Abstract:
A dual area pressure pulmonary modulator apparatus which provides constant flow, pressure cycled ventilatory support to patients that is additionally equipped with fluid conduits in the valve mechanism and body that allow the clinician or user to manually actuate inhalation by occluding a fluid path emanating from the modulator. Such feature is useful for when the device stops cycling due to physiological changes of the patient, for determining if the patient is cycling the device or if the device is automatically cycling by nature of its setting, coordinating medical procedures with the breathing of the patient, increasing the PEEP beyond the intrinsic design PEEP of the device for a given PIP setting, increasing inspiratory hold time, and providing an easy to use alternative mode of operation for users with less sophistication.

Description:
CROSS-REFERENCE TO RELATED PATENTS 
       [0001]    This application claims the benefit under 35 U.S.C. 119(e) of U.S. provisional application Ser. No. 61/337,989 filed Feb. 12, 2010, which is incorporated by reference herein in its entirety. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    This invention pertains generally to respiratory ventilation devices with a constant flow pulmonary modulator and equipped with a manually actuating feature, and more specifically to respiratory ventilation devices with a constant flow pulmonary modulator, as described in U.S. Pat. No. 6,067,984, equipped with a feature to allow the clinician or user to easily manually activate inhalation, thus allowing a user to: 1. cycle the device and initiate inhalation immediately in the event that the device stops providing ventilatory supports and “stalls”; 2. detect if the device is automatically cycling or if the patient is triggering the device; 3. synchronize ventilation with other medical procedures; 4. increase Positive End Expiratory Pressure (PEEP) beyond the intrinsic design value for a given Peak Inspiratory Pressure (PIP) setting; and/or 5. provide an inspiratory hold when desired. 
         [0005]    2. Description of the Background Art 
         [0006]    A fundamental aspect of providing respiratory care to a patient is the ability to provide ventilatory support to patients requiring respiratory assistance. Ventilatory support is typically provided by clinicians through the use of a manual resuscitator or an automatic ventilatory device. 
         [0007]    Manual resuscitators are typically equipped with a self-inflating bag, a set of check valves which control the direction of inhalation and exhalation gases, and a patient interface which is usually either a face mask or a port for connection to and endotracheal tube. Manual resuscitators are usually supplied with a continuous flow of gas containing a known percentage of oxygen. The operator of a manual resuscitator inflates the patient with oxygen enriched air by squeezing the self-inflating bag thus applying pressure and causing gas to flowing into the patient&#39;s lungs. Inhalation ends and exhalation begins when the operator stops squeezing the bag, allowing the pressurized gas in the patient&#39;s lungs to escape to the ambient environment. Most manual resuscitators are equipped with the means to maintain a small minimum positive pressure on the patient&#39;s lungs throughout exhalation commonly called Positive End Expiratory Pressure (PEEP). During exhalation, the self-inflating bag re-inflates and process may be repeated. Manual resuscitators are simple, inexpensive, and are easy to coordinate ventilation with other medical procedures. Unfortunately, manual resuscitators are easy to misuse. A large number of studies have been published which show that irregardless whether the operator of the manual resuscitator is a physician, respiratory therapist or nurse, patients receive volumes of gas per breath (tidal volume) which are too small and respiratory rates which are too quick. This has been shown to create significant adverse effects on patients. 
         [0008]    Automatic ventilatory devices (ventilators) were originally developed to deliver a set amount of volume to the patient in a set amount of time which little patient monitoring capability. In the last 25 years different modes, including pressure control, and increased monitoring capabilities have been added, leading to the modern transport ventilators of today. Most ventilators still use volume and time cycled ventilation modes which operate by delivering to the patient pre-set amount of volumes or constant flow for pre-set amounts of time, regardless of the patient&#39;s lung compliance. Lung compliance is prone to sudden changes during transport, potentially causing patient airway pressures to increase to the point that they will severely injure the patient. Pressure cycled ventilation and pressure control are newer modes of ventilation used to deliver ventilatory support to the patient and which have a number of distinct advantages over volume and time cycled ventilation modes. Pressure cycled ventilation functions by switching to exhalation from inhalation when a certain pressure is reached, regardless of the volume delivered; thus volumes of gas delivered to the patient vary with variances in lung compliances, preventing the patient from receiving a harmful amount of pressure and insuring appropriate ventilation of the patient. 
         [0009]    Modern transport ventilators are battery of pneumatically powered and equipped with numerous ventilation modes, including pressure cycled types of ventilation, various flow control functions, multiple alarm monitoring functions and are also capable of detecting and synchronizing with the patient&#39;s breathing efforts. Although current transport ventilators provide consistent, safe and reliable ventilation, they are extremely expensive. Additionally, the disposable accessories that are required to be used with these ventilators can sometimes cost as much or more than a manual resuscitator. To reduce the high capital costs of these devices, some manufacturers have returned to offering simplified time cycled volume ventilators without any of the standard monitoring, control and alarm features of typical ventilators, nor the option of pressure cycled ventilation. These devices are often classified as automatic resuscitators and, in addition to not being as safe, still cost thousands of dollars and require the use of additional disposable or parts which require sterilization before being reused. In today&#39;s environment of medical cost containment, hospitals and other medical providers have, for the most part, balked at the cost of transport ventilators and the training of additional personnel it would require. 
         [0010]    A Pulmonary Modulator Apparatus (PMA), as described in U.S. Pat. No. 6,067,984 and included herein by reference in its entirety, has been shown to successfully solve the consistency problem of manual resuscitators and the capital expense issues of transport ventilators. Unfortunately a PMA has a number of problems: 1. it can stop cycling due to physiological, mechanical, pneumatic, or environmental changes; 2. it can be hard or impossible for a user to determine if the device is automatically cycling or if the patient is initiating breathing thus increasing the work of breathing for the patient; 3. it is limited to delivering a set level of PEEP that is a constant ratio of PIP; and 4. it has no means of providing an inspiratory hold. 
         [0011]    As described in U.S. Pat. No. 6,067,984, a pressure pulmonary modulator apparatus (PMA) comprises a dual area piston (or diaphragm) having a surface area that rests against an interior end of a inlet chamber, thus sealing the inlet chamber during the inhalation phase of the patient. The dual area piston comprises a primary area defined as the area exposed to the patients pulmonary capacity during inspiration when the piston is in the closed position, and a much larger area which comprises the entire area of the piston which is in fluid communication with the patients pulmonary capacity only during discharge or when the piston is in the open position. When the dual area piston is closed, it prevents compressed gas from escaping and causing the lungs to become charged by the incoming compressed gas. During charging (i.e. inspiration), the pressure in the patients lungs increases until the force of the pressure on the primary area of the dual area piston overcomes the restorative force of the piston. Once the dual area piston begins to open, the full area of the piston is exposed to the pressure of the patient&#39;s lungs causing the piston to move away from the interior end of the inlet chamber to a fully open position almost immediately. The patient&#39;s lung pressure that causes the piston to move into the fully open position is the patient&#39;s peak inspiratory pressure (PIP), which is adjustable by controlling the restorative force on the piston. Once the piston opens, it will remain open until the patient&#39;s lung pressure drops to a value small enough such that the restorative force overcomes the force of the patient&#39;s lung pressure on the full area of the piston. During discharge, the exhaled gases pass by the piston and out of the system through an adjustable flow restrictor (i.e. the rate dial) used to control the rate at which discharge gases are vented into the atmosphere, resulting in the control of discharge duration. The rate dial is essentially a valve, and resistance to exhalation flow is realized by screwing or adjusting the rate dial in our out. Greater resistance to flow results in slower exhalation flows and longer exhalation times. Once the patients lung pressure drops to a value low enough to allow the force of the spring to push the piston closed, the discharge ends and the cycle is repeated. 
         [0012]    The patient may spontaneously breathe by triggering the inhalation prior to the end of exhalation. A one-way valve may optionally be provided to increase the ease of the patient&#39;s inhalation. Under such circumstances, a new inhalation will start when the patient breathes in, reducing the patient&#39;s airway pressure and causing the piston to close and a new inhalation period to start. In addition, the apparatus can be adapted to function as a positive pressure aerosol device by attaching a nebulizer assembly to the inlet chamber of the apparatus. Such a device is useful to those needing the therapeutic effects of aerosol in addition to ventilatory support. 
         [0013]    From time to time it may be useful to put the PMA into a “spontaneous mode” in which inspiration starts only after the patient has initiated it by drawing a breath. This mode is achieved by dialing the rate dial to such a position that the restriction to flow for the set flow of gas provided creates an internal pressure great enough that it maintains a greater force on the open piston/diaphragm than the restorative spring force. In such a condition inhalation is initiated by the patient inhaling enough gas that the pressure drops and the restorative force of the spring causes the piston/diaphragm to close. 
         [0014]    A PMA can stop cycling, and thus stop providing ventilatory support to a patient, due to physiological, mechanical, pneumatic, or environmental changes. Although this has the benefit of alerting the clinician that the situation is changing, the condition is ultimately highly undesirable because the patient still needs ventilatory support and the only manner that ventilatory support may be provided by existing PMAs is by the clinician determining what change occurred and changing the baseline settings of the PMA to compensate. Determining what change occurred can be time consuming, and if the patient is not being provided ventilatory support, clinicians are rushed and almost always don&#39;t have the time. Furthermore, changing the baseline settings of the PMA is often undesirable because it creates a greater degree of uncertainty in a situation that may still be varying and problematic, thus re-stabilizing the patient becomes more difficult. Therefore there is a need for a device with the advantages of a PMA that has the further capability of delivering temporary or alternate ventilatory support regardless of physiological, mechanical, pneumatic, or environmental changes and without changing the baseline settings of the PMA. 
         [0015]    Under most circumstances, a PMA is used with a patient who is unconscious and paralyzed due to the administration of medication by the clinician. The sedation of the patient is necessary because it mitigates the risk that the patients will become hypertensive and fight the ventilatory support of the PMA, or that the patient will simply begin to hyper-ventilate. Maintaining the patient in a sedated state can sometimes be problematic because the effects of the medication can subside, or if the medication has just recently been administered, it will take time for the medication to take effect. Much of the time patients are transitioning from one sedated state to another. In the interests of stabilizing the patient, insuring that the work of breathing is appropriate for the patient, and allowing the clinician to address other possible patient conditions, it is important for the clinician to be able to determine if the patient is truly sedated, and that the breathing of the patient is purely caused by the PMA, or if the patient is still semi-active on a respiratory basis and is triggering the device with slight inhalation efforts. Determining which state the patient is in is very difficult to do with the existing PMA design because it is impossible to tell if the patient or the device is causing the cycling of the PMA. Therefore there is a need for a device with the advantages of a PMA that has the additional capability of providing some feedback to the clinician on the sedative state of the patient. 
         [0016]    Current PMAs have an intrinsic design PEEP for any set PIP. Since some patients may require additional PEEP beyond what is provided for a set PIP, this is a serious limitation of the PMA. Currently, the PMA may be set to deliver an increased PEEP by adjustment of the rate dial or by increasing flow, but this places the device in a mode that will not cycle unless initiated by the patient which is clearly undesirable the vast majority of the time because it increases the work of breathing of the patient and the patient may simply be unable to make the respiratory effort. The situation can be rectified by addition of an in-line PEEP valve placed between the inlet of the modulator and the patient&#39;s airway, but this adds to the cost and clumsiness of the device, and is not practical since additional PEEP is only needed sometimes and as a result clinicians are not likely to keep such devices on hand. Therefore, there is a need for a device with the benefits of existing PMAs that had the additional capability of delivering more PEEP when desired. 
         [0017]    Sometimes there is a need for the clinician or user to create an inspiratory hold which is effectively a pause at approximately the peak pressure of inspiration before the initiation of exhalation, or to simply suspend ventilatory support temporarily. An inspiratory hold (clinically also sometimes referred to as sigh breath) can provide important physiological support of certain types of patients. A pause in ventilatory support can provide a needed opportunity for a clinician to perform a needed procedure without the interference of on-going ventilation. Current PMAs do not have this capacity without inducing major clinical inconvenience and disturbance. One method currently employed using existing PMAs is to create a condition in which the entire exhalation path is occluded, potentially leading to damaging pressure levels, and failing to provide a sustained pressure level support. Another is to remove the modulator from patient tee thus eliminating any pressure support of the patient and risking alveolar collapse. Therefore, there is a need for a device with the benefits of existing PMAs that has the additional capacity of delivering an inspiratory hold, or ventilatory pause, in a manner that will limit the pressure level and will not entirely occlude the exhalation path of the patient. 
         [0018]    In the pre-hospital environment, many of the Emergency Medical Technicians (EMTs) servicing patients during emergency calls do not have the same sophistication and training as Respiratory Therapists and clinicians in the hospitals. As a result, there is sometimes a reluctance to employ existing PMAs because there is a fear that the EMT may face a situation in which they are not entirely sure what the most appropriate adjustment would be in the event that the PMA stops delivering ventilatory support for mechanical or physiological reasons. Existing PMAs don&#39;t have any readily available way to provide these clinicians with a simple back up plan in such event. Therefore, there is a need for a device with the benefits of existing PMAs that has the additional capacity of providing a simple back up plan to clinicians unsure of the changing situation they may be facing. 
         [0019]    The present invention has all the benefits of existing PMAs with the added benefit of solving the previously described problems. Specifically the current invention has the advantage that it will: 1. deliver immediate manually triggered ventilatory support regardless of any changes that may have stopped the PMA from automatically cycling (i.e. delivering automatic ventilatory support); 2. provide valuable feedback to the clinician on the sedative/conscious state of the patient; 3. deliver more PEEP than the intrinsic design PEEP of the PMA for the given PIP and flow setting; 4. deliver an inspiratory hold, or ventilatory pause, in a manner that will limit the pressure level and will not entirely occlude the exhalation path of the patient when desired by the clinician; and 5. provides a simple back up plan that still provides ventilatory support to patients for clinicians unsure of the mechanical and physiological situation they are facing. 
       SUMMARY OF THE INVENTION 
       [0020]    The present invention generally comprises a pressure pulmonary modulator apparatus which will inflate and discharge any respiratory gas from a patient for a wide range of frequencies when provided with a constant flow of gas and which also has the ability to immediately provide inhalation support to a patient at a limited finite level of pressure whenever manually actuated by the clinician while requiring no more parts or cost than existing PMAs. 
         [0021]    An object of the invention is to provide a simplified ventilator apparatus for providing constant flow, pressure cycled ventilatory support to patients and that allows immediate manual initiation of inspiration support. 
         [0022]    Another object of the invention is to provide a simplified ventilator apparatus that provides constant flow, pressure cycled ventilatory support and that allows for easy detection of the sedative state of the patient. 
         [0023]    Another object of the invention is to provide a simplified ventilator apparatus for providing constant flow, pressure cycled ventilatory support and that allows for easy detection of whether the device is in an automatic cycling or spontaneous mode. 
         [0024]    Another object of the invention is to provide a simplified ventilator apparatus for providing constant flow, pressure cycled ventilatory support to children and adults in an emergency situation that allows for higher PEEP settings. 
         [0025]    Another object of the invention is to provide a simplified ventilator apparatus for providing constant flow, pressure cycled ventilatory support to children and adults in an emergency situation that allows the clinician or user to hold a longer inspiration time. 
         [0026]    Another object of the invention is to provide a ventilator apparatus which is disposable and inexpensive. 
         [0027]    Another object of the invention is to provide a ventilator apparatus which allows for the adjustment of peak pressure, positive end expiratory pressure, inspiration duration, and expiration duration. 
         [0028]    Another object of the invention is to provide a ventilator apparatus which can allow the patient to trigger mandatory breaths or to breathe spontaneously. 
         [0029]    Another object of the invention is to provide a ventilator apparatus which can allow the patient to breathe spontaneously entirely, with manual interjections of inspiration by the clinician or user. 
         [0030]    Another object of the invention is to provide a ventilator apparatus which allows inhalation to be initiated by the operator of the apparatus. 
         [0031]    Another object of the invention is to provide a ventilator apparatus which can be equipped, or have a built-in high pressure pop-off valve as a safety feature to prevent the unintended build up of patient airway pressure due to malfunction or misuse. Such a high pressure pop-off valve may be equipped with the means to produce an audible tone which will notify an operator that the patient is experiencing high airway pressures. 
         [0032]    Another object of the invention is to provide a ventilator apparatus which can be easily used in conjunction with a nebulizer to deliver intermittent positive pressure aerosolized medication to the patient at high and low respiratory rates. 
         [0033]    Another object of the invention is to provide a ventilator apparatus which can deliver ventilatory support to patients being transported within or between hospitals. 
         [0034]    Another object of the invention is to provide a ventilator apparatus which can be used to treat patients suffering from sleep apnea. 
         [0035]    Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]    The invention will be more easily understood by a detailed explanation of the invention including drawings. Accordingly, drawings which are particularly suited for explaining the inventions are attached herewith; however, it should be understood that such drawings are for descriptive purposes only and as thus are not necessarily to scale beyond the measurements provided. The drawings are briefly described as follows: 
           [0037]      FIG. 1  is a perspective view of a pressure modulator apparatus in accordance with the present invention. 
           [0038]      FIG. 2  is an exploded perspective view of the apparatus shown in  FIG. 1 . 
           [0039]      FIG. 3  is a sectional view of the apparatus shown in  FIG. 1 . 
           [0040]      FIG. 4  is an exploded perspective view of the apparatus shown in  FIG. 1  and a patient tee adapter in accordance with the invention adapted to function as a resuscitation device with a face mask shown in phantom. 
           [0041]      FIG. 5  is an exploded perspective view of patient tee adapter shown in  FIG. 4 . 
           [0042]      FIGS. 6A and 6B  are an exploded perspective view of a pressure modulator apparatus in accordance with the present invention. 
           [0043]      FIG. 7  is a sectional view of a pressure modulator apparatus in accordance with the present invention. 
       
    
    
     LIST OF REFERENCE NUMERALS 
       [0000]    
       
         
           
               10  Pressure Modulator Apparatus 
               12  Diaphragm Assembly 
               14  Inlet Chamber 
               16  Flow Restrictor Conduit 
               18  Pressure Dial 
               20  Rate Dial 
               22  Modulator Housing 
               24  Modulator Base 
               26  Diaphragm Plate 
               27  Diaphragm Ring 
               28  Interior End 
               30  Spring 
               32  Spring Boss 
               34  External Threads 
               36  Internal Threads 
               38  Pressure Dial Boss 
               40  Cylindrical Sleeve 
               42  Primary Modulator Chamber 
               44  Equalization Conduit 
               46  Secondary Modulator Chamber 
               48  Safety Discharge Orifice 
               50  Rate Dial Exhaust Port 
               52  Flow Restrictor Valve Seat 
               54  Slots 
               55  Tapered Inner End 
               56  External Threads 
               58  Internal Threads 
               60  Rate Dial Boss 
               62  Sealing Ring 
               64  Ambient Actuation Conduit 
               66  Patient Adapter 
               68  Attachment Port 
               70  Pop-Off Valve 
               70  Pop-Off Valve 
               72  Patient Demand Valve 
               74  Gas Inlet Port 
               76  Patient Connection Port 
               80  Flapper 
               82  One-Way Valve Port 
               84  Valve Body 
               86  Face Mask 
               88  Pop-Off Spring 
               90  Pop-Off Piston 
               92  Pop-Off Housing 
               94  Piston Ring 
               96  Piston Seal 
               98  Piston Base 
               100  Piston Ring Orifice 
               102  Piston Seal Orifice 
               104  Piston Base Orifice 
               106  Second Pressure Dial 
               108  Ambient Actuation Conduit 
               110  Third Pulmonary Modulator Apparatus 
               112  Long Diaphragm 
               114  Outer Spring 
               116  Sealing O-ring 
               118  Equalization Conduit 
               120  Ambient Actuation Conduit 
               122  Third Pressure Dial 
               124  Third Inlet Chamber 
               126  Third Modulator Body 
               128  Primary Modulator Chamber 
               130  Secondary Modulator Chamber 
           
         
       
     
       DETAILED DESCRIPTION OF THE INVENTION 
       [0107]    While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment of the invention, with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiment illustrated. 
         [0108]    For illustrative purposes the present invention is embodied in the apparati generally shown in  FIG. 1 through 7 . It will be appreciated that the apparatus may vary as to configuration and as to details in the parts without departing from the basic concepts as disclosed herein. 
         [0109]    Referring first to  FIG. 1 ,  FIG. 2 , and  FIG. 3  a constant flow, pressure modulator apparatus  10  in accordance with the preferred embodiment of the present invention is generally shown. As will be seen, the apparatus comprises a spring-loaded diaphragm assembly  12 , an inlet chamber  14 , a flow restrictor conduit  16 , a pressure dial  18 , a rate dial  20 , a modulator housing  22  and modulator base  24 . The apparatus of the preferred embodiment is fabricated almost completely of injection molded plastic. 
         [0110]    Diaphragm assembly  12  consists of a center diaphragm plate  26  which is captured circumferentially by diaphragm ring  27 . Diaphragm assembly  12  is normally biased in a close position wherein the diaphragm plate  26  rests against the interior end  28  of inlet chamber  14 . A spring  30  is located around a spring boss  32  which maintains spring  30  in a substantially perpendicular orientation relative to diaphragm plate  26 . External threads  34  on pressure-dial  18  engage internal threads  36  within the pressure dial boss  38 , which is located atop modulator housing  22 . Rotating pressure dial  18  causes pressure dial  18  to move longitudinally relative to diaphragm plate  26 , thereby increasing the compressive force on spring  30  as pressure dial  18  is moved closer to diaphragm plate  26 . Pressure dial  18  therefore allows adjustment of the compressive force of spring  30  against diaphragm assembly  12 . Diaphragm plate  26  moves longitudinally within a cylindrical sleeve  40  located within assembly of modulator housing  22  and is in flow connection with a primary modulator chamber  42  formed by the assembly of modulator housing  22  and modulator base  24 . Diaphragm ring  27  can be made of a variety of rubber like compounds but is usually made of silicone plastic or more preferably santoprene, and is pleated so that longitudinal movement of diaphragm plate  26  is minimally restricted. The outer diameter of diaphragm ring  27  is so sized that when inserted into cylindrical sleeve  40  during assembly an airtight seal is formed. Although the outer diameter of diaphragm ring  27  and cylindrical sleeve  40  have been described as round and cylindrical, those skilled in the art can see that other profile shapes are possible without departing from the nature and essence of the invention. 
         [0111]    Flow restrictor port  16  is located within modulator housing  22  and is in flow connection with primary modulator chamber  42 . Rate dial  20  allows for adjustment of the rate of gas escaping from modulator chamber  42  to the atmosphere, and adjusting rate dial  20  allows control of a patient&#39;s exhalation duration and PEEP. An annular flow restrictor valve seat  52  is located within flow restrictor port  16 . Flow restrictor valve seat  52  functions in conjunction with tapered inner end  55  of rate dial  20  to restrict gas from passing through flow restrictor port  16 . Slots  54  in rate dial  20  have a much larger cross-sectional area than flow restrictor port  16  at its largest setting and poses little restriction to flow. The restricting area between flow restrictor valve seat  52  and the tapered inner end  55  of rate dial  20  is adjustable by positioning rate dial  20  axially through use of external threads  56  on rate dial  20  which engage internal threads  58  within the rate dial boss  60 , whereby rotating rate dial  20  causes tapered inner end  55  to move longitudinally relative to flow restrictor valve seat  52 . Flow restrictor valve seat  52  and tapered inner end  55  at the inner end of rate dial  20  functions similar to a needle valve to create a restrictive annular region to restrict the flow of gas there through. Slots  54  remain of constant cross-sectional area throughout the adjustment range of rate dial  20 . Use of tapered inner end  55  and annular valve seat  52  provides for a sensitive adjustment of gas flow resistance. Although the preferred embodiment discloses using a tapered inner end  55  of rate dial  20  with slots  54  therein along with flow restrictor valve seat  52  to restrict gas flow there through, those skilled in the art would recognize that other means for providing adjustable gas flow resistance exist. As an additional safety feature and protection for the patient against the possibility of the rate dial exhaust port  50  becoming occluded, and thereby exposing the patient to dangerous levels of pressure, an additional safety discharge orifice  48  may be placed in the modulator body allowing a secondary escape of gas from the primary modulator chamber  22 . Said safety discharge orifice  48  may be place anywhere in the modulator body provided it creates the means for fluid communication between primary modulator chamber  22  and the ambient environment. The safety discharge orifice  48  is so sized to not provide so great a discharge of gas as to prevent the adjustment of the PMA to needed exhalation times of up to 5 seconds or more, but is large enough so provide a relief of gas in the event that the rate dial exhaust port  50  is occluded. In practice, safety discharge orifice  48  is approximately 0.125″ in diameter. 
         [0112]    During the patient inspiration, diaphragm plate  26  rests against interior end  28  of inlet chamber  14 . This constitutes diaphragm assembly, consisting of diaphragm plate  26  and diaphragm ring  27 , being in a closed position. A sealing ring  62  circumscribing interior end  28  of inlet chamber  14  provides an airtight seal when diaphragm plate  26  rests against interior end  28  of inlet chamber  14 . While diaphragm plate  26  is resting against interior end  28  of inlet chamber  14 , the force of the patient&#39;s pressure on diaphragm plate  26  is equal to the product of the patient&#39;s pressure and the area circumscribed by sealing ring  62 . As the patient inhalation develops and the patient is charged, the patient&#39;s pressure will increase until the force of the patient&#39;s airway pressure on diaphragm plate  26  overcomes the compressive force of spring  30 , which causes diaphragm assembly to open (i.e. diaphragm plate  26  moves away from interior end  28  of inlet chamber  14 ). 
         [0113]    Diaphragm plate  26  includes equalization conduit  44  that provides the intended fluid path between primary modulator chamber  42  and secondary modulator chamber  46 . Equalization conduit  44  works optimally for the described embodiment if in the diameter range of 0.030″ to 0.050″, but has been shown to continue to perform for diameters as small as 0.010″ and as large as 0.125″. Larger sizes may also be possible, but can be less desirable because bigger sizes begin to limit the PMA to smaller exhalation times than may be desired by the clinician. Although equalization conduit  44  is described herein as round, the actual shape is irrelevant provided that the equivalent cross sectional area is made available for the flow of gas between primary modulator chamber  42  and secondary modulator chamber  46 . Furthermore, multiple orifices, or multiple other cross sectional flow shapes can be utilized if desired without departing from what is described, and equivalent performance would be expected provided that the sum of the cross-sectional flow areas is equal to the cross-sectional area of a single equalization conduit  44 . 
         [0114]    Secondary modulator chamber  46  is the enclosed spaced encompassed by the modulator housing  22 , pressure dial  18 , diaphragm plate  26 , and diaphragm ring  27 . An intrinsic property of secondary modulator chamber  46  is that internal pressure within secondary modulator chamber  46  creates a force on the sealing member of the modulator (in this embodiment diaphragm plate  26 ) that is in the same direction as the biasing force (in this embodiment spring  30 ) on the sealing member of the modulator towards the closed position, and which is also in opposition to the resulting force on the sealing member of the modulator as a result of the internal pressure in primary modulator chamber  42 . 
         [0115]    Referring to  FIG. 3  ambient actuation conduit  64  is shown in pressure dial  18 . Ambient actuation conduit  64  provides fluid communication between secondary modulator chamber  46  and the ambient environment. When ambient actuation conduit  64  is un-occluded pressure modulator apparatus  10  provides ventilatory support as previously described, and as is normal for other PMAs. In the event that the clinician places his or her finger over the pressure dial, this will cause the occlusion of ambient actuation conduit  64 . When ambient actuation conduit  64  becomes occluded the pressure in secondary modulator chamber  46  is allowed to rise, thus providing additional force on diaphragm plate  26  in the same direction of the biasing force of spring  30 , and thus the pulmonary modulator apparatus  10  closes. Upon the pulmonary modulator apparatus  10  closing, the patient will begin to be charged with gas and the patient&#39;s airway pressure will rise until such time that the force of the patient&#39;s pressure on diaphragm plate  26 , circumscribed by the sealing ring  62 , overcomes the force of spring  30 . While ambient actuation conduit  64  is occluded, the pressure differential between primary modulator chamber  42  and secondary modulator chamber  46  are minimized through the fluid communication provided by equalization conduit  44 . So long as this is the case, pulmonary modulator apparatus  10  can not behave as a dual area valve that opens at one pressure and closes at another lower pressure, thus cyclical ventilatory support is not provided by pulmonary modulator apparatus  10 , and, upon the patient&#39;s airway pressure reaching sufficient value to overcome spring  30 , the diaphragm plate  26  will move away from sealing ring  62  of just sufficient distance for the patient&#39;s airway pressure to be maintained at a constant value approximately equal to the patient pressure sufficient to overcome spring  30 . The ambient actuation conduit  64  need not necessarily be in the pressure dial, and may be placed anywhere provided that it allow fluid communication between secondary modulator chamber  46  and the ambient environment and have some means of being occluded, either directly by the clinician&#39;s finger, or by some other mechanical means or apparatus. The current embodiment uses a circular cross-sectional shaped ambient actuation conduit  64  that is approximately 2.5 times greater in diameter than equalization conduit  44 , but a wide range of sizes would be sufficient and work equally as well as what is described herein provided that they are larger in cross sectional area than equalization conduit  44  and that they may in some manner or form be occluded by the clinician. As with equalization conduit  44 , the exact shape and number of conduits used to form ambient actuation conduit  64  are not as important as the total combined cross-sectional area and the means to be occluded by the clinician. Of additional importance is that external threads  34  and internal threads  36  be of sufficient fit to prevent undue leaking of gas from secondary modulator chamber  46  into the ambient environment thus having a detrimental effect on the operation of ambient actuation conduit  64 . 
         [0116]    Referring again to  FIG. 4  pressure modulator apparatus  10  and a patient adapter  66  are shown combined together to function as an automatic resuscitator or ventilator. Patient adapter  66  is attached to inlet chamber  14  of pressure pulmonary modulator apparatus  10  via attachment port  68 . Patient adapter  66  is equipped with a pop-off valve  70 , a patient demand valve  72 , a gas inlet port  74  and a patient connection port  76 . The combination of pressure modulator apparatus  10  and patient adapter  66  serves as a automatic resuscitator or ventilator which may be interface with a face mask  80 , as shown in phantom, or an endotracheal tube. 
         [0117]    Gas inlet port  74  allows connection to a source of compressed gas (not shown), such as compressed air or oxygen. The compressed gas source is attached to gas inlet port  74  using a DISS connector, barb, or snap connection (not shown). Internal to gas inlet  74  is an orifice sized to ensure that for an approximate 50 psig compressed gas source, the flow will not exceed approximately 40 liters/minute. Typically, the compressed gas would consist entirely of 100% compressed oxygen but a clinician may use any type of compressed gas as deemed appropriate. The compressed air or oxygen is delivered directly to the patient for inhalation. Gas inlet port  74  can also be so configured that the exiting jet emitting from the sized orifice entrains room air through ports positioned adjacent to said orifice, thus 15 l/min of oxygen may result in delivery of an air oxygen mixture to the patient at a combined rate of 40 l/min. 
         [0118]    Patient demand valve  72  is a one-way valve, comprising of a flapper  80  placed between a one-way valve port  82  and a valve body  84 , which allows air to be entrained from the room environment. Patient demand valve  72  allows the patient to draw in more air than that which is being continuously supplied to patient adapter  66  through gas inlet port  74  from the compressed gas source, thus giving the patient not only the means to initiate the beginning of inhalation but also the duration. In the preferred embodiment, patient demand valve  72  has a very low resistance to flow, which is on the order of approximately 3.5 cm H 2 O at 50 liters/minute. 
         [0119]    Pop-off valve  70  provides a safety feature to prevent the patient airway pressure from exceeding any set, or pre-set, value and consists of pop-off spring  88 , pop-off piston  90 , and pop-off housing  92 . Pop-off piston  90  is biased by pop-off spring  88  and equipped with a sealing edge  94 . Pop-off valve  70  opens anytime the patient&#39;s airway pressure exceeds a preset value whereby the force of the patient&#39;s pressure on pop-off piston  70  overcomes the bias and restorative force of pop-off spring  88 . Pop-off valve  70  can be equipped with a means to create an audible tone and a visual signal when the valve  70  is opened. Although Pop-off valve  70  provides a needed back up pressure relief, it is set at a high enough value that pressure reached to cause it to open may still be dangerous to some patients. Another embodiment of the invention, and one that will result in less parts, is to combine patient demand valve  72  into pop-off valve  70 . Such an embodiment includes equipping pop-off piston  90  with fluid conduits and a flapper that preferentially allow flow into, but not out of, patient adapter  66 . 
         [0120]    Patient connection port  76  allows a connection of a breathing mask  86 , an endotracheal tube (not shown), or a laryngeal mask airway (also not shown) which the patient wears during the breathing process associated with resuscitator  78 . Because the pulmonary modulator apparatus  10  is closed during inhalation, all incoming gas is delivered to the patient through patient connection port  76 . In the preferred embodiment, patient connection port  76  has a 22 mm OD for connection to PEEP masks (not shown) and a 15 mm ID for connection to endotracheal tubes. 
         [0121]    When inhalation pressure reaches that which is dialed on pressure dial  18 , diaphragm plate  26  moves to the fully open position, the patients peak pressure (PIP) to the patients baseline pressure (PEEP) is 10:1, which is consistent with the ratio of the full surface area of diaphragm assembly in pulmonary modulator apparatus  10  and the surface area circumscribed by sealing ring  62 . Pressure dial  18  and pulmonary modulator spring  30  are designed so that the resuscitator delivers a maximum patient peak pressure (PIP) of approximately 55 cm H 2 O and a minimum PIP of approximately 10 cm H 2 O, although these pressures and the referred ratio are not the physical limit of the apparatus. Pop-off valve  70  is designed to relieve pressure if the patient&#39;s airway pressure rises above approximately 60 cm H 2 O. 
         [0122]    Thereby the present invention provides the means for a user to initiate inhalation immediately without changing any baseline settings of the device whenever the invention stops providing ventilatory support (i.e. stalls) regardless if the device stopped cycling due to changes in physiological, mechanical, pneumatic or environmental conditions, by simply occluding ambient actuation conduit  64 . Thereby the present invention is capable of being used by a user to determine the sedative state of a patient by adjusting the device to the spontaneous mode and satisfying oneself that the device only initiates inhalation when ambient actuation conduit  64  is occluded. Thereby the present invention is capable of higher PEEP settings than are otherwise possible by increasing the rate dial setting such that the restriction to flow and the continuous flow of gas provides the desired PEEP pressure, causing the device to be in a spontaneous mode, whereby the user causes cycling of the device by periodically occluding ambient actuation conduit  64 . Thereby the present invention is capable of providing an inspiratory hold by the user occluding and holding ambient actuation conduit  64  for the desired time. Thereby the present invention provides a reliable and simple alternative ventilatory support mode requiring less sophistication by the user and which is realized by the user simply occluding ambient actuation conduit  64  periodically whenever inhalation is desired, and releasing ambient actuation conduit  64  whenever exhalation is desired. 
         [0123]    Referring to  FIG. 6A  and  FIG. 6B  is shown an alternative embodiment to pulmonary modulator apparatus  10 . Instead of a diaphragm assembly using diaphragm plate  26  and diaphragm ring  27 , the referenced alternative embodiment uses a piston assembly consisting of piston ring  94  and a piston seal  96  which is preferably made of a polyethylene or like material, and piston base  98 . Piston seal  96  is placed over piston base  98  and is held in place by piston, ring  94  that is placed over piston seal  96  and caused to be snapped and held into place in reference to piston base  98 . An equalization conduit is caused by aligning during assembly piston ring orifice  100 , piston seal orifice  102 , and piston base orifice  104  such that fluid communication is possible between the primary and secondary modulator chambers of the shown alternative embodiment. Alternative second pressure dial  106  is not equipped with fluid communication means that allow flow communication between the secondary modulator chamber and the ambient environment, instead means are provided by the alternative placement of ambient actuation conduit  108  that is placed in the modulator body as shown, and which functions identically as described in the first and preferred embodiment. With the exception of the inventive concepts described herein, further details of this embodiment are already known in the art and reference is made to U.S. Pat. No. 6,067,984. 
         [0124]    Referring to  FIG. 7  is shown an alternative embodiment to pulmonary modulator apparatus  10 . Third pulmonary modulator apparatus  110  consists of a long diaphragm  112 , outer spring  114 , sealing o-ring  116 , equalization conduit  118 , ambient actuation conduit  120 , third pressure dial  122 , third inlet chamber  124 , third modulator body  126 , primary modulator chamber  128 , and secondary modulator chamber  130 . With the exception of the inventive concepts described herein, further details of this embodiment are already known in the art and reference is made to U.S. Pat. No. 6,067,984. 
         [0125]    Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus the scope of this invention should be determined by the appended claims and their legal equivalents.