In a randomized , controlled , parallel-group , double-blind ( patients and outcome assessors ) superiority trial in the intensive care unit of a tertiary oncology hospital , the authors evaluated whether a restrictive strategy of erythrocyte transfusion ( transfusion when hemoglobin concentration < 7 g/dl ) was superior to a liberal one ( transfusion when hemoglobin concentration < 9 g/dl ) for reducing mortality and severe clinical complications among patients having major cancer surgery .