Fig. 1. Schematic drawing of the kinetic model used to analyze the body’s handling of infused crystalloid fluid. The fluid is infused at a rate k ithat expands a central body fluid space v 1and a peripheral space v 2, both of which strive to return to their baseline volumes V 1and V 2by acting on the dilution-dependent elimination mechanism, k r(which can be set to the urinary excretion). The sum of evaporation, bled plasma, and extravascular fluid retention is represented by the zero-order rate parameter k b.