The use of a compartmental hypothesis for the estimation of cardiac output from dye-dilution curves and the analysis of radiocardiograms

Abstract Three approximate methods for the computation of cardiac output from dye-dilution curves have been analysed using the classical Stewart-Hamilton technique as a reference in a total of 89 curves obtained from 11 dogs. The gamma-function method has a tendency to overestimate on the average (+...
Ausführliche Beschreibung

Abstract Three approximate methods for the computation of cardiac output from dye-dilution curves have been analysed using the classical Stewart-Hamilton technique as a reference in a total of 89 curves obtained from 11 dogs. The gamma-function method has a tendency to overestimate on the average (+7·1%±1·6%), with an 82% probability of falling within ±20% of the Stewart-Hamilton value. The forward-triangle and compartmental methods are approximately equivalent, the first giving a small overestimation of (0·3%±1·2%), and the second a small underestimation of (−3%±1·2%); both methods have a probability of better than 92% of being within ±20% of the Stewart-Hamilton value. The analysis of human radiocardiograms by the compartmental method was encouraging. A number N of equivalent compartments greater than 2·2 for either the right-or left-heart peaks was associated with an abnormal radiocardiogram. In eight normal subjects, N yielded an average of 1·73 for the right heart and 1·69 for the left heart. The compartmental analysis of radiocardiograms, together with a study of other parameters of the curves, would seem to provide a useful assessment of the cardio-vascular function. Ausführliche Beschreibung