Blood transfusion
A total of 1,833 patients (30.9%) received a blood transfusion
in the ICU within a median of 1 (IQR 1 to 2) days.
The initial blood transfusion was given on the first day in
the ICU in 69% of transfused patients (n = 1,209). Transfused
patients were older, were more commonly
unplanned admissions, had greater SAPS II and SOFA
scores, and had a higher incidence of comorbid conditions
than patients who were not transfused [see Table S2
in Additional file 1]. The mean hemoglobin concentration
prior to transfusion was 8.2 ± 1.4 g/dl (24% at < 7 g/
dl, 46.6% at 7 to 9 g/dl, 29.4% at >9 g/dl). Characteristics
of patients according to the number of transfused units
are presented in Table S3 in Additional file 1.
Transfused patients had higher ICU and in-hospital
mortality rates (12.5 vs. 3.2 and 18.3 vs. 6.5%, respectively,
both P < 0.001 pairwise) and longer ICU and hospital
lengths of stay (4 (2 to 11) vs. 1 (1 to 2) and 15 (11 to 26)
vs. 11 (8 to 16) days, respectively, both P < 0.001 pairwise)
than non-transfused patients. There was a relation
between the number of transfused units of blood and the
degree of organ dysfunction/failure during the ICU stay,
as assessed by SOFA scores, length of stay in the ICU, and
mortality rates (Table 3). About 50% of patients who