The Indocyanine Green Extraction Test of Liver Function in Pulmonary Disease

Abstract

Indocyanine green extraction and galactose tolerance have been measured in 6 normal subjects and 27 patients with marked reduction of ventilatory capacity. In 21 of the 27 patients the indocyanine green extraction was definitely abnormal, the other six gave borderline results. The galactose tolerance test was abnormal in 19 of 27 cases with a correlation coefficient of 0.69.The work indicates that a high proportion of patients with obstructive airway disease have evidence of liver dysfunction when conventional liver function tests are normal. It is postulated that this is due to reduced hepatic blood flow and hepatic congestion.REsULTS measurements were taken every 5 min for 20 min and then two further 10 min samples. Analyses were carried out as soon as possible and within one hour of the completion of the test. Galactose was measured using the galactose oxidase method (Hjelm, 1967). The indocyanine green was measured colorimetrically in plasma at 800 nm and the results expressed as per cent retention at 20 min. Arterial blood gases and lung function were measured on the same day and blood sample sent for T. and T. measurements.Previous work here has shown that a galactose half life of over 15 min is abnormal and the six normals in this series support this finding. Cobb and Saunders (1970) had control values for indocyanine green retention at 20 min of 0.56% to 1.08%. Normal values in this series range from 0.32 % to 2.7%. We suggest that values over 3 % are abnormal. METHODThe mean of the indocyanine green results expressed as percentage retention is 4.7%. Twenty-one of the thirty-three patients had values over 3 % and in all these there was marked reduction ofventilatory capacity. The eight patients with pulmonary heart disease had high percentage retention and in four it was over 10%. Six patients with reduced ventilatory function had indocyanine green retention figures within our normal range, but high by comparison with the controls of Cobb and Saunders (1970). Thirty-three patients were studied. Six wereThe intravenous galactose tolerance test was normal; twenty-seven had marked reduction of the abnormal in nineteen cases. The mean was 17.2 min. ventilatory tests of lung function. Eight had pul-All nineteen had marked reduction of ventilatory monary heart disease; eighteen had normal electro-capacity and again some of the more severe cases cardiograms.had the highest levels of galactose half life. Eight The test was carried out at 9.30 after an overnight patients with pulmonary disease had normal glactose fast and with patients at rest. Intravenous galactose half life of 15 min or less but three had abnormal (0.35 gfk) and indocyanine green (0.5 mgfk) were indocyanine green extraction. The correlation injected into one arm and sampling carried out from coefficient r was 0.69 (Fig. 1). the other arm. Samples for dye estimation wereThe relationship of the galactose tolerance and taken every 4 min for 20 min; samples for galactose indocyanine green extraction to the tests of ven-26

The use of computer-assisted experiments in the canine to support the development of a mathematical model for the hepatic removal of indocyanine green dye under normal and reduced hepatic blood flow conditions

“…It was stated that the impairment appeared to continue for some time when, presumably, the circulation was normal, as indicated by presence of normal blood pressures and the lack of evidence of cardiac failure. Edwards et al (1972) conducted a study of human patients presenting varying degrees of reduced ventilatory capacity associated with chronic bronchitis. Twenty-one of 27 patients (78%) who showed a normal liver function by a more conventional galactose tolerance test also showed an abnormal mean percent ICG retention of 4.7% (normal <= 3%), indicative of liver dysfunction.…”