title: A prospective, double-blind, randomized clinical feasibility trial of controlling the storage age of red blood cells for transfusion in cardiac surgical patients.
abstract: BACKGROUND
  Recent evidence demonstrates an association between duration of storage of red blood cells (RBC) and morbidity and mortality after cardiac surgery. We studied the feasibility of two different schemes for categorizing and randomizing age of RBC units transfused in cardiac surgical patients.
  
  
  METHODS
  In Phase 1, 20 subjects were randomly assigned to standard of care (SOC) versus no RBCs with more than 21 days' storage duration. In Phase 2, 23 subjects were randomized to RBCs of 7 +/- 4 versus 21 +/- 4 days' storage duration. The age of study RBC units was masked.
  
  
  RESULTS
  In Phase 1, no patients received RBCs 31 days or older in SOC, and there was overlap in storage age shared in both arms so the predefined feasibility criteria were not met. In Phase 2, it was feasible to deliver specified age RBCs to the 7-day arm (achieved in 100% of subjects), but feasibility was not demonstrated for the 21-day arm (only 50% of subjects transfused with target age RBCs). Significant differences, however, were observed between the 7 +/- 4- and 21 +/- 4-day arms with respect to age of all RBC units (6 +/- 2 vs. 18 +/- 7, p = 0.0002) and maximum age (7 +/- 2 vs. 20 +/- 7, p < 0.0001).
  
  
  CONCLUSIONS
  Given the current storage age distribution of available RBC inventory, use of a SOC arm in future studies is unlikely to result in a large exposure to "old" blood. It is feasible to randomize patients to "younger" RBCs (3-11 days) but design strategies are needed to provide "intermediate-aged" or "old" blood as a comparator.
authors.affiliation: Department of Anesthesiology, Duke Clinical Research Institute, Duke University Medical Center, Durham, NC 27710, USA. elliott.bennettguerrero@duke.edu
authors.forename: Elliott
authors.initials: E
authors.lastname: Bennett-Guerrero
authors.forename: Mark
authors.initials: M
authors.lastname: Stafford-Smith
authors.forename: Peter M
authors.initials: PM
authors.lastname: Waweru
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Bredehoeft
authors.forename: Mary Lee
authors.initials: ML
authors.lastname: Campbell
authors.forename: N Rebecca
authors.initials: NR
authors.lastname: Haley
authors.forename: Barbara
authors.initials: B
authors.lastname: Phillips-Bute
authors.forename: Mark F
authors.initials: MF
authors.lastname: Newman
authors.forename: Nicholas
authors.initials: N
authors.lastname: Bandarenko
mesh_terms: D001793:Blood Preservation / Q000009:adverse effects*; D004311:Double-Blind Method; D017707:Erythrocyte Transfusion / Q000401:mortality*; D006801:Humans; D013903:Thoracic Surgery; D013997:Time Factors