LOGNORMAL-NLSQ TECHNIQUE - INVESTIGATION OF A NEW MATHEMATICAL METHODOF CALCULATING BLOOD-VOLUME

This paper describes the investigation of a new mathematical method of calculating blood volume. The new method determines the blood volume by calculating the product of the mean circulation transit time. The m ean transit time is calculated from the body transport function. To ex amine the accuracy of the LOGNORMAL-NLSQ technique, 45 concentration t ime curves were measured in an in vitro recirculation model with varia ble clearance. The calculated volume was 4 % smaller than the actual v olume. This may be attributed to the functional dead space within the model, and is tolerable for clinical situations. The LOGNORMAL-NLSQ te chnique might acquire considerable importance in future, especially si nce it provides accurate results very quickly.