Validation of volume kinetic analysis of glucose 2.5% solution given by intravenous infusion

Background. The distribution and elimination of glucose solutionscan be analysed by means of a volume kinetic model, but theability of the model to predict plasma dilution (‘modellinearity’) has not been evaluated. Methods. Six male volunteers received four separate infusionsof glucose 2.5%: 10 ml kg^–1 and 15 ml kg^–1 over30 min, and 15 ml kg^–1 and 25 ml kg^–1 over 60 min.The kinetic model was fitted to measurements of plasma glucoseconcentration and haemodilution. Results. The mean volume of distribution for the glucose was9.2 (SEM 0.4) litres while the infused fluid expanded a centralbody fluid space (V₁) of 3.1 (0.3) litres. Increasing the amountof infused fluid, but not the infusion rate, resulted in a proportionalincrease in the area under the curve for plasma glucose andplasma dilution, the only confounder being glycosuria. The biasof computer simulation was slightly increased by rebound hypoglycaemia,which could occur with the highest infusion rates, but the accuracywas almost identical regardless of whether the kinetic parametersfrom all 24 experiments or from any of the subgroups were used. Conclusion. The volume kinetic model for glucose 2.5% is linearand can therefore be used for computer simulation as long asmarked glycosuria does not occur. Br J Anaesth 2003; 90: 600–7