US3714944A

US3714944A - Mixing and humidification apparatus for breathing devices

Info

Publication number: US3714944A
Application number: US00092658A
Authority: US
Inventors: J Price; K Shook
Original assignee: Bethlehem Steel Corp
Current assignee: Bethlehem Steel Corp
Priority date: 1970-11-25
Filing date: 1970-11-25
Publication date: 1973-02-06
Anticipated expiration: 1990-02-06

Abstract

A breathing device having an elongated flexible inlet conduit is provided with removable apparatus for enriching ambient air with predetermined percentages of oxygen and for humidifying the mixture before the mixture is admitted to the device. The apparatus comprises a hollow cylindrical body with a mixing chamber and an oxygen injector extending coaxially into the chamber. An exhaust port is provided in one end of the body to open into the device-conduit, and a series of intake ports surround the injector at the other end of the body to coact with the injector for causing ambient air to mix with oxygen for inhalation by the patient. A removable hollow shell surrounds the body and registers with the intake ports, and the shell has means providing a connection to a source of water vapor for humidifying the oxygen-air mixture in the mixing chamber. In addition, a method is disclosed for weaning a patient away from oxygen dependency, the method comprising the steps of periodically replacing the mixing-body with like bodies having progressively lower percentages of oxygen in the mixture after predetermined time intervals.

Description

United States Patent Price et al.

[451 Feb. 6, 1973 MIXING AND HUMIDIFICATION Assignee:

Filed:

Inventors: James F. Price, Center Valley; Ken- The Bethlehem Corporation,

Bethlehem, Pa.

Nov. 25, 1970 Appl. No.: 92,658

U.S. Cl ..I28/209, 137/604 Int. Cl. ..A6lm 15/00 Field of Search ..l28/209, 210, 197, 187, l94,

128/205, 142, 142.3,145 R, l45.5l45.8,

References Cited UNITED STATES PATENTS FOREIGN PATENTS OR APPLICATIONS Primary Examiner-Richard A. Gaudet Assistant ExaminerG. F. Dunne Attorney-Howson and Howson [57] ABSTRACT A breathing device having an elongated flexible inlet conduit is provided with removable apparatus for enriching ambient air with predetermined percentages of oxygen and for humidifyingv the mixture before the mixture is admitted to the device. The apparatus comprises a hollow cylindrical body with a mixing chamber and an oxygen injector extending coaxially into the chamber. An exhaust port is provided in one end of the body to open into the device-conduit, and a series of intake ports surround the injector at the other end of the body to coact with the injector for causing ambient air to mix with oxygen for inhalation by the patient. A removable hollow shell surrounds the body and registers with the intake ports, and the shell has means providing a connection to a source of water vapor for humidifying the oxygen-air mixture in the mixing chamber. In addition, a method is disclosed for weaning a patient away from oxygen dependency, the method comprising the steps of periodically replacing the mixing-body with like bodies having progressively lower percentages of oxygen in the mixture after predetermined time intervals.

3 Claims, 5 Drawing Figures PATENIEDFEH ma I 4 3,714,944

sum 1 or 2 INVENTORSI JAMES F. PRICE KENNETH SHOOK BY wWX W AT T VS 'PATENTEIJFEBMBB 3,714,944

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MIXING AND HUMIDIFICATION APPARATUS FOR BREATHING DEVICES The present invention relates to breathing apparatus; and more particularly, the present invention relates to apparatus for enriching air with oxygen and to apparatus for humidifying the enriched mixture preparatory to its inhalation by persons having respiratory difficulties. The mixing apparatus of the present invention is particularly suited for use in weaning patients away from oxygen dependency.

It is recognized that pure oxygen tends to dry out the mucous membranes in the respiratory system of the body, and accordingly, apparatus has been proposed for humidifyin'g the oxygen breathed by persons having respiratory difficulties. Examples of such apparatus are disclosed in U.S. Pats. Nos. 2,269,500 and 2,584,450. Although the apparatus disclosed in these patents may operate satisfactorily, the apparatus is complex, bulky and obviously expensive to manufacture.

It is known that some persons may become addicted to oxygen after prolonged usage and that it may be difficult for the person to become accustomed to breathing ambient air after termination of oxygen breathing. A sudden reduction in the supply of oxygen to the body has been known to induce serious physiological and psychological consequences in some patients. At present, there is no known method for reducing a persons oxygen dependency in a manner which obviates the aforementioned difficulties, and this is particularly true for tracheostomy patients who seem to have a greater affinity for oxygen addiction.

With the foregoing in mind, it is the primary object of the present invention to provide compact and relatively inexpensive apparatus for humidifying an oxygen/air mixture supplied to a breathing device, such as a mask.

It is another object of the present invention to provide an improved venturi-type oxygen-air mixer for use with a breathing device and to provide novel humidification apparatus which may be used with the mixer to humidify the mixture supplied to the device.

As a further object, the present invention provides a novel method for weaning a patient away from oxygen dependency.

More specifically, the present invention provides a removable venturi-type oxygen-air mixer for a breathing device and humidification apparatus for use with the mixer to humidify the mixture before it is admitted to the device. The mixer has a cylindrical body defining a mixing chamber, and an oxygen injector extends into the chamber and is surrounded by a series of intake ports. The injector is aligned with an exhaust port in the body, and means surrounding the exhaust port telescopically mates with a flexible conduit providing inlet means for the breathing device. A humidiflcation chamber is provided around the mixer-body by the steps of replacing the oxygen/air mixer at periodic intervals with like mixers having progressively lower oxygen/air ratios.

These and other objects, features and advantages of the present invention should become apparent from the following description when taken in conjunction with the accompanying drawings in which:

FIG. I is a perspective view of a person wearing a breathing mask which covers a tracheostomy and which is connected through a flexible conduit to mixing and humidification apparatus'embodying the present invention; 4

FIG. 2 is an enlarged longitudinal cross-sectional view of the mixing and humidification apparatus of FIG. 1;

FIGS. 3 and 4 are sectional views taken along lines 33 and 4-4, respectively, of FIG. 2;

FIG. 5 is an exploded view of humidification apparatus of the present invention which is adapted for use with a venturi-type mixer integral with a conventional breathing mask for the face. Referring now to the drawings, there is illustrated in FIG. 1 a patient 10 having a breathing mask 11 strapped around his neck to cover a tracheostomy. The mask 11 is of conventional flexible plastic construction and is shaped to engage the contour of the neck. Inlet means is provided to admit to the mask 11 a life-sustaining gas mixture which, in the absence of oxygen enrichment, would comprise substantially 21 percent oxygen and 78 percent nitrogen. In the present instance, the inlet means is an elongated length of flexible, corrugated tubing or conduit 12. Exhaled gas is permitted to exhaust through an orifice 13 in the mask 11.

In accordance with the present invention, mixing apparatus 15 is provided for enriching with oxygen the gas mixture supplied to the patient, and the mixing apparatus is removably connected to the inlet conduit 12 of the mask 11 to enable the total concentration of oxygen in the mixture admitted to the mask 11 to be varied for the purpose of weaning the patient away from oxygen dependency by the method to be described. To this end, the mixer 15 is of low cost molded plastic construction and comprises a hollow cylindrical body 16 forming a mixing chamber 17 and an injector 18 extending into the mixing chamber 17 coaxially with the body 16. In the present instance, the injector 18 is molded integrally with an endwall 16a of the body 16. As may be seen in FIG. 2, the injector 18 has a nozzle portion 19 extending away from the body and having a pair of external ribs 20,20 for telescopically mating with a length of flexible tubing 21 which is connected to a suitable source of pure oxygen. Means is provided to form a series of intake ports 22,22 (FIG. 2) spaced apart in the periphery of the sidewall 16b at one end of the body 16 for admitting ambient air into the chamber 17, and means is provided to define an exhaust port 23 in the other end of the body 16 opposite the injector 18. The injector 18 has a through bore 18a with a reduced portion 18b which is located in the chamber 17 and which operates with inhalation by the patient 10 to produce a venturi action for causing ambient air to be drawn through the

intake ports

22,22 and into the mixing chamber 17 and to mix with oxygen supplied through the tubing 21. After mixing, the enriched oxygen-air mixture flows through the exhaustv port 23 and to the mask 11 through the mask inlet conduit 12.

The mixer is constructed to be removable from the mask inlet conduit 12 and to be interchangeable with like mixers each having a different oxygen-mixture percentage to provide a set of at least three, and in the present instance four, mixers having a range of oxygen/mixture percentages. To this end, means, in the present instances a boss 24, is provided to surround the exhaust port 23 of each mixer and to snugly and telescopically engage inside the inlet conduit 12 of the mask 11. If desired, the boss 24 may taper slightly inward in the direction of flow to facilitate replacement of the mixer 15. In the present instance, the oxygen/mixture percentage of the mixer 15 is established for a given flow range of pure oxygen by providing the reduced portion 18b of the injector bore 18 with a predetermined diameter, for example by drilling. Thus, when supplying pure oxygen at a rate between 4 and 12 liters per minute, for a mixture having a total oxygen concentration of 24 percent, the diameter of the bore 18b should be 0.036 inch, and for total oxygen concentrations of 28 percent, 35 percent, and 40 percent, the corresponding diameters should be 0.061 inch, 0.115 and 0.151 inch, respectively. The inside diameter of the cylinder is approximately 1 inch, and the inside diameter of the bore 18a is approximately three-sixteenth inch. It is to be noted that if the 24- 28- 35 percent mixers were selected as a set, the difference in total oxygen/mixture percentages between the highest and lowest percentage mixers would be 1 1 percent and the difference between the highest and next lowest percentage mixer would be 7 percent. if the 28- 35- 40 percent mixers were selected as a set, the difference in oxygen/mixture percentages between the highest and lowest percentage mixers would be 12 percent and the difference between the highest and next lower percentage mixer would be 5 percent.

According to the method of the present invention, a patient may be weaned away from oxygen dependency by periodically replacing the mixer with like mixers providing different and lower oxygen concentrations. For example, if the patient were using a mixer providing a mixture with an oxygen concentration of substantially 35% or higher, the weaning process would be initiated by replacing that mixer with a second mixer providing an oxygen concentration of substantially 28 percent after a predetermined time interval, and after another predetermined time interval, replacing the second mixer providing an oxygen concentration of substantially 24 percent. Thus, the patients dependency on oxygen is' gradually diminished, and the physiological and psychological effects of abrupt oxygen discontinuation are obviated. The method of the present invention is particularly useful for tracheostomy patients who are believed to possess a greater tendency toward oxygen addiction.

in accordance with the primary object of the present invention, the oxygen enriched mixture is humidified before it is admitted to the patient's breathing mask. To this end, means is provided to define a humidification chamber 30 around the periphery of the body 16. As may be seen in FIG. 2, the chamber 30 is formed by means of a shell 31 which in the present instance has a hollow toroidal shape with aligned

apertures

32 and 33 sized to snugly and slidably receive the mixer-body 16. In the illustrated embodiment, the shell 31 has a longitudinal dimension which is slightly less than the corresponding dimension of the mixer-body 16, and shoulder means 34 is provided adjacent the boss 24 to engage the proximal side of the shell 31 for ensuring proper registry between the chamber 30 and the

intake ports

22,22 when the shell 31 is mounted on the mixerbody 16. As a result, the distal side of the shell 31 is inset slightly from the plane of the body-endwall 16a.

For the purpose of flowing water vapor into the chamber 30, an inlet connection 37 is provided on'the shell 31. As may be seen in FIG. 2, the inlet connection 37 is cylindrical and angulated with respect to the distal side of the shell 31 so that the connection extends substantially parallel to the injector nozzle 19. The inlet connection 37 is sized to be telescopically and snugly received inside a length of tubing 38 which is connected to a suitable source of water vapor.

in order to provide ambient air for the mixingchamber and to prevent air from being completely cut off from the patient in the event of a malfunction of either the oxygen or the water vapor supply, or both, vent means is provided to admit ambient air into the chamber 30. In the present instance, the vent means comprises a first series of

vents

35,35 surrounding the injector l8 and formed by the extension of theports 22 into the endwall 16a of the body 16 and a second series of

circular vents

36,36 spaced apart in the distal side of the shell 31. The circular outline of the shell aperture 32 cooperates with the extension 35 to provide flow passages into the chamber 17 as indicated by the arrows in FIG. 2. With this structure, inhalation by the patient causes water vapor to be drawn through the inlet 37 into the chamber 30 and ambient airto be drawn through the

vents

35 and 36 into the chamber 30. The water vapor and air are then drawn from the chamber 30 through the

intake ports

22,22 into the mixing chamber 17 and mixed with oxygen before flowing through the inlet conduit 12 to the mask 11. As a result, the patient is supplied with a humidified oxygen enriched mixture which avoids dehydration of mucous tissues. If desired, medication may be mixed with the water vapor and thereby readily supplied to the patient.

The humidification apparatus of the present invention may also be employed satisfactorily with the venturi-type mixer 40 embodied in aconventional face-type breathing mask 41 (FIG. 5). As may be seen therein, the mixer 40 has a cylindrical shape with intake ports 43,43 surrounding an oxygen injector 42 and a shoulder 44 adjacent the face-engaging portion of the mask. A humidification chamber is provided around the mixer 40 by a shell which is identical to the previously described shell 31 and which slides on and snugly engages the mixer 40 for securely mounting the shell 31 onto the mask 41. It is to be noted that in the present instance the diameter of the mixer 40 on the mask 41 is substantially the same as the diameter of the removable mixer-body 16 so that the shell 31 may be used interchangeably with either type of mixer.

In view of the foregoing, it should be apparent that novel apparatus which is compact and relatively inexpensive to manufacture has now been provided for humidifying an oxygen enriched air mixture supplied toa patient through a breathing device, such as a mask.

Also, the present invention now provides an improved venturi-type oxygen-air mixer which is particularly suited for use with a breathing device for weaning patients away from dependency on oxygen in accordance with the novel method of the present invention.

While preferred embodiments of the present invention have been described in detail, various modifications, alternations or changes may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

We claim:

1. Mixing apparatus for use with a breathing device having means providing an inlet for admitting an oxygen enriched mixture to the device, said apparatus comprising: a hollow body defining a mixing chamber, means forming intake ports in said body exposed to ambient air and opening into said chamber adjacent one end of said body and means forming an exhaust port in said body at the other end of said body, a hollow injector having a tubular portion projecting into said mixing chamber at said one end of the body terminating at its inner end in an orifice, said injector having a portion projecting away from said body for releasable attachment to a source of oxygen, conduit means connected to said exhaust port and telescopically mating with said inlet means of the device for releasable attachment thereto, and chamber means surrounding said body to provide a substantially closed humidification chamber around said body and in open communication with said intake ports, said chamber means affording flow of ambient air into said body through said ports in a predetermined amount upon a preselected flow of oxygen through said orifice, said humidification chamber means having an inlet connected to a source of water vapor whereby water vapor is mixed with the diluted mixture of ambient air and oxygen in the mixing chamber.

2. Apparatus according to claim 1 wherein said humidification chamber means includes a shell having aligned apertures for slidably and snugly receiving said body said shell and body cooperating to provide an annular chamber in which said water vapor assumes the temperature of the hollow body prior to mixing with the oxygen and including shoulder means on said body for engaging said shell to position one of the walls of said shell to overlie said intake ports and effect said open communication with the intake ports in the body.

3. Apparatus according to claim 2 wherein said intake means comprise a series of ports in the outer wall of said hollow body, each port starting in the end wall at said one end and extending for a portion of the length of said body, one of said aligned apertures of the shell intersecting the intake ports of said hollow body whereby said ports provide a series of vents spaced apart in the periphery of said mixer-body around said injector.