Objective: To determine if red blood cell transfusions in children hospitalized in a critical care unit are associated with an increase in morbimortality. Materials and Methods: An observational cohort analytical study including children with anemia from 1 month to 18 years that were admitted in PICU in a period of thirteen months. Results: 156 children with anemia were included. In 51.5 % the anemia developed after admission. 77 children received a red blood cell transfusion and the median pretransfusion hemoglobin was 7.5 g/dl. 6.5 % of the transfused patients had an adverse Reaction. Between transfused vs not trasfused children a significant difference exist in the admission hemoglobin, volumen of blood loss by extraction and age in the bivariate analysis. The transfused patients had major mortality than the not transfused ones (12.9 % vs. 2.5 %, p =0.014). The development of multiorganic failure also was more frequent in the group transfused (57.1 % vs. 13.9 %, p 0.001). The median of the days of stay in the PICU and time in mechanical ventilation was major in the transfused children than in the not transfused (8 vs 4 days p<0.001 and 6 vs 3 days p=0.001 respectively). A mutivariate analysis showed association between red blood cell transfusions with mortality and multiorganic failure. Conclusion: Red blood cells transfusions are associated with an increase in the Mortality and in the development of Multiorganic Failure. The stay in the PICU and the time of Mechanical Ventilation was major in the children who received transfusion
