ESTIMATION OF SPLANCHNIC BLOOD-FLOW BY THE FICK PRINCIPLE IN MAN AND PROBLEMS IN THE USE OF INDOCYANINE GREEN

Objectives: Measurement of splanchnic blood flow is necessary to evalu ate the effect of therapeutic interventions on splanchnic tissue perfu sion. Systemic indocyanine green (ICG) clearance has been used to esti mate splanchnic blood flow, but the results may be compromised by alte red hepatic dye extraction. We evaluated the applicability of simultan eous estimation of splanchnic and femoral blood flow by dye dilution a nd regional blood sampling in intensive care patients. Methods: 240 si multaneous determinations of regional blood flow were conducted in dif ferent patient groups (cardiac surgery, ARDS, pancreatitis, septic sho ck, preoperative controls). The measurement protocol consists of cathe terizations of hepatic vein, femoral artery and vein and primed consta nt infusion of two different ICG preparations. Results: The method was used successfully in a wide variety of patients. Steady-state dye con centration and sufficient dye extraction was achieved in each group of patients. The coefficient of variation of splanchnic blood flow estim ation was 7 +/- 1% and of femoral blood flow estimation 6 +/- 0%. Ther e was a great intra- and interindividual variation of ICG extraction U se of dobutamine modified the extraction in most patients but did not lessen the performance of the method. ICG extraction was markedly lowe r and the coefficient of variation of both femoral and splanchnic bloo d flow markedly higher with propylene glycol-dissolved ICG preparation as compared with the freeze-dried. Conclusions: The prerequisites for the method of primed, constant infusion of indocyanine green with hep atic vein catheterization are achieved in intensive care patients. The results of splanchnic blood flow estimations based on techniques with peripheral blood sampling should be interpreted with caution, and the use of ICG clearance as a flow-related indicator without the measurem ent of ICG extraction cannot be justified because of the great variabi lity of dye extraction. Certain indocyanine green preparations may gre atly modify the results of the regional blood now determinations.