RESUMO
OBJECTIVES: Artificial colloids, frequently used to prevent hemorrhagic shock in children, impair blood coagulation. To determine the impact of acute isovolaemic hemodilution with artificial colloids on clot formation, we conducted an experimental study in a pediatric animal model. METHODS: Fifteen piglets underwent hemorrhage by withdrawing 40 ml·kg(-1) of blood volume in steps of 10 ml·kg(-1) each within 1 hour. After each withdrawal, the blood loss was randomly compensated by administering 4% gelatin (GEL) or hydroxylethyl starch 130/0.42 (HES) in a ratio of 1 : 1, or isotonic crystalloid solution (ICS) in a ratio of 1 : 4 for isovolaemic hemodilution. Quality of clot formation and platelet function was measured using Thrombelastometry (ROTEM(®)) and Multiple electrode impedance aggregometry (Multiplate(®)) after 10, 20, and 40 ml·kg(-1) blood replacement. RESULTS: Moderate hemodilution (10-20 ml·kg(-1) blood replacement) caused no significant differences among groups (e.g. INTEM(®)-MCF after 20 ml·kg(-1) blood replacement (ICS vs GEL vs HES, P > 0.05). Profound hemodilution with 40 ml·kg(-1) blood replacement showed a significant difference between ICS and both colloids (P < 0.05), but no significant differences between GEL and HES. CONCLUSIONS: Impairment of clot formation by moderate isovolaemic hemodilution did not significantly differ between ICS, GEL, and HES. Profound hemodilution of more than 50% of the estimated blood volume with GEL and HES caused significant impairment of clot formation in comparison to ICS and has to be considered when using high amounts of these synthetic colloids.