Fluid Challenge: From bench to bedside
Résumé
Adverse effects of fluid loading ore not only due to the specific toxicity of infused fluid but also to the amount of the infused fluid. To avoid these adverse effects, the concept of ``Fluid Challenge'' (FC) has been developed. FC tests the ability of the cardiovascular system to increase stroke volume with minimal fluid loading. Hence, FC should not be used for overt hypovolaemia especially at the early phase of shock. Response to fluid challenge should be evaluated with stroke volume measurement. An increase of stroke volume by 10-15% is considered as significant. The most reliable tools to evaluate stroke volume variations are pulmonary thermodilution, transpulmonory thermodilution and Doppler echocardiography. To date, there is no consensus statement on the modalities of FC. Based on published studies, we suggest the use of crystalloids of a perfusion rote of 200-250 mL in 5-10 min. We also suggest evaluating the responsiveness at 20-30 min. Finally, FC should be stopped if signs of fluid overload appear (pulmonary oedema, venous congestion).