The choice of volume expander for fluid
resuscitation in
hemorrhagic shock is still debated. Changes in plasma viscosity (PV) are barely investigated while PV modulates functional capillary density, microcirculation and organ function. The present study evaluated the impact of 2 strategies of fluid
resuscitation in
hemorrhagic shock in pigs. Ten pigs were subjected to
hemorrhagic shock and randomly assigned to a low viscosity fluid regimen (
Lactated Ringer's, LR) group or a high viscosity regimen (hypertonic-hydroxyethyl
starch, HES) for volume
resuscitation. Sublingual microcirculatory flow and tissue
oxygen tension were assessed together with macro- and microcirculatory, biochemical and rheological variables at baseline, 30 minutes after
hemorrhagic shock, immediately after reaching
resuscitation endpoints (R-0), and 60 minutes after
resuscitation (R-60). PV decreased similarly in both groups following
resuscitation (from 1.36 [1.32-1.38] to 1.21 [1.21-1.23] for LR, and from 1.32 [1.31-1.32] to 1.20 [1.17-1.21] mPa.s for HES). No differences were found between the groups for other rheological variables, microcirculatory flow or tissue
oxygen tension at R-0 and R-60. Despite a 6-fold difference in the volumes required to achieve blood flow endpoints, commercially available volume expanders had similar effects on rheological and microcirculatory variables, irrespective of their viscosity. Our findings are consistent with the absence of clinically relevant differences between
crystalloid and
colloid resuscitation of
hemorrhagic shock.