INSUFFLATOR GAS FLOW DEVICE
United States Patent 3853105
An inlet port admits pressurized oxygen and a breathing port is used by the patient. A venturi nozzle directs the pressurized oxygen into a venturi throat which leads to the breathing port and the venturi throat has a plurality of lateral vent ports to the atmosphere. For one mode of operation to treat an unconscious patient, a normally closed valve is operable to release the pressurized oxygen periodically to the venturi nozzle and for treating a conscious patient, a metering means bypasses the closed valve to release the compressed oxygen to the venturi nozzle at a continuous reduced rate.
US Patent References:
Resuscitators
Sanborn - December 1958 - 2865368
Variable constant flow device
Thorburn - August 1960 - 2948296
Intermittent positive pressure breathing apparatus
Windsor - May 1967 - 3319627
RESUSCITATOR
Flynn - February 1973 - 3717147
Resuscitators
Sanborn - December 1958 - 2865368
Variable constant flow device
Thorburn - August 1960 - 2948296
Intermittent positive pressure breathing apparatus
Windsor - May 1967 - 3319627
RESUSCITATOR
Flynn - February 1973 - 3717147
Application Number:
05/393746
Publication Date:
12/10/1974
Filing Date:
09/04/1973
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
128/205.240
International Classes:
A61M16/00; A61M16/20; A62B7/02
Field of Search:
128/145.8,145.5,145.6,145.7,145R,142.3,207,211,274 137/63R 251/206,207,208
Primary Examiner:
Gaudet, Richard A.
Assistant Examiner:
Recla, Henry J.
Attorney, Agent or Firm:
Weilein, Paul A.
Parent Case Data:
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of application Ser. No. 208,688, filed Dec. 16, 1971, and which is a continuation-in-part of application Ser. No. 60,524 entitled INSUFFLATOR GAS FLOW DEVICE invented by Paul E. Kenagy and filed Aug. 3, 1970 both now abandoned.
Claims:
I claim
1. In a device to provide a therapeutic gaseous mixture for inhalation by a patient, wherein the device has an inlet port to receive a pressurized therapeutic gaseous fluid and has a breathing port for use by the patient, the combination of:
2. A combination as set forth in claim 1 in which the metering means is adjustable for different rates of flow.
3. A combination as set forth in claim 2 in which said metering means includes a fixed passage and a valve member having a plurality of ports therethrough of different sizes,
4. A combination as set forth in claim 3 in which said valve member is a rotary member.
5. In a device to provide a therapeutic gaseous mixture for inhalation by a patient, wherein the device has an inlet port to receive a pressurized therapeutic gaseous fluid and has a breathing port for use by the patient, the combination of:
6. A combination as set forth in claim 5 in which said control valve is a normally closed manually operable valve.
7. A combination as set forth in claim 6 in which said control valve is a push button valve.
8. A combination as set forth in claim 5 which includes means to cut off flow through the bypass.
9. A combination as set forth in claim 5 in which said bypass is adjustable for various rates of flow therethrough.
10. A combination as set forth in claim 5 in which said bypass has a fixed portion;
11. A combination as set forth in claim 10 in which said valve member has a plurality of passages therethrough of different flow capacities for registration selectively with said fixed portion of the bypass.
12. A combination as set forth in claim 11 which includes index means to indicate the various positions of the valve member at which the various ports therethrough register respectively with said fixed portion of the bypass.
13. In a device to provide a mixture of air and a therapeutic gas for inhalation by a patient, wherein the device has an inlet port to receive a pressurized therapeutic gas and has a breathing port for use by the patient, the combination of:
1. In a device to provide a therapeutic gaseous mixture for inhalation by a patient, wherein the device has an inlet port to receive a pressurized therapeutic gaseous fluid and has a breathing port for use by the patient, the combination of:
2. A combination as set forth in claim 1 in which the metering means is adjustable for different rates of flow.
3. A combination as set forth in claim 2 in which said metering means includes a fixed passage and a valve member having a plurality of ports therethrough of different sizes,
4. A combination as set forth in claim 3 in which said valve member is a rotary member.
5. In a device to provide a therapeutic gaseous mixture for inhalation by a patient, wherein the device has an inlet port to receive a pressurized therapeutic gaseous fluid and has a breathing port for use by the patient, the combination of:
6. A combination as set forth in claim 5 in which said control valve is a normally closed manually operable valve.
7. A combination as set forth in claim 6 in which said control valve is a push button valve.
8. A combination as set forth in claim 5 which includes means to cut off flow through the bypass.
9. A combination as set forth in claim 5 in which said bypass is adjustable for various rates of flow therethrough.
10. A combination as set forth in claim 5 in which said bypass has a fixed portion;
11. A combination as set forth in claim 10 in which said valve member has a plurality of passages therethrough of different flow capacities for registration selectively with said fixed portion of the bypass.
12. A combination as set forth in claim 11 which includes index means to indicate the various positions of the valve member at which the various ports therethrough register respectively with said fixed portion of the bypass.
13. In a device to provide a mixture of air and a therapeutic gas for inhalation by a patient, wherein the device has an inlet port to receive a pressurized therapeutic gas and has a breathing port for use by the patient, the combination of:
Description:
BACKGROUND OF THE INVENTION
The invention relates generally to the field of artificial respiration, and is more particularly concerned with artificial respiration in those situations where external cardiac massage is administered in emergency cases involving asphyxia and heart failure. Resuscitation is normally required for patients who have been stricken by heart attack, electrical shock, carbon monoxide poisoning, and drowning. Various other causes contribute to asphyxia. In some patients and particularly in older patients, respiratory failure may often be accompanied by a complete lack of pulse, thus indicating a need for cardiac massage. External cardiac massage is a recommended practice and techniques for such massage have improved considerably in recent years.
Usual cardiac massage procedures consist in the application of rapid, firm manual compressions on the sternum at a rate of between 50 and 80 per minute. Normally, compression strokes are applied by the hands of a practitioner who presses one hand upon the other against the sternum. During massage, it is desirable to insufflate the patient's lungs with a large quantity of oxygen or air-oxygen mixture. The recommended technique is to insufflate between every fifth and sixth compression. Resuscitations with positive and negative pressure applications is not indicated in these cases so that a certain relationship can be maintained between the insufflation of the lungs and the imposed heart pulse resulting from the sternum compression.
There is preferably an upper limitation on the pressure of gas delivered to the lungs in order to protect the lungs and not overburden the heart by a too high lung pressure. A low mean lung pressure is desired in order to enhance cardiac output.
Practitioners in the art of cardiopulmonary resuscitation therefore are faced with a compound problem. A relatively large volume of air-oxygen must be introduced into the lungs in a short time interval, but over-distension of the lungs must also be avoided. The present invention overcomes this twofold problem as well as other problems inherent in the known prior art, by providing a unique combination of elements which are susceptible of relatively inexpensive fabrication and which can be manually operated in a simple and facile manner.
SUMMARY OF THE INVENTION
The device has an inlet port to receive a pressurized therapeutic gaseous fluid, for example, compressed oxygen, and has a breathing port for use by the patient. A venturi nozzle is mounted in a venturi throat that leads to the breathing port and a normally closed valve is operable to release the pressurized oxygen periodically to the venturi nozzle.
The venturi throat has at least one lateral vent port to the atmosphere to serve three purposes when the device is used to treat an unconscious patient, namely: to induce atmospheric air into the venturi throat to mix with the oxygen when the valve is opened periodically to fill the lungs of the unconscious patient; to vent the oxygen from the venturi nozzle to the atmosphere when filling the patient's lungs creates a back pressure in the venturi throat while the valve is open; and then to permit the patient to exhale to the atmosphere through the venturi throat when the valve is closed.
In a second mode of operation to treat a conscious patient, the valve is kept closed and a metering bypass around the closed valve releases oxygen to the venturi nozzle at a constant rate that is sufficiently reduced to permit the patient to exhale periodically through the venturi throat to the one or more vent ports of the venturi throat.
The various objects and advantages of the invention will be apparent from the following detailed description and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of the insufflator gas control device attached between a gas supply line and a conventional resuscitator mask;
FIG. 2 is an elevational sectional view of the device as viewed in FIG. 1;
FIG. 3 is a fragmentary vertical sectional view, taken along the line 3--3 of FIG. 2;
FIG. 4 is a transverse sectional view, taken along the line 4--4 of FIG. 2;
FIG. 5 is a view similar to FIG. 2 showing how an adjustable bypass may be provided around the control valve to meter the oxygen at a reduced rate;
FIG. 6 is an enlarged transverse section taken as indicated by the line 6--6 of FIG. 5;
FIG. 7 is a fragmentary section taken as indicated by the line 7--7 of FIG. 6 with a rotary component of the metering bypass in a position to release the pressurized oxygen at a given reduced rate; and
FIG. 8 is a section similar to FIG. 7 with the rotary component of the bypass turned to a position to cut off flow through the bypass.
DESCRIPTION OF THE SELECTED EMBODIMENTS OF THE INVENTION
In FIG. 1 there is illustrated a conventional resuscitator mask 10 having a hollow resilient cushion perimeter 11 adapted to sealingly conform to the area around the patient's nose and mouth. The perimeter 11 is inflatable and deflatable through a valve connection 12 to achieve proper resilience.
The mask is connected to an insufflator device 13 for the intermittent introduction of oxygen to a patient's lungs during treatment. As best shown in FIG. 2, the device 13 has a transversely extending passage 14, one end of which has an inlet port connected through an appropriate connector 15 to a pressurized source (not shown) of a gas, such as oxygen.
In the presently preferred cardiopulmonary resuscitation technique, a sternum compression stroke rate of 50-80 compressions a minute is preferred. It is also desirable to introduce between 128-145 liters of an air-oxygen mixture per minute into the lungs of the patient during the sternum compression. It has been found best to introduce the oxygen-air mixture between the fifth and sixth compressions. In order to achieve the average 135 liters per minute rate, more than one liter per second must be introduced into the lungs.
The connector 15, has therefore a conventional type of quick-acting air valve 16 axially mounted at its inner end, A valve spring 17 is adapted to maintain the valve in a normally closed position. The valve has an actuating stem 18 which is operatively associated with a manually depressible plunger 19 having an exteriorly positioned push button 20 by means of which a head portion 21 of the plunger is movable into engagement with the stem 18 to open the control valve.
A venturi nozzle in the form of a bushing 22 is provided which is threadedly engaged in a threaded passage 22a which connects centrally of the passage 14. Bushing 22 has a restricted flow passage 23 therethrough. The bushing may be easily replaced to meet changed conditions. The passage 23 discharges a jet stream into the inlet end of a venturi throat 24 that is formed by a wall 25 which terminates in a collar portion 26 which provides attachment means for connecting the insufflator device with the resuscitator mask. The venturi throat 24 is frusto-conical in configuration and tapers inwardly from a shoulder 24a formed by the intersection of the venturi throat 24 and a cylindrical throat 26a of larger diameter into which a mask connector 10 fits and is circumferentially sealed by an O-ring 26b. The mask connector 10 forms a breathing port for use by the patient.
The venturi throat is disclosed as conical. However, cylindrical and stepped venturi throats are not thereby excluded as workable configurations. The conical configuration is preferred because it lends itself to efficient mass production. As can be seen in FIG. 4, radial fluid vent passages 27, 27' are provided in the wall 25 of the venturi throat to permit an induced flow of ambient air into the venturi throat 24 as a result of the venturi action by the nozzle 22 when valve 16 is open, and the vent passages further provide for outflow therethrough when exhausting the lungs on exhalation. To prevent any clogging or other interference with the flow through the passages 27, 27', a surrounding sleeve 29 is connected at one end to a housing portion 30 and a ring 31 is added to define a protective annular cavity 32 about the wall 25. The ring 31 is provided with a plurality of fluid flow ports 33 whose total flow area is preferably greater than the total flow area of the passages 27, 27'.
It is desirable that the device be constructed for ease of manipulation and control. Therefore, the sleeve 29 is located and dimensioned so that it will afford a hand grip for the device 13 which places the manual button 20 in a convenient position for manipulation by the same hand that is used for holding the device.
The illustrated embodiment is capable of serving the functional demands of the resuscitation technique. In those situations wherein operating line pressure of the oxygen supply introduced through connector 15 is in the range of 45 psi to 55 psi, the passage 23 preferably has a diameter of substantially 0.055 inch and the jet stream emerges into a venturi throat which is about fifteen-sixteenths inch long and has a major diameter of approximately one-half inch.
The maximum desired mask pressure during insufflation is about 35 to 48 centimeters of water (35-48 cm H 2 O) to guard against too high a lung pressure. This is equivalent to 0.50 to 0.70 psi. As noted before, a low mean lung pressure is also desirable to enhance cardiac output.
Where the supply gas is supplied at approximately 50 psi passages 27, 27' each have a diameter of approximately seven-thirtyseconds inch when four passages are used. The ports 33 of collar 31 are of approximately the same diameter, but since there are eight such ports, their effective flow area is twice that of the passages 27, 27'.
OPERATION
The device 13 is coupled through connector 15 to a source of oxygen which is supplied at approximately 50 psi. Mask 10 is placed over the nose and mouth of a patient and held in position by one hand of a first operator. A second operator begins the sternum compression at the aforesaid rate of 50-80 compressions per minute. After each five compressions, the first operator manually opens valve 16 by momentarily depressing button 20, to direct a jet stream of oxygen into the venturi throat 24. The jet stream creates a venturi effect which creates a pressure differential across the passages 27, 27' to induce a flow of ambient air through the passages 27, 27' into the venturi throat where the air mixes with the oxygen and this mixture is forced through the mask into the patient's lungs. When the rapid insufflation of the oxygen-air mixture completely fills the patient's lungs, back pressure builds up in the mask and in the venturi throat.
The increased back pressure reduces the pressure differential across the jet nozzle 22 with consequent reduction in the velocity of the jet stream and consequent termination of the venturi effect. At the same time the increased back pressure in the venturi throat reverses the pressure differential across the radial vent passages 27, 27' and as long as the valve 16 remains open after the patient's lungs are full, all of the oxygen supplied by the jet stream is released to the atmosphere through the vent passages 27, 27'. It is apparent, therefore, that the duration of the open periods of the valve 16 is not at all critical and that the patient is automatically protected against overinflation of the lungs.
When the valve 16 is again closed after the patient's lungs are filled, the patient's lungs freely contract and exhaust into the venturi throat 24 and out into the atmosphere through the radial vent ports 27, 27'.
Coordination between the first and second operators seeks to achieve normal heart and lung pace relationship. Once a pulse rate is established and breathing becomes partially voluntary, the insufflation stage may be terminated and resuscitation with other equipment instituted.
The illustrated embodiment comprises a device suited to operation under oxygen pressures of about 50 psi. With present conventional pressure regulators such a pressure is usually easily maintained. However, in those instances where such a pressure is not available or cannot be readily provided, the passages 27, 27' and the venturi bore 24 may have different dimensions to achieve the same desired beneficial results.
It is to be noted that the described device does not have any relief valves or check valve or any type of rubber flap. In fact, the only moving part is the one valve mechanism and when the valve is either open or closed for a period of time the device functions without any moving parts whatsoever. The advantage, of course, is that the device is capable of a long trouble-free service life.
The structure of the second embodiment of the invention shown in FIGS. 5-8 is largely similar to the construction of the first embodiment as indicated by the use of corresponding reference numerals to indicate corresponding parts. Actually the only difference is the addition of an adjustable metering device, generally designated 40, which provides a bypass around the valve 16 which may be placed into service whenever desired. The metering device 40 includes a circular enlargement 42 of the connector 15a and an adjacent collar 44 which is rotatably mounted on the connector. The collar 44 backs against the enlargement 42 and is confined by a ring 45 which in turn is secured to the connector 15a by set screws 46.
The enlargement 42 has a single fixed angular passage 48 which terminates at the adjacent face of the rotatable collar 44, the angular passage being enlarged to accommodate a sealing ring 50. The angular passage 48 is dimensioned for the maximum bypass flow that is desired and the rotatable collar 44 is provided with a plurality of ports in the form of angular passages of graduated sizes to register with the fixed angular passage 48 selectively to provide selected rates of bypass flow. For this purpose the rotatable collar 44 has four equally circumferentially spaced angular passages 51-54 respectively. When any one of the four angular passages 51-54 registers with the stationary angular passage 48, it also registers with a radial bore 55 in the body of the connector 15a. Thus, rotary adjustment of the collar 44 affords a choice among four different rates of bypass flow around the valve 16.
Any suitable index means may be provided for guidance in the rotary positioning of the collar 44. In this particular embodiment of the invention the index means comprises a fixed longitudinal external groove 56 which serves as a reference on the enlargement 42 and four similar grooves 57-60 corresponding to the four angular passages 51-54 of the rotatable collar 44 which may be registered with the fixed groove selectively. Suitable indicia may be added to identify the four grooves 57-60 with respect to the four corresponding angular passages 51-54 respectively.
If the second embodiment of the invention is intended to function in the previously described manner of the first embodiment of the invention, the rotatable collar 44 is turned to a position where none of the grooves 57-60 registers with the fixed groove 56. The collar is then at a position at which the sealing ring 50 is pressed against a blank portion of the adjacent face of the rotatable collar to prevent bypass flow. When the bypass is in service the valve 16 is kept closed.
The bypass is used for a patient that is capable of voluntary inhalation and in that event the mask may be omitted. The radial vent ports 27, 27' provide additional needed air from the atmosphere or alternately exhausts the excess oxygen-air mixture to the atmosphere when it is supplied at a greater rate than required to match the rate of inhalation by the patient. On the other hand, when the patient exhales, the radial vent passages 27, 27' accommodate the exhalation as well as the unneeded oxygen that flows into the venturi throat. The patient is permitted to relax and breathe in a normal manner and it is not necessary to maintain a seal between the mask and the patient's face.
It is apparent that other variations within the scope of the invention will occur to those skilled in the particular art. It is therefore desired that the invention be measured by the appended claims rather than by the illustrative embodiments disclosed herein.
The invention relates generally to the field of artificial respiration, and is more particularly concerned with artificial respiration in those situations where external cardiac massage is administered in emergency cases involving asphyxia and heart failure. Resuscitation is normally required for patients who have been stricken by heart attack, electrical shock, carbon monoxide poisoning, and drowning. Various other causes contribute to asphyxia. In some patients and particularly in older patients, respiratory failure may often be accompanied by a complete lack of pulse, thus indicating a need for cardiac massage. External cardiac massage is a recommended practice and techniques for such massage have improved considerably in recent years.
Usual cardiac massage procedures consist in the application of rapid, firm manual compressions on the sternum at a rate of between 50 and 80 per minute. Normally, compression strokes are applied by the hands of a practitioner who presses one hand upon the other against the sternum. During massage, it is desirable to insufflate the patient's lungs with a large quantity of oxygen or air-oxygen mixture. The recommended technique is to insufflate between every fifth and sixth compression. Resuscitations with positive and negative pressure applications is not indicated in these cases so that a certain relationship can be maintained between the insufflation of the lungs and the imposed heart pulse resulting from the sternum compression.
There is preferably an upper limitation on the pressure of gas delivered to the lungs in order to protect the lungs and not overburden the heart by a too high lung pressure. A low mean lung pressure is desired in order to enhance cardiac output.
Practitioners in the art of cardiopulmonary resuscitation therefore are faced with a compound problem. A relatively large volume of air-oxygen must be introduced into the lungs in a short time interval, but over-distension of the lungs must also be avoided. The present invention overcomes this twofold problem as well as other problems inherent in the known prior art, by providing a unique combination of elements which are susceptible of relatively inexpensive fabrication and which can be manually operated in a simple and facile manner.
SUMMARY OF THE INVENTION
The device has an inlet port to receive a pressurized therapeutic gaseous fluid, for example, compressed oxygen, and has a breathing port for use by the patient. A venturi nozzle is mounted in a venturi throat that leads to the breathing port and a normally closed valve is operable to release the pressurized oxygen periodically to the venturi nozzle.
The venturi throat has at least one lateral vent port to the atmosphere to serve three purposes when the device is used to treat an unconscious patient, namely: to induce atmospheric air into the venturi throat to mix with the oxygen when the valve is opened periodically to fill the lungs of the unconscious patient; to vent the oxygen from the venturi nozzle to the atmosphere when filling the patient's lungs creates a back pressure in the venturi throat while the valve is open; and then to permit the patient to exhale to the atmosphere through the venturi throat when the valve is closed.
In a second mode of operation to treat a conscious patient, the valve is kept closed and a metering bypass around the closed valve releases oxygen to the venturi nozzle at a constant rate that is sufficiently reduced to permit the patient to exhale periodically through the venturi throat to the one or more vent ports of the venturi throat.
The various objects and advantages of the invention will be apparent from the following detailed description and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of the insufflator gas control device attached between a gas supply line and a conventional resuscitator mask;
FIG. 2 is an elevational sectional view of the device as viewed in FIG. 1;
FIG. 3 is a fragmentary vertical sectional view, taken along the line 3--3 of FIG. 2;
FIG. 4 is a transverse sectional view, taken along the line 4--4 of FIG. 2;
FIG. 5 is a view similar to FIG. 2 showing how an adjustable bypass may be provided around the control valve to meter the oxygen at a reduced rate;
FIG. 6 is an enlarged transverse section taken as indicated by the line 6--6 of FIG. 5;
FIG. 7 is a fragmentary section taken as indicated by the line 7--7 of FIG. 6 with a rotary component of the metering bypass in a position to release the pressurized oxygen at a given reduced rate; and
FIG. 8 is a section similar to FIG. 7 with the rotary component of the bypass turned to a position to cut off flow through the bypass.
DESCRIPTION OF THE SELECTED EMBODIMENTS OF THE INVENTION
In FIG. 1 there is illustrated a conventional resuscitator mask 10 having a hollow resilient cushion perimeter 11 adapted to sealingly conform to the area around the patient's nose and mouth. The perimeter 11 is inflatable and deflatable through a valve connection 12 to achieve proper resilience.
The mask is connected to an insufflator device 13 for the intermittent introduction of oxygen to a patient's lungs during treatment. As best shown in FIG. 2, the device 13 has a transversely extending passage 14, one end of which has an inlet port connected through an appropriate connector 15 to a pressurized source (not shown) of a gas, such as oxygen.
In the presently preferred cardiopulmonary resuscitation technique, a sternum compression stroke rate of 50-80 compressions a minute is preferred. It is also desirable to introduce between 128-145 liters of an air-oxygen mixture per minute into the lungs of the patient during the sternum compression. It has been found best to introduce the oxygen-air mixture between the fifth and sixth compressions. In order to achieve the average 135 liters per minute rate, more than one liter per second must be introduced into the lungs.
The connector 15, has therefore a conventional type of quick-acting air valve 16 axially mounted at its inner end, A valve spring 17 is adapted to maintain the valve in a normally closed position. The valve has an actuating stem 18 which is operatively associated with a manually depressible plunger 19 having an exteriorly positioned push button 20 by means of which a head portion 21 of the plunger is movable into engagement with the stem 18 to open the control valve.
A venturi nozzle in the form of a bushing 22 is provided which is threadedly engaged in a threaded passage 22a which connects centrally of the passage 14. Bushing 22 has a restricted flow passage 23 therethrough. The bushing may be easily replaced to meet changed conditions. The passage 23 discharges a jet stream into the inlet end of a venturi throat 24 that is formed by a wall 25 which terminates in a collar portion 26 which provides attachment means for connecting the insufflator device with the resuscitator mask. The venturi throat 24 is frusto-conical in configuration and tapers inwardly from a shoulder 24a formed by the intersection of the venturi throat 24 and a cylindrical throat 26a of larger diameter into which a mask connector 10 fits and is circumferentially sealed by an O-ring 26b. The mask connector 10 forms a breathing port for use by the patient.
The venturi throat is disclosed as conical. However, cylindrical and stepped venturi throats are not thereby excluded as workable configurations. The conical configuration is preferred because it lends itself to efficient mass production. As can be seen in FIG. 4, radial fluid vent passages 27, 27' are provided in the wall 25 of the venturi throat to permit an induced flow of ambient air into the venturi throat 24 as a result of the venturi action by the nozzle 22 when valve 16 is open, and the vent passages further provide for outflow therethrough when exhausting the lungs on exhalation. To prevent any clogging or other interference with the flow through the passages 27, 27', a surrounding sleeve 29 is connected at one end to a housing portion 30 and a ring 31 is added to define a protective annular cavity 32 about the wall 25. The ring 31 is provided with a plurality of fluid flow ports 33 whose total flow area is preferably greater than the total flow area of the passages 27, 27'.
It is desirable that the device be constructed for ease of manipulation and control. Therefore, the sleeve 29 is located and dimensioned so that it will afford a hand grip for the device 13 which places the manual button 20 in a convenient position for manipulation by the same hand that is used for holding the device.
The illustrated embodiment is capable of serving the functional demands of the resuscitation technique. In those situations wherein operating line pressure of the oxygen supply introduced through connector 15 is in the range of 45 psi to 55 psi, the passage 23 preferably has a diameter of substantially 0.055 inch and the jet stream emerges into a venturi throat which is about fifteen-sixteenths inch long and has a major diameter of approximately one-half inch.
The maximum desired mask pressure during insufflation is about 35 to 48 centimeters of water (35-48 cm H 2 O) to guard against too high a lung pressure. This is equivalent to 0.50 to 0.70 psi. As noted before, a low mean lung pressure is also desirable to enhance cardiac output.
Where the supply gas is supplied at approximately 50 psi passages 27, 27' each have a diameter of approximately seven-thirtyseconds inch when four passages are used. The ports 33 of collar 31 are of approximately the same diameter, but since there are eight such ports, their effective flow area is twice that of the passages 27, 27'.
OPERATION
The device 13 is coupled through connector 15 to a source of oxygen which is supplied at approximately 50 psi. Mask 10 is placed over the nose and mouth of a patient and held in position by one hand of a first operator. A second operator begins the sternum compression at the aforesaid rate of 50-80 compressions per minute. After each five compressions, the first operator manually opens valve 16 by momentarily depressing button 20, to direct a jet stream of oxygen into the venturi throat 24. The jet stream creates a venturi effect which creates a pressure differential across the passages 27, 27' to induce a flow of ambient air through the passages 27, 27' into the venturi throat where the air mixes with the oxygen and this mixture is forced through the mask into the patient's lungs. When the rapid insufflation of the oxygen-air mixture completely fills the patient's lungs, back pressure builds up in the mask and in the venturi throat.
The increased back pressure reduces the pressure differential across the jet nozzle 22 with consequent reduction in the velocity of the jet stream and consequent termination of the venturi effect. At the same time the increased back pressure in the venturi throat reverses the pressure differential across the radial vent passages 27, 27' and as long as the valve 16 remains open after the patient's lungs are full, all of the oxygen supplied by the jet stream is released to the atmosphere through the vent passages 27, 27'. It is apparent, therefore, that the duration of the open periods of the valve 16 is not at all critical and that the patient is automatically protected against overinflation of the lungs.
When the valve 16 is again closed after the patient's lungs are filled, the patient's lungs freely contract and exhaust into the venturi throat 24 and out into the atmosphere through the radial vent ports 27, 27'.
Coordination between the first and second operators seeks to achieve normal heart and lung pace relationship. Once a pulse rate is established and breathing becomes partially voluntary, the insufflation stage may be terminated and resuscitation with other equipment instituted.
The illustrated embodiment comprises a device suited to operation under oxygen pressures of about 50 psi. With present conventional pressure regulators such a pressure is usually easily maintained. However, in those instances where such a pressure is not available or cannot be readily provided, the passages 27, 27' and the venturi bore 24 may have different dimensions to achieve the same desired beneficial results.
It is to be noted that the described device does not have any relief valves or check valve or any type of rubber flap. In fact, the only moving part is the one valve mechanism and when the valve is either open or closed for a period of time the device functions without any moving parts whatsoever. The advantage, of course, is that the device is capable of a long trouble-free service life.
The structure of the second embodiment of the invention shown in FIGS. 5-8 is largely similar to the construction of the first embodiment as indicated by the use of corresponding reference numerals to indicate corresponding parts. Actually the only difference is the addition of an adjustable metering device, generally designated 40, which provides a bypass around the valve 16 which may be placed into service whenever desired. The metering device 40 includes a circular enlargement 42 of the connector 15a and an adjacent collar 44 which is rotatably mounted on the connector. The collar 44 backs against the enlargement 42 and is confined by a ring 45 which in turn is secured to the connector 15a by set screws 46.
The enlargement 42 has a single fixed angular passage 48 which terminates at the adjacent face of the rotatable collar 44, the angular passage being enlarged to accommodate a sealing ring 50. The angular passage 48 is dimensioned for the maximum bypass flow that is desired and the rotatable collar 44 is provided with a plurality of ports in the form of angular passages of graduated sizes to register with the fixed angular passage 48 selectively to provide selected rates of bypass flow. For this purpose the rotatable collar 44 has four equally circumferentially spaced angular passages 51-54 respectively. When any one of the four angular passages 51-54 registers with the stationary angular passage 48, it also registers with a radial bore 55 in the body of the connector 15a. Thus, rotary adjustment of the collar 44 affords a choice among four different rates of bypass flow around the valve 16.
Any suitable index means may be provided for guidance in the rotary positioning of the collar 44. In this particular embodiment of the invention the index means comprises a fixed longitudinal external groove 56 which serves as a reference on the enlargement 42 and four similar grooves 57-60 corresponding to the four angular passages 51-54 of the rotatable collar 44 which may be registered with the fixed groove selectively. Suitable indicia may be added to identify the four grooves 57-60 with respect to the four corresponding angular passages 51-54 respectively.
If the second embodiment of the invention is intended to function in the previously described manner of the first embodiment of the invention, the rotatable collar 44 is turned to a position where none of the grooves 57-60 registers with the fixed groove 56. The collar is then at a position at which the sealing ring 50 is pressed against a blank portion of the adjacent face of the rotatable collar to prevent bypass flow. When the bypass is in service the valve 16 is kept closed.
The bypass is used for a patient that is capable of voluntary inhalation and in that event the mask may be omitted. The radial vent ports 27, 27' provide additional needed air from the atmosphere or alternately exhausts the excess oxygen-air mixture to the atmosphere when it is supplied at a greater rate than required to match the rate of inhalation by the patient. On the other hand, when the patient exhales, the radial vent passages 27, 27' accommodate the exhalation as well as the unneeded oxygen that flows into the venturi throat. The patient is permitted to relax and breathe in a normal manner and it is not necessary to maintain a seal between the mask and the patient's face.
It is apparent that other variations within the scope of the invention will occur to those skilled in the particular art. It is therefore desired that the invention be measured by the appended claims rather than by the illustrative embodiments disclosed herein.