Goal-directed hemodynamic and fluid optimizations are shown to be a key factor of the medical care during anesthesia.According to medical literature, goal-directed fluid and hemodynamic optimizations are more efficient when based on the dynamic parameters than when based on the statics ones, and the major dynamic criteria is the cardiac output. Unfortunately, transpulmonary thermodilution, the device considered as "The gold standard" to evaluate cardiac output is associated with many complications.Furthermore, devices commercialized in the past decade were not able to replace the transpulmonary thermodilution.