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 . for illustrative purposes the present invention is embodied in the apparati generally shown in fig1 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 . referring first to fig1 , fig2 , and fig3 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 . 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 . 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 . 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 ). 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 . 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 . referring to fig3 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 . referring again to fig4 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 . 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 . 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 . 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 . 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 . 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 . 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 . referring to fig6 a and fig6 b 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 . referring to fig7 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 . 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 .
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 .