IL32565A - Insufflation apparatus for artificial respiration or narcosis - Google Patents

Description

ικ nnon Insufflation Apparatus for Artificial Bespiratic or Narcosis 1 She present invention relates to an insufflation apparatus for performing artificial respiration or narcosis of the type comprising a manually compressible pumping pumping means which automatically restores its shape after In such apparatus the pumping means is provided with at least one check in the for introducing air some other inhalant gas into the pumping and an outlet check at the outlet of the pumping to gas from flowing back from the apparatus of this type operates in substantially the following Upon compression o the pumping means the gas contained therein is forced through the outlet valve and therefrom into the air ducts of the patient via a breathing The pumping means is then released and regains its original shape due to its As the pumping means is restored to its original shape filled with gas through the inlet valve or valves which are connected to the ambient air to a source of another inhalent gas such as oxygen or an anaesthetic The pumping means usually designed as a bag or The bladders now available are of two different one is a single walled bladder of a material which is at the same time and and the other type is a bladder which is provided with a insert for foam rubber and with outer The double walled bladder has the advantage that it gives a lesser degree of fatigue during extended thereby making it possible for a to give artificial respiration continuously for a long period of It a drawback of both types of tho known that the indication of dangerous overpressures the bladder example caused by an obstacle in the air is performed on ouch a subjective basis as the ability of the saver to discover pressure changes in the system by of the feeling of his This basis for said indication especially unsuitable when an unpractlced person has to use of the Since pressures above a certain threshold value in air ducts can severely damage the patient it has to be ensured that such overpressures appear due to incorrect handling of the It has been proposed to solve this problem by providing the bladder with a special pressure relief but there always a risk that such a valve be blocked whereby the patient can still be subjected to dangerous which is especially dangerous when the bladder is supplied with an anaesthetic Another drawback that the known pressure relief valves must be adjusted to a overpressure which does not the patient even over long periods of It important especially when treating babies to be able to obtain for a relative short period a higher initial pressure since for the first expansion of the lungs a considerably higher pressure example 20 40 cm is required than is required for the continued artificial respiration example 3 cm A control device for controlling the throughput of gas in respiratory apparatus has been known patent fication which contains two valves and two diaphragms and in which each of the inlet valves is operatively associated to 2a Preferred of present invention provide an apparatus for artificial respiration which completely eliminate the risk of dangeroue overpressures appearing in the air which is of an extremely simple construction and for a short initial period allows even pressures of values which would be dangerous when applied over a long period of 3 present invention attacks the problem of pressure limitation a quite different point of view than do the known because instead of using separate pressure relief valves the invention provides a pumping means which serves in itself as pressure limitation thereby eliminating all movable which can be blocked According to the invention there is provided insu flation apparatus for artificial respiration and narcosis conprlaing manually co pressible pumping having an inlet connection provided with a check valve arranged to prevent passage of gas from said pumping means through the inlet the pumping 4 the element at such a rate as to cause the pressure in said pumping means to drop to a value below said predetermined These pressure values are chosen with respect to the intended of application and fo different for babies and adult When utilizing a single walled bladder the bladder can be made thicker and more resistant in those areas are by the operator during the rest of the bladder being thinner and sufficiently elastic to serve as the pressure limiting By an arrangement be impossible to construct a bladder which presents very good resistance to repeated compressions while at the same time maintaining the pressure limitation function is then performed by those parts the bladder which are in contact with the When the invention is applied to a double bladder which is provided with an insert having good sel properties and a gas tight outer skin arranged around the the insert must provided with passages or other connections for transferring the pressure prevailing in the inner cavity of the bladder to the outer skin which should be so elastic that it can serve as the resilient Although it is possible to make the insert of a porous material and let the pores in the material serve as the passages transferring the pressure prevailing in the cavity limited by the insert to the outer it is advantageous to provide the insert with special use of a porous material is especially 5 supply thereof to the bladder has been cut It is in any case preferable to the insert of a material absorbs none or only mounts the treating gas to cover the surfaces of the insert contacting the treating gas with a thin film said She elasticity of the membrane or serving as pressure limitation means is preferably such that the overpressure in the system cannot exceed a value of up to about 100 cm preferably up to about 60 cm In a preferred embodiment of the invention utilising a double bladder the channels provided in the insert are designed so that the total flow capacity thereof is sufficient to permit an instantaneous of the pressure prevailing in the inner cavity of the bladder to the outer cavity between the insert and the outer thus preventing dangerous overpressures in the system when the compression frequency is Duo to this design of the channels i is of importance that no channels can be blocked off upon compression of the Xt is therefore important that the are disposed in parts of the insert as will not be blocked off upon compression o the According to a particular embodiment of the invention the channels are disposed near the vertices of an insert shaped as an It is also to be noted that the pressure limitation obtained by the present invention not only functions upon activation of the pumping but also the pressure tends to increase due to excess supply of oxygen or anaesthetic gas to the of the invention are described below by way of example with accompanying drawings in 6 1 is a view in axial section illustrating a pumping according to the invention designed as a single 2 a view in axial along the line IX in Figure of a suitable embodiment of a double walled bladder constructed in accordance with the 3 shows the bladder according to 2 in along the line III III in Figure 4 is a view in axial section illustrating the operatio of bladder according to 2 and 3 upon compression of the bladder shown in is with a first vailed part 2 having good and a second part 1 which is thinner and sufficiently elastic to serve as a pressure limitation The bladder is gas tight and is provided with or more channels or connections 3 for supplying gas to the bladder and a connection 4 which is connected to the respiration mask or a similar device to be applied to the Connections are provided with check valves 5 allowing gas to flow only into the Connection 4 is provided with a valve 6 allowing gas to flow only in the opposite from the The bladder shown in 1 is provided with two channels or connections 3 which are disposed one on either side of the central connection but it of possible to make use of a different number of connections disposed any other possible way without departing from the scope of the When utilising the bladder the part 2 is compression causes an increase in pressure above atmospheric to appear in the As a consequence thereof check valves 5 are closed and check valve 6 The elastic part 1 of the bladder expands and tends to compensate for the decrease in volume of the bladder accompanying preasure caused by the but the elasticity of the elastic part 1 is not at to said pressure As a consequence thereof the compression of the bladder produces a rapid pressure increase therein up to such preseure values example overpressures of 30 60 cm which are required for producing inhalation during normal At greater overpressures in the for example caused by obstacles in the air ducts or escess supply of oxygen or anaesthetic gas to the the elastic part 1 of the bladder becomes store elastic and when the overpressure in the bladder has reached a predeterainded value which does not the patient said part 1 becomes so elastic that any force tending to further increase the pressure in the bladder will immediately be compensated by a corresponding expansion of the elastic part In this overpressure in bladder will not be able to exceed said broken line 11 in 1 gives an idea of a possible shape of the elastic part 1 after said limit pressure has been reached in the The arrow S indicates how said part be further expanded without pressure increase for a further amount of anaesthetic gas is supplied into the 2 and illustrate how the invention can be applied to a double walled bladder comprising an outer skin 1 which is disposed around a insert In this case the outer skin which is made of a gas tight elastic material 6uch as serves as ressure limitation The outer skin can be provided with 8 folds nuiaber of which is four the embodiment shown in 2 and bladder is further provided with an inlet tion and an outlet the outer skin tightly secured to these The connection 3 is provided with check valve 5 allowing to flow only into the and connection 4 is provided with a check valve 6 allowing gas to flow only out from the connection 4 is either directly or by means of a gas conduit connected to a suitale respiration mask In order to achieve the pressure limitation aimed the insert 2 is provided with channels 7 interconnecting inner cavity 8 of the bladder and the outer cavity 9 between the and the outer In particular eabodiment the insert has approxiiaately the shape of an channels 7 being disposed near the vertices of the The apparatus provided with a double walled bladder according to the invention in the following manner which is illustrated in When the apparatus is to be connectio 4 is connected to a respiration which is against the mouth and the of the The operator supports the a the inlet and outlet connections 4 and the artificial respiration begins with of the bladder by the arrow thereby forcing the gas contained i the inner cavity 8 into the respiratory through connection check valve and the respiration When a su icient volume o g has been forced into the lunge operator releases the bladder which regains its original shape due to the shape restoring property of the insert and new gas is the bladder 9 Upon of the bladder the gas contained in the inner cavity 8 flows not only through check valve but also through the channels this manner the prevailin in the inner cavity is transferred to the outer cavity 9 formed by between the insert 2 and the outer akin of the channels It is assumed in Figure 4 that the air ducts are partly or completely obstructed that the gas flow indicated by the arrow B decreases or but for the pressure limitation provided by the present dangerous overpressures could appear the In pumping means according to Figures 2 to 4 such a dangerous however cannot since the outer skin is so elastic that any tendency to dangerous overpreseures in the system will immediately be compensated by a corresponding expansion of the outer skin as by the broken line 10 in Figure operation of according to Figures 3 and 4 will consequently be such that compression of the bladder during normal conditions of operation obstacles in the air no excessive supply of anaesthetic gas to the produces an the bladder which is sufficient to overcome the resistance in the air ducts and produce artificial whereas compression of the bladder when the pressure therein has Reached a predetermined threshold value normally is not dangerous to the produces an increase of the volume of the bladder expansion of the outer skin which as great as the decrease in volume caused by Figure 2 illustrates the case when an overpressure is up in the system due to continuous supply of for example anaesthetic and not by compression of the Also in this figure the normal of the outer skin 1 indicated in continuous the shape of the outer skin after the highest overpressure has been in the system being illustrated by the broken line additional supply of gas to the bladder which tends to Increase the pressure therein will be by a further expansion of the outer skin in the direction of the arrow It is not necessar that the outer skin 1 be loosely arranged to the In this case the bonded portions of the outer skin are preferably disposed suc parts of the bladder as are in contact with the operator during The folds of the outer skin can be used for the ion of relatively small overpressures appearing i the the indication being performed by the inflation of said It not sufficient to provide an indication only by of folds such as since the highes overpressure which can be indicated in such a way is usually too low and since an indication of this type requires a continuous surveyance of the shape of the oute akin Therefore pressure limiting means is also required as provided by the insufficientOCRQuality

Claims (1)

1. 32565/2 - 11 - Insufflation apparatus for artificial respiration and narcosis comprising manually compressible pumping cieans having an inlet connection provided with a check valve arranged to prevent passage of gas from said pumping means through the inlet connection the pumping means further having an outlet connection for placing in coraaunication with the air ducts of a patient, the outlet connection being provided with a check valve arranged to prevent passage of gas to said pumping means through the outlet connection, the pumping means including at least one thin and gas-tight resilient membrane element forming at least part of the outer vail of the pumping means and exposed on its inner side to the gas pressure within the pumping means, said membrane element being free to expand in response to pressure within the pumping means and being so constructed that below a predetermined threshold value of the pressure within said pumping means, hich threshold value is such as to be not harmful to a patien , the membrane element does not expand significantly, whereas when said threshold value is reached the membrane expands, during continued compression of the pumping means or continued supply of inhalent gas thereto at least to an extent sufficient to prevent any significant increase in pressure within said pumping means above said threshold value. Insufflation apparatus according to claim 1, wherei the or each said membrane element is so made that when said threshold value is reached during compression of said pumping means,continued compression of the pumping means will cause expansion of the membrane element at such a rate as to cause the pressure in 12 - 32565/2 3. Insufflation apparatus according to claim 1 or 2, in which the pumping means is a single walled bladder having first and second portions which are made integral* said first portion being self-restoring and thicker than said second portion which forms the thin gas-tight resilient membrane eleaent. 4· Insufflation apparatus according to claim 1 or 2, in which the pumping means is a double walled bladder comprising a self-restoring insert surrounded by a gas-tight outer skin providing the or each said thin gas-tight resilient membrane element and being free from the insert over at least one portion, and in that the insert is provided with passages interconnecting the free portion or portions of the outer skin and the vavity defined by the insert. 5. Insufflation apparatus according to claim 4» in which the channels or passages are disposed in such parts of the insert as are free from the outer skin upon compression of the bladder. 6. Insufflation apparatus according to claim 4 or 5» in which the bladder has the general shape of an ellipsoid, and in which the channels or passages provided in the insert are disposed near the vertices of said ellipsoid. 7· Insufflation apparatus according to any of claims 4 to 6, in which the total flow capacity of the channels is sufficient to prevent dangerous overpressures in the system even when the compression frequency is high. 8. Insufflation apparatus according to any of claims 4 to 7» in which the insert is made of a material which absorbs none of, or only small amoun of the treating gas. 13 32565/2 9» Ineufflation apparatus according to any of claims 4 to 8, in which the surfaces of the insert contacting the treating gas are covered with a thin film which is impermeable to oaid gas* 10. Ineufflation apparatus substantially as hereinbefore described wih reference to. and as shown in Figure 1 of the accompanying drawings· 11. Ineufflation apparatus substantially as hereinbefore described with reference to, and as shown in, Figures 2 to 4 of the accompanying drawings. For the Applicants Dr. Yitzhak Hess