Pettila V, Westbrook AJ, Nichol AD, Bailey MJ, Wood EM, Syres G, Phillips LE, Street A, French C, Murray L, Orford N, Santamaria JD, Bellomo R, Cooper DJ, Blood Observational Study Investigators T, Anzics-Clinical Trials Group T.; Crit Care. 2011 Apr 15;15(2):R116
INTRODUCTION: In critically ill patients, it is uncertain whether exposure to older red blood cells (RBCs) may contribute to mortality. Therefore, we aimed to evaluate the association between the age of RBCs and outcome in a large unselected cohort of critically ill patients in Australia and New Zealand. We hypothesized that exposure to even a single unit of older RBCs may be associated with an increased risk of death.
METHODS: We conducted a prospective, multicenter observational study in 47 ICUs during a 5-week period between August 2008 and September 2008. We included 757 critically ill adult patients receiving at least one unit of RBCs. To test our hypothesis we compared hospital mortality according to quartiles of exposure to maximum age of RBCs without and with adjustment for possible confounding factors.
RESULTS: Compared with other quartiles, [mean maximum red cell age: 22.7 days; mortality 121/568 (21.3%)] patients treated with exposure to the lowest quartile of oldest RBCs [mean maximum red cell age: 7.7 days; hospital mortality: 25/189 (13.2%)] had an unadjusted absolute risk reduction in hospital mortality of 8.1% (95% CI 2.2-14.0 %). After adjustment for APACHE III score, other blood component transfusions, number of RBC transfusions, pre-transfusion hemoglobin concentration, and cardiac surgery, the odds ratio for hospital mortality for patients exposed to the older three quartiles compared to the lowest quartile was 2.01 (95% CI 1.07- 3.77).
CONCLUSIONS: In critically ill patients, in Australia and New Zealand, exposure to older RBCs is independently associated with an increased risk of death.
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