Rapid assessment of cardiac output and central blood volumes from indicator dilution curves without precalculation using programmable calculators

1980 ◽  
Vol 11 (2) ◽  
pp. 105-112
Author(s):  
Mark A. Cole ◽  
Donald W. Crawford
1977 ◽  
Vol 233 (3) ◽  
pp. H350-H355
Author(s):  
L. D. Homer ◽  
A. Small

A model incorporating the effects of recirculation time lag, cardiac output, clearance, volume of distribution, and the variance of the distribution of recirculation times is applied to the analysis of indicator dilution curves. Experiments on dogs with use of radioactively labeled diethylenetriaminepentaacetic acid were done to evaluate the model. This five-parameter model can be fitted to data obtained during the period from less than 1 min to 3 h after a single injection of indicator. Estimates of cardiac output and clearance are in satisfactory agreement with estimates obtained by alternative techniques. Estimates of the time lag and volume of distribution are of physiologically plausible magnitude. The variance of the distribution of recirculation times is a new parameter, of which the possible usefulness to physiologists is discussed.


1965 ◽  
Vol 20 (6) ◽  
pp. 1365-1366 ◽  
Author(s):  
Ralph J. Gorten

A compact, lightweight scintillation detector which can be firmly attached to the anterior chest was fabricated in order to better adapt the isotope-precordial counting technic for measurements of cardiac output during exercise. In this manner useful indicator-dilution curves can be obtained without arterial puncture at light-to-heavy levels of bicycle ergometer or treadmill exercise. The use of a thin crystal and the omission of lead shielding and collimation of the detector is possible with a soft-energy gamma-emitting indicator of blood flow such as iodinated (I125) albumin. cardiac output during exercise; lightweight precordial scintillation detector; iodione 125; isotope-precordial counting technic Submitted on May 28, 1965


1964 ◽  
Vol 19 (5) ◽  
pp. 1024-1027 ◽  
Author(s):  
Hans U. Wessel ◽  
Charles F. Hepner ◽  
Gordon W. James ◽  
Paul Kezdi

An analog computer was designed for on-line computation of the area under indicator-dilution curves. From a model circulation and from two dogs, 165 tricarbocyanine green dilution curves were recorded with a cuvette densitometer, together with the computed area and signals indicating 60% and 30% of the peak deflection on the down slope of the curve. An IBM 709 digital computer was programmed to compare automatically and conventionally computed flow rates, to analyze sources of error in the computer, and to determine the goodness of fit of the extrapolated exponentials. The results indicated stable operation of the computer. The mean difference between the computer and graphic integration was minus 1.0% ± 2.4% for 78 flow estimates in the model, and 1.9% ± 2.5% for 30 cardiac output in the dogs. Data suggest that the computer does not introduce a significant error provided the dilution curves are also suitable for established graphic methods of integration. special purpose analog computer; instrumentation; cardiac output Submitted on December 6, 1963


1961 ◽  
Vol 16 (5) ◽  
pp. 891-895 ◽  
Author(s):  
Geoffrey D. Thorburn

A study was made of 135 dye-dilution curves, 77 of which were obtained from dogs and 58 from man. It was previously shown that the degree of asymmetry of indicator dilution curves varies with changes in flow, volume, and path length, and this has been found to influence the estimates of cardiac output made from the initial part of the curves by the forward triangle and Dow methods, and by a new method described in this paper. This variation may be minimized by the calculation of separate constants for each injection site and by keeping the variation in flow and volume as small as possible. Errors are likely to arise when these methods are used outside the range of the normal data. It has been found that this variation in asymmetry is mainly responsible for the scatter in the estimates of cardiac output using these methods. The agreement between the forward triangle and the Dow methods was found to be very close and the reason for this is discussed. Submitted on February 13, 1961


1963 ◽  
Vol 10 (1) ◽  
pp. 16-23
Author(s):  
N. F. Moody ◽  
H. D. Barber ◽  
B. A. Holmlund ◽  
J. E. Merriman

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