NZ544257A - Variable volume resuscitator - Google Patents

Abstract

A resuscitator (1) wherein the air chamber (11) is formed from at least three nestable sections (16a-16f) that are adapted to slide telescopically relative to each other along the longitudinal axis to pump air from the air chamber (11) through an outlet (18).

Description

NEW ZEALAND PATENTS ACT, 1953 No: 544257 Date: 19 December 2005 COMPLETE SPECIFICATION IMPROVEMENTS RELATING TO RESUSCITATORS intellectual Property Office of N.Z.

VS DEC RECEIVED I, GARY NOEL STEVENSON, 2/57 Preston Crescent, Belleknows, DUNEDIN 9011, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement Field of the Invention The present invention relates to resuscitation apparatus for assisting in resuscitating people or animals that have stopped breathing.

Background to the Invention Various medical conditions can cause a person to stop breathing. When this occurs, paramedics, veterinarians or other people providing assistance attempt to resuscitate the patient by introducing air into their lungs. This can be achieved by traditional mouth-to-mouth resuscitation, or more recently using a resuscitator apparatus. A resuscitator, such as shown in 10 Figure 1, is a pump like device that includes an air chamber with a reciprocating pump mechanism, and a latex, thermoplastic, rubber, polycarbonate or other material oudet mouthpiece ^ (such as a mask) designed to be placed over the mouth and/or nose of the person or animal being resuscitated. By operating the pump mechanism, air is drawn through an inlet valve and directed into the patient's lungs via their mouth, nose or snout.

A number of drawbacks exist for traditional human resuscitators. Firstiy, they are designed primarily for use on adults, and are often unsuitable or even dangerous for use on children. This is because the volume of the pump cylinder is of a size to provide the required volume of air for an adult. If used for a child, too much air might be pumped into the child's lungs thereby causing damage. Further, because the mouthpiece or mask of a typical resuscitator 20 is designed for adults, it does not form a proper fit over the mouth and/or nose of a child. However most bag, or cylindrical resuscitators on the market do incorporate a separate mouthpiece or mask for differing adult, child or infant facial forms.

^ Similar drawbacks also exist for traditional animal resuscitators. Firstiy, they are designed and manufactured with discrete volumes for specific animal species, and animal size 25 within that species, and are unsuitable for use on other animals. This is because the volume of the pump cylinder is of a size to provide the required volume of air for that particular animal and species size. If, say, an adult unit is used for an underdeveloped or young animal, too much air might be pump into the patient's lungs, thereby causing damage.

Further, traditional resuscitators are bulky, and awkward to transport and often more 30 than one volumetric size unit must be carried for exceptional circumstances.

Summary of the Invention It is an object of the present invention to make a resuscitator that at least partially overcomes the drawbacks of existing resuscitators, or at least provides the public with a useful 35 choice from existing apparatus.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated 5 otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art The term "comprising" as used in this specification means "consisting at least in part of". Related terms such as "comprise" and "comprised" are to be interpreted in the same 10 manner.

In this specification, patient can refer to a human or an animal and a mouthpiece is any article that can cover a mouth, snout and/or nose or any other respiratory opening of a human or animal.

In one aspect the present invention may be said to consist in a resuscitator comprising: 15 an air chamber with a longitudinal axis and an inlet, an outlet in the air chamber through which air can flow from the chamber, and wherein the air chamber is formed from at least three nestable sections that are adapted to slide telescopically relative to each other along the longitudinal axis to pump air from the air chamber through the oudet.

Preferably, the nestable sections are adapted to collapse into a nested configuration for storage.

Preferably, the outlet is adapted for connection to a mouthpiece.

Preferably, the resuscitator further comprises a mouthpiece connected to the oudet.

^ Alternatively, the oudet comprises a mouthpiece.

Preferably, the mouthpiece comprises a diverging wall extending to an opening with a 25 first diameter, the diverging wall comprising an internal diameter that varies along the axis of the mouthpiece, and wherein at least a portion of the mouthpiece can be retracted or folded back to expose a portion of the mouthpiece that has a diameter smaller than the first diameter.

Preferably, the resuscitator further comprises a releasable locking mechanism for retaining one or more of the nestable sections in a fixed relationship with one or more adjacent 30 nestable sections to substantially prevent relative sliding between those respective sections in the longitudinal direction to reduce the effective volume of the chamber.

In another aspect the present invention may be said to consist in a resuscitator comprising: a variable volume air chamber with a longitudinal axis and an inlet, an oudet in the variable volume air chamber through which air can flow from the chamber, and a pump 35 mechanism for forcing air from the chamber through the oudet, wherein the wall of the variable volume air chamber comprises at least three sections that are adapted to slide relative to each other along the longitudinal axis to vary the volume of the air chamber, and the resuscitator further comprising a releasable locking mechanism for retaining one or more of the sections in a fixed relationship with one or more adjacent sections to substantially prevent relative sliding 5 between those respective sections in the longitudinal direction to reduce the effective pump volume of the chamber.

Preferably, the at least three sections are formed as concentrically nestable cylinders, the diameters of the sections being such that each pair of adjacent cylinders can slide relatively to allow one of the adjacent cylinders to slide and nest concentrically within the other adjacent 10 cylinder.

Preferably, the pump mechanism comprises the at least three sections wherein by manoeuvring the sections between an extended and nested state, air is pumped from the chamber through the oudet.

Preferably, the releasable locking mechanism comprises a separate releasable locking 15 mechanism for each pair of adjacent sections, each mechanism comprising one or more protrusions on a first section of the pair engaging in a channel formed in a second section of the pair, the protrusion adapted to slide within the channel and allow the sections of the pair to slide longitudinally relative to each other, the channel further comprising a recess extending there from for engagement with the protrusion and prevention of the relative longitudinal sliding movement.

Preferably, the nestable sections are adapted to collapse into a nested configuration for rage.

Preferably, the oudet is adapted for connection to a mouthpiece.

Preferably, the resuscitator further comprises a mouthpiece connected to the oudet. Alternatively, the oudet comprises a mouthpiece.

Preferably, the mouthpiece comprises a diverging wall extending to an opening with a first diameter, the diverging wall comprising an internal diameter that varies along the axis of the mouthpiece, and wherein at least a portion of the mouthpiece can be retracted or folded back to expose a portion of the mouthpiece that has a diameter smaller than the first diameter.

Preferably, the at least three sections are adapted to collapse into a nested configuration 30 for storage.

In another aspect the present invention may be said to consist in a resuscitator comprising a variable volume air chamber with a longitudinal axis, a mouthpiece or mask or mask through which air can flow from the chamber, and a pump mechanism for forcing air from the 35 chamber through the mouthpiece or mask or mask, wherein the wall of the chamber is formed from two or more sections that are adapted to slide relative to each other in the direction of the longitudinal axis to vary the volume of the air chamber, the resuscitator further comprising a releasable locking mechanism for retaining one or more of the sections in a fixed relationship with one or more adjacent sections to substantially prevent relative sliding between those sections 5 in the longitudinal direction to reduce the effective pump volume of the chamber.

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The 10 disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

Brief Description of the Drawings Preferred embodiments of the invention will be described with reference to the 15 following drawings of which: Figure 1 shows an existing resuscitation device, Figure 2a shows a cross-sectional side view and plan view of a first embodiment of a resuscitator according to the present invention, the resuscitator including a locking mechanism, / Figure 2b shows a cross-sectional side view of the first embodiment in a collapsed configuration, Figure 2c shows a cross-sectional exploded sided view of the resuscitator shown in Figure 2a, Figure 2d shows a cross-sectional plan view of the first embodiment of the resuscitator in a collapsed configuration, Figures 2e and 2f show a side view of the first embodiment of the resuscitator in collapsed and extended configurations respectively, Figure 3 shows an internal wall of one section of the resuscitator air chamber with 10 locking mechanism, Figure 4 shows the mouthpiece in an extended and a retracted state, Figure 5 shows the resuscitator in its collapsed configuration and retained in a holder, Figure 6 shows the resuscitator with an extraction tube attached, Figure 7 shows a second embodiment of the resuscitator, Figures 8a and 8b show a cross-sectional side view of a third embodiment of the resuscitator in a partially and fully extended configurations respectively with the inlet and oudet shown, Figure 9 shows the second embodiment of the resuscitator in a compact configuration, Figures 10a and 10b show top (B-B) and bottom (C-C) cross-sectional views of the 20 second embodiment of the resuscitator in its compact configuration, Figures 11a and lib show a cross-sectional view and side/plan elevation view respectively of the oudet valve in further detail, Figures 12a and 12b show a cross-sectional view of the oudet valve in patient exhale and pumped inhale positions respectively, Figures 13a and 13b show a full and cut-away perspective view of the assembled resuscitator according to the third embodiment, Figure 14 shows another embodiment of the mouthpiece.

Detailed Description of the Preferred Embodiments Figures 2a to 2f show various views of a first embodiment of a resuscitator 1 according to the invention. Figures 2a, 2c and 2f show the resuscitator in an extended state or configuration. Figures 2b, 2d and 2e show the resuscitator in a collapsed state or configuration. It will be appreciated that the dimensions shown in the Figures are indicative and not limiting. The resuscitator comprises a variable volume air chamber 11 (e.g. see Figure 2a) connected to a 35 mouthpiece 12. The mouthpiece could, for example, be an oxygen type mask or similar. The mouthpiece can also cover the nose and/or mouth. A first valve 13a (see Figure 2c) is placed between the mouthpiece 12 and the air chamber 11 to allow air to pass from the chamber 11 to the mouthpiece 12. A second valve 13b (see Figure 2f) allows exhaled air to vent. An air intake valve 14 is placed on the top of the chamber 11 to provide an air inlet. Preferably, the non-5 return inlet valve 14 has a latex seal or similar flexible material with a raised intake head. The first and second valves 13a, 13b form part of an oudet that enables air to pass from the inside of the air chamber 11 to the outside of the air chamber (which will typically be to the inside of an attached mouthpiece 12 ) and in particular to a patient. The oudet might also comprise any other portions integrated with or extending from the chamber 11 (such as a conduit) to allow for 10 passage of air. The oudet or parts thereof may be adapted to be coupled permanendy or detachably to a mouthpiece, for example mouthpiece 12. Alternatively, the oudet could be considered to comprise the mouthpiece 12 in addition to the other components comprising the air oudet. Similarly, the inlet allows for air to move into the air chamber 11, the inlet comprising the air intake valve 14 and any other components which effect movement of air into the 15 chamber.

The chamber 11 comprises a cylindrical 16a wall fixed to the top of the chamber and one or more nestable cylindrical walls 16b-16f. In particular, the wall of the air chamber 11 is formed from a top section 16a and two or more concentrically nestable sections 16b-16f which can slide axially along the longitudinal axis 20 in the directions shown by arrows 15 in a telescopic 20 manner. Preferably, the sections 16a-16f are each formed as a cylinder, although other configurations are possible. For example, the sections may have a cross-sectional shape that is square or any other polygon. Each of the nestable sections 16b-16f is adapted to slide and nest within the lower adjacent section so that the entire chamber 11 can be collapsed such that the nestable sections 16b-16f are all nested within the top section 16a. The sections 16a-16f are 25 sealed in a suitable manner to form the air chamber 11. In the preferred embodiment, the chamber 11 is formed from a top section 16a and five cylindrical sections 16b-16f concentrically nestable sections that are slidably engaged in a telescopic manner, although it will be appreciated by those skilled in the art that two or more concentrically nestable sections could be used in conjunction with the top section 16a.

Figure 2d shows a cross-sectional plan view of the apparatus 1, where each of the nested walls 16a-16f of the chamber 11 are shown in dotted lines. A top portion 28 (not shown for clarity) moulded as part of chamber 16a, (or alternatively attached as an engaging lip and recess) covers the sections. The sections 16a-16f of the chamber 11 are manufactured from suitable thermoplastic, other plastics or other materials.

Each pair of corresponding sections 16a,16b; 16b,16c;16c,16d; 16d,16e and 16e,16f may all have a releasable locking mechanism for preventing relative axial sliding 15 between the two sections of the pair. The locking mechanism will be described with reference to Figure 3, which shows an example of the locking mechanism in relation to section pair 16a,16b. It will be 5 appreciated that a similar arrangement may be used for the other sections, as required.

Figure 3 is a side elevation of one half of the internal face of the top section 16a. The locking mechanism includes at least one protrusions (such as a nib e.g. 17b) protruding radially from the lower adjacent section 16b. In a preferred embodiment, each nestable section 16b-16f includes one or more protruding nibs (e.g.l7b-17f) disposed diametrically opposite each other as 10 depicted in Figure 2c. Each nib e.g. 17b slidably engages in a channel or other guide e.g. 21a formed in or disposed on the corresponding upper adjacent section of the pair as seen in Figure 2a. There is sufficient tolerance between the nib 17b and the width of the channel 21a to enable the nib 17b and section 16b from which it protrudes to slide in both directions 15 longitudinally along the channel 21a of the upper adjacent section 16a. When the nib 17a is located in the 15 channel 21a it also substantially prevents rotation of the upper section 16a with respect to the adjacent lower section 16b.

Each channel e.g. 21 may also comprise at least one recess e.g. 22 formed in the section 16a-16e protruding laterally from the channel 21. The recess 22 is dimensioned to receive the nib 17b when it is lined up and the section 16a is rotated either clockwise or anticlockwise. The 20 recess may also include a resistance fit or other mechanism or shaping to retain the nib within the recess. By manoeuvring the upper section 16a such that the nib 17b sits within the recess 22, the upper section 16a and lower section 16b are locked to prevent relative sliding movement between them.

A similar locking mechanism is preferably also disposed on the other sectors of the 25 sections 16a, 16b comprising a channel 21a (shown as light grey lines) in 16a and the nibs 17b protruding from section 16b. Other sections 16b, 16c, 16d and 16e include similar channel arrangements 21b, 21c, 21d, and 21e to receive respective nibs 17c, 17d, 17e, and 17f from a corresponding lower adjacent sections 16c, 16d, 16e and 16f. Each section 16a-16e may be independendy locked relative to its corresponding adjacent lower section, as required. 30 The nestable sections provide a pumping mechanism. When the sections 16a-16f are in their folly extended configuration, such as shown in Figure 2a, the full volume of the chamber is filled with air through the intake valve 14. By pressing down on the top section 16a, it and the remaining nestable sections 16b,16c; 16c, 16d; 16d,16e and 16e,16f slide relative to each other and telescopically collapse into a nested state (such as shown in Figure 2b), such that they are 35 positioned concentrically within the top section 16a as further shown in Figure 2d. In doing so, the ak contained within the chamber 11 is forced through the opening 18 and out through the opening of the mouthpiece 12. Pulling the top section 16a up again via the assistance of an optional adjustable strap 23, restores the volume of the chamber and it is refilled with ak through the valve 14. The optional adjustable top strap 23 extending from the top surface of the 5 apparatus enables the top section 16a to be manipulated in this manner. This process can be repeated to pump ak into the lungs of a patient.

Optionally, a formed conduit 36 is provided, either moulded to or attached in the some manner to the top section 16a. This enables pure oxygen to be injected into the chamber 11 via a pressure regulated oxygen cylinder or similar so that oxygen can be pumped into the patient by a 10 similar reciprocating pump action as described above. It will be appreciated that the conduit 36 might be formed as part of or attached to the section 16f or opening 18 to enable oxygen to enter the chamber 11.

The releasable lockable sections enable the effective pumping volume of the chamber 11 to be varied. By selectively locking one or more of the sections to thek corresponding lower 15 adjacent sections, this prevents the expansion and nesting of those sections taking place. For example, if section 16a is twisted such that the nibs 17 lock into the recesses e.g. 22 in the inner surface of top section 16a, then section 16b can no longer extend from section 16a. Therefore, when the pumping action takes place, only section 16c, 16d, 16e and 16f will collapse into sections 16b, 16c, 16d and 16e respectively, which all in turn will collapse into sections 16a and 20 16b. This means a volume of ak equivalent to section 16a will not be pumped into the patient's lungs. Different combinations of sections 16b-16f could be locked and unlocked as requked to alter the effective pumping volume of the chamber.

^ The mouthpiece 12 is formed from a suitable resilient and flexible material such as latex or rubber. The mouthpiece comprises a neck 18 which is connected to the base of the chamber 25 11 and has an aperture and valve 13a there-through for allowing ak to pass between the chamber 11 and the mouthpiece 12. A wall extends from the narrow neck 18 and diverges into a wider diameter opening 24, which can be placed over the mouth and/or nose of the patient being resuscitated. The wall of the mouthpiece may, for example, be diverging such that the diameter increases linearly as the wall diverges from the neck 18 to the main aperture 24, or else the 30 diameter may alter in a non-linear manner, such as parabolicaily, or such as that shown in Figure 2a and Figure 6. Preferably, the aperture 24 is of a suitable diameter for placing over the nose and/or mouth of an adult patient. The diverging wall provides least one point at which the diameter is smaller to that of the main aperture and of a suitable diameter to cover the nose and mouth of a child patient. The resilient and flexible nature of the mouthpiece 12 enables the 35 main aperture 24 to be folded back and over at least part of the mouthpiece 12 (as shown in Figure 4) to expose a smaller inner diameter opening 25 of the mouthpiece 12. In such a state, the mouthpiece 12 is then suitable for placing over the nose and/or mouth of a child. The main opening 24 of the mouthpiece 12 may be adapted to be retracted to a range of different positions, providing a range of opening diameters suitable for different sized patients. The mouthpiece can 5 be made from latex, thermoplastic, rubber, polycarbonate or other suitable material.

In alternative embodiments, the mouthpiece will enable folding back of opening 24, which could be of a suitable diameter size for a child, along opening 25 to expose the opening 25 which could be of a suitable diameter size for placing over the nose and/or mouth of an infant or baby. Referring to Figure 14, in yet a further alternative, the sizes are possible. The first opening 10 24 is sized for an adult, the second opening 25 is for a child and the third opening 26 is for an infant. The mouthpiece could be folded back at openings 25 and 26, to expose the opening 26 of a suitable perimeter size for the placing over the nose/mouth of an infant or baby.

Clearly, the mask could be adapted in a similar manner for use on animals of different sizes.

Figure 5 shows the apparatus in its compact state in which it has been packed away in a holder 30. To do so each cylindrical section 16b-16f is manipulated such that its respective nibs 17b-17f sit within the channels e.g. 21 formed in the corresponding upper adjacent section. Each section is then collapsed and nested in the upper adjacent section such that the entire chamber is placed in a compact configuration in which each section is nested concentrically within its 20 corresponding upper adjacent section and top section 16a. In this state the overall height of the chamber 11 is approximately that of the top section 16a. In addition, the mouthpiece 12 is folded back at least partially over the top section 16a of the chamber 11 to reduce the height profile of the apparatus or in another embodiment, the mouthpiece is retracted into the orifice of section 16a. Optionally, the holder 30 could be an adaptation of the top section 16a. In the 25 closed position, the top section 16a could encompass sections 16a to 16e in a sealed compact configuration.

In this compact state the device can then be placed in a low profile container 30 or other type of holder or as described above it could be in a sealed compact configuration as sections 16b to 16f retracted inside section 16a.. The holder may be sealed with a hinge/lid 30 arrangement in a manner to ensure the apparatus is stored hygienically or alternatively in a vacuum sealed bag as a compact configuration.

As mentioned, the overall height of the chamber when in the compact configuration is approximately that of the top section 16a, or in the more general case, the height of the largest section. Therefore, by use of three or more nestable sections, it is possible to achieve an air 35 chamber volume that is sufficient to enable resuscitation, but still provide a largest nestable section that is small enough to enable a useful compact configuration. Where only two nestable sections are used it would be necessary to have larger sections to achieve the same chamber volume. In having the larger sections, the compact configuration where one section is nested in the other would not be as low profile as is the case where three or more nestable sections are 5 used.

To use the apparatus 1, it is removed from the holder 30 and the mouthpiece 12 is returned to its fully extended configuration as shown in Figure 2a. The nested cylindrical sections 16b-16f of the chamber 11 are then retracted out into their fully extended position as shown in Figure 2a. The mouthpiece 12 can then be placed over the nose and/or mouth of an 10 adult patient being resuscitated. By pushing and pulling the chamber in a reciprocating manner the volume of the chamber is expanded and compressed thus pumping air from the valve 14 through the valve 13a to the mouthpiece 12 and into the patient's lungs.

Where a smaller adult or child or animal is being resuscitated, the mouthpiece 12 is folded back, such as shown in Figure 4, to expose a smaller diameter aperture 25 (or alternatively 15 opening 26 when available) which can then be placed over the mouth and/or nose of the smaller patient. In addition, the effective pumping volume of the chamber 11 can be altered or reduced as required in consideration of the smaller lung capacity of the patient being attended to. For example, where an older child or animal is being resuscitated, the top section 16a can be rotated and locked to section 16b to prevent relative sliding. Therefore, upon pushing the pump 20 chamber only sections 16c, 16d, 16e and 16f will slide and nest in top section 16a, 16b thereby reducing a volume of air pumped into the lungs of the patient equivalent to section 16b. In addition, for an even smaller child or animal, section 16c may be locked to section 16b, thereby meaning only sections 16d, 16e and 16f nest into top section 16a. This reduces further the volume of air pumped into the child's or animal's lungs, by the equivalent of the volume of 25 sections 16b and 16c. The mouthpiece or mask 12 might also be further retracted to expose an even smaller diameter opening commensurate with the patient's mouth/nose size.

Alternatively, it could be the lower walls that are locked in place, as required to reduce the volume of the pump chamber. The apparatus could be clearly labelled to indicate which section(s) should be rotated and locked or unlocked when treating a patient of a particular size or 30 age. Note that for safety purposes, the initial setting is that required for the smallest patients lung capacity to be resuscitated by the apparatus.

Figure 6 shows an optional solids removal accessory 31, which may be utilised in conjunction with a preferred embodiment of the invention or alternatively an existing resuscitator apparatus. The solids removal accessory 31 includes a tracheal suction tube 32 formed from 35 silicone rubber or other suitable material that is flexible. The tracheal suction tube has one end 33 for placement in the mouth or throat of the patient. At an opposite end, a rigid plastic right-angle discharge opening 34, and a telescopic portion 35 that engages in the silicone tube 32, are provided. This enables the tube discharger to be extended as required. Part-way along the length of the tube an opening 38 is provided with a valve 37 connecting the opening to the air 5 chamber 11. A membrane 41 in the valve allows air to pass through but prevents solids from entering the pump chamber. Upon pumping the apparatus in the usual manner, a suction is formed in the tube 32 via the valve 37 thus forming a vacuum sucking solids from the mouth and/or throat of the patient. The solids are then ejected out the discharge opening through a non-return valve 42. It will be appreciated the removal accessory could also remove liquids and 10 other materials.

In another embodiment of the apparatus, each channel e.g. 21 formed in the sections 16a-16e, has more than one nib recess formed along the length of the channel. This provides further lockable positions to further increase the range of distinct effective pumping volumes the apparatus could provide.

In an alternative embodiment, the nib protrudes radially from the upper adjacent section of a section pair, and the channel in which the nib slides is formed in the lower adjacent section of the pair.

In a second embodiment, a spring mechanism could be included to bias the sections into the fully extended position, whereby once a downward force is removed from the top 20 section of the chamber, the sections return to the extended position.

Another embodiment of the invention is shown in Figure 7. In this embodiment, the air chamber 70 has a wall that is formed from a number of collapsible sections that concertina under pressure, in a manner similar to bellows. The sections are biased by a spring embedded in the wall, so that the wall is in an extended state. Under pressure by a hand or similar placed on the 25 top surface of the bellows the wall collapses and the sections concertina into a collapsed state. This forces air out from the chamber 70 and through the valve 13a into the mouthpiece. When the hand is released, the wall returns to the extended state, and air re-enters the chamber through valve 14. Exhaled air from the patient vents through valve 13b.

A third embodiment of the invention is shown with respect to Figures 8a to 14b. This 30 third embodiment is similar to the first embodiment, but with a differendy configured inlet and oudet 80, 81. The third embodiment can comprise three or more nestable sections, and as shown in Figures 8a and 8b preferably comprises five nestable sections 82a-82d. The nestable sections 82a-82d can be the same or similar to those described in relation to the first embodiment with respect to Figures 2a to 6.

Figure 8a shows the resuscitator of the third embodiment in a partially extended configuration and Figure 8b shows the resuscitator in a fully extended configuration. Figure 9 shows a cross-sectional view of the resuscitator in a fully compact configuration. Figures 10a and 10b show respectively cross-sectional views B-B and C-C as indicated in Figure 9.

The oudet 81 which comprises a valve will be described in further detail with reference to Figures lla-12b. The oudet 81 comprises a conduit 110 that extends to a tapered air intake 111 that is connected to the bottom nestable section 82e of the resuscitator. The tapered air intake 111 comprises a straight cylindrical wall 130b extending from the tapered section 130a and an annular lip 130c. The tapered air intake 111 comprises a number of air oudet apertures 111a to 10 11 If. The oudet 81 also comprises a tapered valve member 113 with a tapered top surface 114 that is adapted to abut and seat against an inside tapered surface 115 of the air intake 111. The valve member 113 also comprises a boss 127a and associated seating portion 127b disposed annularly around the boss 127a. The valve member 113 also comprises apertures, 116a 116f that allow for flow of air from the air chamber 11 through the conduit 110 to a connected 15 mouthpiece 12 (not shown in Figures 11a to 12b) or to the ambient air. The valve means 113 further comprises a diaphragm, flapper valve or similar 117 attached to the top surface and covering the apertures 116a-116f. The diaphragm 117 prevents flow of air in the direction of arrow B through the apertures 116a-l 16f, but allows flow of air in the direction of arrow A.

Figures 12a and 12b show the oudet in cross-sectional form as it is connected to the 20 lower section 82e of the air chamber 11. The lowest section 82e is partially shown with an opening 121 that allows air to pass from the chamber 11 through the bottom or base wall 122 of the section 82e into the remainder of the oudet 81. Preferably, the aperture 121 forms part of the oudet 81. The lowest section 82e of the air chamber 11 comprises an annular wall 123 that extends around the perimeter of the aperture 121 extending from the bottom wall 122. An 25 annular lip 124 extends laterally from the wall 123 to define a snap-lock recess 125. The annular lip 130c of the tapered air intake 111 is adapted to snap-lock into the recess 125 to couple the conduit 110 and air intake 111 over the aperture 121 in the base 122 of the bottom section 82e. The valve member 113 is positioned inside the tapered means 111 between the base 122 thus retaining it in place although movable between an open and closed state.

Operation of the oudet 81 and in particular the valve means therein will be described with reference to Figures 12a, 12b. The oudet 81 can be in an open (inhale) state (see Figure 12b), which allows for air to flow from the air chamber 11 through the conduit 110 of the oudet and through to ambient air, preferably through a mouthpiece 12 if it is connected to the oudet 81. The oudet can alternatively be in a closed (exhale) state (see Figure 12a) in which air cannot pass from the chamber 11 through the outlet 81, but allows for exhaled air from a patient to vent through to ambient air.

Referring to Figure 12a, in the exhale state the valve member 113 is seated to close off the aperture 121 in the base 122 of the bottom section 82e. When a patient exhales, the exhaled 5 air will hit the diaphragm 117 thus preventing the exhaled air from traveling through the openings 116a, 116b into the interior of the air chamber 111 via the aperture 121. The differential pressure from the exhaled air will coerce the valve means 113 to seat against the opening 121 of the lower section 82e of the air chamber 11. In particular, the boss 127a extends into the interior portion formed by the annular wall 123 such that the annular seating portion 10 127b abuts the top of the annular wall 123. This closes off the aperture 121. By moving into this position, the apertures 111a to lllf will be exposed and the exhaled air will be vented through the apertures 111a to lllf into ambient air as shown by arrows C. This closed state prevents any matter exhaled or ejected from the patient from entering the air chamber, but allows for venting of exhaled air, as shown by arrows C. There might also be mesh as a diaphragm 150 to prevent 15 matter entering the chamber 11, and/or lodging in between the member 113 and intake 130a Figure 12b shows the inhale state, which occurs when the resuscitator is operated to pump air into the patient's lungs. The air will force the valve member 113 from the closed exhale state to the inhale state as shown. When the valve member 113 is put into the inhale state the tapered face 114 seats against the inner surface 115 of the air intake 111, thus closing off the 20 apertures 111a to lllf. This prevents air escaping from the air chamber 11 into ambient air. Instead, the air is directed through the openings 116a-116f past the diaphragm 117 and through the conduit 110 as shown by arrows D and ultimately into the patient's lungs.

Referring to Figure 9, the inlet 80 comprises a valve formed of a number of apertures (e.g. 90a, 90b) machined into the top surface of the top section 82a. A diaphragm or flapper 25 valve 91 is placed over the apertures 90a, 90b, which allows for ingress of air into the chamber 11 as shown by arrow A but prevents flow of air from the chamber 11 back to ambient air as shown by arrow B.

Figures 13a, 13b show an isometric view of the assembled resuscitator according to the third embodiment.

The inlet 80 comprising 90a, 90b and 91 could be formed as part of 82e in order to allow air to be drawn into the chamber 11.

Claims (19)

-15- What I Claim Is:

1. A resuscitator comprising: an air chamber with a longitudinal axis and an inlet, 5 an oudet in the air chamber through which air can flow from the chamber, and wherein the air chamber is formed from at least three nestable sections that are adapted to slide telescopically relative to each other along the longitudinal axis to pump air from the air chamber through the oudet. 10

2. A resuscitator according to claim 1 wherein the nestable sections are adapted to collapse into a nested configuration for storage.

3. A resuscitator according to claim 1 or 2 wherein the oudet is adapted for connection to a mouthpiece. 15 20

4. A resuscitator according to claim 3 further comprising a mouthpiece connected to the oudet.

5. A resuscitator according to claim 1 or 2 wherein the oudet comprises a mouthpiece.

6. A resuscitator according to claim 4 or 5 wherein the mouthpiece comprises a diverging wall extending to an opening with a first diameter, the diverging wall comprising an internal diameter that varies along the axis of the mouthpiece, and wherein at least a portion of the mouthpiece can be retracted or folded back to expose a portion of the mouthpiece that has a 25 diameter smaller than the first diameter.

7. A resuscitator according to any preceding claim further comprising a releasable locking mechanism for retaining one or more of the nestable sections in a fixed relationship with one or more adjacent nestable sections to substantially prevent relative sliding between those respective 30 sections in the longitudinal direction to reduce the effective volume of the chamber.

8. A resuscitator comprising: a variable volume air chamber with a longitudinal axis and an inlet, an oudet in the variable volume air chamber through which air can flow from the 35 chamber, and -16- a pump mechanism for forcing air from the chamber through the outlet, wherein the wall of the variable volume air chamber comprises at least three sections that are adapted to slide relative to each other along the longitudinal axis to vary the volume of the air chamber, 5 and the resuscitator further comprising a releasable locking mechanism for retaining one or more of the sections in a fixed relationship with one or more adjacent sections to substantially prevent relative sliding between those respective sections in the longitudinal direction to reduce the effective pump volume of the chamber. 10

9. A resuscitator according to claim 8 wherein the at least three sections are formed as concentrically nestable cylinders, the diameters of the sections being such that each pair of | adjacent cylinders can slide relatively to allow one of the adjacent cylinders to slide and nest concentrically within the other adjacent cylinder. 15

10. A resuscitator according to claim 8 or 9 wherein the pump mechanism comprises the at least three sections wherein by manoeuvring the sections between an extended and nested state, air is pumped from the chamber through the oudet.

11. A resuscitator according to any one of claims 8 to 10 wherein the releasable locking 20 mechanism comprises a separate releasable locking mechanism for each pair of adjacent sections, each mechanism comprising one or more protrusions on a first section of the pair engaging in a channel formed in a second section of the pair, the protrusion adapted to slide within the channel | and allow the sections of the pair to slide longitudinally relative to each other, the channel further comprising a recess extending there from for engagement with the protrusion and prevention of 25 the relative longitudinal sliding movement.

12. A resuscitator according to any one of claims 8 to 11 wherein the nestable sections are adapted to collapse into a nested configuration for storage. 30

13. A resuscitator according to any one of claims 8 to 12 wherein the oudet is adapted for connection to a mouthpiece.

14. A resuscitator according to claim 13 further comprising a mouthpiece connected to the oudet. 35 - 17-

15. A resuscitator according to any one of claims 8 to 12 wherein the oudet comprises a mouthpiece.

16. A resuscitator according to claim 14 or 15 wherein the mouthpiece comprises a 5 diverging wall extending to an opening with a first diameter, the diverging wall comprising an internal diameter that varies along the axis of the mouthpiece, and wherein at least a portion of the mouthpiece can be retracted or folded back to expose a portion of the mouthpiece that has a diameter smaller than the first diameter. 10

17. A resuscitator according to any one of claims 8 to 16 wherein the at least three sections are adapted to collapse into a nested configuration for storage.

18. A resuscitator comprising a variable volume air chamber with a longitudinal axis, a mouthpiece or mask or mask through which air can flow from the chamber, and a pump 15 mechanism for forcing air from the chamber through the mouthpiece or mask or mask, wherein the wall of the chamber is formed from two or more sections that are adapted to slide relative to each other in the direction of the longitudinal axis to vary the volume of the air chamber, the resuscitator further comprising a releasable locking mechanism for retaining one or more of the sections in a fixed relationship with one or more adjacent sections to substantially prevent relative 20 sliding between those sections in the longitudinal direction to reduce the effective pump volume of the chamber.

19. A resuscitator formed of at least three nestable sections, substantially as hereinbefore described with reference to the accompanying figures 2A to 6, 8A to 14. 25