2.5. Risultati delle prove di perfusione Results of the Perfusion Tests |
|
2.5. Results of the Perfusion Tests |
|
2.5.1. Perfusion Tests with Bovine Blood |
|
Portata di perfusione cc/min Flow | 80 | Sangue:
Blood: |
||
Trasudamento % Seepage | -- | Ht | 31.5 | |
Totale perdite % Leakages | 7.8 | PCO2 | 43.0 | |
P arteriosammHg Arterial pressure | 150 | PO2 | 31.2 | |
P venosammHg Venous pressure | 20 |
Portata di perfusione cc/min | 78-100 | Sangue: | ||
Trasudamento % | -- | Ht | 29.5 | |
Totale perdite % | 29 | PCO2 | 37.0 | |
P arteriosammHg | 80-205 | PO2 | 63.8 | |
P venosammHg | 17-25 |
Portata di perfusione cc/min | 122 | Sangue: | ||
Trasudamento % | -- | Ht | 37.0 | |
Totale perdite % | 41.6 | PCO2 | 38.0 | |
P arteriosammHg | 93 | PO2 | 13.9 | |
P venosammHg | 20 |
Portata di perfusione cc/min | 145 | Sangue: | ||
Trasudamento % | -- | Ht | 36.0 | |
Totale perdite % | 31 | PCO2 | 66.4 | |
P arteriosammHg | 76 | PO2 | 39.3 | |
P venosammHg | 12 |
Portata di perfusione cc/min | 112 | Sangue: | ||
Trasudamento % | -- | Ht | 27.0 | |
Totale perdite % | 1.8 | PCO2 | 84.5 | |
P arteriosammHg | 120 | PO2 | 23.1 | |
P venosammHg | 20 |
Portata di perfusione cc/min | 100 | Sangue: | ||
Trasudamento % | 16.9 | Ht | 34.0 | |
Totale perdite % | 20 | PCO2 | 41.2 | |
P arteriosammHg | 76 | PO2 | 27.8 | |
P venosammHg | 15 |
Portata di perfusione cc/min | 145 | Sangue: | ||
Trasudamento % | -- | Ht | 38.0 | |
Totale perdite % | 38 | PCO2 | 36.9 | |
P arteriosammHg | 145 | PO2 | 13.8 | |
P venosammHg | 21 |
Portata di perfusione cc/min | 213 | Sangue: | ||
Trasudamento % | 12.7 | Ht | 31.5 | |
Totale perdite % | 31.9 | PCO2 | 15.2 | |
P arteriosammHg | 104 | PO2 | 13.4 | |
P venosammHg | 14 |
Portata di perfusione cc/min | 190 | Sangue: | ||
Trasudamento % | 18.3 | Ht | 36.0 | |
Totale perdite % | 21.1 | PCO2 | 30.6 | |
P arteriosammHg | 180 | PO2 | 28.2 | |
P venosammHg | 19 |
Portata di perfusione cc/min | 145 | Sangue: | ||
Trasudamento % | -- | Ht | 26.0 | |
Totale perdite % | 10.34 | PCO2 | 76.0 | |
P arteriosammHg | 115 | PO2 | 16.0 | |
P venosammHg | 20 |
Portata di perfusione cc/min | 210 | Sangue: | ||
Trasudamento % | 17.1 | Ht | 25.0 | |
Totale perdite % | 42.2 | PCO2 | 35.5 | |
P arteriosammHg | 181 | PO2 | 27.4 | |
P venosammHg | 21 |
Portata di perfusione cc/min | 90 | Sangue: | ||
Trasudamento % | 46 | Ht | 37.0 | |
Totale perdite % | 54.1 | PCO2 | 70.3 | |
P arteriosammHg | 169 | PO2 | 29.0 | |
P venosammHg | 16 |
Portata di perfusione cc/min | 145 | Sangue: | ||
Trasudamento % | 35.8 | Ht | 26.0 | |
Totale perdite % | 37.8 | PCO2 | 51.2 | |
P arteriosammHg | 180 | PO2 | 25.5 | |
P venosammHg | 18 |
We executed also some tests injecting a dilator (Isoptin, of Knoll
A.G., 1cc) into the placenta #5, obtaining appreciable variations of pressure:
Tab.23/A: placenta #5 (with Isoptin).
Tab.23/B: placenta #5 (as above, with higher
flow).
Portata ingresso cc/min Input flow | 112 |
P arteriosa mmHg Arterial Pressure | 30 |
P venosa mmHgmmHg Venous Pressure | 20 |
Portata ingresso cc/min | 165 |
P arteriosa mmHg | 63 |
P venosa mmHg | 21 |
These data confirm that the high pressure measured in the arterial
cannulas is not due to formation of coagulates in the placenta during the
incannulation.
The time of perfusion spans between 5 and 29 minutes. The seepage
causes the elevation of the haematocrite of the blood beyond the physiological
values, reason for which the test cannot be hold for greater times, unless
we use a bigger reservoir.
In fact the arterial pressure, after some minutes of perfusion with
blood, starts to increase, even if we attempt to contrast the phenomenon
with Isoptin or higher partial pressure of CO2. In our opinion it is due
to the increase of the viscosity of the blood, caused mainly by the increase
of haematocrite. In fact the perfusion with isotonic solution at the same
PCO2 of the blood of the umbilical arteries, even if hold beyond 20 minutes,
does not give place to the described problem. Moreover the increase of
viscosity influences the pressure due to the arterial cannulas: during
the tests, increments of the order of 200 mmHg have been detected, such
to cause obvious difficulties of determination of the effective arterial
pressure.
The observed values of seepage of plasma (averaging 24,3% of the
perfusion flow) confirm something that had already been discovered by other
Dutch researchers [38] during experiments
hold with isotonic solution rather than with blood.
2.5.2. Perfusion Tests with Formaldehyde |
|
Placenta |
|
|
|
2 |
|
|
|
3 |
|
|
|
4 |
|
|
|
5 |
|
|
|
6 |
|
|
|
The obtained values of pressure are lower than the ones recorded in
literature [38]. We found a remarkable reactivity
to the concentration of carbon dioxide in the perfusion fluid. During the
first experiments, that were carried out without bubbling CO2 into the
water, we always had an increment of the inlet pressure, at steady flow,
such to produce lacerations. The increase started within 4 minutes from
the beginning of the perfusion and reached the full scale of our instrument
(360 Torr) in 3 to 7 more minutes.
What is known on the reactivity of the human placenta is derived from
experiments of perfusion on placentas after the childbirth: we do not have
quantitative data from the medical literature, and our aims did not include
this type of study.
The transition from isotonic solution to fixation solution gives place
to positive or negative not meaningful variations of the arterial pressure
(lower than 10 Torr): the viscosity of the two fluids is similar and seems
that they are not cause of reactions of constriction or expansion.
Table 25 and 26 summarize
the perfusion data and the morphometric values obtained at the laboratory
of Pathological Anatomy of the hospital San Paolo on the first two fixed
placentas.
Placenta |
|
|
|
1 |
|
|
|
2 |
|
|
|
3 |
|
|
|
4 |
|
|
|
5 |
|
|
|
6 |
|
|
|
Vessel order | Vein mm | Artery mm | |
Chorionic |
|
|
|
Trunci |
|
|
|
Rami | I |
|
|
II |
|
|
|
III |
|
|
|
IV |
|
|
|
Ramuli |
|
|
|
V. term. e sinusoids |
|
|
The first orders of vessels introduce two arteries for each vein. The
physician who carried out the measurements supposes that the situation
is presumably opposite starting from the rami.
He verified that the perfusion had been executed correctly, as the
fixing fluid was been able to reach all the placental vessels up to the
sinusoids.
Some microphotographies are evidence that our method of perfusion is
useful to carry out the measurements of the placental vessels.
The figures 51 and 52 are related to the same the type of section of a not perfused placenta and of a perfused placenta. They evidence a remarkable difference: the not perfused villi appear constituted mainly by connective tissue, while as a result of perfusion they are quite more expanded. Data of table 26 better define the exposed concepts.
Fig.53: Stem villus (ramus of IV the order, the last one that
has a muscular layer).
Section in resin, magnified x1150. Placenta not perfused.
Figures 53 and 54 allow a comparison between perfused and not perfused vessels pertaining to same the level.
Fig.54: Stem villus (ramus of IV order). Section in resin,
magnified x1150.
Placenta perfused with fixing solution.
The sections in paraffin are 4 mm thick,
the ones in resin approximately 1 mm.
The figure 55, related to a ramus of II order,
reveals the usual vasoconstriction of the placenta after the childbirth:
the section of vessels is filled by the connective tissue and by the muscular
tissue of the vessels themselves.
The measurements carried out on the terminal villi of the perfused
placentas did not evidence differences compared to data from the literature
[20].
![]() ![]() |
Abstract ![]() |
Index ![]() |
Download ![]() |
Links ![]() |
Contact us ![]() |
3.1. ![]() |