GB2177595A - Traction device for beds - Google Patents

Abstract

A bed comprises a plurality of inflatable, transversely arranged air sacs adapted to provide a patient supporting surface in normal use, wherein at least the air sacs forming the head and thorax sections of the bed are partially filled with blocks of material capable of providing a substantially flat supporting surface for the head and thorax of the patient in the event of collapse of the air sacs. The blocks are normally made from foamed plastics or rubber and are dimensioned so as to extend between about 50 and 70% of the inflated height of an air sac and to substantially fill the inflated thickness of an air sac. <IMAGE>

Description

SPECIFICATION Traction device for beds This invention relates to support appliances ofthe kind which are formed from a plurality of inflatable air sacs. One commerically successful support appliance ofthis kind is known as the low air loss bed and is described in various embodiments in British Patents Nos. 1,442,994, 1,474,018 and 1,601,808. The low air loss bed utilises up to about 21 transversely arranged air sacs, which are preferably constructed from water vapour permeable material, enabling watervapour generated in the vicinity of the patient's skin to be removed by transpiration through the air sac material and flushed away in the airflowing through the air sacs.

The low air loss bed has been shown to be very effective in the nursing of seriously sick patients, particularlythose suffering from bed sores, or whose condition would otherwise make them very liable to incur such afflictions. There is one class of patients, however, who upto now could not be nursed on beds formed from air inflated sacs and these are patients suffering from spinal injuries. The problem here is that, for such patients, it is essential that theirspine and neck are maintained in an accurately defined direction. It would not be possible, however, to ensure this if they were nursed on an air bed, since failure ofthe air supply would result in collapse ofthe sacs and loss ofthe defined supported surface.

However, patients with spinal injuries, are an important class of patients who would benefit from nursing on bedsofthis kind,sincetheirinjuries requirethat they lie essentially immobile for long periods and this puts them at great risk of incurring pressure sores.

According to one aspect of the present invention, therefore, there is provided a support appliance, com- prising a plurality of inflatable, transversely arranged airsacs,wherein at leastthe airsacs forming the head section ofthe appliance are partially filled with blocks of material capable of providing asubstantiallyflat supporting surface for the head and thorax ofthe patient, in the event of an interruption in the air supply.

It has been found that, if generally rectangular blocks of material are inserted in each of the air sacs, forming at least the head section ofthe bed, the patient can be adequately supported, even when the bed is in a deflated condition while still maintaining adequate control overthe cervical area of the patient.

In the deflated condition, the patient's head and thor axfalls onto the blocks of material inside the airsacs and provides safe support until the ain supply can be restored. Thus, the patient is able to enjoy the comfort and benefit of nursing on a bed having differentially pressurised air sacs, without running the risk of dis- placement of the spine in the event of a powerfailure ieading to loss ofairsupply.

Another purpose of partially filling the sacs with blocks of foam, which is not necessarily related to nursing patients with cervical injuries, is when transporting patients from one area in a hospital to another. In such cases, the air support appliance has to be disconnected from its power source and the air sacs rapidly deflate. However, by using air sacs which contain blocks of foam, as described herein, the patient can be supported on the foam blocks during transit or while the bed is disconnected from its exter nal power source.

The blocks of material contained within the air sacs, are conveniently made from polyurethane foam and shaped to fill the inflated thickness ofthe air sacs. The blocks of material such as polyurethane foam extend in height between about 50% and 70% of the inflated height of the air sac, so that in the inflated condition, the head and thorax is supported, at least partly, by the air in the partially filled sacs.

As is necessary in the nursing of spinal injuries, the patient is maintained undertraction, by a harness passing around the patient's chin, and traction maintained by weight supplied to a lanyard passing over a pulley at the head section ofthe bed. In accordance with a preferred feature ofthe invention, traction is maintained by a traction unit, comprising a frame attached to the head-board and including a pulley for the lanyard and a catch to ensure the head section of the bed cannot be raised while the traction unit is in use.

One embodiment ofthe present invention will now be described, with reference to the accompanying drawings, in which: Figure 1A is a perspective view of a low air loss bed, showing the traction unit in place, Figure 1B is an enlarged view of part ofthetraction unit showing the catch in position which ensures that the head section can not be raised, Figure2 shows a side elevation of one air sac, showing in ghosted lines, a block of supporting material within, Figure 3 shows a section taken along the line A-A in Figure 2.

Referring to Figure 1 of the drawings, the bed 1 is of the same general kind as described and illustrated in the drawings of British Patent No. 1,474,018, consisting of a number of air sacs 2, which are inflated by an airsupplyfed to the sacs via longitudinal tubular members 3, extending beneath the sacs 2. The air sacs are pressurised to differential pressures, the precise pressure in each group of sacs being determined by the weight of the patient and the part of the patient's body impinging on the particular section. In the view illustrated in Figure 1, the head section of the bed is divided into a head and neck supporting section 4, a thorax supporting section 5 and a seat sec- tion 6.The remaining sections of the bed are not shown in Figure 1.Sections 4, 5 and 6will be inflated to different pressures and maintained at such pressures with a controlled throughput of air as described in British Patent No. 1,601,808. Attached to a head board 7 is the traction unit which comprises a parallelogram frame 8 rigidly connected at its lower end 9to a bar 10, attached to the head-board 7. The headboard 7 conveniently has projections which slot into receiving sockets 11 attached to the frame of the bed.

Abarortube 12,carrying a pulley (not shown) can be mounted in any of the recesses 13, formed in the frame 8 of the traction unit. In use, a harness is placed around the chin ofthe patient and is attached via a lanyard passing around the pulleytoasuitable weight. In this way, a traction can be maintained on the cervical area of the patient.

As described in British Patent No. 1 ,474,018,the low air loss bed will normally be provided with means for raising the head and thorax sections 4 and 5, However, as such movement cannot be permitted when nursing a patient suffering from spinal injuries, means are provided on the traction unitfor locking the head section ofthe bed. For this purpose, the traction unit is provided with a latch 14, shown more clearly in Figure 1 b. The latch 14comprises a hook 15 arranged to engage with the frame 16 of the undercarriage of the bed and thereby prevent the sections 4 and 5 being raised if the bellows at the head ofthe bed are inadvertently operated. The hook 15 is pivotably mounted on the unit 8 but can be locked in position by a spring loaded pin 17.

The construction ofthe modified air sacs is shown in Figures 2 and 3. Within each air sac 2, is a rectangular block of foamed plastics or rubber material 18, which in the particular example illustrated, extend about 60% of the inflated height ofthe air sac 2. As can be seen from Figure 2, the block 18stopsshortofthe tubular inletfitting 19 and outlet fitting 20, so as notto impede the flow ofairinto and out of the bag in normal use. The block of material 18, however, fills the entire thickness of the sac, as can clearly be seen from Figure 3.This means that when the air sac is deflated, a substantially flat surface is formed bythe contiguous surfaces 21 of the tops of the blocks 18, and this provides a suitable baseforsupporting the patient. The width of the frame is such as notto restrict the air inlet and exhaust holes 20. The blocks of material 18 can be inserted into the air sacs through a zip 22 of a nylon of substantially air-tightconstruction. The blocks offoam are enciosed in a membrane of air-impermeable material such as the plastic sold underthetrade mark "Piatilon",the seams of which are welded to envelopthefoam in an air impermeable membrane. This prevents fluids being absorbed and retained within thefoam.

Although in the particular embodiment, only the head and thorax section have been described as being partiallyfilled with blocks offoam material, it is within the scope of the present invention to provide beds in which all the air sacs contain blocks of foam material. It may be advantageous in the seat section ofthe bed,to provide blocks of material which are V-shaped when seen in the direction shown in Figure 2, so as to provide a greater depth of air cushion in this region. It may also be desirable to vary the height ofthe blocks depending on the weight of the part of the patient's body in that region. It may also be advantageous to provide air sacs which are partiallyfilled with foam blocks for other purposes than nursing or patients with spinal injuries. Forexample,where there is a reduced airsupply,the reduction in the effective volume of the sacs will partially compensate forthis. Generally, when foam blocks are used to fill the sacs, a foam of semi-rigid nature is preferably used so that a firm, flat base will be provided on deflation ofthe sacs. Thus, cardiac resuscitation procedures can becarried out in an emergency on rapidly deflating the sacs.

It will be appreciated that by providing access through the air sacs via the zip 22, the blocks 18 can be replaced and blocks of different heights or shapes inserted.

Claims (6)

1. A bed which comprises a plurality of inflatable transversely arranged air sacs adapted to provide a patient supporting surface in normal use, wherein at least the air sacs forming the head and thorax sec- tions of the bed are partiallyfilled with blocks of material capable of providing a substantially flat sup- porting surfaceforthe head and thorax ofthe patient in the event of collapse of the air sacs.

2. A bed according to claim 1 in which the blocks are dimensioned so as to extend between about 50 and 70% of the inflated height of an air sac and to substantially fill the inflated thickness of an air sac.

3. A bed according to claim 1 or claim 2 in which the blocks of material are formed from foamed plastics or rubber.

4. A bed according to any one of the preceding claims in which the blocks of material are enveloped and sealed in a sheet material which is impervious to gases and liquids.

5. A bed according to any one ofthe preceding claims which includes a traction unit, comprising a frame attached to the headboard of the bed for supporting a pulley and aweightto provide traction to the patient's spine.

6. A bed according to claim 5 in which the head section of the bed includes a latch for selectively locking the head section to the base while the traction unit is in use.