J. D. COHN, K. ITO AND L. R. M. DEL GUERCIO 
PULMONARY INDICATOR 
TRANSPORT OF DOG 
Figure 4. — Analysis of contrast dilution curves for cal- 
culation of pulmonary circulation time is illustrated 
above. The original contrast dilution curve is shown 
in the insert. Curve smoothing is performed and the 
data is then replotted, by use of the calibration 
wedges, onto a logarithm scale. Each curve is recon- 
structed for exponential indicator washout and an ap- 
pearance time is identified for the left sided compon- 
ent of the contrast dilution curve. In this manner data 
are obtained for calculation of pulmonary circulation 
time, as shown in Table I, through use of equation 
(2). 
gen contrast dilution curves and averaged 
3.13 ± 0.57 (S.D.) seconds. 
SUMMARY 
The ability to record multiple contrast dilu- 
tion curves in an array pattern over the cardio- 
pulmonary silhouette allows for detailed eval- 
uation of hemodynamic function. This newly 
developed technique employs a single injection 
1089 
of a small amount of non-radioactive, radio- 
paque contract agent. The small dose injected 
has no effect on cardiac function. The nonin- 
vasive recording system faithfully transcribes 
changes in blood flow distribution, vascular vol- 
ume and stepwise washout from the ventricular 
chambers. This allows analysis of hemodynamic 
and circulatory phenomena related to cardiac 
function, intravascular shunting and cardiac 
ejection fraction. 
An experimental model was utilized to eval- 
uate the contrast dilution analyzer system in 
the analysis of transit time functions. Excellent 
correlation was noted between expected mean 
particle transit time and mean transit time de- 
rived from the contrast dilution curve data. 
Pulmonary circulation time is an important 
adjunct in the analysis of respiratory and hemo- 
dynamic function. This variable was ascer- 
tained in intact mongrel dogs through analysis 
of contrast dilution curve recordings. Pulmo- 
nary circulation time in six normal, intact, 
anesthetized dogs averaged 3.13 ±: 0.57 (S.D.) 
seconds. 
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