EFFECTS OF STORED RED BLOOD CELL TRANSFUSION IN CARDIOPULMONARY FUNCTION AND INFLAMMATION: AN EXPERIMENTAL MECHANISTIC STUDY

Abstract

Background: Red blood cell (RBC) transfusion has been associated to deleterious inflammatory and respiratory effects. However, the mechanisms related to these phenomena are incompletely understood. Aims: To develop an experimental model of homologous stored RBC transfusion using hypovolemic swine aiming to evaluate its acute effect on cardiopulmonary function, microcirculation, pulmonary and systemic inflammation. Methods: Sixteen anesthetized and instrumented swine (60–70 kg) were submitted to controlled hemorrhage (25% of volemia). Two units of non-filtered RBC from each animalwereprocessedandstoredfor14 days.Afterhypovolemia,eightanimalsreceived Lactated Ringer’s solution (three times the removed blood volume). The transfusion group received the two units of RBC and Lactated Ringer’s solution (to complete blood volume removed). Both groups were followed up to 6 h after resuscitation. Microcirculation was assessed with a laserdopplerflowmetry probe at ileum. Plasma and pulmonarycytokines’ concentrations(IL-6, IL-1,IL-10, IL-21, TNF-alpha) were measuredas well as nitrate concentrations and cytokines and NOS2 gene expression in the lungs. Results: RBC transfusion significantly increased oxygen venous saturation and oxygen delivery. Microcirculatory evaluation was similar between groups, and also were pulmonary mechanics and gas exchange. Nitrate and cytokines concentration in the plasma and lungs were similar between groups. However, RT-qPCR for cytokinesdemonstrated an increase (twofold) in mRNA level for NOS2 and a 0.5-fold decrease in mRNA content for IL-21 in the transfused group. Conclusions: Stored homologous RBC transfusion does not induce clinically significant effects on microcirculation and respiratory function up to 6 h after transfusion.