Does red blood cell transfusion affect clinical outcomes in critically ill patients? A report from a large teaching hospital in south Iran.

Background: Despite the beneficial effects, RBC transfusion can be associated with infectious and non-infectious complications in critically ill patients.

Objectives: Investigate current RBC transfusion practices and their effect on the clinical outcomes of patients in intensive care units (ICUs).

Design: Retrospective observational study.

Setting: Three mixed medical-surgical adult ICUs of a large academic tertiary hospital.

Patients and methods: From March 2018 to February 2020, all adult patients admitted to medical or surgical ICU. Patients who received one or more RBC transfusions during the first month of ICU admission were included in the "transfusion" group, while the remaining patients were assigned to the "non-transfusion" group.

Main outcome measures: Mortality and length of ICU and hospital stay.

Sample size: 2159 patients.

Results: Of 594 patients who recieved transfusions, 27% of patients received red blood cell (RBC) products. The mean pre-transfusion hemoglobin (Hb) level was 8.05 (1.46) g/dL. There was a significant relationship between higher APACHE II scores and ICU mortality in patients with Hb levels of 7-9 g/dL (OR adjusted=1.05). Also, ICU mortality was associated with age (OR adjusted=1.03), APACHE II score (OR adjusted=1.08), and RBC transfusion (OR adjusted=2.01) in those whose Hb levels were >9 (g/dl).

Conclusion: RBC transfusion was associated with an approximately doubled risk of ICU mortality in patients with Hb>9 g/dL. High APACHE II score and age increase the chance of death in the ICU by 8% and 3%, respectively. Hence, ICU physicians should consider a lower Hb threshold for RBC transfusion, and efforts must be made to optimize RBC transfusion practices.

Limitations: Single-center and retrospective study.