Effects of red blood cell transfusion on hemodynamic parameters: a prospective study in intensive care unit patients

BACKGROUND: The aim of the study was to investigate the effect of red blood cell (RBC) transfusion on hemodynamic parameters including transpulmonary thermodilution (TPTD)-derived variables.

METHODS: We compared hemodynamic parameters obtained before and after RBC transfusion (2 RBC units) in 34 intensive care unit (ICU) patients.

RESULTS: Directly after RBC transfusion, we observed a significant increase in hematocrit (28 ± 3 vs. 22 ± 2%, p < 0.001), hemoglobin (9.4 ± 0.9 vs. 7.6 ± 0.8 g/dL, p < 0.001), arterial oxygen content (CaO₂) (12.2 ± 1.2 vs. 9.9 ± 1.0 mL/dL, p < 0.001), and oxygen delivery (DO₂) (1073 ± 369 vs. 934 ± 288 mL/min, p < 0.001) compared with baseline. Cardiac output (CO) (8.89 ± 3.06 vs. 9.42 ± 2.75 L/min, p = 0.020), cardiac index (CI) (4.53 ± 1.36 vs. 4.82 ± 1.21 L/min/m², p = 0.016), and heart rate (91 ± 16 vs. 95 ± 14 bpm, p = 0.007) were significantly lower following RBC transfusion while no significant change in stroke volume (SV) was observed. Mean arterial pressure (MAP) (median 87 vs. 78 mmHg, p < 0.001) and systemic vascular resistance index (SVRI) (median 1212 vs. 1103 dyn*s*cm⁻⁵*m², p = 0.001) significantly increased directly after RBC transfusion. Global end-diastolic volume index (GEDVI), extravascular lung water index (EVLWI), and pulmonary vascular permeability index (PVPI) did not significantly change.

CONCLUSIONS: In ICU patients, the transfusion of 2 RBC units induces a significant decrease in CO and CI because of a significant decrease in heart rate (while SV remains unchanged). Despite the decrease in CO, DO₂ significantly increases because of a significant increase in CaO₂. In addition, RBC transfusion results in a significant increase in MAP and SVRI. No significant changes in TPTD-parameters reflecting cardiac preload (GEDVI), pulmonary edema (EVLWI), and pulmonary vascular permeability (PVPI) are observed following RBC transfusion.