ASSESSMENT OF THE HEPATIC CIRCULATION IN HUMANS - NEW CONCEPTS BASED ON EVIDENCE DERIVED FROM A D-SORBITOL CLEARANCE METHOD

D-Sorbitol (SOR) is safe, is easy to measure, and has an exceptionally high extraction ratio in the normal liver of 0.93 +/- 0.05 (mean +/- SD). Together with the general interest in hepatic hemodynamics, these facts motivated us to review the usefulness of this compound for the assessment of liver plasma flow in humans. We concluded that in subjec ts without liver disease the nonrenal clearance of SOR-measured noninv asively-very closely approximates hepatic plasma flow. Because of its lower and more variable extraction ratio, indocyanine green should no longer be used without hepatic vein catheterization. Even in patients with cirrhosis, SOR exhibits higher hepatic extraction ratios than ind ocyanine green. To fully explore the potential of SOR in the evaluatio n of such patients attention needs to be paid to the complex changes i n architecture and function occurring in this disease. In cirrhotics t he noninvasively measured nonrenal clearance of SOR presumably approxi mates the flow through intact and capillarized sinusoids (functional f low) and reflects the amount of blood having functional contact with h epatocytes. The theoretic background of the method, its accuracy, furt her research needs, and potentials of various approaches are discussed in detail.