Title:
Method and apparatus for controlling the oxygen content of the blood of living animals
United States Patent 2414747


Abstract:
The invention relates to means for automatically controlling the oxygen content of the blood in living animals, being more particularly designed for use by aviators, but also adapted for use in hospitals and in other places. It is the object of the invention to introduce oxygen into the lungs...



Inventors:
Kirschbaum, Harry M.
Application Number:
US44948942A
Publication Date:
01/21/1947
Filing Date:
07/02/1942
Assignee:
Kirschbaum, Harry M.
Primary Class:
Other Classes:
137/2, 137/624.15, 250/215, 250/226, 356/41
International Classes:
A61B5/00
View Patent Images:



Other References:
None
Description:

The invention relates to means for automatically controlling the oxygen content of the blood in living animals, being more particularly designed for use by aviators, but also adapted for use in hospitals and in other places.

It is the object of the invention to introduce oxygen into the lungs of the subject when needed, this being determined automatically by the condition of his blood. To this end the invention consists in the method and apparatus as hereinafter set forth: In the drawing: Figure 1 is a diagrammatic view of an apparatus for carrying out my invention; Figure 2 is an enlarged view of the control means; Figure 3 is a section through the control valve; and Figure 4 is a section through the nose piece through which the oxygen is supplied.

-It is a well-known physiological fact that blood when oxygenated is of a bright red color and becomes darker when it loses its oxygen content.

Making use of this, I have devised a means of controlling an oxygen administering apparatus by the color or light absorption capacity of the blood circulating through a portion of the animal tissue. For instance, in the lobe of the ear there are minute blood vessels or capillaries through which blood is constantly circulating. By directing a beam of light through this tissue the character of the light will be modified by the color of the blood which intercepts its path. A light sensitive electric cell exposed to this beam will respond to such changes so that in connection with suitable amplifying and relay means it is adapted to operate a valve controlling the oxygen supply.

The oxygen may be introduced into the lungs of the subject by any suitable means such as a flexible conduit leading to a nose piece. Thus when the blood is in normal condition the oxygen supply is cut off, but whenever the blood is insufficiently oxygenated its change in character will automatically bring about an opening of the valve and without any attention on the part of the subject. This renders it particularly adapted for use by aviators, whose attention is frequently so concentrated on the control of the machine as to cause them to neglect turning on the oxygen supply when needed.

Various forms of apparatus may be used for carrying out my invention, but as diagrammatically illustrated, A is a conduit leading from a source of oxygen supply. B is a means for regulating the rate of flow of gas through said con2duit. C is a control valve and D a conduit leading from the valve to a nose piece E, or other means for administering the gas to the subject.

The automatic operating means for the valve C may be of any suitable construction, either mechanical or electrical, which is under the control of means sensitive to blood changes. As illustrated, the valve is periodically opened by a timing mechanism which is actuated by an electric motor whenever the latter is energized. F is a motor and G a step-down transmission mechanism including a rotating crank H provided with a crank pin I. J is a slidable member for opening the valve which extends into the path of the 1s pin I so that once in each revolution of the crank the valve will be opened. This valve, as illustrated, comprises a casing K having an inlet port connected to the conduit A and an outlet port connected to the conduit D. Within the casing is a valve seat K' located between the inlet and outlet ports, and a valve K2 connected to a plunger K3 is normally held to its seat by the tension of a spring K4. The slide J is connected to the stem K3, and thus whenever it is displaced by the pin I, the valve K2 will be lifted from its seat to permit flow of oxygen from the conduit A to the conduit D.

The controlling means comprises a light-sensitive cell L and illuminating means M. These are connected to each other by a resilient loop N so that they may be clamped against opposite sides of the lobe of an ear, as indicated at O.

The specific construction of the elements L and M is not a part of the instant invention. The element L is, however, of such a character as to be responsive to changes in the character of light falling thereupon. As the source of light is in the element M on the opposite side of the lobe of the ear, it must be transmitted through said lobe and thus is affected by the color or opacity of the blood circulating through the capillaries.

Thus a change from the bright red of oxygenated blood to the darker bluish color of blood deficient in oxygen will affect the current generation in the element L. This current passes through conductors P to the amplifying means Q, which also may be of any suitable construction, and the amplified current actuates a relay switch R controlling the supply of current to the motor F. The arrangement is such that the switch R is open when the blood is in normal' condition and is closed when there is lack of oxygen in the blood, thereby starting the motor F and periodically actuating the valve K.

W The timing of the actuating mechanism is preferably such as to correspond approximately with the breathing cycle of the subject, so that a pulse of oxygen is admitted with each inhalation of the breath. It is not, however, necessary that the oxygen should be supplied in pulses as the valve may remain open continuously during the period in which oxygen is needed. The advantage of the pulsating operation is that the quantity of oxygen supplied may be more easily regulated. For convenience in use, the control means L, M and the nose piece or nozzle E may be mounted on a head frame S which holds them in proper relative position. A gauge T may be used in connection with the amplifying means Q to visually indicate the current variation due to blood changes.

For use by aviators it may be necessary to adjust the device to correspond to individual characteristics. Such adjustment may be effected while the subject is on the ground and may be used in connection with other testing means for individual responses. When such adjustment is made the aviator may be assured that it will respond in a similar manner when he is in the air thereby avoiding any danger of lack of oxygen when it is needed.

What I claim as my invention is: 1. In a method of controlling the oxygen content in the blood of a living animal, the steps of modifying a light beam by variations in light absorption capacity of a portion of the animal tissue through which blood is circulating, varying an electrical current by said modified light beam and controlling the introduction of oxygen into the lungs of the animal, by said variations in current.

2. In a method of controlling the oxygen content in the blood of a living animal, the steps of transmitting light through a portion of the animal tissue in which the blood is circulating, and directing the transmitted light upon a photoelectric cell whereby the current generated by, said cell is varied in accordance with modifications in the blood due to deficiency in oxygen, and controlling the introduction of oxygen into the lungs of the animal by said current variations.

3. An apparatus for automatically controlling the oxygen content in the blood of a living animal subject, comprising means for transmitting light through a portion of the animal tissue in which blood is circulating, a photo-electric cell positioned to receive the transmitted light whereby the current generated by said cell will be varied in accordance with modifications in the transmitted light due to modifications in the blood stream, means for supplying oxygen to the lungs of the subject, and means for controlling said supply by the current from said cell.

4. An apparatus for automatically controlling the oxygen content in the blood of a living animal comprising a photo-electric cell, a member containing a light source, means for clamping said cell and member on opposite sides of a portion of the animal tissue in which blood is circulating, and means for supplying oxygen to the lungs of the animal controlled by the current from said cell.

5. An apparatus for automatically controlling the oxygen content in the blood of a living animal subject comprising a photo-electric cell, a member containing a source of light, means for clamping said cell and member on opposite sides of a portion of the tissue of the subject in which blood is-circulating, means for supplying oxygen to the lungs of the subject, and means controlling said supply in itself controlled by said photo-electric cell.

6. An apparatus for automatically controlling the oxygen content in the blood of a living animal subject comprising a photo-electric cell, a member containing a source of light,'means for clamping said cell and member on opposite sides of a lobe of an ear of the subject whereby the light transmitted through said lobe will be modified by changes in the blood circulating through said lobe due to oxygen deficiency, an oxygen supply, a conduit leading from said supply connecting with the lungs of the, subject, a valve controlling admission of oxygen from said supply to said conduit, and means controlled by the current generated in said photo-electric cell for operating said valve.

7. An apparatus for automatically controlling the oxygen content in the blood of a living animal subject comprising a photb-electric cell, a member containing a source of light, means for clamping said cell and member on opposite sides of a lobe of an ear of the subject whereby the light transmitted through said lobe will be modified by changes in the blood circulating through said lobe due to oxygen deficiency, an oxygen supply, a conduit leading from said supply and provided with a nozzle for engaging the nostrils of the subject, a head frame connected to said nozzle, ploto-electric cell and light source member for holding the same in operative relation to the subject, a valve controlling admission of oxygen from said supply to said conduit, and means controlled by the current from said cell for controlling the operation of said valve.

HARRY M. KIRSCHBAUM.