The effect of blood storage duration on in-hospital mortality: a randomized controlled pilot feasibility trial

Whether the duration of storage of blood has an impact on patient outcomes remains controversial. The objective was to determine feasibility of a comparative effectiveness trial to evaluate duration of storage of blood before transfusion on in-hospital mortality.

A single-center randomized controlled trial was performed at an acute care hospital in Canada between June and December 2010, involving consecutive hospitalized patients needing blood transfusion. Patients (n=910) were randomly assigned in a 1:2 ratio to receive freshest available versus standard-issue (oldest available) blood. Four feasibility criteria were measured: proportion of eligible patients randomized, contrast in age of blood between treatment groups, real-time data acquisition, and trial impact on blood outdating. In-hospital mortality was also reported.

A total of 1075 of 1129 patients (95.2%) were eligible and 910 of 1075 (84.7%) were randomized: 309 received freshest available blood (1157 units), and 601 received standard-age blood (2369 units). Contrast in mean age of the oldest blood transfused between groups was 14.6 days: 12.0 (standard deviation [SD], 6.8) days in the fresh arm and 26.6 (SD, 7.8) days in the standard arm. Weekly recruitment and event reporting were achieved for all patients. The blood outdate rate was 0.10%. In-hospital mortality was 10.5%: 35 deaths (11.3%) in the fresh arm and 61 deaths (10.1%) in the standard arm (odds ratio, 1.13; 95% confidence interval [CI], 0.73, 1.76).

It is feasible to conduct a large comparative effectiveness trial comparing the effect of freshest available versus standard-issue blood on in-hospital mortality. The wide CI around the estimate for in-hospital mortality supports the need for a large trial.