[Blood transfusion in intensive care: an epidemiological observational study]

Packed red blood cell (PRBC) transfusion is frequent in intensive care unit (ICU). However, the consequences of anemia in ICU patients are poorly understood. Our aim was to evaluate the prevalence, indications, pre-transfusion hematocrit and hemoglobin levels, and outcomes of ICU patients transfused with PRBC.

Prospective cohort study conducted at a medical-surgical ICU of a teaching hospital during a 16-month period. Patients' demographic, clinical, laboratory and transfusion-related data were collected. Logistic regression was used after univariate analyses.

A total of 698 patients were evaluated and 244 (35%) received PRBC, mainly within the first four days of ICU (82.4%). Transfusion was more frequent in medical and emergency surgical patients. The mean pre-transfusion hematocrit and hemoglobin were 22.8% ± 4.5% and 7.9 ± 1.4 g/dL, respectively. Transfused patients received 4.4 ± 3.7 PRBC during ICU stay and 2.2 ± 1 PRBC at each transfusion. The ICU (39.8% versus 13.2%; p < 0.0001) and hospital (48.8% versus 20.3%; p < 0.0001) mortality rates were higher in transfused patients. Mortality increased as the number of transfused PRBC increased (R² = 0.91). In logistic regression, predictive factors for PRBC transfusion were hepatic cirrhosis, mechanical ventilation (MV), type and duration of ICU admission, and hematocrit. The independent factors associated to hospital mortality were MV, transfusions of more than five PRBC and SAPS II score.

PRBC transfusions are frequent in ICU patients, especially in those with medical and emergency surgical complications, longer ICU stay, and hepatic cirrhosis and in need of MV. Pre-transfusion hemoglobin levels were lower than those previously reported. In our study, PRBC transfusion was associated with increased mortality.