Comparison of Fluid Kinetic Model of Normal Saline with Hartmann's Solution in Adult Volunteers

ABSTRACT

BACKGROUND: Changes in the volume of fluid space expanded by intravenous infusion of crystalloid solution have been analyzed using mathematical models. Crystalloids with similar osmolality would reveal no significant differences in distribution and elimination from the body. But each solution has different ionic composition, this can affect fluid volume kinetics. Therefore, we evaluated the fluid volume kinetics of normal saline and Hartmann's solution. METHODS: After infusion of 15 ml/kg of normal saline (n=5) and Hartmann's solution (n = 4) over 30 min and measured a serial hemoglobin concentration. The changes were expressed as fractional dilution and then plotted against time. The curves were fitted to two-volume model using non linear least square fitting process. RESULTS: Central and peripheral volume space were present. There were no significant differences between the two groups on central volume, peripheral volume and expansion ratio of fluid space per body weight and expansion ratio of peripheral volume. The expansion ratio of central volume was greater in Hartmann's solution than normal saline from 25 min to 60 min after infusion. Hartmann's solution expanded fluid space higher than normal saline on initial period. CONCLUSIONS: There were no significant differences in fluid kinetic parameters between normal saline and Hartmann's solution. However, the volume expansion effect of Hartmann's solution was more rapid than normal saline in early infusion period.