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Gastric secretion of water never stops
completely even during prolonged fasting.
On the other hand,
the stomach continuously empties itself
but nonetheless,
always contains some residual value
following a liquid meal,
an increased amount of water is secreted
into the stomach being mixed with the
meal and thus contributing to postprandial
gastric volume.
In studies of gastric retention using the saline
load test.
Gastric secretion of water was neglected
and postprandial gastric volume was equated with
volume of meal remaining in the stomach.
Today,
I would like to analyze with you the
respective role of the meal and of gastric
water secretion in the determination of
intragastric volume.
And to evaluate if in fact,
water secretion can be neglected.
In the present studies,
we have used this smaller water load
250 ml instead of
750 M L in the saline load
test.
And we have injected this tilt water
instead of saline.
This method was found to avoid Emsis which
occasionally occurs with the sailing load test.
Furthermore,
we use the di dilution technique to repeatedly
determine gastric volume during
fasting and following the water load
without having to completely empty the stomach.
The principle of the technique is illustrated on the first
slide
mhm.
Following a meal containing thinner red
as illustrated in yellow,
the stomach contains an unknown volume
V.
One having a concentration of thinner
red C one which can be
determined by sampling
the unknown volume V.
One can be determined by adding a
known amount of red.
And by using dilution principle
as illustrated in red.
A known volume V two of a thin
red solution having a concentration C two
is then injected after
mixing,
we have a situation which is illustrated in orange
intragastric volume.
V one V two has a thin
red concentration C three,
which can be determined by sampling stomach contents.
The equation describing this situation is listed
below and can be solved for V one.
Since this is the only unknown term of the
equation,
the sum of the two sampling volumes for
determining C one and C three
are chosen to be equal to the volume
injected V two.
Thus,
this double sampling and delusion technique
does not modify intragastric volume
by repeating this manipulation at 10 minute
intervals during fasting and
following a liquid meal,
it is possible to repeatedly determine
intragastric value.
The method was used in five patients with pyloric
outlet obstruction attributed to peptic
ulcer disease.
And we have compared the results with those obtained
in 11 normal subjects.
Total gastric volume is presented on the vertical
axis over time on the horizontal
axis during fasting and
following a 250 mL water mill
in normal subjects in green
fasting gastric volume is 16
mL.
Following the meal volume increases
to only 150 mL and
gradually decreases to fasting volume in
40 to 60 minutes.
In our patients with pyloric outlet obstruction,
as illustrated in yellow fasting
volume was increased threefold to 47 M
L.
Following the meal volume increased
to 220 M L
decreased rapidly up to 20 minutes
and then so slowly that it had not yet returned to
fasting value after 60 minutes.
What do these volumes represent
immediately after a water meal?
The gastric contents is mostly the water
meal with only a small
fraction reflecting reflecting gastric
secretion.
However,
as time passes by and gastric secretion
and emptying proceed,
a gradually increasing fraction of gastric contents is
secreted to
in the fasting state.
All gastric contents is secreted juice.
Thus an increased postprandial gastric volume
such as the one illustrated in yellow
could result from either slow gastric empty
or increased water secretion or both.
During the same experiments,
we have determined simultaneously gastric secretion
and gastric empty using a property of pheno
red that has not yet been mentioned,
it is not absorbed or secreted or
absorbed by the stomach.
Thus,
finna red can be used simultaneously as a delusion
indicator to determine the gastric volume as
shown in the slide and as a marker for
gastric emptying.
However,
before presenting to you the second step of the
calculation,
I'll show you what people usually would like to ask
me when I discuss this part of the method
to avoid this,
I will make any effort to simplify my description,
to understand the technique.
It is necessary to consider separately thinner red
and water.
These two components are illustrated here
as two separate containers.
Although in fact,
they are intimately mixed in
red,
the mass of phe are red present in the stomach at a particular
time.
The value of pr can be
calculated by multiplying the fre
concentration of gastric contents by
intragastric volume.
OK.
This is illustrated by W in white on the slide
by comparing intragastric mass of pinna
red say at time zero.
And at time 10,
1 can determine the rate of emptying for
pr during the time interval 0 to
10.
This rate is expressed in milligrams per minute and
is illustrated by G E times pr
in green and red on the slide.
Now to determine the rate of emptying of water in
milliliter per minute.
A two step calculation is required.
First,
we divide the rate of emptying of thin red
by intragastric mass of finna red to obtain
G E illustrated in green.
That is the fractional emptying rate for thin or red.
The slide illustrates that G E the fractional
emptying rate for red is also the fractional
emptying rate for water.
Assuming that finna red is homogeneously uh
is an homogeneous solution in water.
Then,
since we have previously calculated W
gastric water volume in white,
we cannot determine the rate of water emptying
G E times W.
And by difference,
the rate of water secretion in white.
On the other hand,
the mass of red and the volume of
water infused as a meal is precisely
known 250 men.
In the present case,
it is therefore possible to split compartment
W in two
compartment.
Number one represent the meal,
it is empty during fasting and is not
replenished.
Once intragastric infusion is terminated.
In contrast compartment,
number two is gastric secretions and
the portion that is emptied is constantly
replaced by water secretion.
We have already seen what happens to total gastric water
volume.
That is the sum of compartment number one
and number two.
In the two groups of patients,
we are now going to analyze independently.
Compartment number one,
that is the M L of meal
present in the stomach and compartment
number two,
that is gastric secretion.
Gastric volume is illustrated on the ordinate
over time.
And the abs for the 11 normal subjects
in green is total gastric volume already shown
previously in white
is the fraction of meal remaining in the stomach
during fasting.
By definition,
gastric volume is only secreted juice
following the meal.
The white line corresponds to the M L of
meal that has not yet been emptied.
That is the meal compartment.
In the previous slide,
the decline of the green line.
This reflects only emptying
the distance between the green and the white line represents
secretion compartment in the previous slide and
reflects both emptying and secretion.
Note that the two lines are parallel.
Indicating that if any increase of water
secretion of water secretion is
induced by the mill,
it is compensated by a simultaneous increase
of emptying.
After 60 minutes,
gastric contents is composed only of gastric
creations which reproduces the fasting
situation.
The next slide further illustrates this concept.
The rate of water secretion in M L per minute
is shown on the vertical axis.
Over time.
On the horizontal axis results
obtained in normal subjects is shown in white
following the meal.
A five fold increase of water secretion is
observed compared to fasting.
However,
this response is short lasting and has
disappeared by 20 minutes.
Thus,
a stimulation of emptying must occur
simultaneously to prevent an increase of
the secretion compartment.
Results obtained in patients with pyloric outlet
abstraction are shown in red.
Fasting secret rate is increased
threefold compared to normal subjects.
But the response to the meal is not increased.
20 minutes later,
water secret has returned to fasting value.
A significant increase of water secretion compared to
normal thus exists during fasting
and from 20 to 60 minutes after the
meal.
This difference is illustrated by the red stars.
This gastric hyper secretion combined
with a delayed gastric empty is responsible for
the increased postprandial residual volume.
This point is illustrated in the next two slides.
Gastric volume is illustrated on the ordinate
over time on the season.
In patients with pyloric outlet abstraction.
The yellow line represents the total gastric volume
previously seen.
The red line is the fraction of meat in the stomach and
reflects only empty
during the 1st 20 minutes.
The two lines are reasonably parallel but they
subsequently diverge the yellow line
plateauing while the red line continues downwards
at 60 minutes.
The distance between the two lines which illustrates the
secretion compartment is larger than at
30 minutes or during fasting,
it then represents 60% of the gastric
quote residual unquote.
Thus,
two factors that markedly increase gastric volume
postprandially are one slower
emptying and two increased gastric secretion
shown in the previous slide.
The alteration of gastric emptying in patients with pyloric
outlet abstraction are illustrated in the next
slide independently from water secretion.
The fraction of the meal remaining in the stomach
is shown on the vertical axis over time
on the horizontal axis.
For normal subjects in white and for
patients with outlet obstruction in red.
The slope of decline of these quote
mili of meal unquote
represents only emptying without
interference of secretion.
It appears clearly that empty is abnormally delayed in
patients with pyro outlet obstruction.
But that the difference is much less impressive than
when total volume is considered.
Could I have the light piece slide down?
In conclusion,
evaluation of gastric retention using a
water or saline load test
is and remains a good clinical method.
However,
the results should be interpreted cautiously in
the presence of gastric hypersecretion.
For example,
in py outlet obstruction produced by peptic or
disease.
Large postal gastric volume may be
found with only minor delay of gastric
empty.
Thank you.