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MONITORING 
use to determine whether it's plus or minus 5 
per cent? What is the standard, quite precisely? 
Chairman : I use a graduate and a stop 
watch, and there is no alternative. 
Questioner (Unidentified) : A trivial ques- 
tion — in your pulse flowmeter, you show a neat 
parabolic cross section of flow profile, and I 
assume that's why Dr. Franklin got his linearity 
between the empiric data and the device he used. 
I'd like to ask if you have any built-in assump- 
tions as to what the velocity profile has to be 
when you'll be working with pulse? 
Dr. Meindl :I think the fortunate thing about 
the pulse flowmeter is that you can be entirely 
devoid of any preconceptions about what the 
profile is and it still does the job for you. It 
will tell you exactly what that profile is. 
B. W. Sauer, Clemson University, South Car- 
olina : My question is in reference to the, again, 
velocity profile. Could we assume that such an 
instrument could be used to measure the variable 
velocity profile, say, in turbulent flow? 
Dr. Meindl: The answer is simple — no. In 
the instrument that I use or that I described, 
you could not calculate volume of flow or veloc- 
ity in turbulent flow. If you want to do that, it 
requires the use of additional transducers. It 
can be done, but it's a more complicated process 
than the one that I described. 
Chairman: Is it conceivably feasible? 
Dr. Meindl: I feel that it's conceivable that 
you could do it. 
Chairman : So do 1. 1 think that it shows very 
much promise on that very basis, that it shows 
promise of providing precisely the thing that 
you indicated. That is why I agree with Jim 
that a Pulse Doppler, theoretically at least 
(there doesn't exist a practical one as yet), 
shows promise of providing a measure of ab- 
solute volume flow. It is the only instrument 
that does show that promise in a practical sense. 
I think it's very clear that from this after- 
noon's work that while it may be possible to 
telemeter things, it's difficult to put them into a 
form II telemeter. The measurement is the ma- 
jor diflRculty. We still obviously are having con- 
siderable difficulty measuring blood pressure 
and blood flow. There's no question of it, and 
so I'm happy to see such good people working in 
these very areas. 
Now then with regard to our visitor from 
France. He's used a Perouneau pulse flowmeter 
and he has a very brief comment. 
D. Y. LoiSANCE, Broussais Hospital, Paris, 
France: For two years, we have been using 
a Pulse Doppler flowmeter designed by Dr. 
Peronneau in Paris. May I have the first slide 
please? This Doppler flowmeter allows the re- 
cording of velocity profile in a vessel. Zero is 
obtained without occluding the vessel. We can 
recognize internal diameter of this vessel on 
the echogram. To assess the volume flow, we as- 
sume that the profile recorded on one diameter 
of the vessel is representative of all of the diam- 
eters. And by a semi-annular arranging of a 
small part of the flow, we can guess the total 
volume flow. May I have the second slide please? 
We use this flowmeter in a lot of demonstra- 
tions in dogs and in humans, in acute and in 
chronic experiments. In an acute experiment, we 
record profile of velocity in different parts of 
the aorta. I will speak to you about the readings 
we get in the portal vein and hepatic artery be- 
fore and after a side-to-side portacaval shunt. 
We choose this model because we were expect- 
ing a very strange velocity profile. I put velocity 
transistor on the portal vein in two different lo- 
cations — one on the distocervical portal vein 
just on the side of the portacaval shunt and one 
before the portocaval shunt. An additional 
probe is placed on the hepatic artery. We can 
change the outflow resistance of the hepatic cir- 
culation by a snare which controls the flow in 
the hepatic vein. May I have the next slide ? 
These are aorta regions in normal dogs. You 
can see a velocity profile in the different parts 
of the portal vein. This velocity profile is never 
parabolic and very often, in 50 per cent of our 
dogs, we get this very strange velocity profile. 
It seems like we have two different parts in the 
flow. Here is hepatic artery velocity profile and 
in the hepatic artery we never get parabolic 
velocity profile. May I have another slide? 
Here again is a normal velocity profile in a 
normal portal vein in a different part of the 
portal vein. Here is a velocity profile down- 
stream to the side-to-side portocaval shunt in 
two different conditions. Here is a suprahepatic 
vein open and here is one closed. Here we can 
record the bidirectional flow. In this condition 
