Background: Synthetic colloids cause dilutional coagulopathy. The aims of our study were to determine whether the natural colloid albumin induces a lesser degree of coagulopathy compared to synthetic colloids, and the comparative effectiveness of fibrinogen concentrate to reverse coagulopathy following dilution with these solutions.
Methods: Coagulation was assessed with rotational thrombelastometry after stimulation with tissue factor (EXTEM) and in the presence of a platelet inhibitor (FIBTEM). With EXTEM, clotting time (CT), clot formation time CFT), alpha angle (AA) and maximum clot firmness (MCF) were recorded. With FIBTEM, only MCF was recorded. These parameters were assessed ex vivo in blood from 10 healthy volunteers; diluted 1:1 with either saline, Ringer's acetate, buffered/unbuffered hydroxyethyl starch, buffered/unbuffered dextran (synthetic colloids) or 5% albumin. Samples were analyzed before/after addition of fibrinogen concentrate.
Results: FIBTEM MCF decreased significantly upon dilution (> 50% reduced) with all colloid solutions (p ≤ 0.02), although a significantly greater coagulopathic effect was seen for samples diluted with synthetic colloids versus albumin (p ≤ 0.001). A significant reduction in the platelet component of clot strength (EXTEM MCF - FIBTEM MCF) was seen for samples diluted with synthetic colloids (p < 0.001) but not albumin (p = 0.10). Following addition of fibrinogen, FIBTEM MCF, EXTEM MCF and AA were significantly higher, and CFT was significantly shorter in samples diluted with albumin versus those treated with synthetic colloids (p ≤ 0.001).
Conclusion: Hemodilution using albumin induced a lesser degree of coagulopathy compared with the synthetic colloids. In addition, albumin-induced coagulopathy was more effectively reversed following addition of fibrinogen concentrate compared with coagulopathy induced by synthetic colloids.