Device for supplying a liquid to a body cavity of a person or an animal and subjecting it to a determined pressure

A apparatus composed of a flexible bag containing a biological fluid in an enclosure sealed by a cover. The flexible bag is connected to a cavity in the human body through a tube that passes through a cover in the enclosure. In order to supply the biological fluid under an adjustable pressure to the cavity, the enclosure is connected to a source of pressurized air by means of an adjustable valve and a pressure regulator so that the pressure of the liquid in the cavity remains constant.

FIELD OF THE INVENTION 
The present invention concerns a method and a device for supplying a liquid 
at a determined pressure to a body cavity of a person or an animal for the 
purpose of an endoscopic examination or operation, the liquid being 
supplied from a source contained in a watertight and sterile flexible bag, 
connected to the said cavity by a watertight and sterile tube. 
BACKGROUND OF INVENTION 
The number of endoscopic examinations and operations is growing constantly. 
In order to obtain a good image of the body's cavity to be observed or in 
which one wants to operate, one generally feeds biological liquid to this 
cavity, the role of which may be to inflate the cavity and to evacuate the 
material coming from a tissue resection which, otherwise, would quickly 
render the operating field opaque. The feed pressure is essentially 
variable, depending on the tissues forming the cavity to be observed or to 
be operated on. The maintenance of constant pressure is of great 
importance, as an increase as well as a decrease of pressure in the cavity 
can lead to serious repercussions for the patient. In fact, excessive 
pressure may cause infiltrations of the liquid into the patient's body and 
damage to the cavity itself. A depression can have other results which are 
just as serious. If, for instance, during the resection of a tumor on a 
bladder wall, done by means of electric resistance, a sudden decrease in 
pressure could, in an untimely manner, cause the bladder wall to come into 
contact with the heating element and be pierced, with all the serious 
consequences this would entail. 
To measure the pressure of the liquid in the supply tube, a pressure sensor 
is installed in the supply tube. Such a sensor, however, poses a problem. 
One must, in fact, create a column of air in order to measure its 
pressure. To this end, the sensor must be installed at the end of a 
lateral tube, placed above the liquid level, and one measures the pressure 
of the air trapped in this lateral tube. To avoid any contact between the 
biological liquid and the sensor, a filter is installed at a certain 
distance from the sensor. The danger of this filter is that if it 
accidentally comes into contact with the liquid, some liquid will remain 
on the filter, and air bubbles will form in the tube, completely 
distorting the measurement. Since the risk of then seeing significant 
excessive pressure cannot be excluded, one must consider all the 
consequences that this would entail. The use of a security valve cannot be 
considered as, during the procedure, liquid could come into contact with 
nonsterile areas, which poses the risk of migration of microbial germs 
toward the irrigated cavity. Given these risks, some practitioners prefer 
to use the pressure created by a column of liquid, the height which is 
chosen according to the desired pressure. The drawback is that, depending 
on the desired pressure, there may not be enough vertical space in an 
operating room. 
Until now, all irrigation devices operating with a pump used a peristaltic 
pump, which is the only pump in which no mechanical part come into contact 
with the liquid and is thus compatible with the sterility of the supply 
liquid. The drawback to these volumetric pumps is that sinusoidal pressure 
is created in the supply liquid. In some cases, this sinusoidal pressure 
variation is unacceptable, as in the case of an endoscopic operation on 
the uterine tube, where the pressure must be perfectly constant. Moreover, 
with a peristaltic pump equipped with a pressure sensor, there is always a 
reaction time, so the pressure can fluctuate, and, in reality, it 
fluctuates constantly. 
SUMMARY OF INVENTION 
The purpose of the present invention is to remedy these drawbacks, at least 
in part. 
To this end, the purpose of the present invention is a method to supply a 
liquid at a determined pressure to a body cavity of a person or an animal, 
for the purpose of an endoscopic examination or operation, the liquid 
being supplied by a source contained in a watertight and sterile flexible 
bag, connected to the said cavity by a watertight and sterile tube, 
characterized by the fact that the said bag is then put in a watertight 
enclosure, and that this enclosure is connected to a source of fluid, the 
pressure of which is adjustable. Another purpose is a device to supply a 
liquid at a determined pressure to a body cavity of a person or an animal, 
for the purpose of an endoscopic examination or operation, consisting of 
at least one watertight and sterile flexible bag to contain the liquid to 
be supplied and a supply tube, connected to the said bag in a watertight 
and sterile fashion, characterized by the fact that it consists of at 
least one watertight enclosure in which the said bag is put and that this 
enclosure has an input port connected to a source of fluid under 
adjustable pressure and an opening for the watertight passage of the said 
supply tube though the wall of this enclosure. 
The advantages of the method and the device, object of the invention, are 
numerous. The most important one springs from the fact that the displayed 
pressure is truly the pressure in the supply tube and the irrigated 
cavity, and that this pressure does not fluctuate. In the completely 
improbable event that excessive pressure should occur, one can make use of 
a security valve which is connected to the compression fluid and not the 
supply liquid, so that there is no risk of contamination of the supply 
liquid. The above-mentioned problems, linked to pressure measurement, no 
longer exist as it is the compression fluid's pressure which is being 
measured and not the supply liquid's. In addition to the great reliability 
of the device according to the invention, its great simplicity should also 
be pointed out, as one has but to connect the pressurization enclosure of 
the supply liquid to a source of pressurized air which exists in every 
operating room. The peristaltic supply pump's electronic servo-system, as 
well as the pump itself, are thus no longer necessary, substantially 
reducing the cost of the equipment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
This device is made up of a watertight enclosure 1, the walls of which are 
sufficiently rigid to resist the pressure which will be created in the 
enclosure. It is hermetically closed with a cover 2 equipped with a 
security valve 3, calibrated in function of the maximum acceptable 
pressure. The enclosure 1 is connected to a source of pressurized air S by 
means of a control valve 4 and a pressure regulator 5. This enclosure 
contains a flexible bag 6 containing the biological liquid to be used to 
irrigate a body cavity 7 of a person or an animal. A tube 8 goes through 
the wall of the enclosure 1 and is used to connect the flexible bag 6 to 
the cavity 7. A coniform joint 13 is used to ensure the watertightness of 
the tube 8 through the wall of the enclosure 1. An outlet tube 9 connects 
this cavity to a recovery tank 10. A valve 11 or, preferably, a pump, is 
used to regulate the flow-rate in this tube 9, in function of the surgery 
or the examination being carried out by the practitioner. This outlet 
flow-rate is determined by the clarity of the liquid in the cavity which 
allows the practitioner to see the surgical field on a video screen, so 
that he can circulate a higher or lower flow-rate in function of the 
sharpness of the image which he observes on the screen. 
Whatever the flow-rate is, the pressure in the enclosure 1, and thus in the 
flexible bag 6, the tube 8 and the cavity 7, is constant and corresponds 
to the one displayed on the pressure regulator 5. As the pressure 
regulator operates to maintain a constant pressure, it constantly adapts 
to the outlet flow-rate, as well as to leaks. If the pressure tends to 
lower, it immediately compensates for it. Should, for example, a solid 
body plug the outlet of the cavity 7, which can happen in the case of an 
endoscopic resection, there is no risk of an increase of pressure, even a 
temporary one, as the pressure will remain constant as long as the setting 
of the pressure regulator has not been modified. The security valve 3 is 
only there in the event that an adjusting mechanism should fail as, in 
fact, this would be the only risk of an abnormal pressure increase. It 
should be pointed out, moreover, that it was not possible to equip earlier 
irrigation systems with a security valve because of the risks of 
contamination, should the previously invoked valve be activated. Thanks to 
the method and device, object of the invention, the presence of this valve 
does not pose a problem, because it acts on the compression fluid and not 
on the irrigation circuit itself. 
A heating element 12 may be installed in the enclosure 1, this heating 
element 12 being powered by a thermostatic adjustment mechanism (not 
shown). 
Generally, the biological liquid for endoscopic surgery in the field of 
arthroscopy is set up in two bags connected to the same supply tube 8. In 
this case, one merely needs to provide for a second enclosure, identical 
to the enclosure 1, to hold the second bag. 
In addition to the advantages mentioned previously, one can also point out 
that the device, object of the present invention, does not have any 
electric current except for the heating, which is limited to 40 W, which 
constitutes an advantage which cannot be overlooked. 
As opposed to irrigation pumps of prior art, the reaction time is quasi 
instantaneous, while with the pumps known in the art, using a servo-system 
in function of the pressure, measured by compressing a column of air by 
the supply liquid, two causes of inertia are added. The first is the 
compression of the air in the column, the second is the repercussion time 
in the supply liquid from the time the order has been sent to the 
peristaltic pump. The clinical tests run, using the described device, 
clearly showed this advantage compared with irrigations systems known in 
the art. 
The device illustrated by FIGS. 2 to 6 includes a housing 14, formed by a 
bottom 14, two opposed lateral walls 16 and 17, assembled by tie rods 18 
also acting as a spacer frame, the internal space being closed by a cover 
19, which is lodged on the two bearing surfaces 20 of the two opposed 
walls 16 and 17. 
Two cylinders 21 are mounted with their longitudinal axes disposed 
perpendicularly to the lateral walls 16 and 17. FIG. 3 shows the mounting 
of the cylinders 21 in the housing 14 in greater detail. The walls 16 and 
17 are made up of plaques, each with two holes drilled through it, 
respectively 22 and 23, corresponding markedly to the internal diameter of 
the cylinders 21. The rear wall 17 presents an annular internal bearing 
surface 24, meant to hold a transparent disk 25, in plexiglass, for 
example. This disk 25 presents an annular part 25a which is set between 
the bearing surface 24 and a sealing gasket 26, compressed between one end 
of the cylinder 21 and the annular part 25a. The other end of the cylinder 
21 compresses a sealing gasket 27 against an internal annular bearing 
surface 28 of the front wall 16, the assembly of the walls 16 and 17 and 
the cylinders being accomplished by the tie rods 18. Each cylinder 21 
presents an opening 29 to allow the introduction of pressurized air. This 
air comes from a source of air compressed at 600 kPa and enters a 
precision manometer-pressure reducing valve 30 (FIG. 5), adjustable by 
means of a button 30a from which it emerges at the displayed pressure. In 
this example, it is a Festo (Germany) manometer-pressure reducing valve. 
Each enclosure installed within the cylinders 21 is closed by a transparent 
door 31, in this example in plexiglass. The internal face of this door 
presents an annular groove in which a sealing gasket 32 is inserted. The 
lateral face of this door 31, opposed to its articulation hinge 33, 
presents a catch pin 34, while the fixed part of the housing bears a 
toggle type fastening mechanism including (FIG. 4) an articulated catch 
element 35 at the end of a rod 36, the other end of which is hinged to a 
base 37 which is part of the housing 14. The length of this rod 36 and 
thus, the space between the two hinge axes is adjustable thanks to a 
system with an adjustment screw 38. This closing system allows one to set 
the sealing gasket's 32 degree of compression. The open position of the 
catch element 35 has been illustrated in a dot-and-dash line. 
As illustrated by FIG. 3, a watertight supply bag 39 containing biological 
liquid is put into each cylindrical enclosure. Each door 31 presents a 
security valve 40 set at 30 kPa in the event that the machine is used for 
endoscopic orthopedic surgery, as well as an opening 41 for the watertight 
passage of a feed tube 42. In this case, in a traditional manner, one has 
one Y tube made up of two tubes 42, each one leaving from one of the 
supply bags 39 and ending in a common supply tube 43 leading to the 
operating field. Each tube 42 ends in a striking pin 44 to pierce the 
supply bag 39. Between the striking pin 44 and the common tube 43, each 
tube presents a sealing plug 45 and a clamp 46, used to control the 
opening and closing of the tube 42. 
FIG. 2 further illustrates a tube supplying compressed air 47 and a low 
voltage electric current (24 V) to heat the biological liquid, as well as 
valves 48 to start the pressurization to the value displayed by the 
manometer-pressure-reducing valve 30 of the cylindrical enclosures 21. 
FIG. 3 further shows an electric resistance 49 for heating the biological 
liquid. This resistance 49 is buried in a plastic sheet stuck on the 
external face of the lower part of the cylinder 21. The heating is done by 
means of simple contact between the flexible bag 39, which hugs the form 
of the lower part of the cylinder 21, and the lower part of this cylinder. 
The resistance is calculated to increase the biological liquid's 
temperature by a factor of 18.degree. to 20.degree. C. compared with the 
ambient temperature, so that the temperature at the bag's outlet is 
approximately 42.degree. C. so that, once the liquid arrives in the cavity 
to be irrigated, its temperature should be between 38.degree. and 
40.degree. C. 
Various interesting particularities of this machine may be brought up here. 
Its two lateral opposed walls are transparent, which allows both the 
surgeon and the theater nurse to check the level of the supply bag 39. 
Moreover, one of the transparent walls with the 
manometer-pressure-reducing valve 30 displaying the pressure and, if need 
be, allowing one to modify it thanks to the adjustment button 30a, may be 
turned toward the surgeon, who only has to be aware of the pressure and 
the fill level of the supply bag. The other opposed transparent wall is 
meant to be turned toward the theater nurse, who thus has access to the 
enclosures 21 through the transparent doors 31, which allows her to open 
and close the tubes 42 with the clamps 46 and, if need be, if two bags of 
biological liquid prove to be insufficient, to replace one. 
To do so, she simply has to cut off the supply from the corresponding 
enclosure using the valve 48, to empty air from the enclosure by pulling 
on the corresponding security valve 40 and opening the door 31. She 
removes the strike pin 44 from the empty bag, removes the bag 39, replaces 
it with a full bag and pushes in the strike pin 44, closes the door 31 and 
opens the valve 48. This entire intervention is carried out without ever 
bothering the surgeon as it is done on the wall located, from his point of 
view, on the back of the machine. 
The doors 31 are made of a thick plexiglass plaque, which gives it enough 
rigidity to attain watertightness with one single closing point. 
The tubes 42, with the incorporated sealing plug, allow one to introduce 
the strike pin 44 through the opening 41 of the door 31 and to close this 
opening by pushing the plug 45 in. 
The assembly of the front 16 and rear 17 walls with the help of the tie 
rods serving as spacers makes for an extremely simple assembly of the 
whole. The low voltage electric current with 40 W power allows the 
amperage to be reduced to below 2 A, so that the machine does not need 
electric accreditation. The cylinders, the cylindrical enclosures' floors 
and doors, all in plexiglass, enable good thermal insulation of the 
biological liquid. 
The heating of the biological liquid by contact between the lower surface 
of the cylinders 21 and the supply bags 39 should also be mentioned. This 
type of heating without a water bath presents an important advantage. In 
fact, a water bath constitutes an ideal medium for the growth of germs. If 
any part of the connection between the supply bag 39 and the strike pin 44 
should accidently come into contact with the water bath's water, there is 
a high risk of contamination, a risk which is avoided by the type of 
heating using the surface of cylinder 21, the external face of which is 
heated by the resistance 49.