Anemia during and at discharge from intensive care: the impact of restrictive blood transfusion practice

Abstract

To document the prevalence of anemia among patients admitted to intensive care (ICU) and, among survivors, at ICU discharge when restrictive transfusion practice was used. This was an observational cohort study. Ten of the 26 general ICUs in Scotland. One thousand twenty-three sequential ICU admissions over 100 days, representing 44% of all ICU admissions in Scotland during the study period, studied daily from admission to discharge or death in the ICU. None. The median transfusion trigger used, in the absence of bleeding, was 78 g/l (interquartile range 73-84); <2% of transfusion triggers were above the upper limit of the national transfusion trigger guideline (100 g/l). Overall, 25% of admissions had a hemoglobin concentration <90 g/l at ICU admission. Seven hundred sixty-six patients admitted survived to ICU discharge. Among these, the prevalence of anemia (male <130 g/l; female <115 g/l) at ICU discharge was 87.0 (95% CI: 83.6 to 89.9)% for males and 79.6 (74.8 to 83.7)% for females. Of the male survivors 24.1 (20.3 to 28.3)% and of the female 27.9 (23.4 to 33.2)% had a hemoglobin <90 g/l at ICU discharge. The prevalence was similar for patients with and without pre-existing ischemic heart disease. Logistic regression found independent associations between having a hemoglobin concentration <90 g/l at ICU discharge and the first measured hemoglobin in ICU, the presence of acute renal failure and thrombocytopenia during ICU stay. Anemia is highly prevalent in ICUs that use restrictive transfusion triggers. The impact of anemia on functional recovery after intensive care requires investigation.