Patent Document

SPECIFIC REFERENCE TO RELATED APPLICATIONS 
     The present application is a divisional application which claims priority to and incorporates by reference application Ser. No. 09/550,986 filed Apr. 17, 2000, U.S. Pat. No. 6,595,212. 
    
    
     BACKGROUND OF THE INVENTION 
     Obstructive sleep apnea is a common disorder that involves tissue occlusion of the nasopharyngeal airway during sleep which impedes a patient&#39;s normal breathing cycle. Multiple sequential apnea episodes may result in severe sleep disruption of which the patient may not even be aware. Moreover, swollen tissue in the airway often results in excessive heavy snoring. Extreme sleep apnea is a serious disease which may affect as much as three percent of the adult population, and heavy snoring is much more common, particularly with overweight individuals. 
     Surgical intervention is always an option in alleviating obstructive sleep apnea or heavy snoring, however, most patients prefer to address the problem with non-invasive treatment. One treatment program involves the use of continuous positive airway pressure delivered to the patient&#39;s airway to maintain the airway in a continuously open state during sleep. The equipment required to deliver continuous positive airway pressure to the airway of a patient includes a fan or blower for generating a pressurized flow through a hose coupled to a mask or nasal device which the patient places over his or her nose and uses straps about the head to fasten the device in place. 
     Many patients cannot tolerate the application of continuous positive airway pressure, particularly because of the discomfort associated with exhalation against a continuous positive pressure. An attempt has been made to alleviate this problem by the provision of a method and apparatus which provides a substantially constant elevated airway pressure to the patient&#39;s airway, with periodic short term reductions of the elevated airway pressure to a pressure of lesser magnitude. A further advance in such treatment involves the application of alternative high- and low-level positive airway pressure wherein the low-level pressure coincides with the breath exhalation of the patient&#39;s breathing cycle. 
     A method and apparatus for the application of continuous positive airway pressure to a patient&#39;s airway is disclosed in U.S. Pat. No. 4,655,213, issued to Rapoport et al. The concept of providing a substantially constant elevated airway pressure with periodic short-term pressure reductions is disclosed in U.S. Pat. No. 4,773,441, issued to John B. Downs. A bi-level system of applying alternating high- and low-level positive airway pressure to a patient&#39;s airway is disclosed in U.S. Pat. No. 5,148,802, issued to Sanders et al. 
     The methods and apparatus disclosed in the prior art for treating patients afflicted with such maladies as sleep apnea and snoring present a number of problems which need to be addressed. The equipment utilized in such treatment is far too bulky and cumbersome. The air stream delivered to the patient tends to dehydrate the nasopharyngeal tissue. The unnatural sensation and discomfort experienced by the patient in overcoming the positive pressure during breath exhalation results in many patients abandoning the use of a system that is in all other respects quite beneficial. 
     SUMMARY OF THE INVENTION 
     The present invention comprehends the treatment of such disorders as obstructive sleep apnea or heavy snoring by providing an apparatus capable of delivering a pressurized burst or pulse of air to a patient&#39;s nasopharyngeal airway at the moment of termination of the patient&#39;s breath exhalation during the breathing cycle. The pulse of pressurized airflow is sufficient to prevent the development of airway tissue occlusion and maintain the airway open for normal breathing. 
     Hence, it is a primary objective of the present invention to provide a method of alleviating sleep apnea or snoring by delivering ambient air to a patient&#39;s airway in the form of an air bolus, wherein the patient&#39;s exhaled air is utilized to actuate an energy storing means to cause delivery of the air bolus into the airway. 
     Still another objective of the present invention is to provide an apparatus capable of providing a pressurized pulse of air through a nasal device and into the nasopharyngeal airway of a sleeping patient, wherein the pressurized airflow is triggered by the breath exhalation of the patient and will continue sequentially with each exhaled breath. 
     It is also an objective of the present invention to provide an apparatus as heretofore described which preferably includes a nasal device for attachment to a patient&#39;s nose, and a housing with a chamber capable of storing a fresh air supply for release to the nasal device and into the patient&#39;s airway to thus promote a normal breathing cycle. 
     It is also an objective of the present invention to provide an apparatus as heretofore described which is self-contained as a unitized structure that obviates the need for auxiliary remote bedside equipment requiring a large fan or compressor. 
     Practice of the method of this invention comprises the steps of providing a primary airflow conduit for delivering ambient air into the patient&#39;s airway and providing a bolus chamber in airflow connection with the airflow conduit which is capable of delivering a bolus of ambient air. Energy storing means responsive to the patient&#39;s breath exhalation is utilized to force the bolus of air from the chamber and through the conduit and into the patient&#39;s airway. The patient&#39;s exhaled air is used to actuate or trigger the energy storing means and cause, by the release of its energy, the delivery of the bolus of air to the patient&#39;s airway. 
     The invention also provides an apparatus in the form of a unitary structure, such as a containment housing, with the housing being coupled to a nasal device. The nasal device may be a mask sealed to the patient&#39;s face and about the nose or a device comprising a pair of nasal delivery members, such as disclosed in U.S. Pat. No. 5,687,715, issued to Landis et al. The containment housing of the apparatus includes a first chamber for receiving breath exhaled by the patient and a second chamber for storing fresh air for delivery back to the patient at a predetermined time during the patient&#39;s breathing cycle. The chambers are expandable and operatively interconnected whereby expansion of the first chamber causes expansion of the second chamber. An energy storing means is provided within the containment housing which is adapted to operate, at the moment of completion of the patient&#39;s breath exhalation, to contract both of the expandable chambers and cause a momentary burst of pressurized airflow to be ejected from the second chamber and through the nasal device to the patient&#39;s airway. The pressurized airflow is only momentary, whereby completion of air inhalation occurs naturally and voluntarily by the patient. 
    
    
     Details of the method of the present invention and the elements and structural characteristics of several embodiments of the apparatus will become apparent from the ensuing detailed description when considered in reference to the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic representation which illustrates both the method and basic apparatus for practicing the present invention. 
     FIGS. 2 and 3 are schematic representations which illustrate the physical principles underlying the method and basic operation of the apparatus of the present invention. 
     FIGS. 4 and 5 are elevational views in vertical section of a bench-test embodiment of the apparatus of the present invention. 
     FIG. 6 is an elevational view in vertical section of the apparatus which incorporates the structural and operative characteristics first disclosed in FIGS. 1-5. 
     FIG. 7 is an elevational view in partial vertical section illustrating an alternative embodiment of the apparatus of the present invention. 
     FIG. 8 is an elevational view in vertical section illustrating still another alternative form for the apparatus of the present invention. 
     FIG. 9 is a perspective view of certain components intended for use in still another embodiment of the present invention. 
     FIG. 10 illustrates a novel or ancillary use contemplated for the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 schematically illustrates an assembly  10  including an airflow generator  12 , an electromagnetic solenoid  14 , a dual valve assembly  16 , a normally-open electrical switch  18 , and a mask  20 . The airflow generator  12  may be a blower or fan of the type used to produce a pressurized airflow. The solid line arrows mark the air stream flow path, beginning with ambient air drawn into the airflow generator as indicated by arrow  22 . The electric current to operate the flow generator is supplied through conductors  24  and  26 , which also supply current to solenoid  14  through switch  18 . The airflow generator  12  is intended to operate continuously whereby a constant head of pressurized air is maintained to the solenoid  14 . However, the solenoid  14  is normally closed and will permit air passage there through to the dual valve assembly  16  only when the solenoid  14  is caused to open by switch  18 . 
     The dual valve assembly  16  of FIG. 1 includes a flexible circular diaphragm  28  and a disc valve  30  mounted on the diaphragm  28 . In its relaxed position (not shown), the diaphragm  28  will cover and seal apertures, such as aperture  32  and aperture  34 . The disc valve  30  is a circular flexible thin rubber membrane which normally seals against the inside surface of the diaphragm  28  but will flex open in response to pressurized airflow from the solenoid  14  and allow the airflow to pass through the valve arrangement and thence into mask  20 . 
     It should be noted that the mask  20  is provided with a normally-closed disc valve  36  which will respond to inhalation by the patient and open to permit entry of ambient air. The mask  20  is meant to be worn in sealed relation to the nose of a patient whereby ambient air during inhalation will pass into the mask past valve  36 . Exhaled breath will cause valve  36  to close whereby the breath flow will be in the direction of the dotted line arrow  38  and into the dual valve assembly  16 . Breath pressure entering the dual valve assembly  16  causes the disc  30  to seal against the diaphragm  28  and stretches the diaphragm  28  from a sealing linear disposition (not shown) to the position shown in FIG. 1. A spring-biased switch trigger or toggle  40  extending from switch  18  is contacted by the outwardly-flexed diaphragm  28  whereby the toggle  40  is pivoted from left to right as shown in FIG.  1 . This pivoting action of the toggle  40  sets the switch internally whereby, as the diaphragm  28  relaxes, the toggle  40  will pivot back to its original position and, at the same, close internal contacts of the toggle  40  to complete the electrical circuit to the solenoid  14 . The solenoid  14  is thereby caused to cycle open and then immediately re-close after having permitted a burst of pressurized air to move into the dual valve assembly  16  and past the disc valve  30  and into the mask  20 . The pressurized airflow burst is directed into the nasopharyngeal airway of the patient as the patient&#39;s inhalation action occurs, and ambient air moves through valve  36  to allow the patient to complete the breath intake voluntarily. The subsequent exhalation by the patient repeats the described process whereby a pulse or burst of pressurized air is delivered to the mask  20  and thence to the patient&#39;s airway as a function of each breathing cycle. 
     Although FIG. 1 broadly illustrates the underlying method of the present invention, it is preferred that the apparatus for practicing the method be contained in a compact housing positioned adjacent the head of the patient and that it is not dependent upon a continuously operating bedside blower or household electrical connection for its energy source. Presently preferred embodiments of the invention involve utilization of dual chambers contained in a compact housing, as illustrated and explained hereinafter with references to FIGS. 2-8. 
     FIGS. 2 and 3 demonstrate the physical principles underlying the mechanical operation of the several embodiments set forth and hereafter discussed in reference to FIGS. 4-8. FIG. 2 shows a pneumatically expandable-contractible exhalation chamber  50  that becomes inflated by the exhaled air from a patient at a certain pressure above atmospheric pressure so that a top plate  52  of the chamber  50 , having an area Al, is raised against a compressible elastic element  54 . The elastic element  54  may be a compression spring having a constant K. The total vertical force exerted against the elastic element  54  is the product exhaled air pressure multiplied by the top plate area Al. The elastic element  54  is compressed until its downward force equals the upward force of the top plate  52 . An equilibrium position is obtained when the total upward force equals the spring constant multiplied by a distance d, where d is the distance of movement measuring the shortening of the elastic element  54 . 
     FIG. 3 shows a pneumatically expandable-contractible bolus chamber  60  that works against an elastic element  54   1 . The force in the compressed elastic element  54   1  is then applied to the bolus chamber  60  that is already filled with fresh air at atmospheric pressure when the exhaled breath is released from chamber  50 . The elastic element  54   1  exerts a downward force on a top plate  62  of the chamber  60 . The top plate  62  has an area A 2 , where Al (FIG. 2) is greater than A 2 . The air contained in the chamber  60  is under a positive initial pressure which is available to create a momentary airflow or bolus capable of relieving an apneic obstruction in a patient&#39;s airway. Valve and linkage means (not shown) operatively-connected between chamber  50  and chamber  60  would be utilized to mechanically translate the expanding action of chamber  50  to cause chamber  60  to simultaneously expand and draw in ambient air, and to allow both chambers to simultaneously expand and draw in ambient air, and to allow both chambers to simultaneously contract when the momentary positive airflow (bolus) has been ejected from chamber  60 . 
     FIGS. 4 and 5 illustrate bench model apparatus for practicing and demonstrating the method of the present invention. FIG. 4 shows a structure or apparatus  70  defining an exhalation chamber  72  and a bolus chamber  74 . In the use of the apparatus exhaled breath from the patient enters the exhalation chamber  72  through an entry port  76 . Inboard from the entry port  76  is a circular semi-flexible silicon disc  78 a which co acts with spaced-apart valve seats  78   b  and  78   c . The disc  78   a  is movable between a first position, as shown in FIG. 4, to a second position, as shown in FIG. 5, and is responsive to low pressure airflow to change its position. Air enters chamber  72  through entry port  76 , causing the disc  78   a  to close off an outlet passage  84  whereby all entering air will flow to the chamber  72 . Sidewall structure serves as linkage  86  between the chambers. The expansion of chamber  72  in response to airflow directed thereto through the entry port  76  causes the linkage  86  to shift to the left as shown in FIG. 4 also undergoes expansion. Both of the chambers  72  and  74  have pleated accordion-like exterior sidewalls  88  and  90  which facilitate expansion of the chambers. As chamber  74  expands from the disposition shown in FIG. 4 to that which is shown in FIG. 5, and in response to the expansion of chamber  72 , motion of linkage  86  causes chamber  74  to expand and draw air in through a central passage  92 . The airflow through passage  92  moves past open flapper valve  80  and into the chamber  74 . The initial negative pressure in chamber  74  as it begins to expand causes a valve  82  to close and valve  80  to open whereby the chamber  74  takes in ambient air through the passage  92 . The expansion of the chambers  72  and  74  and the movement of linkage  86  causes a compression spring  94  to compress from its expanded disposition shown in FIG. 4 to a contracted position as shown in FIG.  5 . When both chambers  72  and  74  have fully expanded and the exhalation has ended, the force of energy in the spring  94  causes the linkage  86  to shift back from the disposition shown in FIG. 5 to that which is shown in FIG. 4 whereby the volume of air in each chamber is pressurized to create simultaneous discharge airflows. Specifically, the lack of pressure from exhalation and contraction of chamber  72  causes the valve disc  78   a  to close off the port  76  whereby air from the chamber  72  will be discharged through the outlet  84 . Simultaneously, contraction of the chamber  74  causes valve  80  to close and valve  82  to open and eject pressurized air though passage or discharge port  96 . The bolus of air forced out of chamber  74  past valve  82  constitutes air available for delivery to a patient&#39;s airway. 
     FIG. 6 illustrates apparatus in accordance with the present invention which operates pursuant to the principles explained in reference to FIGS. 2-5. The apparatus  104  shown in FIG. 6 comprises a mask  106  and a housing  108 . The housing  108  is rigidly attached to the mask assembly whereby the mask  106 , once strapped in operative position against the face of a patient, serves as a housing support. In the embodiment of the invention illustrated in FIG. 6, it is not particularly important that the mask seals against the patient&#39;s face because a nasal device  110  is utilized for airflow communication attachment to the patient&#39;s nares as hereafter explained in greater detail. Within the housing  108  is a bolus chamber  112  and an exhalation chamber comprised of four compartments  114 ,  116 ,  118 , and  120 . The housing  108  has a central air passage  122  adapted to take in ambient air through a filter  124 . The air passage  122  constitutes a conduit extending from the filter  124  and centrally through the housing  108  and into the bolus chamber  112 . The apparatus  104  as heretofore described presents a means of practicing the method of the invention in a unitary compact form that is relatively simple in its operational concept. With the mask  106  disposed against the face and about the nose of the patient, air is inhaled centrally through the housing passage  122 . Valve structure  132  opens during inhalation whereby the air moves from the passage  122  and across the bolus chamber  112  and thence past the valve structure  132  and through a conduit  126  to the patient&#39;s airway. The valve structure  132  constitutes a stretchable diaphragm  132   a , a flexible valve disc  132   b  carried on the diaphragm, and opposed valve seats  132   c  and  132   d . The valve  132  is a dual valve structure which normally seals against the valve seat  132   c  to prevent passage of air from passage  122  to and into conduit  126 . The valve structure is a diaphragm  132   a  that supports a flexible disc  132   b  that normally seals against an opening in the center of the diaphragm  132   a . The valve  132  allows airflow in one direction only by the peripheral flexure of the disc  132   b  away from the diaphragm  132   a , and the diaphragm  132   a  is capable of stretching or rolling, in response to airflow from passage  122 , to passage  146 . Inhalation by the patient though the nose connection  110  establishes an ambient airflow into the filter  124 , across the passage  122 , and through the valve  164  and  132  to the conduit  126 . Upon exhalation, airflow from the airway of the patient is delivered through conduit  126  and downwardly into passage  146 , with the valve  132  preventing any airflow into bolus chamber  112 . The exhaled air stream from the patient moves through the passage  146  and into valve structure  148  and thence into a manifold or distribution chamber  150 . The pressurized airflow from the manifold  150  is distributed through openings  152  into compartments  114 - 120 , which constitute the exhalation chamber. 
     The resultant build-up of air pressure within the compartments  114 - 120  of the exhalation chamber causes a shift in the internally-disposed rigid linkage  162 . The linkage  162  is adapted to shift from a chamber-empty position (not shown) and to the right, as viewed in FIG. 6, to a chamber-filled position. As the exhalation chamber takes in air and expands, ambient airflow causes valve  164  to open to allow the ambient air to fill bolus chamber  112 . Termination of the patient&#39;s exhaled breath results in a slight back pressure in the manifold  150 , causing the disc  148   a  to shift from its sealed position against valve seat  148   b  to a second sealed position against valve seat  148   c . An energy storing means, in the form of compression spring  166 , acts to push the rigid linkage  162  from right to left as viewed in FIG. 6, thereby causing contraction of the exhalation chamber and the bolus chamber  112 . 
     This results in the air within the exhalation chamber compartments  114 - 120  to be expelled through outlet port  154 . Air pressure within the bolus chamber  112  causes valve  164  to close whereby the bolus of air is forced against the diaphragm  132  such that disc  132 b will peripherally flex to allow the bolus to proceed into conduit  126  and thence through the nasal connection  110  and into the patient&#39;s airway. The ambient air previously captured in the bolus chamber  112  is forced as a pulse or thrust into the patient&#39;s airway just as the patient is starting to inhale. The bolus of air delivered to the patient&#39;s airway is sufficient to cause the inhalation to begin. The apneic obstruction in the airway is caused to relax whereby the patient finishes the breath inhalation as part of the natural breathing cycle. 
     Also illustrated in FIG. 6 is a reservoir  170  into which medication in liquid form may be stored and allowed to disperse into the bolus chamber  112 , the rate of dispersal being controlled by a metering device  172 . Many patients who are afflicted with sleep apnea also suffer asthmatic symptoms, including swelling of mucous membranes and bronchial tube spasms manifested by shortness of breath, whereby gasping causes the individual to awaken. The administration of medication into the air stream and thence into the bronchial tubes during inhalation is now common and can be quite effective in promoting natural sleep. The,provision of the reservoir  170  for this purpose, whereby droplets of medication can be metered into the bolus of air in the chamber  112 , is an elective option that can be made available to the user of the device illustrated in FIG.  6 . 
     FIG. 7 illustrates an alternate embodiment of the apparatus of the present invention comprising a unified structure  180 . The structure  180  includes a housing  182  coupled to a mask  184 . Within the housing  182  is a bolus chamber  186  partially defined by a flexible diaphragm  188 . A nasal device  214  constitutes a means for attaching the apparatus in flow communication with a patient&#39;s airway. The function of apparatus  180  begins immediately upon it being placed in its operative position, with the nasal device  214  inserted into the patient&#39;s nares. As the patient inhales, ambient air enters through inlet  190  and moves through passage  194  and thence into the chamber  186 . Flapper valve  198  pivots to an open position during inhalation. Inhalation continues by passage of air through the conduit  200  and into the patient&#39;s airway. Exhaled breath passes out through the conduit  200  and into the chamber  186 . A slight pressure is sufficient to close valve  198  whereby the exhaled breath progresses past open valve  202  and outwardly through passage  204 . A pressuresensitive electrical switch  206  is caused to close its contacts by the exhaled breath moving thereagainst, completing a circuit to an energy storing means in the form of batteries  208  that actuate a solenoid  210 . Closure of the switch  206  is only momentary and sufficient to energize the solenoid  210  whereby its plunger  212  acts against the diaphragm  188 , causing the diaphragm to flex from right to left as shown in FIG. 7, and then return to its start position. The resulting increased air pressure within the chamber  186  is forced through the conduit  200  and into the patient&#39;s airway. Means, in the form of a thumb screw  216  threaded into an accommodating aperture in the housing  182 , may be utilized to regulate the intensity of the air pressure bolus within the chamber  186  by allowing minimal controlled leakage. 
     FIG. 8 illustrates apparatus  220  which utilizes the interaction of permanent magnets to cause delivery of a bolus of air to the patient&#39;s airway. The apparatus  220  comprises a housing  222  and a mask  224 . The mask  224  must, in this embodiment, be of the type that seals tightly about the nose of the patient whereby breathing occurs entirely through the apparatus. Within the housing  222  is a bolus chamber  225  partially defined by a flexible rolling diaphragm  230 . Centrally located on the diaphragm  230  is a flexible disc valve  230 A which normally blocks apertures  234  and  236  provided in the face of a piston  238 . The only outlet from the chamber  225  is a passage  240  normally closed by a valve structure  244 . The valve structure  244  comprises a flexible diaphragm  244   a  with openings  244   b  therethrough and a centrally-attached flexible disc  244   c . The piston  238  is mounted to be reciprocal within the housing  222  from a retracted position, as shown in FIG. 8, to a fully extended position which would be to the left. 
     To facilitate its operation, the apparatus  220  is positioned: usually strapped in place, against a patient&#39;s face whereby the nose is within the mask  224 . Ambient air is inhaled by the patient through an opening  246 . The inhaled airflow is drawn through the hollow body of the piston  238  and through the openings  234  and  236 . Disc valve  230   a  is caused to flex open by the pressure of the inhaled air stream whereby air passes through chamber  225  and thence through openings  244   b  in the valve structure  244 . Disc valve  244   c  is flexed open by the positive pressure of the inhaled air stream. Upon completion of inhalation, the patient exhales, causing the valve structure  244  to close whereby the exhaled breath is channeled through a conduit  250  and thence into a rearward chamber  252  in the housing  222 . Within the chamber  252 , the exhaled air stream strikes against a rotatable impeller  254  having an axle  256  and radially outwardly-extending blades  258 . The hub  260  of the impeller  254  has a recessed area containing a coil spring  262 . Attached to the impeller  254  is a split disc-shaped permanent magnet  264 . Spaced from the magnet  264  and attached to the piston  238  is another permanent magnet  266 . The magnets  264  and  266  are preferably rare earth Neodymium discs, one of which is firmly attached to the hub  260  of the impeller  254 , and the other being firmly affixed to the back side of the piston  238 . Such magnets, made from a Neodymium iron-boron material, have seven to ten times more holding or repulsion force than other magnetic materials. The magnets are magnetically charged to repulse each other whereby, when magnet  264  is rotated on its axis 180° the repulsive force causes the magnet  266  to move from right to left as viewed in FIG. 8, thereby causing the piston  238  to move from its first or starting position to its second or extended position such that diaphragm  230  is deformably distended in the direction of the mask  224 . 
     As shown in FIG. 8, the magnets  264  and  266  are in an equilibrium position, however, when exhaled air from the patient moves through conduit  250  and thence through the rearward chamber  252 , the air pressure against the impeller blades  258  cause the impeller  254  to rotate 180° until the air stream escapes through housing opening  246 . The rotation of the impeller  254  rotates the split magnet  264  relative to the split magnet  266  whereby a magnetic repulsive force acting between the magnets causes the piston to move away from the magnet  264 . A light-duty return spring  262  disposed about the shaft and bearings of the impeller  254  returns the impeller  254  to its starting position whereby the repulsive force between the magnets is neutralized. When the piston  238  is driven from its first position to its second position within the housing  222 , the bolus of air contained within the chamber  224  is driven against and past the valve structure  244  and thence to the airway of the patient. The apparatus  220  serves to provide a bolus of air into the patient&#39;s airway at the termination of each exhalation by the patient during the patient&#39;s breathing cycle and, in each sequential cycle, the patient completes inhalation naturally and without assistance before the next exhalation occurs. 
     In view of the description of the operation of the various embodiments of the present invention heretofore presented, it should be apparent to those skilled in the art that the method of the invention may be practiced by the provision of a mechanical variation such as shown in FIG.  9 . FIG. 9 illustrates a pair of vanes  270  rotatably mounted on an axis  272 . The vanes  270  can be driven to rotate by exhaled breath coming from a mask  274  to thereby rotate the shaft or axis  272  and correspondingly wind an energy-storing device  278 . At the completion of each exhalation by the patient, a wound spring within the energy-storing device  278  will then cause the shaft  272  to counter-rotate whereby an impeller  280  and planetary gears  282  will force a pressurized airflow back into the mask and thence into the airway of the patient. The aforedescribed function occurs as an incident of each breathing cycle of the patient. 
     A further use of the invention is contemplated as shown in FIG. 10 which would include first and second masks  284  and  286  by which a first person  288  could provide hands-free ventilation to a second distressed person  290 . For this embodiment, momentary positive air pressure would be provided to the first mask  284 , an exhalation chamber, and a collection or bolus chamber (not shown) as illustrated in accordance with the invention embodiments herein previously described. The exhalation chamber would receive the exhaled breath of the first assisting person  288 , and the bolus chamber would be adapted to deliver fresh ambient air to the second distressed person  290 . With the device  292  coupled intermediate to the first and second persons, by means of hoses  294  and  296 , a pressurized flow of ambient air could be delivered from the assisting person  288  to the distressed person  290  as a resuscitation measure. 
     While various embodiments of the present invention have been disclosed and described herein, it should be understood that the preferred version of the apparatus is compact, portable, and comparatively inexpensive as compared to prior art devices that utilize large blowers or compressors to achieve a similar function by continuous or bi-level airflow provision. It should be further understood that while the invention has been disclosed and described with reference to specific alternative embodiments, there are variations and modifications which may be introduced that will nevertheless come within the scope and spirit of the invention as defined by the appended claims.

Technology Category: a