The effect of plasma transfusion in an experimental two-hit animal model of transfusion-associated circulatory overload with heart failure

Background - Transfusion-associated circulatory overload (TACO) is a leading cause of transfusion-related morbidity and mortality. TACO follows a two-hit pathophysiology, where comorbidities like cardiac or renal failure act as the first hit followed by blood transfusion as a second hit. Observational studies suggest that plasma transfusion is more likely to cause TACO than other blood products. We conducted a randomized animal study to gather evidence that plasma transfusion can induce TACO. Material and methods - As a first hit a large myocardial infarction was created in male Wistar rats. Then animals were randomized to receive 4 units of solvent/ detergent-treated pooled plasma (SDP), fresh frozen plasma (FFP), a colloid control (albumin 5%) or a crystalloid fluid control (Ringer's lactate) (n=10 per group). The primary outcome was the difference between pre- and post-transfusion left-ventricular end diastolic pressure (& UDelta;LVEDP). Secondary outcomes were markers for acute lung injury; lung wet/dry weight ratio, PaO2/FiO2 ratio and pulmonary histological assessment. Results - Pre-transfusion characteristics were similar between groups. & UDelta;LVEDP increased significantly after transfusion with SDP (7.7 mmHg; 4.5-10.5) and albumin (13.0 mmHg; 6.5-15.2), but not after FFP (7.9 mmHg, 1.1; 11.3) compared to infusion with Ringer's lactate (0.6 mmHg; 0.4-2.2), p=0.007, p=0.0005 and p=0.14 respectively. There were no significant differences in & UDelta;LVEDP between groups receiving SDP, FFP or albumin. There was no increase in acute lung injury in any group compared to other groups. Discussion - Circulatory overload, measured as & UDelta;LVEDP, was induced after transfusion of SDP or albumin, but not after infusion of Ringer's lactate. These results show that the effect of plasma transfusion on & UDelta;LVEDP differs from fluid overload induced by crystalloid infusion. Colloid osmotic pressure may be an important component in the development of TACO and should be a target for future research.