, preoperative ANH further attenuates myocardial injuries. Optimization of preischemic myocardial oxygen delivery and/or consumption and the postconditioning effects of endogenous EPO are potential mechanisms for ANH-induced cardioprotection.
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Prophylactic platelet (PLT) transfusion practices have become more conservative as studies support a threshold for transfusions at 10 x 10(9) per L. This change in practice may reduce our use of PLT transfusions. ⋯ Many prophylactic PLT transfusions were given at PLT counts higher than the recommended trigger. Although the new transfusion guidelines altered transfusion practice, only a minor change in overall PLT usage was observed. Other changes in transfusion practices, such as dose per transfusion or sampling interval, will be required before significant reduction in the costs and hazards of prophylactic PLT transfusions can be realized.
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The traditional method of calculating blood volume for pediatric transfusion in the UK is weight (kg) x aimed increment in hemoglobin concentration (Hb; g/dL) x the transfusion factor, usually quoted at 3 or 4. This equation is without evidence base. The aim was to assess how the volume of red cells (RBCs) affects the increase in serum Hb in children and to devise a formula that allows accurate volume calculation. ⋯ The following equation should be used to calculate transfusion volumes: weight (kg) x increment in Hb (g/dL) x 3/(hematocrit [Hct] level of RBCs). This predicts that with a UK standard Hct of 0.6, 10 mL/kg gives an increment of 2 g/dL. Care must be taken not to risk hypervolemia, while minimizing donor exposure. Hb estimation 1 hour after transfusion is the same as 7 hours after transfusion.
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New testing methods such as nucleic acid amplification testing (NAT) and chemiluminescent serologic assays have been introduced, more precise estimates for infectious window periods are available, and a new method for estimating the residual risk (RR) of transfusion-transmitted infections (TTIs) has been developed. Thus, available RR estimates for Canada need to be updated. ⋯ New tests have reduced an already low risk of TTI in Canada. HCV RR estimates by two different methods differed but both were low.