Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion

• Published in: Cochrane database of systematic reviews 2012-04, Vol.4 (4), p.CD002042-CD002042
• Main Authors: Carson, Jeffrey L, Carless, Paul A, Hebert, Paul C
• Format: Article
• Language: English
• Subjects: Erythrocyte Transfusion - adverse effects; Erythrocyte Transfusion - mortality; Erythrocyte Transfusion - standards; Hematocrit - standards; Hemoglobin A - analysis; Humans; Practice Guidelines as Topic; Randomized Controlled Trials as Topic; Reference Values; Transplantation, Autologous - standards; Transplantation, Homologous - mortality; Transplantation, Homologous - standards
• ISSN: 1469-493X
• DOI: 10.1002/14651858.cd002042.pub3

Most clinical practice guidelines recommend restrictive red cell transfusion practices, with the goal of minimising exposure to allogeneic blood. The purpose of this review is to compare clinical outcomes in patients randomised to restrictive versus liberal transfusion thresholds (triggers). To examine the evidence for the effect of transfusion thresholds on the use of allogeneic and/or autologous red cell transfusion, and the evidence for any effect on clinical outcomes. We identified trials by searching; The Cochrane Injuries Group Specialised Register (searched 01 Feb 2011), Cochrane Central Register of Controlled Trials 2011, issue 1 (The Cochrane Library), MEDLINE (Ovid) 1948 to January Week 3 2011, EMBASE (Ovid) 1980 to 2011 (Week 04), ISI Web of Science: Science Citation Index Expanded (1970 to Feb 2011), ISI Web of Science: Conference Proceedings Citation Index- Science (1990 to Feb 2011). We checked reference lists of other published reviews and relevant papers to identify any additional trials. Controlled trials in which patients were randomised to an intervention group or to a control group. Trials were included where intervention groups were assigned on the basis of a clear transfusion 'trigger', described as a haemoglobin (Hb) or haematocrit (Hct) level below which a red blood cell (RBC) transfusion was to be administered. Risk ratios of requiring allogeneic blood transfusion, transfused blood volumes and other clinical outcomes were pooled across trials, using a random effects model. Data extraction and assessment of the risk of bias was performed by two people. Nineteen trials involving a total of 6264 patients were identified, and were similar enough that the results could be combined. Restrictive transfusion strategies reduced the risk of receiving a RBC transfusion by 39% (RR 0.61, 95% CI 0.52 to 0.72). This equates to an average absolute risk reduction (ARR) of 34% (95% CI 24% to 45%). The volume of RBCs transfused was reduced on average by 1.19 units (95% CI 0.53 to 1.85 units). However, heterogeneity between trials was statistically significant (P