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Title:
PORTABLE RESUSCITATION SYSTEM
Document Type and Number:
WIPO Patent Application WO/2007/045905
Kind Code:
A1
Abstract:
A portable resuscitation system comprises a carrier unit optionally having a base (1) , an integral upstanding rear wall (2), side walls (3,4) and a part front wall (6), defining a partially open fronted enclosure (7), and having a gas / oxygen cylinder located, optionally in a holder (8), on the base of the carrier unit with a manifold assembly (50) mounted on and connected with the cylinder gas outlet (15), a connection means (56) releasably securing the manifold assembly to the rear wall of the carrier unit. A suction device connected with the oxygen cylinder gas outlet through the manifold and driven by pressurised gas from the cylinder with a suction jar for receiving material collected by the suction device and having an oxygen supply outlet for delivering breathable oxygen, displacement of the oxygen cylinder within the carrier being prevented by the oxygen battle holder and manifold assembly.

Inventors:
MORE ROBIN (GB)
Application Number:
PCT/GB2006/003925
Publication Date:
April 26, 2007
Filing Date:
October 20, 2006
Export Citation:
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Assignee:
NUTEC MEDICAL LTD (GB)
MORE ROBIN (GB)
International Classes:
A61M16/00; A45C5/14; A45C13/00
Domestic Patent References:
WO2004084981A12004-10-07
WO2004000841A12003-12-31
Foreign References:
US20040051264A12004-03-18
US6213266B12001-04-10
Attorney, Agent or Firm:
DRAGGETT, Peter, Thornton (Fosters Wing Anstey Hall, Maris Lan, Trumpington Cambridge CB2 2LG, GB)
Download PDF:
Claims:
Claims

1. A portable resuscitation system comprising a carrier unit, a lightweight gas cylinder, a suction device driven by pressurised gas from the oxygen cylinder, a manifold through which pressurised gas will flow and which operatively connects the oxygen cylinder and the suction device, a suction jar for receiving material collected by the suction device, and oxygen supply means for delivering oxygen for breathing by a patient, the manifold being located on the carrier unit and all other components being directly located on the carrier unit or indirectly located on the carrier unit through the manifold, and the carrier unit being adapted to define a manual carrying handle, characterised by the presence of one or more features adapting the carrier unit to suit specific purposes.

2. A portable resuscitation system according to claim 1, characterised in that the one or more features adapting the carrier unit to suit specific purposes do not hamper the movement and manoeuvring of the system to and from a patient in trying environments.

3 A portable resuscitation system according to claim 2, characterised in that the one or more features adapting the carrier unit to suit specific purposes do not extend beyond the unit by too great a degree or are retractable into the unit.

4. A portable resuscitation system according to claim 1 , characterised by one or more movable handles which are adjustable to be to be retained relatively vertically above the centre or gravity of the fully laden unit in use.

5. A portable resuscitation system according to claim 3, characterised by one or more rolling means which are installed in a permanent position such that they do not extend beyond the unit by too great a degree or are retractable into the unit.

6. A portable resuscitation system according to claim 3, characterised by one or more movable trays in or on any of the rear or sides of the unit.

7. A portable resuscitation system according to claim 3, characterised by outwardly movable attachment means in or on any of the rear or sides of the unit to allow the carrier unit to be supported on an external structure, which attachment means comprise one or more movable trays.

8. A portable resuscitation system according to claim 3, characterised by a movable equipment support arm mounted within and extendable from and retractable into the unit.

9. A portable resuscitation system according to claim 1, characterised by a modular construction such as to permit the modular attachment of particular features adapting the carrier unit to suit specific purposes.

10. A portable resuscitation system according to claim 9, characterised in that the carrier unit is provided with attachment points that can cooperate with such additional components to be attached to the carrier unit.

11. A portable resuscitation system according to claim 10, characterised in that when such features adapting the carrier unit to suit specific purposes are absent, the attachment points that can cooperate with such additional components do not hamper the movement and manoeuvring of the system to and from a patient in trying environments.

12. A portable resuscitation system according to claim 11, characterised in that the attachment points do not extend beyond the unit by too great a degree or are retractable into the unit.

13. A portable resuscitation system according to claim 10, characterised by one or more further carrier units which are removably mounted on the carrier unit.

14. A portable resuscitation system according to claim 10, characterised by a component of the resuscitation system which is readily removably mounted in the carrier unit.

15. A portable resuscitation system according to claim 14, characterised in that the component is the manifold or a holder for the cylinder or receiving jar.

16. A portable resuscitation system according to claim 1, characterised by one or more cut-outs incorporated into the carrier unit wars in the form of a trade mark representation of a permanent nature.

Description:

Portable Resuscitation System

This invention relates to a portable resuscitation system which may be adapted for use in a variety of situations and primarily intended for medical purposes.

This invention is mainly concerned with the structure of a carrier unit adapted for use with an oxygen cylinder or other resuscitation equipment as well as associated items of apparatus which may need to be carried by medical personnel for use in emergency situation. This invention therefore also concerns a portable resuscitation system which can be used in the field, mainly to keep patients alive until proper medical arrangements can be made.

The carrier unit may also be adapted for fitting to a variety of mobile structures such as emergency trolleys and stretchers, beds and chairs and emergency service or military vehicles, or in static locations, such as an emergency or first aid station in an industrial plant or air, land or sea transportation, from which the portable system for resuscitation needs to be moved to an emergency site

Systems to aid resuscitation in hospitals are well known, and they generally include oxygen piped through the hospital's services and suction devices to clear obstructed airways, both of which are often powered by the same pressurised oxygen supply. Such systems are excellent for use in hospital at a static location, such as a bed in a ward or in an operating theatre.

However they rely on the connection to oxygen or suction supply tubes plumbed in to the hospital and so they are useless when a patient is in transit or is not close to connecting points.

In order to overcome these problems, previous attempts have been made to provide some form of mobile resuscitation system that can accompany a patient being moved around a medical facility. Unfortunately the result of these previous attempts was an extremely heavy device that could not be carried easily by a member of medical staff, but instead required attachment and support by the bed. These devices are therefore very cumbersome, tended to snag on the environment or otherwise hamper the movement and manoeuvring of the unit to and from the patient, and have failed to properly address the problem of providing an easily and safely portable system for resuscitation when away from a permanent resuscitation installation. i

Further, such primitive portable resuscitation devices as are known are wholly unsuitable for use in any location other than a hospital. Not only, as discussed above, are they too heavy for safe or easy carrying by an individual, but they expose the delicate parts to potential damage in anything other than a controlled environment.

In outside field situations, such as the scene of a car crash or other emergency or on a battlefield or conflict zone, or in static locations, such as an emergency or first aid station in an industrial plant or air, land or sea transportation, from which the portable system for resuscitation needs to be carried to an emergency site, a major part of the emergency or first aid treatment is to ensure airways remain open and that the person keeps breathing, so there is a great need for resuscitation equipment to keep people alive until proper medical arrangements can be made.

Unfortunately, there are no proper portable gas-driven resuscitation systems that can be easily and safely carried into the field and/or around industrial plant or air, land or sea transportation, and which are up to being used in such difficult conditions and/or difficult terrain or access, where this could be literally the difference between life and death.

Simple portable oxygen delivery systems are known, but these make use of plastic material straps to support and carry the bottle. However, the repeated exposure of these plastic straps to atmospheres with increased oxygen concentration leads to the degradation of the physical strength thereof. As such the straps can fast become brittle and break.

Therefore it is an object of the present invention to provide a resuscitation system that is lightweight, totally portable and functional, and can protect parts of the equipment from damage during transport and use. It is a further aim to provide a resuscitation system that is adapted for use in a range of trying environments both inside and outside hospital.

One such carrier unit and system is shown and described in our published patent specification no. GB 2400 321 A (also published as WO 2004/0841 Al).

In that previous disclosure there is provided a carrier unit for a portable resuscitation system, the carrier unit comprising

a base having an integral upstanding rear wall with side walls defining a rigid and at least partially open fronted enclosure, within which may be housed, in use; an oxygen cylinder with a manifold assembly mounted on and connected with the oxygen cylinder gas outlet, a suction device connected with the oxygen cylinder gas outlet through the manifold and driven by pressurised gas from the oxygen cylinder, a suction jar for receiving material collected by the suction device and oxygen supply means for delivering breathable oxygen.

Another object of this invention is to provide a carrier unit forming a portable resuscitation system incorporating one or more desirable and preferred features adapting the carrier unit to specific selected purposes.

It is another object of the present invention to provide a resuscitation system that is lightweight, totally portable, and further is adapted to facilitate its movement during transport and use in a range of trying environments, including dragging over a rough surface or difficult terrain and manoeuvring the system into difficult confined spaces.

To achieve this, it is an object of this invention is to provide a carrier unit forming a portable resuscitation system which is relatively streamlined. Thus, whilst it may incorporate one or more desirable and preferred features adapting the carrier unit to specific selected requirements, none of these provide anything that will snag on the environment in in-the-field situations, or otherwise hamper the movement and manoeuvring of the unit to and from the patient.

Another object of the present invention is to provide a modular construction such as to permit the modular attachment of particular features adapting the carrier unit to suit specific purposes.

To achieve this, it is an object of the invention that the carrier unit is provided with attachment points that can cooperate with such additional components to be attached to the carrier unit.

It another object that when such features adapting the carrier unit to suit specific purposes are absent, the attachment points that can cooperate with such additional components do not hamper the movement and manoeuvring of the system to and from the patient in a range of trying environments.

In order to meet the objectives, according to the present invention there is provided a portable resuscitation system comprising a carrier unit, a lightweight gas cylinder, a suction device driven by pressurised gas from the oxygen cylinder, a manifold through which pressurised gas will flow and which operatively connects the oxygen cylinder and the suction device, a suction jar for receiving material collected by the suction device, and oxygen supply means for delivering oxygen for breathing by a patient, the manifold being located on the carrier unit and all other components being directly located on the carrier unit or indirectly located on the carrier unit through the manifold, and the carrier unit being adapted to define a manual carrying handle, characterised by the presence of one or more features adapting the carrier unit to suit specific purposes.

The operation of such a system is described in our published patent specification no. GB 2 400 321 A (also published as WO 2004/0841 Al) for the portable resuscitation system described therein, and is broadly as follows:

When the need for a resuscitation system is realised, the system as a whole may be carried by means of a handle or other strapping to its site of use. The weight of the system, preferably about 6 kg, is light enough to be easily carried by any one person.

Once the site of use has been reached, the system is manoeuvred into close proximity with the person requiring resuscitation. This may involve difficult manoeuvring such as through an emergency site, such as a wrecked car, industrial plant or air or sea transportation. In such circumstances, its sturdy protective design, described further below, means that the more delicate equipment is protected from damage during such transport and manoeuvring even if it includes dragging over a rough surface.

Once in close proximity to the person requiring resuscitation, the medical personnel can use the breathing apparatus and suction apparatus in the conventional way by controlling both the rate of oxygen delivery and the suction.

Once the system has been used, and the patient hopefully resuscitated, the component parts that have been removed may be put back into the carrier unit and it may then be manoeuvred away from the patient.

A first group of portable resuscitation systems according to the present invention is characterised in that the one or more features adapting the carrier unit to suit specific purposes do not hamper the movement and manoeuvring of the system to and from the patient in a range of trying environments, including dragging over a rough surface or difficult terrain and manoeuvring the system into difficult confined spaces.

A sub-group of portable resuscitation systems according to the present invention is characterised in that the one or more features adapting the carrier unit to suit specific purposes do not extend beyond the unit by too great a degree or are retractable into the unit.

A second group of portable resuscitation systems according to the present invention is characterised by a modular construction such as to permit the modular attachment of particular features adapting the carrier unit to suit specific purposes.

A sub-group of portable resuscitation systems according to the present invention is characterised in that the carrier unit is provided with attachment points that can cooperate with such additional components to be attached to the carrier unit.

Another sub-group of portable resuscitation systems according to the present invention is characterised in that when such features adapting the carrier unit to suit specific purposes are absent, the attachment points that can cooperate with such additional components do not hamper the movement and manoeuvring of the system to and from the patient in a range of trying environments.

In all forms of the portable resuscitation systems according to the present invention, it is preferred that the carrier unit defines an at least semi-rigid enclosure within which at least some of the components are located to protect them from damage during transport and use of the resuscitation system.

Such a carrier unit protects the other components from damage caused during transport and/or use of the resuscitation system, and so must not only provide a support structure to which the manifold and other components can be attached (directly or indirectly) but also an effective shell around the relevant components.

This may be achieved in a variety of ways, but it is currently preferred that the carrier unit comprises a generally rectangular box with a base having an integral upstanding rear wall and side walls and a front part wall, defining a rigid and at last partially open-fronted enclosure with that has an open top. The part wall may extend over any proportion of the front face, the extent thereof controlling the amount of the box that is enclosed on five sides.

The carrier unit may also have a lid which fits over the open top and further protect the contents during transit. Such a lid may be of a complementary shape to the carrier unit and may slide thereover, or be hinged or pivoted to rotate to a closure position, and be held by appropriate catch mechanisms.

All such configurations are easy to construct, and also provide a secure space within which the other components can be located.

It is preferred that the carrier unit and lid if present are constructed from pieces of sheet material that if appropriate are integrally formed or connected together to form the box structure discussed above. Indeed it is preferred that the carrier unit and the lid if present are formed from aluminium sheet material or carbon fibre composite material as each offer excellent strength to weight ratios.

The enclosure that may be defined by the carrier unit can be totally rigid or it may be partially rigid with strong yet flexible material forming some parts. For example as discussed below the carrier unit may form part of a carrying container such as a rucksack. In such situations a protective enclosure may be formed in combination by rigid parts of the carrier unit and further flexible parts of the carrying container.

The resuscitation system may also be provided with an openable lid that can be shut when the system is not in use and opened when it is. Such a lid can be permanently connected to the carrier unit, and be openable by hinging, sliding or other mechanisms, or it might be totally removable from the carrier unit.

When in place the lid and carrier unit would substantially wholly contain the other components to protect them from damage. When the lid is open, the carrier unit may continue to protect at least a part of the components, but access to the resuscitation equipment is permitted.

It is preferred that the carrier unit and lid if present are constructed from pieces of sheet material that if appropriate are integrally formed or connected together to form the box structure discussed

The resuscitation system unit according to the present invention must be easily portable, and to assist this the carrier unit is provided with a handle. To assist one handed carrying, a single handle on an upper part of the carrier unit is preferred, e.g. at or near the upper end of the rear wall, or one or both of the side walls. It is preferred that the carrying handle is displaced or displaceable inwardly of such mountings to be relatively vertically, and preferably as nearly vertically as possible, above the centre or gravity of the fully laden unit. This arrangement provides better balance when transported by hand.

A permanently off-set handle offers better strength and relatively simple construction.

On the other hand, it may be desirable or preferred to adapt the carrier unit to not only be better balanced when transported by hand, but to provide an unobstructed upper space through which the other components can be loaded and unloaded. This may be achieved in a variety of ways.

For example as discussed above the carrier unit may have lid which fits over the open top and further protects the contents during transit, which may slide thereover, or be hinged or pivoted to rotate to a closure position. The handle may be mounted in a position on the lid such that in the closure position the handle is as nearly above the centre or gravity of the fully laden unit as possible.

Alternatively, one or two cooperating (preferably one) flip-down handles may be mounted on a suitable part of the internal surface of the rear wall and/or one or both side walls in such a way that it may be readily rotated into its use position. The mounting means may comprise hinging, pivoting, sliding or retractable arms that are configured and adapted to be latched or locked to hold them in a position as nearly above the centre or gravity of the fully laden unit as possible.

The latch may be able to hold them in several positions. For example, an arm may have a projection cooperating with several notches preventing its further rotation on an arcuate member mounted on a suitable part of the external surface of the rear wall and/or one or both side walls, with a clamp screw. Such an arrangement provides better balance for different weight distributions within the carrier unit when transported by hand.

A first group of portable resuscitation systems according to the present invention is characterised in that the one or more features adapting the carrier unit to suit specific purposes do not hamper the movement and manoeuvring of the system to and from the patient in a range of trying environments, including dragging over a rough surface or difficult terrain and manoeuvring the system into difficult confined spaces.

A sub-group of portable resuscitation systems according to the present invention is characterised in that the one or more features adapting the carrier unit to suit specific purposes do not extend beyond the unit by too great a degree or are retractable into the unit.

Thus, a first embodiment of the first group is characterised by the presence of one or more movable handles which are adjustable to be to be retained relatively vertically above the centre or gravity of the fully laden unit in use. To provide better balance when transported, it or they is/are preferably as nearly vertically as possible thereabove. As above, each may be mounted in or on any of the rear or side walls or a lid of the unit.

To assist use of the system in the field the carrier unit may either be part of, or may be mounted in, a rucksack or other manually portable carrying case.

A rucksack is particularly useful in situations were the resuscitation system must be carried a substantial distance or over difficult terrain where the carrier needs to keep their hands free.

When in a rucksack the carrier unit need be no more than a rigid generally flat plate. Such a base plate would preferably be of a size approximately the same as that defined by the components such that they do not extend off it by too great a degree. The rucksack could define the other parts of any enclosure or a box-shaped carrier unit could be located within a rucksack.

As a major intended purpose of the resuscitation system is in emergency situations, it may be required to manoeuvre the system into difficult confined spaces. To achieve this, the carrier unit may have a substantially flat face on which the system as a whole can be dragged. For ease this can be the rear surface of the carrier unit as this also assists mounting on a wall.

In its most basic form the base plate can comprise a rigid plate on one side of which the components are mounted. In such a version the reverse of the plate can serve as the surface for sliding.

Alternatively, the carrier unit may have two substantially flat faces on the junction of which the system as a whole can be dragged. For ease this can be the junction of the rear wall and the base plate, which may be rounded to serve as a better surface for sliding.

Notwithstanding the need to manoeuvre the system into difficult confined spaces in emergency situations, the unit may as above be kept in a static location, such as an emergency or first aid station in an industrial plant or air, land or sea transportation, from which the portable system for resuscitation needs to be moved to an emergency site. In such circumstances, at least part of the route from the emergency or first aid station to a use location may be over relatively easy terrain, such as the floor of a catwalk, corridor, passageway or walkway.

The carrier may wish to keep the (albeit slight) weight of the unit off their hands, e.g. if carrying other equipment, but not incur the extra effort in order to overcome the friction in sliding or dragging it over even a relatively even surface. The unit may therefore be provided with at least one, and preferably at least two, lightweight rolling means, e.g. a roller or wheel, for ready movement during transport and use.

However, such rolling means should not hamper the movement and manoeuvring to and from the patient in a range of trying environments. Thus, it is preferred that any such rolling means do not extend beyond the unit by too great a degree, or that they be retractable into the unit. Suitable rolling means include one or two (preferably one) pairs of rollers or wheels. These may be mounted on or in one or both of the rear wall or base of the carrier unit.

Often, one such pair is mounted on or in the junction of the rear wall and the base plate, which may be rounded substantially concentrically with the rolling means, and often towards opposite ends of the junction of the rear wall and the base plate.

Such rolling means may be installed in a permanent position, in which case it is preferred that they be recessed into the carrier unit, e.g. housed in complementary recesses in the carrier unit, and turning on axles or spindles that span the recesses into the carrier unit, such that the carrier unit can be still be readily dragged over a rough surface.

Alternatively, the rolling means, e.g. one or two (preferably one) pairs of rollers or wheels may mounted to turn on axles or spindles on arms that may be pivoted and/or slidably and/or retractably mounted on, e.g. the rear wall. Then, when the .arms are in their rest position, the rolling means are, e.g. housed in complementary recesses in the carrier unit, but the arms when required, can be rotated or slid to a use position outwardly, e.g. of the rear wall or the base plate of the unit, optionally with a cooperating spring bias and/or damping. They may them be returned to the rest position when the unit needs to be dragged over a rough surface, or when in use on a patient requiring resuscitation. Each may be locked in its use and stored positions.

Where the arms are slidingly retractable, the mounting means may comprise friction sliding sleeves housing the arms to govern lateral sliding of the arms to extend them outwardly of the unit.

In use, the unit may be towed on its rolling means by a handle. The unit is in a lower position than when being carried, i.e. supported on the ground, so that such a handle must be longer than the single carrier handle on an upper part of the carrier unit described above.

It may be advantageous to preserve the streamlining of the unit that the unit is provided with (usually) one extendable and retractable handle, to assist one handed towing. A single such handle on an upper part of the carrier unit is preferred, e.g. at or near the upper end of the rear wall. This may be a fixed telescopic towing handle or one slidably mounted on the unit. In either case, it is preferred that it is mounted on an inner face of the unit.

The towing handle may be a separate integer from the carrying handle described above, or they may be one and the same.

A first group of portable resuscitation systems according to the present invention is characterised in that the one or more features adapting the carrier unit to suit specific purposes do not hamper the movement and manoeuvring of the system to and from the patient in a range of trying environments, including dragging over a rough surface or difficult terrain and manoeuvring the system into difficult confined spaces.

A sub-group of portable resuscitation systems according to the present invention is characterised in that the one or more features adapting the carrier unit to suit specific purposes do not extend beyond the unit by too great a degree or are retractable into the unit.

Thus, a second embodiment of the first group is characterised by the presence of one or more rolling means which are installed in a permanent position such that they do not extend beyond the unit by too great a degree or are retractable into the unit.

The resuscitation system might also be destined for use in water and to assist in its support it may be further provided with an inflatable buoyancy device to support it for use in water. The buoyancy device may be normally stored in a deflated state, but may be inflated on manual activation of a switch or automatically activated on contact with water.

The present invention is in most occasions very stable when placed upright on a surface, but if the surface is uneven or if the centre of gravity of the whole system has been raised, for example by using an extendable drip support arm (described below), it may be advantageous to enhance the stability. Therefore the present invention may be further provided with one or more retractable stabilising arms on the carrier unit.

Not least because of its use on site in emergency situations, it is preferred that the carrier unit and lid if present are electrically non-conductive. This can be achieved using non-conductive materials for construction, e.g. high strength plastics, or by treating any conductive material to electrically insulate them.

For example aluminium sheet material could be powder coated, and carbon fibre composite could be manufactured to ensure an outer layer of non-conductive resin.

The resuscitation system may also be provided with a light or lights.

The purpose of the light will govern the details of their incorporation, but it is currently preferred that at least part of the handle is formed of translucent material and that a light is provided within the handle to shine out. Such a handle light could be directed generally downwards to illuminate the functional components of the resuscitation system. Also a flashing or signalling light such as a strobe may be provided, especially if the unit is at an emergency site.

These lights might aid in the location of the unit in the dark or obscured visibility conditions. A signalling light can be connected to the base or to an extension arm connected to the base or the rear or a side wall. (This may be an integer which is also a towing handle and/or a support arm for the portable resuscitation system in use - see below). A solar panel may also be provided to recharge a battery powering the light or lights.

A first group of portable resuscitation systems according to the present invention is characterised in that the one or more features adapting the carrier unit to suit specific purposes do not hamper the movement and manoeuvring of the system to and from the patient in a range of trying environments, including dragging over a rough surface or difficult terrain and manoeuvring the system into difficult confined spaces.

A sub-group of portable resuscitation systems according to the present invention is characterised in that the one or more features adapting the carrier unit to suit specific purposes do not extend beyond the unit by too great a degree or are retractable into the unit.

A third embodiment of the first group is characterised by the presence of one or more movable trays in or on any of the rear or sides of the unit. These are convenient in the operation of the first embodiment to provide a work surface when required. Such a tray may, e.g. be used for receiving ancillary materials and devices used in the course of the resuscitation.

Usually, such trays are mounted in or on or form part of at least one of the rear or side walls of the carrier unit. Alternatively (or additionally), such trays may be mounted on two side walls to span the rear wall, or on the rear and front part wall to span a side wall. Usually, only one such tray is mounted on one of the rear or side walls of the carrier unit. Often, one such tray is mounted on the rear wall of the carrier unit.

The trays may be sliding and/or folding trays that are stored within or against the relevant wall and may be deployed to provide a work surface when required, Such a tray might, when not in use, form part of the protective structure of the carrier unit.

Any of such trays may be flip-up trays, which at rest are normally folded down parallel to or in the plane of the relevant wall, but when required, can be rotated up to a use position, usually perpendicular to the relevant wall.

Alternatively, any of such trays may be flip-down trays, which at rest are normally folded up parallel to or in the plane of the relevant wall, but when required, can be rotated down to a use position, usually perpendicular to the relevant wall.

Such trays may be arranged to be dropped down or raised up and retained horizontally, either inwardly or outwardly of the carrier unit. To provide a more compact unit for transporting by hand, it is preferred that the or each tray if more than one are present are constructed to be dropped down or raised up and retained horizontally, outwardly of the carrier unit.

Where any tray that is provided is a folding tray, it is normally mounted in such a way that it may be readily rotated into its use position. The mounting means may comprise hinging, pivoting, sliding or retractable arms that are configured so as to cooperate with hinges, pivots, axles, spindles, dowels, pegs, rods, slots, holes and/or apertures in or on a suitable part of the external surface of the rear wall and/or one or both side walls

Thus, e.g. an arm may be pivoted and/or slidably and/or retractably mounted on a cooperating integer on each side wall, and a tray may span and unite the arms across the outward facing surface of the rear wall of the unit.

Alternatively, two arms may be pivoted and/or slidably and/or retractably mounted on cooperating integers on the rear wall, and a tray may span and unite the arms across its outward facing surface.

In either case, when the .arms are in their rest position, they tray is normally folded down or up parallel to or in the plane of the relevant wall. When required, it can be rotated up or down to a use position, usually at right angles to the rear wall.

If the tray is a flip-down tray, it may be so arranged that when dropped down, it is retained horizontally under gravity in abutment with part of the relevant wall, optionally with a, e.g. spring latch.

If the tray is a flip-up tray, it must be so arranged that when raised up, it is retained horizontally against gravity in some way. For example, the tray and or any the arms may be hooked over an external structure.

Alternatively (or additionally) the arms when extended may self-support automatically, using known mechanical mechanisms of a repeat-ratchet kind or a known form of "over-centre 1 mechanism.

Flip-up trays may also be provided with spring bias against gravity and/or damping and a spring latch to hold them in a retracted position.

Where any tray that is provided is a sliding or retractable tray, it is normally mounted in such a way that it may be readily slid into its use position. The mounting means may comprise friction sliding sleeves housing the arms of a tray such that lateral sliding of the arms would extend them outwardly, e.g. of the rear wall of the unit.

The portable resuscitation system of all embodiments of the present invention may in certain circumstances be advantageously connected to external structures. For example it might be wall mounted at an emergency or first aid station in an industrial plant or air, land or sea transportation, or on a ladder, part of a crash trolley or the side of a bed, in such a way that it may be readily accessible and then removed and carried to a use location as needed.

It is therefore preferred that the carrier unit or other relevant part of resuscitation system is further provided with attachment means to allow the carrier unit to be supported on an external structure. Such attachment means may take a variety of forms dependent on the item to which the system is to be attached, and the desired security/strength of that attachment.

The attachment means may comprise one or more hinging, pivoting, sliding or retractable arms, usually as a pair, that are configured to locate over a suitable part of the external structure when hinged, pivoted or extended outwardly from their non-use position.

The arm or arms may be shaped such that it or they will locate around a generally horizontal member of the external structure or (such as a railing, the rung of a ladder, part of a crash trolley or the side of a bed, or a support bar or rail on an external structure, such as a wall) and the unit will hang therefrom.

As described above for trays, usually, such an arm or arms are mounted in or on or form part of at least one of the rear or side walls of the carrier unit. Alternatively (or additionally), a pair of such arms may be mounted on two side walls on opposite sides of the rear wall, or on the rear and front part wall on opposite sides of a side wall.

The means are movable between a stored position and a use position, and stored within or against the relevant wall to ensure they do not get in the way when not in use, but may be deployed to provide an attachment when required.

The means may comprise any number or such arms, or pairs of such arms, which may be mounted on or in and/or extend across the rear wall or side walls of the carrier unit. The means may comprise a single arm, which may be mounted on or in or span the rear wall or a side wall of the carrier unit. This will usually be elongate across its direction of movement in use, and shaped such that they will locate around a generally horizontal member of an external structure. For example, the arms may partly or completely transversely span the external face of the rear or side walls of the carrier unit. However, usually, a pair of such arms is mounted on or in, or on a wall on opposite sides of, one of the rear or side walls of the carrier unit. Often, one such pair is mounted on the rear wall of the carrier unit.

The arm or arms are often towards the top end of the relevant wall of the carrier unit, so that when hooked over an external structure, the wall and/or the junction of the wall and the base plate rests against and is supported by part of the external structure over which it is located.

Where there is not a member of the external structure to do this, it may be desired for security of the attachment that the attachment means comprise two pairs of arms, one towards the top end of the relevant wall of the carrier unit, and the other towards the base plate and the bottom end of the relevant wall, so that both may be hooked over an external structure.

Alternatively (or additionally) the lower arms may be replaced by a simple fastener or restraint, such as a belt, strap, lashing or tie, so that the unit can be secured in a temporary fashion, especially at an emergency site.

Any of such means usually comprise flip-up arms, which at rest are normally folded down parallel to or in the plane of the relevant wall to ensure they do not get in the way when not in use, but when required, can be rotated outwardly up to a use position, usually perpendicular to the relevant wall.

If the means is a flip-up means, it may when raised up from its non-use position, be retained horizontally by the part of the external structure over which it is located, e.g. a generally horizontal member of the external structure (such as a railing, the rung of a ladder, part of a crash trolley or the side of a bed, or a support bar or rail on an external structure, such as a wall).

Flip-up means may also be provided with spring bias against gravity and/or damping and a spring latch to hold them in a retracted position.

Alternatively (or additionally) the arms when extended may self-support automatically, using known mechanical mechanisms of a repeat-ratchet kind or a known form of "over-centre 1 mechanism.

Less preferably, such means may be flip-down means, which at rest are normally folded up parallel to or in the plane of the relevant wall to ensure they do not get in the way when not in use, but when required, can be rotated down to a use position, usually perpendicular to the relevant wall.

Flip-down means are less preferred, since to support the carrier unit in their use position, they must be latched or locked to hold them in position, and the the latch or lock must be able to take the weight of the fully laden unit. Such an arrangement is inherently weak.

Where any means that is provided is a sliding or retractable means, it is normally mounted in such a way that it may be readily slid into its use position. The mounting means may comprise friction sliding sleeves housing the arms of a tray such that lateral sliding of the arms would extend them outwardly, e.g. of the rear wall of the unit.

A fourth embodiment of the first group is characterised by the presence of outwardly movable attachment means in or on any of the rear or sides of the unit to allow the carrier unit to be supported on an external structure, which attachment means comprise one or more movable trays.

As described in detail above, the means may comprise one or more hinging, pivoting, sliding or retractable arms that are configured to locate over a suitable part of the external structure when hinged, pivoted or extended from their non- use position. The arm or arms are configured so as to cooperate with hinges, pivots, axles, spindles, dowels, pegs, rods, slots, holes and/or sleeves in or on a suitable part of the external surface of the rear wall and/or one or both side walls.

Where the attachment means comprise a single, usually elongate, arm, that partly or completely transversely spans the external face of the rear or side walls of the carrier unit, the tray effectively is formed by the top surface of the arm when deployed to attach, and then provides a work surface when required. Such an arm/tray might, when not in use, form part of the protective structure of the carrier unit.

Usually, however, a pair of such arms is mounted on or in, or on a wall on opposite sides of, one of the rear or side walls of the carrier unit, and the tray effectively unites the top surface of the arm when deployed to attach, and then provides a work surface when required. Such a tray might, when not in use, form part of the protective structure of the carrier unit.

Any of such trays may be flip-up trays, which at rest are normally folded down parallel to or in the plane of the relevant wall, but when required, can be rotated outwardly up to a use position, usually perpendicular to the relevant wall.

Less preferably, for the reasons given above, such means and trays may be flip- down means or trays, which at rest are normally folded up parallel to or in the plane of the relevant wall to ensure they do not get in the way when not in use, but when required, can be rotated outwardly down to a use position, usually perpendicular to the relevant wall.

When treating a person using the resuscitation equipment provided by the present invention it may be desirable to use equipment that requires to be higher than the carrier unit, e.g. equipment that requires a pressure head to operate, such as a parenteral drip, e.g. infusion bags such as drips. To assist this, the present invention preferably is further provided with a support arm.

A first group of portable resuscitation systems according to the present invention is characterised in that the one or more features adapting the carrier unit to suit specific purposes do not hamper the movement and manoeuvring of the system to and from the patient in a range of trying environments, including dragging over a rough surface or difficult terrain and manoeuvring the system into difficult confined spaces.

A sub-group of portable resuscitation systems according to the present invention is characterised in that the one or more features adapting the carrier unit to suit specific purposes do not extend beyond the unit by too great a degree or are retractable into the unit.

A fifth embodiment of the first group is characterised by the presence of a movable equipment support arm mounted within and extendable from and retractable into the unit.

In the operation of the resuscitation system, this support arm may conveniently be extended upwardly of the unit, and used to support equipment that requires to be higher than the carrier unit, e.g. equipment that requires a pressure head to operate, such as a parenteral drip, e.g. infusion bags such as drips.

When retracted into the unit, the support arm is protected from damage during transport and manoeuvring even if it includes dragging over a rough surface, and it does not snag on the environment or otherwise hamper the movement and manoeuvring of the unit to and from the patient requiring resuscitation. Once the device has been used, and the patient hopefully resuscitated, the drip support arm is retracted into the unit.

Such a support may also be used for other ancillary materials and devices used in the course of the resuscitation.

The arm may be pivoted and/or slidably mounted on a cooperating integer on an inward facing surface of the rear wall or a side wall of the unit. The arm may be a rod of constant cylindrical cross section. It may be a solid rod or a tubular rod.

The rod may be slidably mounted in one or more cooperating female integers on the rear or a side wall, in which it may be selectively locked in its use and stored positions, e.g. by a clamp screw.

Alternatively, the arms may be pivoted on mounting means on the rear or a side wall. The mounting means should be configured and adapted to be latched or locked to hold the arm in its rest and use positions. For example, an arm may have a latching projection cooperating with a notch preventing its further rotation on a member mounted on an internal surface of the rear wall and/or a side wall, or a clamp screw.

Where the rod is a tube, it may also be telescopic, and held in its extended use position by sliding friction between the telescopic sleeves, and/or locked by a clamp screw.

When used as a drip support arm in the operation of the system, the arm is conveniently provided at or towards its top end with one or more hooks, such that infusion bags such as drips can be hung from them. The position of the hooks may be adjustable to allow infusion bags such as drips can be hung from the hook(s) relatively vertically above the centre or gravity of the fully laden unit in use. To provide better balance when in use, it or they is/are preferably as nearly vertically as possible thereabove.

As described above, it may be advantageous that the unit is provided with (usually) one extendable and retractable handle, to assist one handed towing. It may be advantageous to preserve the lightness and the versatility of the system that the unit is provided with one extendable and retractable integer which is both a towing handle and a support arm.

The portable resuscitation system in use may not be supported on an external structure, e.g. by attachment means as described above, and may be used on the ground resting on its base. When supported on the base panel, and especially if the support arm is extended, the stability of the unit may need enhancing. Therefore, a retractable stabiliser arm may be provided e.g. at the bottom of the front part wall. Similar further stabiliser arms may be provided on the rear and/or side walls.

A second group of portable resuscitation systems according to the present invention is characterised by a modular construction such as to permit the modular attachment of particular features adapting the carrier unit to suit specific purposes.

A sub-group of portable resuscitation systems according to the present invention is characterised in that the carrier unit is provided with attachment points that can cooperate with such additional components to be attached to the carrier unit.

Another sub-group of portable resuscitation systems according to the present invention is characterised in that when such features adapting the carrier unit to suit specific purposes are absent, the attachment points that can cooperate with such additional components do not hamper the movement and manoeuvring of the system to and from the patient in a range of trying environments.

A first embodiment of the second group is characterised by the presence of one or more further ('second, third, etc') carrier units which are removably mounted on the ('first') carrier unit.

Such further carrier units which are mounted on the first carrier unit are modular extensions of the first carrier unit, which together with the first carrier unit form a single larger unit.

This can be moved manoeuvred to and from the patient in a range of trying environments, including being carried, towed, dragged over a rough surface or difficult terrain and manoeuvred into difficult confined spaces by the carrier and/or towing handle(s) mounted on the first carrier unit.

These modular extensions may be used as extra storage compartments to house extra components such as a further gas cylinder (in particular an oxygen cylinder) and spare parts and ancillary equipment used in the course of the resuscitation, such as breathing tubes or airways.

The use of gas driven suction in the system obviously increases the rate of gas use. Therefore to prolong the supply of oxygen, in resuscitation systems according to the present invention, especially those designed to be used far from medical support, it may be preferred to further provide a manual suction pump to supplement the gas driven suction device. This can be stored and/or transported within a further carrier unit.

It may also be appropriate to increase the amount of pressurised gas supplied within the system, such that longer periods of use can be undertaken. Such extra cylinders could contain extra oxygen or might instead have other medical gasses such as the anaesthetic sold under the trade mark Entonox, or analgesics.

Such further carrier units which are mounted on the first carrier unit will usually have a similar or the same general nature and shape as the first unit units. That is, it is preferred that each further carrier unit comprises a generally rectangular box with a base having an integral upstanding rear wall and side walls and a front part wall, defining a rigid and at last partially open-fronted enclosure with that has an open top. The part wall may extend over any proportion of the front face, the extent thereof controlling the amount of the box that is enclosed on five sides.

Each further carrier unit may also have a lid which fits over the open top and further protect the contents during transit. Such a lid may be of a complementary shape to the carrier unit and may slide thereover, or be hinged or pivoted to rotate to a closure position, and be held by appropriate catch mechanisms.

They may be mounted on any convenient position on the first carrier unit, and may be connected thereto by any suitable means. Usually, such further carrier units are mounted on at least one of the rear or side walls of the unit, leaving the front free.

If the rear is provided with a substantially flat face or a junction of the rear wall and the base plate, which may be rounded to serve as a better surface for sliding, on which the system as a whole can be dragged, rolling means, e.g. rollers or wheels for ready movement during transport and use, or attachment means to permit attachment of the resuscitation system to an appropriate external structure, then it may be desired to leave the rear wall free. One or both side walls of the first carrier unit may then be used to mount further carrier units on the first carrier unit.

To provide better balance when transported, two further units should be mounted, one on each side wall, that are preferably as nearly equal in weight and lading as possible.

The relevant, e.g. side walls of the first carrier unit are provided with means to permit attachment of such further modules. These include so-called mushroom pegs on either of the first or second/third units, which engage in respective keyhole slots formed in the second/third units or first unit, as appropriate.

If more robust attachment to the first carrier unit is required than can be provided by mushroom pegs, then the one (set of) units may, e.g. be provided with short threaded set-pins with quick-release, e.g. half-turn butterfly nuts that engage holes or slots in the other (set of) units. The means to permit attachment of further modules will usually have a number of locations at the respective top and bottom of the relevant faces as appropriate of the carrier unit units.

In order to meet an object of the present invention that the first carrier unit for a portable resuscitation system remain relatively streamlined, the means to permit attachment of such further modules should not provide anything that will snag on the environment in in-the-field situations, or otherwise hamper the movement and manoeuvring of the unit to and from the patient. It is therefore preferred that the male members of such means to permit attachment are on such further modules, including the mushroom pegs and set-pins, are on the second/third units.

A second group of portable resuscitation systems according to the present invention is characterised by a modular construction such as to permit the modular attachment of particular features adapting the carrier unit to suit specific purposes.

A sub-group of portable resuscitation systems according to the present invention is characterised in that the carrier unit is provided with attachment points that can cooperate with such additional components to be attached to the carrier unit.

Another sub-group of portable resuscitation systems according to the present invention is characterised in that when such features adapting the carrier unit to suit specific purposes are absent, the attachment points that can cooperate with such additional components do not hamper the movement and manoeuvring of the system to and from the patient in a range of trying environments.

A second embodiment of the second group is characterised by the presence of a component of the resuscitation system which is readily removably mounted on the carrier unit. By 'readily removably mounted' herein is meant that a component of the resuscitation system is securely fastened to the carrier unit structure in a use position without being clamped positively into place, but is readily removable when necessary.

These components include a pressurised gas (usually oxygen) cylinder, optionally in a removable holder, a manifold assembly mounted on and connected with the oxygen cylinder gas outlet, a suction device connected with the oxygen cylinder gas outlet through the manifold and driven by pressurised gas from the oxygen cylinder, a suction jar for receiving material collected by the suction device, optionally in a removable holder, and oxygen supply means for delivering breathable oxygen.

They may be mounted on any convenient position on the first carrier unit, and may be connected thereto by any suitable means. Usually, such components are mounted on at least one of the rear or side walls of the unit, often the rear wall, leaving the front free.

The relevant, e.g. rear, wall(s) of the carrier unit are provided with means to permit attachment of such components.

These include so-called mushroom pegs on either the component or the wall of the unit, which engage in respective keyhole slots formed in the wall of the unit or the component. If more robust attachment to the first carrier unit is required, the slots may be provided with clips or latches to retain the heads of the mushroom pegs in the slots in the wall of the unit or the component.

Alternatively, the means to permit attachment of such components may be annularly-grooved pegs on either the component or the wall of the unit, which extend through holes formed in the wall of the unit or the component, and are retained with clips fitting into the groove in the pegs.

A component of the resuscitation system which is readily removably mounted on the carrier unit may constitute a means by which another item of a unit is indirectly securely fastened to the carrier unit structure.

Thus, for example if the manifold is designed to be removably mounted in such a way, it also serves to locate and/or mount the gas / oxygen cylinder within the carrier unit. If connected up to the manifold, other equipment such as the face mask, oxygen supply tube and suction tube may be indirectly secured. For this reason, it is advantageous and preferred to secure the manifold.

Similarly, the gas / oxygen cylinder and/or the receiver jar may each sit in and/or be embraced by a holder or enclosure that is readily removable for replacement of its contents simply e.g. disengaging a peg from its keyhole slot. Thus, a holder that is removably mounted in such a way, it also serves to locate and/or mount the gas / oxygen cylinder and/or receiver jar within the carrier unit.

Additionally, the enclosed space defined by the unit may be divided by one or more inner panels or bars, which would section off regions into which the gas / oxygen cylinder and/or the receiver jar may each sit in and/or be embraced and could securely locate by vertical sliding. Such panels and/or bars are also means to permit readily removably mounting of a component of the resuscitation system by which it is securely fastened to the carrier unit structure in a use position without being clamped.

Such panels and/or bars may also be advantageously readily removably mounted in the resuscitation system, e.g. a bar may have a head at one end and extend through holes formed in the front and rear wall, and be retained by gravity and/or clips.

A carrier unit forming a part of a portable resuscitation system in accordance with this invention is described and illustrated with reference to the drawings, showing embodiments by way of example only.

Figures 1a, 1b and 1c show a perspective view and side views of a carder unit forming a portable resuscitation System Figure Id shows the front view.

Figure 2 shows the carrier unit of Figure 1 with an added cylinder retainer means,

Figure 3 shows the carrier of Figure 1 with the drip support extended,

Figure 4 shows the carrier including selected resuscitation equipment, and

Figure 5 shows in detail the manifold assembly.

Referring to Figures 1 to 3 of the drawings the carrier unit is shown without items of resuscitation equipment. The carrier unit comprises a base 1 having an integral upstanding rear wall 2 with side walls 3 and 4, the whole defining a rigid and at least partially open-fronted enclosure. The upper side of the rear wall Z has a carrying handle 5 which is displaced inwardly and mounted by two lugs 5a. This arrangement provides better balance when transported by hand.

The front of the unit is closed by a panel 6 in combination with a drop-down panel 7 which forms a tray (as shown in Figs 1a and 1b) or when raised (Fig 1c) a close-off to the front to aid protection of the internal contents.

The tray 7 is hinged by a pin 7a and slot 7b at each side whereby the tray may be raised to position coplanar with the panel 6 and then allowed to drop with the top edge of panel 6 engaging slots 7c at each side to retain the tray 7 in the raised position.

The tray is lowered by lifting to disengage the edge of panel 6 from slots 6c, thus allowing the tray to pivot outward and to be retained horizontally by abutment with the top edge of the panel 6.

The carrier includes a holder 8 to embrace an oxygen, or other gas or fluid, bottle and a cross-bar 9 to prevent sideways displacement of the holder 8. The bar 9 is of constant circular-cylindrical cross section. It may be a solid bar or a tubular bar. In this particular embodiment each of its opposite ends is riveted to the respective front and rear wall.

The rear wall 2 has hook members 10 disposed at each side and pivoted at 10a to each respective side wall 3 or 4. The hook members are shown in a retracted position in Fig 1 , but maybe pivoted outward to the positions shown in Fig 1 b enabling the carrier to be attached to a horizontal bar of a trolley, wheel chair or bed as example.

A tray "T" effectively unites the flip-up arms 10 by spanning the width between the arms and is a flat metal sheet welded at each of its opposite ends one of the arms.

As shown in figure 1a the tray lies flat and adjacent to the outward facing surface of the rear wall of the unit when the arms 10 are in their retracted position. When the arms are extended as shown in Figure 1b then the tray T lies substantially horizontal (as shown in Figure 1b) and projects, as do the arms 10, at right angles to the rear wall. If the arms are hooked over a support then the tray T can be used as a shelf for various purposes. Alternatively (or additionally) the arms 10 when extended may self-support automatically, using known mechanical mechanisms of a repeat-ratchet kind or a known form of "over- centre 1 mechanism.

The side wall 3 includes a support 11 for a tube 12 having a carrier 13 to retain a drip bag or bottle. The tube can be extended upward from the position shown in Fig 1a to that shown in Fig. 3 and can be retained in a selected position by clamp screw 14. The tube 12 (which may be telescopic) is hidden in its support 11 on the inside of the unit as shown in figure 1a.

Fig.2 shows a second oxygen bottle holder 8a attached to the side wall 3. So- called mushroom pegs "M 1 ; have respective top and bottom locations indicated in Figure 1a.

These pegs (not visible in Figure 1a) project from the back face of bottle holder 8 and their shape is similar to that shown in Figure 5 under reference number 56. They engage in respective keyhole slots formed in the back face and side face, as appropriate, of the carrier unit.

The rear wall 2 includes a plurality of keyhole slots 20, which cooperate with mushroom headed pegs on items of apparatus to be attached and to be included in the carrier unit. Keyhole slots 21 are also provided in one or both side walls 3 and 4. The carriers 8 and 8a each have two mushroom pegs on the rear to engage slots on the rear wall 2 and the side wall 3 respectively.

Fig. 5 shows a manifold assembly 50 which operatively couples with the gas outlet 15 (not shown in detail) on the top of an oxygen bottle by means of a spear (or so called Schrader connector 51. A gas:-flow control valve 52 and pressure gauge 53 are included with a gas supply tube connect-or 54 and regulator unit 55. A mushroom headed peg 56 provides means for connecting the manifold to the back wall 2 using one of the keyhole slots.

The manifold is located in but can easily be removed from the rear wall 2 without any clamping arrangement being necessary. When the peg 56 is engaged with slot 21a, and the manifold 50 coupled with the gas bottle outlet 60, the whole manifold and bottle assembly is firmly located in and connected to the carrier unit but nevertheless readily removable for replacement simply by disengaging the peg 56 from its keyhole slot 20a.

In use, a pressurized oxygen cylinder with a manifold assembly mounted thereon and connected with the oxygen cylinder gas outlet is located in the carrier unit 8, as shown in Fig, 4, and retained by the peg 56 locating in a slot 20a as described. A plunger valve "P" connects selectively the tube 54 with oxygen cylinder gas outlet through the manifold 50. A suction jar for receiving material collected by the suction device is located in the carrier adjacent to the oxygen cylinder and this includes oxygen supply means for delivering breathable oxygen to a mask or cannula (not shown).

The carrier unit thus includes means to permit readily releasable connection of the manifold to the rear wall of the carrier unit, and a readily releasable holder 8 for locating the oxygen cylinder and the bar 9 to prevent displacement of the oxygen cylinder within the carrier; the bar 9 also serving to locate and retain the suction receiver jar.

In a modification, as shown in Fig. 4, the drip support tube and mounting assembly 11 , 12, 13, 14 is repositioned and located on the rear of the back wall 2 and a fold-out stabilising arm 46 is included at the base of the front panel 6.

In addition to the keyhole slots formed at various illustrated positions in the rear wall and in each side wall of the unit, other slots in the form of generally T- shaped cut outs are provided. Those in the back wall of the unit are reference "K" in Figure 1d. Identically shaped ones are formed as shown in each opposite side wall 10.

These T-shaped cut outs allow optionally for straps to be used so that the unit can be carried back-pack fashion, Even if straps are not so used, the large number of cut outs in the unit as a whole lessen its overall weight and this is important in context given the way the unit will be used .

Even the front wall 6 has cut outs and these consist, firstly, of horizontal paired slots S (figure id referenced) and secondly of two clockwise-orientated stylised arrows in combination .with the cut out letters "RSM" (again, see Figure 1d for the references).

These last-named cut outs S thereby constitute simultaneously a way of lessening still further the weight of the unit whilst cleverly displaying one trade mark (RSM) and the stylised clock wise-moving twin arrows device under which the unit may in commercial reality may sold.

This permanent cutting of the trade mark into the unit could be extremely important, again in context, when one considers that these units may habitually come to be referred to as (for example "RSM" units and the altogether more conventional trade mark labelling or stencilling practice could easily be distorted, damaged, or rubbed off altogether in the sorts of conditions under which these units will see service. It could be literally the difference between life and death if these marked units are instantly and permanently recognisable.