Title:
Respiration apparatus
United States Patent 2121311


Abstract:
Our invention relates to artificial respirators, and especially to apparatus of this type which is suitable for maintaining respiration during surgical operations on the lungs of a patient. Broadly, there are two types or kinds of respiration apparatus, the first being employed to revive persons...



Inventors:
Wilhelm, Anderson Emil Einar
Vilhelm, Johanson Georg Karl
Application Number:
US1399635A
Publication Date:
06/21/1938
Filing Date:
04/01/1935
Assignee:
GASACCUMULATOR SVENSKA AB
Primary Class:
Other Classes:
92/94, 128/203.17, 137/102, 251/58
International Classes:
A61M16/00
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Description:

Our invention relates to artificial respirators, and especially to apparatus of this type which is suitable for maintaining respiration during surgical operations on the lungs of a patient. Broadly, there are two types or kinds of respiration apparatus, the first being employed to revive persons who are apparently dead, and the second being used for sustaining respiration during operations.

In the respiration apparatus used to revive persons who are apparently dead, an injector is used, the pressure and suction sides of which, respectively, are connected alternately with the inhaling conduit: Apparatus of this kind consequently operates so that air or oxygen gas is forced into the lungs up to a definite pressure, whereupon the gas is sucked out until a pressure somewhat below atmospheric pressure is obtained. Thereupon, the cycle is repeated.

The apparatus hitherto used for sustaining respiration during operations has relied on the inhaling muscles of the patient continuing to work and the patient himself doing all or most of the respiration. Respiration apparatus of this kind supplies the gas to the lungs in a continual current, but when the patient exhales, means are provided for passing the gas through a branch conduit. A resistance to flow is placed in this branch conduit or at the outlet thereof, so that 80 a predetermined pressure is necessary for flow to take place therethrough.

This is necessary on account of the nature of the respiratory action. The respiration muscles do not Influence the lungs directly, but act upon 85 the pleural sacs so that these expand or are pressed together. Hence, there arises a partial vacuum or an excess of pressure between the pleural sac and the lung which results in inhalation or exhalation from the lung in order to '40 equalize the pressure. The lung therefore lies more or less as an expanded elastic bladder within the pleural sac. The elastic tension In the lung is normally equal to 90 to 100 mm. of water column. In order to prevent the lung from shrinking or collapsing when the chest is opened during an operation, the lung's own tension must be compensated for by increasing the respiration pressure level an amount corresponding to the above elastic tension of the lung.

Usually the positive respiration pressure is produced by submerging the outlet of the branch conduit a suitable depth below the surface of a liquid so that the column of the liquid from the surface down to the outlet of the exhalation or branch conduit must be forced down Lefore the exhaling gas can escape.

In this kind of apparatus the Inhalation is effected in such a way that the patient reduces the pressure in the lungs by means of the res- 6 piration muscles to such an extent that gas from the apparatus flows thereinto.

Both these types of respiration apparatus are, however, of no use for more complicated operations on lungs, especially for operations-in which the chest is entirely or partly cut open so that the respiration muscles do not function satisfactorily or even do not function at all, Successful use of the foregoing type of respiration apparatus is possible only if the operation affects but one of the lungs and only if such operation may be rapidly performed. If the operation is of longer duration it is probable that the patient will die because the respiration proceeds at greatly reduced efficiency. This is because the opened lung does no work, but serves as an equalizer for the other lung, so that only one-half of the gas inhaled by the other lung consists of fresh air, while the other half consists of consumed air from the lung being operated upon. In the most complicated cases when both the pleural sacs must be opened, there is practically no chance of the patient surviving. In such cases the second of the above mentioned types of respiration apparatus is wholly useless S0 because the motive power required is furnished by the respiration muscles of the patient. * The first type of respiration apparatus cannot be used in this case either, as it works at a neutral respiration pressure level, and hence, as soon as the pleural sacs are opened, the lungs shrink.

One of the objects of our present invention is to provide a respiration apparatus in which the Inhalation is effected by forcing gas into the lungs during a period of increasing elastic tension of the lungs, and the exhalation is effected by letting gas out during a period of decreasing elastic tension of the lungs. In both cases, however, a positive minimum pressure, adjustable from case to case, is maintained which allows an exhalation from the patient without relying on his own respiration action.

A further object of our invention is the provision of apparatus of the above type in which the period of the artificial respiration is not forced to take place out of phase with respect to the natural periodicity, but may be re-synchronized by the patient himself by means of sudden attempted inhalations or exhalations, which are involuntary, and usually represent the uncon- / scious reaction of the patient against a wrong periodicity.

Further objects and advantages of our invention will be apparent from the following description, considered in connection with the accompanying drawing which forms part of this specification and which is a cross-sectional view of a preferred embodiment of our invention.

In the figure, reference character I indicates a cylinder containing gas, such as oxygen. A pressure reducing valve 2, pressure governor 3 and an equalizer 4 are interposed in the conduit leading from this cylinder. The. gas contained in cylinder I is under high pressure and valve 2 is a standard reducing valve for reducing the pressure of the gas passing therethrough. Pressure governor 3 is provided with valve mechanism controlled by a spring-pressed diaphragm and serves to maintain the pressure of the gas on the discharge side thereof at a constant value. Equalizer 4 comprises a chamber having an appreciable volumetric capacity bounded by a spring-pressed diaphragm and serves as a surge chamber to prevent sudden fluctuations in pressure which might occur too rapidly to be equalized by pressure governor 3. From the equalizer 4 a supply conduit 5 leads to the main valve chamber 7 of the apparatus, a throttle valve 6 being interposed in the conduit. The valve chamber 7 contains an inhalation valve 8 and an exhalation valve 9, the valve members of which are connected with each other by means of a spindle 12 to which is also connected a quick action mechanism 11 arranged in the pressure chamber 10. Mechanism I may consist of any pressure responsive snap action device and, as shown, comprises two levers connected to each other, the outer ends of said levers being connected to fixed points on the walls of chamber 10. One of these levers 49 includes a spring 50, interconnected between its two parts, the other lever 51 being connected to the spindle 12 and by means of spring 52 to the diaphragm 53, this latter being under pressure from spring 54. If the pressure in chamber 10 is increased, diaphragm 53 will slowly move against pressure of spring 54, thereby increasing the tension of spring 52. At a certain pressure this tension is equal to the component along the spindle 12 of the pressure from spring 50. Upon further in60 crease of pressure in chamber I0 the tension in spring 52 will cause lever 51 to move upwardly, thereby causing the angle between the levers to approach 180° and giving rise to a very rapid decrease of the said component of pressure from spring 50. The diaphragm 53 being balanced by springs 52 and 54 during this movement also moves upwardly, thus maintaining tension in spring 52. The spindle 12 therefore suddenly will snap to its highest position. The reverse is true upon a reduction in pressure. It will thus be apparent that valves 8 and 9 have no intermediate positions, but are either fully open or closed. Between the valve chamber 7 and the pressure chamber 10 a check valve 13 is arranged which allows a very rapid flow of gas into the chamber 10 as soon as the pressure in chamber 7 has attained a certain value, but which prevents reverse flow therethrough. A conduit 14 provided with a suitably adjustable throttle 15 is arranged as an outlet to the atmosphere from chamber 10.

The valve chamber 7 is divided by a wall 16 between the valves 8 and 9 into two chambers.

The chamber between the valve 13 and the valve 8 is connected with the inhalation valve housing 18 by means of a conduit 17, the chamber between the valve 8 and the wall 16 is connected with the supply conduit 5, and the chamber between the wall 16 and the valve 9 Is connected with the exhalation valve housing 20 by means of a conduit 19. Both the inhalation valve housing 18 and the exhalation valve housing 20 are each divided into valve chambers 21 and 22, respectively, and diaphragm chambers 23 and 24, respectively.

The tensions of the diaphragms are provided by springs 25 and 26, respectively. Spindles 27 and 28, respectively, connect the diaphragms with a second inhalation valve 29 and a second exhalation valve 30, respectively.

The inhalation valve chamber 21 is connected by means of the inhalation conduit 31 with the respiration mouth piece 32 and by this with the lungs, as schematically outlined at 33. From the inhalation conduit 31 a pressure equalizer conduit 34 communicates with the diaphragm chamber 24 of the exhalation valve 20. Exhalation conduit 35 connects the valve chamber 22 of the exhalation valve 20 with the respiration mouth piece 32, and a pressure equalizer conduit 36 establishes communication between conduit 35 and the diaphragm chamber 23 of the inhalation valve 18.

An electric heater 37 is arranged in connection with inhalation conduit 31, and may also effect the gasification of narcotics in a reservoir 38. The temperature is measured by the thermometer 39. If desired, the inhaling gas may be moistened in the container 40. The level of respiration is read off on the manometer 41, arranged in one of the pressure equlizer conduits, for instance in the conduit 36.

The device works in the following way. Assume that all valves are in the positions shown in the figure. The gas flows from the cylinder through the reducing valve 2, the pressure governor 3, the equlizer 4 and the conduit 5 with the throttle 6 to the chamber above the wall 16.

The valves 8 and 29 being open, the gas continues through the conduit 17, the valve chamber 21, the conduit 31 and the mouth piece 32 to the lungs 33, which during a period of increasing elastic tension caused by their expansion, are filled with fresh gas. The pressure of fluid being delivered to the lungs is transmitted to the diaphragm chambers 23 and 24 by means of the pressure equalizer conduits 36 and 34. A relatively small pressure increase causes the valve 30 to be opened by the diaphragm connected therewith. At first, however, this has no effect, as the valve 9 is still closed. When the maximum pressure of the lung has been attained, the valve 29 is closed by its diaphragm.

The closing of valve 29 causes the pressure in the chamber above the wall 16 to increase very rapidly, and the gas, after having attained a certain pressure, flows into the pressure chamber 10 through the valve 13. After a short time, for instance A of a second, the valve spindle 12 is suddenly moved upwardly, thus closing the valve 8 and opening the valve 9. The exhalation period now begins, the consumed gas leaving the lungs 33 through the mouth piece 32, the conduit 35 and the valves 30 and 9. By closing the valve 8, the gas supply to the pressure chamber 10 has been cut off. Thereafter, the gas will be slowly discharged from this chamber through the conduit 14 and'the throttle 15. A short time after the exhalation period has begun the valve 29 is opened due to the reduced pressure in diaphragm chamber 23, but this, however, has no effect, as the valve 8 is still closed and the valve 13 does not permit flow from chamber. 10.

The exhalation period continues until the 6 pressure has fallen to the positive minimum value, below which it is not allowed to sink on account of the elastic tension of the lungs. The spring 26 is adjusted so that the valve 30 will be closed by its diaphragm when this pressure is reached, and the exhalation period stops. The valve 29 and the valve 30 are now in their proper positions for the start of the next respiration cycle, ani this begins immediately, when the pressure in the pressure chamber 10 has fallen sufficiently for the mechanism 1 to move spindle 12 downwardly to open valve 8 and close valve 9.

The respiration cycle is now repeated in the same manner as above described.

It will be seen that the frequency of the periods may be regulated by adjusting throttle 15 which determines the time required for the pressure to drop in chamber 10 sufficiently to actuate mechanism I I.

From the above description it appears that the maximum pressure at the end of the inhalation period can be arbitrarily regulated by adjusting spring 25. In a corresponding way the positive, minimum pressure, which stops the exhalation period, may be adjusted by means of the spring 26. Normally, a relatively small amount of gas is delivered between these two positions and consequently the movements of the lungs are relatively small, which is necessary in order not to disturb the physician in his operation. The apparatus, as above described, is therefore not suitable as a reviving apparatus, partly for the reason that it causes too small respiration movements of the lungs, and partly on account of its respiration level being unsuitable for this purpose. However, the apparatus can be easily adjusted so as to serve for reviving purposes. Two handles 42 and 43 are arranged in connection with the inhalation valve 18 and the exhalation valve 20, respectively. By 46 means of the handle 42 an additional spring 44 may be rendered effective by means of which the maximum pressure may be increased to a value suitable for reviving apparatus. The handle 43 is arranged to lock the valve 30 in oen 60 position so that the exhalation is unimpeded.

If the respiration muscles of, the patient are able to function even to an insignificant degree, the patient unconsciously reacts against a wrong respiration periodicity by movements that counteract the normal period of the respiration of the apparatus. The respiration apparatus is sensitive to such re-synchronizing impulses. For this purpose, a valve 46, auxiliary to the exhalation valve 30, is provided. These two valves are connected with each other and with the diaphragm 45 by means of a lever 47 so arranged that inward movement of the diaphragm first completely closes valve 30, provided that the valve 30 is not locked, without actuating valve 46, but further movement of the diaphragm rapidly opens valve 46. In case the valve 30 is locked, and the apparatus is working as a reviving apparatus, the diaphragm 45 immediately opens valve 46. The valve 46 is arranged in a conduit 48, which connects the pressure chamber 10 with the atmosphere.

If it is assumed that the patient suddenly attempts to inhale with his own lung muscles during the course of an exhalation period of the apparatus, a vacuum is produced in the lungs 33 which is transmitted by the conduit 31 and the equalizer conduit 34 to the diaphragm chamber 24. This vacuum causes the diaphragm 45 to move inwardly sufficiently to open the valve 46.

Either the exhalation period of the apparatus has already been stopped by the normal closing of the valve 30 or this valve is closed by the movement of the diaphragm caused by the attempted inhalation. The pressure chamber 10 is immediately emptied by the opening of valve 46 and the mechanism II closes the valve 9 and opens valve 8, thereby starting a normal inhalation period. The re-synchronizing has, in this manner, been effected.

If the re-synchronizing takes place during a period of inhalation of the apparatus by an attempted exhalation of the patient, the conduit 35 and the pressure equalizer conduit 36 transmit an immediate excess of pressure to the diaphragm chamber 23, which causes the valve 29 to close. A corresponding excess of pressure is transmitted by the conduit 31 and the pressure equalizer conduit 34 to the diaphragm chamber '24 of the valve housing 20. The valve 30 is immediately opened thereby, and the valve 46, should it have been opened, is closed. In this way the passage between the pressure chamber 10 and the atmosphere at valve 46 is closed (throttle 15 remains open), and the valves 8 and 9 are moved to their proper position for the beginning of an exhalation period. Thus, in this case, a complete resynchronizing has been effected.

While we have shown and described one preferred embodiment of our invention, it is to be understood that this has been done for purposes of illustration only, and that the scope of our invention is not to be limited thereby, but is to be determined by the appended claims viewed in the light of the prior art. What we claim is: 1. In a respiration apparatus, means for stopping an inhalation period at a maximum positive pressure, means for stopping an exhalation period at a minimum positive pressure to thereby constantly maintain positive pressure in said apparatus while said apparatus is in use, and pressure responsive means for actuating said means.

2. In a respiration apparatus, a valve for stopping an inhalation period, means for closing said valve responsive to a maximum positive pressure, a valve for stopping an exhalation period, and means for closing the last-mentioned valve responsive to a minimum positive pressure to thereby constantly maintain positive pressure in r5 said apparatus while said apparatus is in use.

3. In a respiration apparatus, a mouthpiece, an inhalationl conduit connected to said mouthpiece, an inhalation valve in said conduit, a first diaphragm for actuating said valve, an exhalation conduit connected to said mouthpiece, an exhalation valve in said exhalation conduit, and a second diaphragm for actuating said exhalation valve, said first diaphragm being responsive to an increase in pressure in said mouthpiece to close said inhalation valve and said second diaphragm being responsive to an increase in pressure in said mouthpiece to open said inhalation valve, each of said diaphragms acting independently of the other. 4. In a respiration apparatus, a mouthpiece, an inhalation conduit connected to said mouthpiece, an inhalation valve in said conduit, a first diaphragm for actuating said valve, an exhalation conduit connected to said mouthpiece, an exhalation valve in said exhalation conduit, and a second diaphragm for actuating said exhalation valve, both of said diaphragms being subjected directly to fluid pressure, said first diaphragm being responsive to an increase in pressure in said exhalation conduit to close said inhalation valve and said second diaphragm being responsive to an increase in pressure in said inhalation conduit to open said exhalation valve.

5. In a respiration apparatus, a mouthpiece, an inhalation conduit connected to said mouthpiece, an inhalation valve in said conduit, a first diaphragm for actuating said valve, an exhalation conduit connected to said mouthpiece, an exhalation valve in said exhalation conduit, a second diaphragm for actuating said exhalation valve, each of said diaphragms acting independently of the other to actuate the respective valves independently, said first diaphragm being responsive to an increase in pressure in said mouthpiece to close said inhalation valve and said second diaphragm being responsive to an increase in the pressure in said mouthpiece to open said exhalation valve, and means for controlling the frequency of the actuation of said valves by said diaphragms.

6. In a respiration apparatus, a mouthpiece, an inhalation conduit connected to said mouthpiece, an inhalation valve in said conduit, a first diaphragm for actuating said valve, an exhalation conduit connected to said mouthpiece, an exhalation valve in said exhalation conduit, a second diaphragm for actuating said exhalation valve, said first diaphragm being responsive to an increase in pressure in said mouthpiece to close said inhalation valve and said second diaphragm being responsive to an increase in pressure in said mouthpiece to open said exhalation valve, and means operative upon an increase in pressure within said mouthpiece for controlling the frequency of the actuation of said valves by said diaphragms.

7. In a respiration apparatus, a source of gas under pressure, a mouthpiece, an inhalation conduit connecting said source with said mouthpiece, a first inhalation valve and a second inhalation valve in said conduit, an exhalation conduit connecting said mouthpiece with the atmosphere, a first exhalation valve and a second exhalation valve in said exhalation conduit, means for closing said first inhalation valve in response to an increase in pressure in said mouthpiece, means for opening said first exhalation valve in response to an increase in pressure in said mouthpiece, and means operative upon an increase in the pressure within said mouthpiece for simultaneously closing said second inhalation valve and opening said second exhalation valve.

8. In a respiration apparatus, a source of gas under pressure, a mouthpiece, an inhalation conduit connecting said source with said mouthpiece, a first inhalation valve and a second inhalation valve in said conduit, an exhalation conduit cohnecting said mouthpiece with the atmosphere, a first exhalation valve and a second exhalation valve in said exhalation conduit, means for closing said first inhalation valve in response to an increase in pressure in said mouthpiece, means for opening said first exhalation valve in response to an increase in pressure in said mouthpiece, means forming a pressure chamber connected to said inhalation conduit between said first and second inhalation valves, a one-way valve opening from said inhalation conduit into said chamber, throttling means connecting said chamber with the atmosphere, and means responsive to an increase in pressure in said chamber for simultaneously closing said second inhalation valve and opening said second exhala- 6 tion valve.

9. In a respiration apparatus, a source of gas under pressure, a mouthpiece, an inhalation conduit connecting said source with said mouthpiece, a first inhalation valve and a second inhalation valve in said conduit, an exhalation conduit connecting said mouthpiece with the atmosphere, a first exhalation valve and a second exhalation valve in said exhalation conduit, means for closing said first inhalation valve in response to an increase in pressure in said mouthpiece, means for opening said first exhalation valve in response to an Increase in pressure in said mouthpiece, means forming a pressure chamber connected to said inhalation conduit between said first and second inhalation valves, a one-way pressure responsive valve opening from said inhalation conduit into said chamber, said first inhalation valve being arranged to close at a lower pressure than is required to open said oneway valve, throttling means connecting said chamber with the atmosphere, and means responsive to an increase in pressure in said chamber for simultaneously closing said second inhalation valve and opening said second exhalation valve.

10. In a respiration apparatus, a valve for stopping an inhalation period, means for closing said valve responsive to a maximum positive pressure, a valve for stopping an exhalation period, and means for closing the last-mentioned valve responsive to a minimum positive pressure, either of said means being adjustable so as to be operative at different pressures.

11. In a respiration apparatus, a valve for stopping an inhalation period, a spring-pressed diaphragm for closing said valve responsive to a maximum positive pressure, additional spring means, means for rendering said additional spring means operative to increase the value of the pressure at which said diaphragm responds to close said valve, a valve for stopping an exhalation period, and means for closing the last-mentioned valve responsive to a minimum positive pressure. 12. In a respiration apparatus, a valve for stopping an inhalation period, means for closing said valve responsive to a maximum positive pressure, a valve for stopping an exhalation period, means for closing said valve responsive to a minimum positive pressure, and means for maintaining the last mentioned valve open against the action of the second-mentioned means.

13. In a respiration apparatus, a valve for stopping an inhalation period, a spring-pressed diaphragm for closing said valve responsive to a maximum positive pressure, additional spring means, means for rendering said additional spring means operative to increase the value of the pressure at which said diaphragm responds to close said valve, a valve for stopping an exhalation period, means for closing the last-mentioned valve responsive to a minimum positive pressure, and means for maintaining said last-mentioned valve open against the action of the last-mentioned means.

14. In a respiration apparatus, a source of gas under pressure, a mouthpiece, an inhalation conduit connecting said source with said mouth- 76 piece, an inhalation valve in said conduit, an exhalation conduit connecting said mouthpiece with the atmosphere, an exhalation valve in said exhalation conduit, a pressure chamber, means responsive to a normal increase in pressure in said mouthpiece for admitting gas under pressure to said chamber, means responsive to an increase in pressure in said chamber for simultaneously closing said inhalation valve and opening said exhalation valve, and means responsive to an abnormal reduction of pressure in said mouthpiece for reducing the pressure in said chamber.

15. In a respiration apparatus, a source of gas Sunder pressure, a mouthpiece, an inhalation conduit connecting said source with said mouthpiece, a first inhalation valve and a second inhalation valve in said conduit, an exhalation conduit connecting said mouthpiece with the atmosphere, a. first exhalation valve and a second exhalation valve in said exhalation conduit, a first diaphragm for closing said first inhalation valve in response to a normal increase of pressure in said mouthpiece, a second diaphragm for opening said first exhalation valve in response to a normal increase of pressure in said mouthpiece, a pressure chamber, means responsive to a normal increase of pressure in said mouthpiece for admitting gas under pressure to said chamber, means responsive to an increase of pressure in said chamber for simultaneously closing said second inhalation valve and opening said second exhalation valve, a conduit connecting said chamber to the atmosphere, a valve in the lastmentioned conduit, and means operatively connecting said second diaphragm with the lastmentioned valve for opening said last mentioned valve in response to an abnormal reduction of pressure in said mouthpiece. 16. In a respiration apparatus, a source of gas under pressure, a mouthpiece, an inhalation conduit connecting said source with said mouthpiece, a first inhalation valve and a second inhalation valve in said conduit, an exhalation conduit connecting said mouthpiece with the atmosphere, a first exhalation valve and a second exhalation valve in said exhalation conduit, a first diaphragm for opening said first inhalation valve in response to a normal decrease of pressure in said mouthpiece, a pressure chamber, means responsive to a normal increase of pressure in said mouthpiece for admitting gas under pressure to said chamber, means responsive to an increase of pressure in said chamber for simultaneously closing said second inhalation valve and opening said second exhalation valve, a conduit connecting said chamber to the atmosphere, a valve in the last-mentioned conduit, and a second diaphragm operatively connected to the last-mentioned valve and to said first exhalation valve and responsive to a normal decrease of pressure in said mouthpiece for closing said first exhalation valve and responsive to an abnormal reduction of pressure in said mouthpiece for opening the valve in said lastmentioned conduit.

EMIL EINAR WILHELM ANDERSON.

GEORG KARL VILHEIM J ON.