Vox sanguinis
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Review Comparative Study
Rationale for randomized controlled trials and for intention-to-treat analysis in transfusion medicine: are they one and the same?
Articles on the appropriateness of intention-to-treat (ITT) vs. as-treated (AT) analyses of randomized controlled trials (RCTs) have highlighted issues relevant to drug trials, such as approaches suitable for 'explanatory' vs. 'pragmatic' RCTs. These considerations are less relevant to transfusion medicine RCTs, especially those of red blood cell transfusion therapies where the main issue is whether to include in the analysis randomized patients who did not receive transfusion. This article discusses issues pertinent specifically to transfusion medicine RCTs, and the thesis presented here is that the primary analysis of any transfusion medicine RCT must be based on the ITT principle. ⋯ Deviations from the ITT principle may be valid only when other conditions are met to ensure that non-adherence to ITT will not bias the results. For RCTs of red blood cell transfusion therapies, such conditions include that the RCTs be double-blind and that transfusion criteria should be applied consistently. Nonetheless, the rationale for ITT can be reversed in equivalence and non-inferiority trials where the finding of no difference is the objective of the research; thus, both ITT and AT analyses should be presented in these settings.
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Randomized Controlled Trial Comparative Study
Rationalizing blood transfusion in cardiac surgery: the impact of a red cell volume-based guideline on blood usage and clinical outcome.
Cardiac surgery is currently considered one of the heaviest users of red blood cells. An explanation may be found, in part, in considering the effect of the heavy clear fluid load associated with cardiopulmonary bypass. This may result in the artificial depression of haemoglobin concentration, overestimating the requirement for red cell transfusion if this is the sole parameter considered. To address this issue, we examined the impact of a red cell volume-based transfusion guideline on transfusion requirement. ⋯ In elective cardiac surgery patients, considering haemoglobin concentration alone may overestimate the requirement for red cell transfusion. More research is required to determine the impact of restrictive transfusion policies on clinical outcome following cardiac surgery.