Title of Invention	A PRESSURE REGULATING DEVICE CAPABLE OF BEING USED WITH A BREATHING ASSISTANCE APPARATUS AND A BREATHING ASSISTANCE APPARATUS FOR SUPPLYING GAS TO A PATIENT IN COMBINATION WITH SAID DEVICE
Abstract	A pressure regulator (134) according to the present invention is disclosed for regulating the expiratory flow (130) in a CPAP system (118). Prior art CPAP systems are typically regulated by adjusting the pressure at the gas supply. Similarly the gas supply is not able to provide high frequency oscillations on top of the main level of pressure delivered to the patient. The regulator (134) according to the present invention comprises submerging a tube (136) into a column of water (138) to pass the expiratory gases of the user, thereby providing a back pressure corresponding to a positive mean pressure together with bubbling providing pressure variations. Improvements are included for adjusting the level to which the tube is submerged (146) and for ensuring constant water level (218).

Title of Invention

A PRESSURE REGULATING DEVICE CAPABLE OF BEING USED WITH A BREATHING ASSISTANCE APPARATUS AND A BREATHING ASSISTANCE APPARATUS FOR SUPPLYING GAS TO A PATIENT IN COMBINATION WITH SAID DEVICE

Abstract

A pressure regulator (134) according to the present invention is disclosed for regulating the expiratory flow (130) in a CPAP system (118). Prior art CPAP systems are typically regulated by adjusting the pressure at the gas supply. Similarly the gas supply is not able to provide high frequency oscillations on top of the main level of pressure delivered to the patient. The regulator (134) according to the present invention comprises submerging a tube (136) into a column of water (138) to pass the expiratory gases of the user, thereby providing a back pressure corresponding to a positive mean pressure together with bubbling providing pressure variations. Improvements are included for adjusting the level to which the tube is submerged (146) and for ensuring constant water level (218).

Full Text	FIELD OF THE INVENTION The present invention relates to the use of a pressure regulator in conjunction with a breathing assistance apparatus, particularly though not solely, for regulating the pressure of gases supplied to a patient from a humidified Positive End Expiratory Pressure (PEEP) apparatus. BACKGROUND ART The use of a medical apparatus to facilitate breathing is well known in the art. The apparatus may take the form of a simple oxygen mask or tent which supplies oxygen at "slightly above atmospheric pressure. Such devices merely assist a person to breath and work with the person"s lungs. Ventilators which operate at high frequency have been suggested in the past. There are two types of high frequency ventilators known in the art. One type, as exemplified by US Pat. No. 2,918,917 (Emerson), employs a reciprocating diaphragm to vibrate a column of gas supplied to a subject. The vibration is in addition to the subject"s respiration, natural or artificial, and at a much more rapid rate, for example, from 100 to more than 1500 vibrations per minute. The Emerson apparatus is primarily designed to vibrate the patient"s airway and organs associated therewith, although Emerson also recognized that high frequency vibration causes the gas to diffuse more rapidly within the airway and therefore aids the breathing fiinction. However, the Emerson apparatus is incapable of supporting the patient"s full ventilation and must be used in conjunction with the patient"s spontaneous breathing or with another apparatus which produces artificially induced inhalation and exhalation. The second type of high frequency ventilator is the jet pulse ventilator as "exemplified in US Patent No. 4,265,237 (Schwanbom et al.). The Schwanbom et al. ventilator produces high frequency, high pressure pulses of air which are capable of fully ventilating a patient. The respiration pulse enters with a pressure of 0.2 bar to 2.7 bar. This pressure is sufficient to expand the lungs during inspiration. Expiration is caused by the natural compliance of the lungs after the jet of air is stopped. Accordingly, it can be seen that Schwanbom et al must rely on the compliance of the lungs in order to fully ventilate the patient. If the lung compliance is low, greater pressure must be used. Schwanbom et al also supply a source of lower pressure gas for spontaneous breathing by the patient. While such jet pulse ventilators are useful for some applications, they are not generally applicable and their use is limited mostly to experimental work. An improvement on these types is disclosed in US Patent No. 4,821,709 (Jensen) which provides high frequency oscillations in the gases supplied to a patient using a flexible diaphragm. Jensen provides a more practical method of ventilating a patient Swithout spontaneous breathing of the patient, or the need for a separate ventilator. US Patent No. 4,646,733 (Strot et al.) proposes an apparatus for producing high frequency oscillations in gases supplied to a patient using a valve controlling the exhaled gases. It would be desirable to have a simple system for providing high frequency pressure oscillations for spontaneously breathing patients particularly for non invasive forms of support, where the \|mean pressure level of gases provided to the patient can be adjusted. . DISCLOSURE OF INVENTION It is an object of the present invention to provide a pressure regulator which goes some way to overcoming the above-mentioned disadvantages, or which will at least provide the healthcare industry with a useful choice. Accordingly, the present invention provides a pressure regulating device capable of being used with a breathing assistance apparatus which conveys inhaiatory gas to, and removes exhalatory gas from, a patient requiring breathing assistance, said device comprising: a container which, in use, contains a body of liquid, and is configured to have a substantially constant level of said liquid, in use, a conduit having proximate and distal ends, wherein said proximate end is adapted to be connected to a breathing assistance apparatus for accepting exhalatory gases from said breathing assistance apparatus, in use, and said distal end is adapted to be submerged in said body of liquid in said container, the arrangement being such that, in use, the mean pressure of said gas supplied to a patient is capable of being adjusted by a level to which said distal end of said conduit is caused to be submerged in said body of liquid contained in said container. The present invention also provides a breathing assistance apparatus for supplying gas to a patient to assist said patient"s breathing, comprising: gas supply means adapted to supply gas to said patient; delivery means with a plurality of ports adapted to deliver said gas to said patient; inhaiatory gas transport means for conveying said gas from said gas supply means to said delivery means; exhalatory gas transport means for conveying said patient"s exhalations from said delivery means; a container which, in use, contains a body of liquid, and is configured to have a substantially constant level of said liquid, in use; a conduit having proximate and distal ends, wherein said proximate end is adapted to be connected to the breathing assistance apparatus, for accepting exhalatory gases from the breathing assistance apparatus, in use, and said distal end is adapted to be submerged in said body of liquid in said container; the arrangement being such that, in use, said patient is caused to be delivered a substantially constant mean pressure of the gas, and said mean pressure is capable of being adjusted by altering the level to which said distal end of the conduit is submerged in said body of liquid. To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will , "suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure 1 is a block diagram showing a typical configuration for supplying breathing assistance to a patient, Figure 2 is a plan view of the pressure regulator with the lid on according to the preferred embodiment of the present invention, Figure 3 is a side view of the pressure regulator according to the preferred embodiment of the present invention. Figure 4 is a cross-section of the pressure regulator according to the preferred embodiment of the present invention, Figure 5 is an alternative side view of the pressure regulator according to the preferred embodiment of the present invention, Figure 6 is a perspective view of the short conduit which extends into the water chamber according to the preferred embodiment of the present invention, Figure 7 is a cross-section of the complete pressure regulator according to the preferred embodiment of the present invention, and Figure 8 is a cross-section of a further embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a means of producing the variations or oscillations in the pressure of gases supplied to a patient connected to a positive pressure ventilation device. By submerging the end of the exhalatory conduit into a water column the resulting bubbles generate a variation or ripple in the mean pressure of gases delivered to the patient. In doing so it also provides a simple method of varying the mean pressure of gases supplied to the patient by variation of the level to which the end of the exhalatory conduit is submerged within the water column. In order to keep the mean pressure of gases supplied " "to the patient constant the level of submergence of the end of the exhalatory conduit must be kept constant and an apparatus for ensuring this occurs is also disclosed. Referring now to Figure 1 in which a typical application is depicted. A humidified Positive End Expiratory Pressure (PEEP) system is shown in which a patient 119 is receiving humidified and pressurised gases through a nasal mask 128 connected to a " inhalatory conduit 121. It should be understood that the present invention, however, is not limited to the delivery of PEEP gases but is also applicable to other types of gases delivery systems and may not necessarily involve humidification. Inhalatory conduit 121 is connected to the outlet 112 of a humidification chamber 110 which contains a volume of water 115. Inspiratory conduit 121 may contain heating means or heater wires 120 which heat the walls of the conduit to ensure a constant humidity profile along the conduit and therefore reduce condensation of humidified gases within the conduit. As the volume of water 115 within humidification chamber 110 is heated, water vapour begins to fill the volume of the chamber above the water"s surface and is passed out of the humidification chamber 110 outlet 112 with the flow of gases (for example air) provided firom a gases supply means or blower 118 which enters the chamber 110 through inlet 116. The humidified gases pass through the inhalatory conduit 121 to the mask 128 attached around the patient"s 119 mouth. The excess gases then flow through the exhalatory conduit 130 to a pressure regulator 134. Pressure Regulator In the preferred embodiment of the present invention the pressure regulator 134, takes the form of discharging the flow of exhalatory gases into a chamber 204 containing a column of water 138. The gases flowing through the exhalatory conduit 130 are discharged into the body of water 138 irom a short conduit 136 which extends from the expiratory conduit into the chamber 204. This results in a bubbling effect, whereby the gases eventually exit the chamber 204 via the outlet port 152, which can also be used to initially fill the chamber 204 with water. The outlet port 152 includes shielding to prevent liquid aerosols created by the vigorous bubbling on the surface of the water from being expelled. "It will be appreciated that the short conduit 136, could equally be integrated into the end of the expiratory conduit 130. Referring now to Figures 2 through 7, the pressure regulator 134 and associated components are seen in more detail. The exhalatory conduit (130, Figure 1) fits into the end of the short conduit 136 which in turn is attached to the lid 144 of the water chamber 2oi,via connector 146. The connector 146 includes a number of resilient ridges or plastic toggles 148 which lock into annular grooves 150 in the short conduit, 136 to keep it locked in a desired position during use. The chamber 204 is filled with a body of water 138 up to a" predetenmined level 140. It will be appreciated that any appropriate liquid could be used instead of water. It will be appreciated that for control over the mean pressure of supplied gases it is which necessary to vary the level of the short conduit 136 is^ submerged in the body of water 138. Stepped variations in the pressure of gases delivered to the patient of i^ cm H^O each, are thought adequate for most applications, and is achieved by i equally spacing each of the annular grooves (150)^/2 cm apart. A contoured gripping portion 147 is provided at the end of the short conduit 136 which attaches to the exhalatory conduit 130, to allow easy adjustment. In one embodiment, the pressure is adjustable over a range from 4-8 cm H2O but it will be appreciated that this can be modified to requirements. The pressure regulator according to the preferred embodiment of the present invention is shown in Figure 7, adjusted to its highest pressure setting. The settings could be indicated by a number above ■each groove 150 on the short conduit 136, which would be visible above the connector 146. Constant Water Level In the preferred embodiment, the present invention is used in conjunction with a humidified PEEP respirator. As such, the exhalatory gases will have quite high levels of humidity, some at which will inevitably condense in the body of water 138 in the pressure regulator 134. Thus, over time the volume of water in the water chamber 204 will rise and if unchecked will result in risine pressure of gases supplied to the patient and resultant that adverse side effects. To ensure ^the water level is kept constant the water chamber 204 is provided with an overflow facility 218 also seen in Figures 2 to 7. Because of the vigorous bubbling occurring at the top of the body of water a simple lip over which excess liquid, can flow would be ineffective and therefore some form of filtering or damping is required. In order to mitigate the effect of the vigorous bubbling near the top of a chamber 200 a main outlet port 202 from the main chamber 204 is provided at a substantially lower level than where the bubbles would nonnally be expected to occur. However, the bubbling also causes pressure waves throughout the body of the liquid. These pressure waves would normally be reflected through the main outlet port 202 into a levelling or immediate overflow chamber 206 and therefore result in more water escaping than it is desired. To alleviate the effect of the pressure waves a wave shield 208 is located in an intermediate "position between the upper level of the water 210 and the main outlet port 202. This masks the outlet port 202 from the majority of the pressure waves due to the surface bubbling. This effectively means that the water level in the levelling chamber 206 is relatively calm and substantially representative of the mean (as opposed to the instantaneous) water level in the main chamber 204. The water level in the intermediate overflow/revelling chamber 206, dn tum^is regulated by an overflow port 212 situated on a raised adjacent platform 214. The overflow port 212 is surrounded by a slightly cylindrical raised partition 216 in order to overcome the effect of any small remaining waves in the intermediate overflow chamber 206. The water then flows into the detachable overflow container 218 which when foil ."may be detached in use and emptied. Both the main chamber 204 and the intermediate overflow chamber 206 are integrally injection moulded using a clear plastic. The separate overflow container 218, is also injection moulded using a clear plastic as is the separate short conduit 136. Further Embodiments It will also be appreciated that the apparatus used to vary the mean water level in the main chamber may take a number of forms. While in the preferred embodiment a slidable conduit is used, other forms such as concertina baffle or rotatable conduit, for example, that would be equally applicable. It will also be appreciated ^rurther forms of the overflow facility will be possible. For example,the further embodiment shown in Figure 8, uses a thin slot 162 to pass water into a second chamber 160, where baffles smooth any variations before the overflow opening 166 into the overflow chamber 168. Advantages Allows easy adjustment of the mean pressure level, Allows high frequency pressure oscillations for spontaneously breathing patients. Maintains constant mean pressure with low or no maintenance. Disposable and cheap compared with prior art ventilators. WE CLAIM ; 1. A pressure regulating device capable of being used with a breathing assistance apparatus which conveys inhalatory gas to, and removes exhalatory gas from, a patient requiring breathing assistance, said device comprising: a container which, in use, contains a body of liquid, and is configured to have a substantially constant level of said liquid, in use, a conduit having proximate and distal ends, wherein said proximate end is adapted to be connected to a breathing assistance apparatus for accepting exhalatory gases from said breathing assistance apparatus, in use, and said distal end is adapted to be submerged in said body of liquid in said container, the arrangement being such that, in use, the mean pressure of said gas supplied to a patient is capable of being adjusted by a level to which said distal end of said conduit is caused to be submerged in said body of liquid contained in said container. 2. A pressure regulating device as claimed in claim 1, wherein there is provided a connection means attached to said container and engaging said conduit, whereby, in use, said conduit is adapted to be adjusted in axial position in predetermined increments, with respect to said connection means. 3. A pressure regulating device as claimed in claim 2, wherein said conduit has at least one partial groove, and said connection means has at least one matching partial resilient ridge or toggle, for adjustment of axial position of said conduit with respect to said connection means. 4. A pressure regulating device as claimed in claim 2 or 3, wherein said predetermined increments are one centimetre each. 5. A pressure regulating device as claimed in any one of claims 1 to 4, which is provided with an overflow means for regulating the level of said body of liquid with respect to said container, to said constant level. 6. A pressure regulating device as claimed in claim 5, wherein said overflow means is provided with a damping means for damping any perturbations in said level of said body of liquid, such that, in use, said overflow means is capable of regulating the "mean" level of said body of liquid. 7. A pressure regulating device as claimed in claim 6, wherein said damping means comprises an underwater outlet from said container, said damping means being located at a position, which, in use is substantially below the level of said body of liquid, and means for reducing the pressure waves which, in use, are produced in said body of liquid by the exhalations of said patient flowing there-through, said means for reducing the pressure waves being located at a position which, in use, is between the level of said body of liquid and said underwater outlet. 8. A pressure regulating device as claimed in any of claims 5 to 7, wherein a removable container is provided, such that, in use, the overflow from said body of liquid is caused to flow through said overflow outlet into said removable container. 9. A pressure regulating device as claimed in any of claims 1 to 8 wherein said body of liquid is substantially composed of water. 10. A pressure regulating device as claimed in any one of claims 1 to 9, wherein said device is constructed substantially from clear plastic materials. 11. A breathing assistance apparatus for supplying gas to a patient to assist said patient"s breathing, comprising: gas supply means adapted to supply gas to said patient; delivery means with a plurality of ports adapted to deliver said gas to said patient; inhalatory gas transport means for conveying said gas from said gas supply means to said delivery means; exhalatory gas transport means for conveying said patient"s exhalations from said delivery means; a container which, in use, contains a body of liquid and is configured to have a -substantially constant level of said liquid, in use; a conduit having proximate and distal ends, wherein said proximate end is adapted to be connected to the breathing assistance apparatus, for accepting exhalatory gases from the breathing assistance apparatus, in use, and said distal end is adapted to be submerged in said body of liquid in said container; the arrangement being such that, in use, said patient is caused to be delivered a substantially constant mean pressure of the gas, and said mean pressure is capable of being adjusted by altering the level to which said distal end of the conduit is submerged in said body of liquid. 12. A breathing assistance apparatus as claimed in claim 11, which is provided with a humidifier for humidifying said gas prior to its delivery to said patient, said humidifier being disposed within, or in fluid communication with said inhalatory gas transport means. 13. A pressure regulating device capable of being used with a breathing assistance apparatus, substantially as herein described, with particular reference to, and as illustrated in the accompanying drawings. 14. A breathing assistance apparatus for supplying gas to a patient to assist said patient"s breathing, substantially as herein described, with particular reference to, and as illustrated in the accompanying drawings.

Full Text

FIELD OF THE INVENTION
The present invention relates to the use of a pressure regulator in conjunction with a breathing assistance apparatus, particularly though not solely, for regulating the pressure of gases supplied to a patient from a humidified Positive End Expiratory Pressure (PEEP) apparatus. BACKGROUND ART
The use of a medical apparatus to facilitate breathing is well known in the art. The apparatus may take the form of a simple oxygen mask or tent which supplies oxygen at "slightly above atmospheric pressure. Such devices merely assist a person to breath and work with the person"s lungs.
Ventilators which operate at high frequency have been suggested in the past. There are two types of high frequency ventilators known in the art. One type, as exemplified by US Pat. No. 2,918,917 (Emerson), employs a reciprocating diaphragm to vibrate a column of gas supplied to a subject. The vibration is in addition to the subject"s respiration, natural or artificial, and at a much more rapid rate, for example, from 100 to more than 1500 vibrations per minute. The Emerson apparatus is primarily designed to vibrate the patient"s airway and organs associated therewith, although Emerson also recognized that high frequency vibration causes the gas to diffuse more rapidly within the airway and therefore aids the breathing fiinction. However, the Emerson apparatus is incapable of supporting the patient"s full ventilation and must be used in conjunction with the patient"s spontaneous breathing or with another apparatus which produces artificially induced inhalation and exhalation.
The second type of high frequency ventilator is the jet pulse ventilator as "exemplified in US Patent No. 4,265,237 (Schwanbom et al.). The Schwanbom et al. ventilator produces high frequency, high pressure pulses of air which are capable of fully ventilating a patient. The respiration pulse enters with a pressure of 0.2 bar to 2.7 bar. This pressure is sufficient to expand the lungs during inspiration. Expiration is caused by the natural compliance of the lungs after the jet of air is stopped. Accordingly, it can be seen that Schwanbom et al must rely on the compliance of the lungs in order to fully ventilate the patient. If the lung compliance is low, greater pressure must be used. Schwanbom et al also supply a source of lower pressure gas for spontaneous breathing by the patient. While such jet pulse ventilators are useful for some applications, they are not generally applicable

and their use is limited mostly to experimental work.
An improvement on these types is disclosed in US Patent No. 4,821,709 (Jensen) which provides high frequency oscillations in the gases supplied to a patient using a flexible diaphragm. Jensen provides a more practical method of ventilating a patient Swithout spontaneous breathing of the patient, or the need for a separate ventilator. US Patent No. 4,646,733 (Strot et al.) proposes an apparatus for producing high frequency oscillations in gases supplied to a patient using a valve controlling the exhaled gases.
It would be desirable to have a simple system for providing high frequency pressure oscillations for spontaneously breathing patients particularly for non invasive forms of support, where the |mean pressure level of gases provided to the patient can be adjusted. . DISCLOSURE OF INVENTION
It is an object of the present invention to provide a pressure regulator which goes some way to overcoming the above-mentioned disadvantages, or which will at least provide the healthcare industry with a useful choice.
Accordingly, the present invention provides a pressure regulating device capable of being used with a breathing assistance apparatus which conveys inhaiatory gas to, and removes exhalatory gas from, a patient requiring breathing assistance, said device comprising:
a container which, in use, contains a body of liquid, and is configured to have a substantially constant level of said liquid, in use,
a conduit having proximate and distal ends, wherein said proximate end is adapted to be connected to a breathing assistance apparatus for accepting exhalatory gases from said breathing assistance apparatus, in use, and said distal end is adapted to be submerged in said body of liquid in said container,
the arrangement being such that, in use, the mean pressure of said gas supplied to a patient is capable of being adjusted by a level to which said distal end of said conduit is caused to be submerged in said body of liquid contained in said container.
The present invention also provides a breathing assistance apparatus for supplying gas to a patient to assist said patient"s breathing, comprising:
gas supply means adapted to supply gas to said patient;
delivery means with a plurality of ports adapted to deliver said gas to said patient;
inhaiatory gas transport means for conveying said gas from said gas supply means to said delivery means;

exhalatory gas transport means for conveying said patient"s exhalations from said delivery means;
a container which, in use, contains a body of liquid, and is configured to have a substantially constant level of said liquid, in use;
a conduit having proximate and distal ends, wherein said proximate end is adapted to be connected to the breathing assistance apparatus, for accepting exhalatory gases from the breathing assistance apparatus, in use, and said distal end is adapted to be submerged in said body of liquid in said container;
the arrangement being such that, in use, said patient is caused to be delivered a substantially constant mean pressure of the gas, and said mean pressure is capable of being adjusted by altering the level to which said distal end of the conduit is submerged in said body of liquid.
To those skilled in the art to which the invention relates, many changes in
construction and widely differing embodiments and applications of the invention will
, "suggest themselves without departing from the scope of the invention as defined in the
appended claims. The disclosures and the descriptions herein are purely illustrative and are
not intended to be in any sense limiting.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 is a block diagram showing a typical configuration for supplying breathing assistance to a patient,
Figure 2 is a plan view of the pressure regulator with the lid on according to the preferred embodiment of the present invention,
Figure 3 is a side view of the pressure regulator according to the preferred embodiment of the present invention.
Figure 4 is a cross-section of the pressure regulator according to the preferred embodiment of the present invention,
Figure 5 is an alternative side view of the pressure regulator according to the preferred embodiment of the present invention,

Figure 6 is a perspective view of the short conduit which extends into the water chamber according to the preferred embodiment of the present invention,
Figure 7 is a cross-section of the complete pressure regulator according to the preferred embodiment of the present invention, and
Figure 8 is a cross-section of a further embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides a means of producing the variations or oscillations in the pressure of gases supplied to a patient connected to a positive pressure ventilation device. By submerging the end of the exhalatory conduit into a water column the resulting bubbles generate a variation or ripple in the mean pressure of gases delivered to the patient. In doing so it also provides a simple method of varying the mean pressure of gases supplied to the patient by variation of the level to which the end of the exhalatory conduit is submerged within the water column. In order to keep the mean pressure of gases supplied " "to the patient constant the level of submergence of the end of the exhalatory conduit must be kept constant and an apparatus for ensuring this occurs is also disclosed.
Referring now to Figure 1 in which a typical application is depicted. A humidified Positive End Expiratory Pressure (PEEP) system is shown in which a patient 119 is receiving humidified and pressurised gases through a nasal mask 128 connected to a " inhalatory conduit 121. It should be understood that the present invention, however, is not limited to the delivery of PEEP gases but is also applicable to other types of gases delivery systems and may not necessarily involve humidification. Inhalatory conduit 121 is connected to the outlet 112 of a humidification chamber 110 which contains a volume of water 115. Inspiratory conduit 121 may contain heating means or heater wires 120 which heat the walls of the conduit to ensure a constant humidity profile along the conduit and therefore reduce condensation of humidified gases within the conduit. As the volume of water 115 within humidification chamber 110 is heated, water vapour begins to fill the volume of the chamber above the water"s surface and is passed out of the humidification chamber 110 outlet 112 with the flow of gases (for example air) provided firom a gases supply means or blower 118 which enters the chamber 110 through inlet 116.
The humidified gases pass through the inhalatory conduit 121 to the mask 128 attached around the patient"s 119 mouth. The excess gases then flow through the exhalatory conduit 130 to a pressure regulator 134.

Pressure Regulator
In the preferred embodiment of the present invention the pressure regulator 134, takes the form of discharging the flow of exhalatory gases into a chamber 204 containing a column of water 138. The gases flowing through the exhalatory conduit 130 are discharged into the body of water 138 irom a short conduit 136 which extends from the expiratory conduit into the chamber 204. This results in a bubbling effect, whereby the gases eventually exit the chamber 204 via the outlet port 152, which can also be used to initially fill the chamber 204 with water. The outlet port 152 includes shielding to prevent liquid aerosols created by the vigorous bubbling on the surface of the water from being expelled. "It will be appreciated that the short conduit 136, could equally be integrated into the end of the expiratory conduit 130.
Referring now to Figures 2 through 7, the pressure regulator 134 and associated components are seen in more detail. The exhalatory conduit (130, Figure 1) fits into the end of the short conduit 136 which in turn is attached to the lid 144 of the water chamber 2oi,via connector 146. The connector 146 includes a number of resilient ridges or plastic toggles 148 which lock into annular grooves 150 in the short conduit, 136 to keep it locked in a desired position during use. The chamber 204 is filled with a body of water 138 up to a" predetenmined level 140. It will be appreciated that any appropriate liquid could be used instead of water.
It will be appreciated that for control over the mean pressure of supplied gases it is
which necessary to vary the level of the short conduit 136 is^ submerged in the body of
water 138. Stepped variations in the pressure of gases delivered to the patient of i^ cm H^O
each, are thought adequate for most applications, and is achieved by i equally spacing each of the
annular grooves (150)^/2 cm apart. A contoured gripping portion 147 is provided at the end
of the short conduit 136 which attaches to the exhalatory conduit 130, to allow easy
adjustment. In one embodiment, the pressure is adjustable over a range from 4-8 cm H2O
but it will be appreciated that this can be modified to requirements. The pressure regulator
according to the preferred embodiment of the present invention is shown in Figure 7,
adjusted to its highest pressure setting. The settings could be indicated by a number above
■each groove 150 on the short conduit 136, which would be visible above the connector 146.
Constant Water Level
In the preferred embodiment, the present invention is used in conjunction with a
humidified PEEP respirator. As such, the exhalatory gases will have quite high levels of

humidity, some at which will inevitably condense in the body of water 138 in the pressure
regulator 134. Thus, over time the volume of water in the water chamber 204 will rise and
if unchecked will result in risine pressure of gases supplied to the patient and resultant
that adverse side effects. To ensure ^the water level is kept constant the water chamber 204 is
provided with an overflow facility 218 also seen in Figures 2 to 7.
Because of the vigorous bubbling occurring at the top of the body of water a simple
lip over which excess liquid, can flow would be ineffective and therefore some form of
filtering or damping is required. In order to mitigate the effect of the vigorous bubbling
near the top of a chamber 200 a main outlet port 202 from the main chamber 204 is
provided at a substantially lower level than where the bubbles would nonnally be expected
to occur. However, the bubbling also causes pressure waves throughout the body of the
liquid. These pressure waves would normally be reflected through the main outlet port 202
into a levelling or immediate overflow chamber 206 and therefore result in more water escaping than it is desired.
To alleviate the effect of the pressure waves a wave shield 208 is located in an intermediate
"position between the upper level of the water 210 and the main outlet port 202. This masks
the outlet port 202 from the majority of the pressure waves due to the surface bubbling.
This effectively means that the water level in the levelling chamber 206 is relatively
calm and substantially representative of the mean (as opposed to the instantaneous) water
level in the main chamber 204. The water level in the intermediate overflow/revelling chamber 206,
dn tum^is regulated by an overflow port 212 situated on a raised adjacent platform 214. The overflow port 212 is surrounded by a slightly cylindrical raised partition 216 in order to overcome the effect of any small remaining waves in the intermediate overflow chamber 206.
The water then flows into the detachable overflow container 218 which when foil ."may be detached in use and emptied. Both the main chamber 204 and the intermediate overflow chamber 206 are integrally injection moulded using a clear plastic. The separate overflow container 218, is also injection moulded using a clear plastic as is the separate short conduit 136. Further Embodiments
It will also be appreciated that the apparatus used to vary the mean water level in the main chamber may take a number of forms. While in the preferred embodiment a slidable
conduit is used, other forms such as concertina baffle or rotatable conduit, for example,
that would be equally applicable. It will also be appreciated ^rurther forms of the overflow

facility will be possible. For example,the further embodiment shown in Figure 8, uses a thin slot 162 to pass water into a second chamber 160, where baffles smooth any variations before the overflow opening 166 into the overflow chamber 168. Advantages
Allows easy adjustment of the mean pressure level,
Allows high frequency pressure oscillations for spontaneously breathing patients.
Maintains constant mean pressure with low or no maintenance.
Disposable and cheap compared with prior art ventilators.

WE CLAIM ;
1. A pressure regulating device capable of being used with a breathing assistance
apparatus which conveys inhalatory gas to, and removes exhalatory gas from, a patient
requiring breathing assistance, said device comprising:
a container which, in use, contains a body of liquid, and is configured to have a substantially constant level of said liquid, in use,
a conduit having proximate and distal ends, wherein said proximate end is adapted to be connected to a breathing assistance apparatus for accepting exhalatory gases from said breathing assistance apparatus, in use, and said distal end is adapted to be submerged in said body of liquid in said container,
the arrangement being such that, in use, the mean pressure of said gas supplied to a patient is capable of being adjusted by a level to which said distal end of said conduit is caused to be submerged in said body of liquid contained in said container.
2. A pressure regulating device as claimed in claim 1, wherein there is provided a connection means attached to said container and engaging said conduit, whereby, in use, said conduit is adapted to be adjusted in axial position in predetermined increments, with respect to said connection means.
3. A pressure regulating device as claimed in claim 2, wherein said conduit has at least one partial groove, and said connection means has at least one matching partial resilient ridge or toggle, for adjustment of axial position of said conduit with respect to said connection means.
4. A pressure regulating device as claimed in claim 2 or 3, wherein said predetermined increments are one centimetre each.
5. A pressure regulating device as claimed in any one of claims 1 to 4, which is provided with an overflow means for regulating the level of said body of liquid with respect to said container, to said constant level.

6. A pressure regulating device as claimed in claim 5, wherein said overflow means is provided with a damping means for damping any perturbations in said level of said body of liquid, such that, in use, said overflow means is capable of regulating the "mean" level of said body of liquid.
7. A pressure regulating device as claimed in claim 6, wherein said damping means comprises an underwater outlet from said container, said damping means being located at a position, which, in use is substantially below the level of said body of liquid, and means for reducing the pressure waves which, in use, are produced in said body of liquid by the exhalations of said patient flowing there-through, said means for reducing the pressure waves being located at a position which, in use, is between the level of said body of liquid and said underwater outlet.
8. A pressure regulating device as claimed in any of claims 5 to 7, wherein a removable container is provided, such that, in use, the overflow from said body of liquid is caused to flow through said overflow outlet into said removable container.
9. A pressure regulating device as claimed in any of claims 1 to 8 wherein said body of liquid is substantially composed of water.
10. A pressure regulating device as claimed in any one of claims 1 to 9, wherein said device is constructed substantially from clear plastic materials.
11. A breathing assistance apparatus for supplying gas to a patient to assist said
patient"s breathing, comprising:
gas supply means adapted to supply gas to said patient;
delivery means with a plurality of ports adapted to deliver said gas to said patient; inhalatory gas transport means for conveying said gas from said gas supply means to said delivery means;

exhalatory gas transport means for conveying said patient"s exhalations from said delivery means;
a container which, in use, contains a body of liquid and is configured to have a -substantially constant level of said liquid, in use;
a conduit having proximate and distal ends, wherein said proximate end is adapted to be connected to the breathing assistance apparatus, for accepting exhalatory gases from the breathing assistance apparatus, in use, and said distal end is adapted to be submerged in said body of liquid in said container;
the arrangement being such that, in use, said patient is caused to be delivered a substantially constant mean pressure of the gas, and said mean pressure is capable of being adjusted by altering the level to which said distal end of the conduit is submerged in said body of liquid.
12. A breathing assistance apparatus as claimed in claim 11, which is provided with a humidifier for humidifying said gas prior to its delivery to said patient, said humidifier being disposed within, or in fluid communication with said inhalatory gas transport means.
13. A pressure regulating device capable of being used with a breathing assistance apparatus, substantially as herein described, with particular reference to, and as illustrated in the accompanying drawings.
14. A breathing assistance apparatus for supplying gas to a patient to assist said
patient"s breathing, substantially as herein described, with particular reference to, and as illustrated in the accompanying drawings.

Documents:

0256-mas-2001 abstract-duplicate.pdf

0256-mas-2001 abstract.jpg

0256-mas-2001 abstract.pdf

0256-mas-2001 claims-duplicate.pdf

0256-mas-2001 claims.pdf

0256-mas-2001 correspondence-others.pdf

0256-mas-2001 correspondence-po.pdf

0256-mas-2001 description (complete)-duplicate.pdf

0256-mas-2001 description (complete).pdf

0256-mas-2001 drawings-duplicate.pdf

0256-mas-2001 drawings.pdf

0256-mas-2001 form-1.pdf

0256-mas-2001 form-13.pdf

0256-mas-2001 form-19.pdf

0256-mas-2001 form-26.pdf

0256-mas-2001 form-3.pdf

0256-mas-2001 form-5.pdf

0256-mas-2001 others.pdf

0256-mas-2001 petition.pdf

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Patent Number

216505

Indian Patent Application Number

256/MAS/2001

PG Journal Number

13/2008

Publication Date

31-Mar-2008

Grant Date

13-Mar-2008

Date of Filing

20-Mar-2001

Name of Patentee

FISHER & PAYKEL LIMITED

Applicant Address

A COMPANY DULY INCORPORATED UNDER THE LAWS OF NEWZEALAND, 78 SPRINGS ROAD, EAST TAMAKI, AUCKLAND,

Inventors:

#	Inventor's Name	Inventor's Address
1	CRAIG ROBERT JEFFREY	373 EAST COST ROAD, MAIRANGI BAY, AUCKLAND,
2	GRAEME WOOLMORE	52 WELLINGTON STREET, PUKEKOHE, AUCKLAND,
3	ANTHONY JAMES NEWLAND	1/163 RIDDELL ROAD, GLENDOWIE, AUCKLAND,

PCT International Classification Number

A62B 18/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA