Influence of tissue perfusion on the outcome of high-risk surgical patients needing blood transfusion

Introduction

The objective of this study was to evaluate the clinical outcomes of patients who required intraoperative blood transfusion, aiming to compare the pretransfusion hematimetric values with tissue perfusion markers.

Methods

A prospective single-center cohort study. Patients were selected in the operative room of a tertiary hospital. Adult patients who required blood transfusion during the intraoperative period were included in the study. Arterial and central venous blood samples were collected at the moment in which the blood transfusion decision was made.

Results

Sixty-one patients were included, with a mean age of 68 years. The POSSUM score was 36.2 ± 10.3 and the MODS score was 2.4 ± 1.9. At the time of the blood transfusion the mean hemoglobin level was 8.4 ± 1.8 g/dl. The overall inhospital mortality rate was 24.6%. The ScvO₂ cutoff point for the ROC curve was equal to 80% (AUC = 0.75; sensitivity = 80%; specificity = 65.2%). Patients who received a blood transfusion and had ScvO₂ ≤ 80% (n = 29), in comparison with those with ScvO₂ > 80% (n = 32), had lower mortality rates (12.5% vs 47.1%; P = 0.008) and lower incidence of postoperative complications (58.9% vs 72.9%; P = 0.06). Blood transfusion with a ScvO₂ ≤ 80% was also associated with reduced use of vaso-pressors (5.9% vs 36.8%; P = 0.009), lower incidence of hypoperfusion (17.6% vs 52.6%; P = 0.009) and lower incidence of infection (23.5% vs 52.6%; P = 0.038) in the postoperative period.

Conclusion

In patients submitted to major surgery, the ScvO₂ appears an important variable to be taken into consideration to decide for or against blood transfusion, since transfusions with adequate perfusion, reflected by ScvO₂ > 80%, are associated with higher mortality rates and worse clinical outcomes.