EP0799010A1

EP0799010A1 - Device intended in particular for the prevention of pressure sores

Info

Publication number: EP0799010A1
Application number: EP95936504A
Authority: EP
Inventors: Albrecht Hörlin
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-10-16
Filing date: 1995-10-16
Publication date: 1997-10-08
Anticipated expiration: 2015-10-16
Also published as: DE59507448D1; EP0799010B1; DE4436652C1; DK0799010T3; ES2139946T3; ATE187634T1; WO1996011659A1

Abstract

The invention concerns a device intended in particular for the prevention of pressure sores and for treating shock lung. The device is fitted on the underside of a patient's bed and comprises a drive unit actuated by a motor and capable of imparting to the bed frame a precessional motion about the drive unit. The drive unit can be a bearing cage or gear mechanism. As a result of the particular design of elements incorporated in the drive unit, which generate a motion at an angle to the parallel plane of the bed frame, the bed frame is made by the drive unit to move in a precessional path about the drive unit. The drive unit can impart a minimal precessional motion to the bed frame and by so doing can ensure that the position of a bedridden patient undergoes constant tiny adjustments. This prevents the patient from developing pressure sores and, in the treatment of shock lung, allows those alveolar structures in the lung which are still intact to remain aerated. Peripheral or stop elements ensure that the frame is secure during its excursion from its horizontal position as it executes precessional motion and limit the excursion amplitude.

Description

Device, in particular for pressure ulcer prophylaxis

DESCRIPTION

The invention relates to a device at the bedside, in particular for decubitus prophylaxis.

Seriously ill patients are usually considerably restricted in their mobility in the bed. Paralyzed patients in particular (paraplegia, stroke) are either hardly or not at all capable of self-mobility. You lie more or less motionless in bed. The consequence of this is that the points of contact of her body on the bed surface, as a rule the sacral area, the heels and the shoulders, never change, unless by external force.

In the area of a support point, the bone presses the skin above it onto the support surface. The skin is compressed to a certain extent so that the blood flow in this area is restricted or suspended. As a result, there is an undersupply of oxygen, hypoxia or anoxia in this circumscribed area. If this situation persists for a long time - just a few hours are enough - there are circumscribed tissue defects with cell dying (necrosis), the pressure ulcer.

If treated insufficiently, the patient can become infected (e.g. through hospital germs). It is not uncommon for sepsis to occur, which can lead to death, particularly in seriously ill and thus defensively weakened patients.

Depending on the extent and stage of the increasingly progressive process, therapeutic measures are on the one hand the surgeon see restoration of the necrotic area, on the other hand the nursing treatment with intensive skin care, antibiotic local therapy, massage and last but not least the constant repositioning of the patient to protect the affected area and keep it vital. These measures require a high level of personnel, time and money, which is sometimes only insufficiently carried out mainly due to a lack of personnel.

In addition to the therapeutic measures that are inevitable in the case of a pressure ulcer, there is therefore a great need for measures that can prevent the development of pressure ulcers from the outset.

The case is similar in the treatment of shock lung (RDS = adult respiralory distress syndrome). This clinical picture causes a so-called membrane hydro, due to the shock. the interalveolar septa in the lungs are massively thickened by edema fluid, fibrin, inflammable infiltrates and finally connective tissue formation, so that gas exchange with the alveoli is no longer possible. There is an internal suffocation (respiralory distress). Therapeutic ventilation must be provided, which of course only makes sense if intact alveolar structures are still accessible for ventilation. In order to optimally ventilate these areas in the lungs, as has already been shown, it is advantageous to keep changing the position of the body and thus the lungs. Appropriate patients are now also ventilated in the prone or lateral position. This leads to conceivable nursing problems.

A movement bed is known from the area of the "Feldenkrais Method", which can perform certain movements and transfer it to the patient. For example, German published patent application DE 38 00 496 discloses a movement bed to support the so-called "Feldenkrais method". Here is supposed to O 96/11659 3 PC17EP95 / 04061

Improvement in muscle tone and physical and psychological relaxation can be achieved by the patient standing, sitting or lying down using various relatively gentle movements, such as slowly, alternately lifting the arms or legs, slightly rotating the trunk and the like same, either carried out by yourself or can be carried out passively by the teacher. In order to achieve slight twisting of the spine and counter-movements of the extremities on both sides, the mattress frame twists oscillating about its longitudinal central axis. This simulates movements or movement sequences that usually occur with natural movements. A movement transmission from the bed to the person inside is achieved with the aid of a drive which puts the mattress frame, which is composed of a large number of moving parts, into a very complex movement sequence.

This bed with a suggested period of torsional movement of 3 to 20 seconds is not suitable for decubitus prophylaxis or for the treatment of shock lung, since such a short period would be perceived as annoying in the long run.

Another type of mobile bed is provided in the German patent application DE 42 39 942 for the treatment of sleep disorders. In order for this to be set into a rocking motion, however, it must be suspended from the ceiling in the manner of a hammock, which makes its use in the inpatient clinic area practically impossible.

Especially for pressure ulcer prophylaxis and therapy of the shock lung, attempts have already been made to replace the costly and time-consuming manual repositioning of the bedridden patient with an automatic repositioning. This is currently achieved using water, air or foam-filled special mattresses, some of which are available on conventional cranes core beds, but some are only available integrated in special beds. They have movable elements or chambers that can be filled with air and water, which are controlled by a central unit or pump via a complex mechanism or valve control in such a way that there are constant changes in the contact surface and thus the contact points of the patient lying on such a mattress.

A disadvantage of these known models is that the bedridden patient is unacceptably impaired by them. He is disturbed on the one hand by the not inconsiderable noises of these drives / pumps, and on the other hand by the vibrations triggered by them and prevented from sleeping. This is also due to the often disproportionately large deflections of the support surface, which cause the known devices for decubitus prophylaxis, and by which the patient literally

is "rocked". In addition, these systems are very complex and, in addition to the expensive special mattresses, have a large number of maintenance-intensive components such as pumps, controls, valves, lines and seals. Another disadvantage is that these special beds or special mattresses require special disinfection treatment and cannot be treated in the usual way in the disinfection spray room, since the maintenance-intensive components have to be protected against the ingress of disinfection liquid. This, in turn, results in additional labor, increases costs and is also very time-consuming.

The present invention seeks to remedy these disadvantages. On the basis of this prior art, the object of the invention is to provide a device, in particular for pressure ulcer prophylaxis, by means of which a bed-ridden patient is constantly shifted in position almost imperceptibly for him, without the patient being disturbed by noises or fibrations that are immediately available when needed, i.e. without changing the patient's bed, and so on is compact and expediently designed so that it can be manufactured at low cost and can also be integrated into a conventional bed to save costs. Furthermore, this device should be designed in such a way that a sick bed equipped with it can usually be disinfected in the disinfection chamber.

According to the invention, this object is achieved by the teaching of claim 1. Further embodiments of the invention are the subject of the dependent claims. According to the invention, a device which can be mounted on the underside of a bed frame is proposed, which is characterized by a drive device which is arranged essentially symmetrically around the center of gravity of the bed frame, support and patient and through which the bed frame or the surface normal onto the bed frame in a precession movement can be offset around this drive device.

It has been observed that even minimal movements, such as those of healthy people, even if they are completely alcoholized, during sleep represent a sufficient rearrangement so that decubitus ulcers never occur and intact alveolar lung areas can be adequately ventilated. According to the invention, these minimal constant repositionings of the patient are achieved by the precession movement of the patient bed.

The drive device, which is intended to set the bed base of the patient bed in such a precessional movement, can be in various designs.

In particular, the drive device actuated by a motor has a ball cage which is arranged concentrically essentially around the center of gravity of the bed and in which a driven ball rotates. The annular ball cage is similar to that of a ball bearing. It is composed of two ring-shaped halves, of which the upper, directly on the Bed frame attached to the bottom is floating over the ball. The lower half is firmly connected to a horizontal reference or support surface. This means that the circular ball track always remains in a horizontal plane in this half. The ball represents an eccentric support point of the bed with respect to the actual center of gravity.

Peripheral elements are arranged in the edge area of the patient bed grate for the safe storage of the patient bed grate deflected from its horizontal during the precision movement. The gravity acting on the center of gravity, which if desired can be supported by a tensile force exerted by the peripheral elements on the bed frame, thus exerts a leverage effect, which the upper, floating half of the two-part ball cage turns into a light one

Tilt position offset to the horizontal. As a result, the bed frame mounted on this upper half of the ball cage naturally assumes the same tilting position with respect to its horizontal position. If the ball revolves, this tilting position is then continuously changed and the desired precision movement of the bed frame is obtained.

As already mentioned, the circular track of the ball in the lower half of the cage is always in a horizontal plane. If the ball track is in the upper half of the cage, firmly attached to the bed frame, in a parallel to the bed frame

Level, this bed frame cannot assume a horizontal rest position as long as the ball is in the cage. In this case, a mechanism must therefore be provided which, when the drive device is switched on and off, forces the ball into the cage or at least partially removes it from the cage. This can advantageously be avoided by the fact that the ball raceway in the upper half of the cage lies in a plane that does not run parallel to that of the bed frame, but rather at a certain angle of inclination to it. The upper half of the cage can then be dimensioned such that the bed frame and bed surface are horizontal when the ball reaches the point closest to the bed frame surface.

The ball can be driven, for example, with the aid of a crank drive. It is also possible that, instead of the ball, a crank pin formed on the crank rotates in a circular guide rail which is attached to the underside of the bed frame. This can be designed analogously to the upper half of the cage.

It is also conceivable that the drive device is composed of at least three hydraulic cylinders with spring return that are symmetrically grouped around the center of gravity. The up and down movement of the cylinders, for example, was controlled via an eccentric control so that the precession movement of the bed resulted from it. When using hydraulic cylinders without spring return, a rotary cylinder can take over the control. In any case, in this embodiment of the central element, it makes sense to spherically support the bed or the bed frame in its center of gravity and to use almost noiseless solenoid valves for the hydraulic system.

So that the patient is bothered as little as possible by noise or vibrations, the use of electric motors for driving the drive device is preferred. In the ball cage, the crank mechanism, in the hydraulic cylinders with spring return the eccentric control can be conventionally electrically driven without any problems; the rotary cylinder control requires the use of an electrical pacemaker.

In their simplest embodiment, the peripheral elements can have elastically deformable rubber blocks. However, spring bolts are preferred. When using hydraulic cylinders in the drive device, it is also possible to equip the peripheral elements with hydraulic cylinders as well. These could then be included in the control and support the precessional movement of the bed as active elements. This in turn could reduce the dimensions of the hydraulic cylinders of the drive device.

The drive device, around which the bed base executes a precision movement, can also be designed as a gear transmission. The drive device embodied as a gear transmission has an upper bearing and a lower bearing, a disk or a ring with an inclined surface rotating between these bearings, which sets the bed frame in a precessional movement. The gear mechanism is designed so that a so-called drive wheel is driven by a motor with a gear, which drives a further gear wheel rotating between an upper and a lower bearing. This indirectly driven gearwheel either has an attached disk or ring or a disk which is arranged in the center of the driven gearwheel and has an inclined surface, this attached disk which triggers the precession movement having circumferentially different axial heights.

The upper storage is connected to the bed grate by a holding device. The lower bearing is connected to a mounting frame. A connecting element is provided between the bed frame and the receiving frame, which is arranged between the bed frame and the lower bed frame. This connecting element can be arranged and connected either on the receiving frame or on the receiving frame and bed frame. The holding device, which is connected to the bed frame and to which the upper supports are fastened, has a stop element which engages in the connecting element which is arranged between the receiving frame and the patient bed frame. The connecting element is designed such that the stop element arranged on or connected to the holding device projects into the connecting element, wherein this stop element limits the deflection of the precession movement of the bed base by the circumferential inclination element. The stop element carries out a vertically upward and downward lifting movement in the connecting element during the rotation of the inclination element.

According to a preferred embodiment, the inclination element or the disk or the ring with an inclined surface can be incorporated in the gear transmission of the drive device, that is to say can be formed or arranged in the center of the indirectly driven gear.

The upper bearing and the lower bearing have an inner and outer bearing ring. The inner bearing ring of the upper bearing is firmly connected to the disk which is arranged in or on the gearwheel and has an inclined surface. The outer bearing ring is firmly attached to the holding device. The inner ring of the lower bearing is firmly connected to the indirectly driven gearwheel and rotates with this ring, the outer bearing ring being fixed firmly on the receiving frame.

The entire drive device is encased in a liquid-tight manner by a flexible or flexible rubber or plastic material which is resistant to the disinfectant used in hospitals. The rubber or plastic jacket is flexible and follows the precession movement of the drive device.

The normal course of nursing and other therapy is not disturbed when the present invention is used, since the drive devices and the peripheral elements can be integrated quickly and inexpensively into conventional hospital beds with the usual equipment (for example, electrically adjustable backrests, attachment options for additional devices, etc.). In these, the bed frame usually rests with its edge area on a circumferential bearing projection of the bed frame. A carrier plate can be mounted on this bearing projection be stored with the dimensions of the bed frame, which carries the drive device. The bed frame in turn is then mounted directly on the support plate and thus the elements of the device. This means that the dimensions of a conventional hospital bed remain unchanged, which is an advantage for smooth hospital operation.

In addition to low noise and low vibrations, the controlled, minimized movement of the bed is essential for the well-being of a bedridden patient. This is first of all made possible by the present invention in a practical and uncomplicated manner via the dimensioning of the components of the drive device (for example ball and cage radius, gear wheel diameter, bearing height and height of the inclination element) and also via the control, which is as problem-free as it is exact which can be used for the drive device in its respective embodiment.

The parameters of such a controlled and minimized movement of the bed can advantageously be set and changed by means provided on the control. It was found that the frequency of a complete precessional movement of the bed should not be less than 1/10 min in order not to be perceived as disturbing by the patient. Of course, in the interest of the patient, this frequency should be kept as low as possible and be individually adjustable. It can also be reduced to 1/1 h if physical and disease-related conditions are met, while the patient is always repositioned in constantly changing positions, so that pressure ulcers are effectively prevented and the intact alveolar structures of the lungs remain available for gas exchange .

What has just been said about the frequency also applies accordingly to the amplitude of the precession movement. The limit value of the amplitude, which is still well tolerated by the patient, is allowed within a radius of about 25 cm around the center of gravity of the bed frame do not deflect more than 3 cm from the horizontal. In accordance with the individual circumstances, the amplitude of the precession movement of the bed should of course be set as low as possible using the means provided on the control. The amplitude of the precession movement can preferably be regulated in a range of 3 cm to 10 cm deflection from the horizontal. Conventional protective means, such as, for example, grids, can advantageously be attached to the circumferential bed profile, even after the mounting of the holding device carrying parts of the drive device, which is below the bed frame, in order to prevent the patient from falling out in the event of larger deflection amplitudes and To secure patients overall.

The invention is explained in more detail below with reference to exemplary embodiments with reference to the accompanying drawings. In these drawings:

Fig. 1 is a plan view of an embodiment of the device according to the invention, and

2a-d side views of the embodiment of FIG. 1 in longitudinal section in each phase of the precession movement.

Fig. 3 shows a schematic representation of the side view of a drive device with gear transmission.

Fig. 4 shows a schematic representation of the top view of the gear transmission with inclination element.

In Fig. 1, the bed frame 1 of an ordinary hospital bed is shown in plan view. Only the outline of this bed frame 1 is shown, so that the elements of the device according to the invention are visible. With these visible outline edges and their adjoining edge areas, the bed frame 1 normally lies on corresponding circumferential bearing projections of the bed frame. Between these bearing projections on the bed frame and the underside of the bed frame 1, symmetrical spring bolts are arranged as peripheral elements 3. They are of the type that they always exert a pulling force on the underside of the bed frame.

The center of gravity of the bed frame 1, support and patient is assumed here approximately in the center of gravity of the bed frame 1. The drive element 2 is shown as an annular ball cage 4 arranged concentrically around this center of gravity, in which the ball 5 rotates.

2a-d are greatly exaggerated for clarification and symbolize some precessional movement states of the bed base 1. They correspond to the four striking points of the ball track in which it intersects the axes of the bed frame 1. 2a and 2c, the ball 5 lies in the sectional plane indicated by arrows in FIG. 1. In Fig. 2b it lies behind, in Fig. 2d in front of this section plane. It is therefore only shown in broken lines in FIG. 2d. All of the representations have in common that the plane 9 of the ball raceway 8 in the upper cage half 7 is “obliquely”, ie does not run parallel to the plane of the bed frame 1, but encloses an angle α with it. In this configuration, as can be seen from FIG. 2a, the bed frame 1 can be in a horizontal or rest position even if the ball 5 always remains in the cage 4. The counterclockwise movement of the ball then leads to a kind of modified precession movement, since the main plane is not the horizontal. Nevertheless, the minimal positioning of the patient preventing a pressure ulcer is of course also ensured by such a precision movement. Original documents page 8, 1st section ensured on the quasi last page after minimal rearrangement of the patent. 3 shows a schematic representation of a drive device which is designed as a gear transmission. A holding device 12 is arranged below the bed frame 1. This holding device extends essentially centrally to the longitudinal extension of the bed over the entire width of the bed from left to right bed frame. This holding device is designed in the manner of a flat bearing surface, the edge regions extending transversely to the longitudinal direction extending away from the bed frame. In the area of the holding device 12, which is closest to the motor with gear 16, a stop element 15 adjoins the rounded holding device area. This stop element 15 is firmly connected to the holding device following the precession movement and engages in a connecting element 14. This connecting element 14, which between

Receiving frame 17 and bed frame 1 is arranged, in particular as a limit stop for limiting the deflection amplitude of the bed frame from the horizontal. According to FIG. 3, the precession movement of the bed base 1 is achieved by the rotation of an inclination disk 13 with an axial height expansion that is variable with respect to its circumference. The inclination disc is designed in the manner of a wedge disc in such a way that points lying opposite one another deviate from one another in their axial height expansion in such a way that a deflection amplitude in the range of 3 to 10 cm is ensured. The gear 18, which is driven by a gear connected to the motor 16, rotates between an upper bearing 11 and a lower bearing 10. In the center, in the gear 18, an inclination disk 13 is arranged. This inclination disc 13 is fixed to the inner bearing ring of the upper bearing 11. The outer bearing ring is firmly connected to the holding device. The gearwheel 18 is connected to the inner bearing ring of the lower bearing 10, the outer bearing ring of the lower bearing 10 being connected to the receiving frame 17. The outer bearing ring 'of the upper bearing 11 is fixed to the

Holding device fixed. The inner ring of the lower bearing 10 is firmly connected to the indirectly driven gearwheel and rotates with this laser ring, the outer bearing ring being firmly fixed on the receiving frame. Motor and transmission are also arranged and fixed in the receiving frame 17. In the exemplary embodiment shown in FIG. 3, the part of the wedge disk 13 with the greatest possible axial extent is located on the side of the drive device opposite the motor. The stop element 15 is inclined in the connecting element 14 in the direction of the receiving frame. The inclined disk 13 is integrated in the driven gear 18 and is set into a rotational movement indirectly via the driven gear surrounding it.

If the part of the inclination disk 13 with the highest axial extent is in the area of the upper bearing 11, which is arranged in the immediate vicinity of the engine and transmission, then the stop element 15 is located in the upper area of the connecting element 14, which then limits the deflection of the precession movement .

The arrangement of the gear drive of the drive device of FIG. 3 is shown in a schematic representation from FIG. 4; a smaller gear 19 is driven via the motor with gear 16. This engages in the larger gear 18, in the center of which is arranged a wedge disk or inclination disk with different height expansions with respect to the flank height of the peripheral gear. In the direction of the longitudinal axis of the bed frame, the stop element 15, which engages in the connecting element 14, is arranged centrally on the longitudinal axis of the bed frame.

Claims

PATENT CLAIMS

1. Device, in particular for decubitus prophylaxis, which is mounted on the underside of a bed grate, characterized by a drive device actuated by a motor and arranged essentially symmetrically below the center of gravity of bed grate (1), support and patient ( 2), by means of which the sickbed grate (1) can be set into a precision movement around this drive device.

2. Device according to claim 1, characterized in that the drive device (2) has a concentric to the center of gravity, annular cage (4) and a circumferential ball (5) therein, the cage (4) being formed in two parts, and its upper half (7), which is directly attached to the grate, is floatingly supported on its lower half (6) via the ball (5), with peripheral elements (3) in the edge area of the sickbed grate (1) for the safe storage of the during the precession movement its horizontal position deflected bed base (1) are arranged.

3. Apparatus according to claim 2, characterized in that the track (8) of the ball (5) in the lower half of the cage (6) is always in a horizontal plane, while the track (9) of the ball (5) in the upper half of the cage (7) lies in a plane inclined to the plane of the grate (1).

4. Apparatus according to claim 1, characterized in that the drive device (2) is designed as a gear transmission, with a disc or a between an upper bearing (9)> and a lower bearing (10)

Rotates ring (11) with an inclined surface, over which the bed frame (1) is set in a precessional movement.

5. The device according to claim 4, characterized in that the upper bearing (9) via a holding device (12) is connected to the bed frame (1) and the lower bearing (10) is connected to a receiving frame (13), wherein A connecting element (14) is arranged between the bed frame (1) and the receiving frame (13).

6. The device according to claim 4 and 5, characterized in that the holding device (12) engages via a stop element (15) in the connecting element (14) so that it can limit the deflection of the precession movement of the crane bed base (1).

7. Device according to one of claims 4 to 6, characterized in that the disk or the ring (11) is designed as an inclination disk or ring with an axially variable axial extent that can vary over the circumference.

8. The device according to claim 7, characterized in that the inclination element is incorporated in the gear mechanism of the drive device (2).

9. Device according to one of the preceding claims, characterized g e k e n n z e i c h n e t that means for changing the frequency and amplitude of the precession movements.

10. Device according to one of the preceding claims, characterized in that the frequency of the precession movement is in the range from 1/10 min to 1 / lh.

11. Device according to one of the preceding claims, characterized in that the maximum amplitude of the precession movement reached within a radius of about 25 cm radius around the drive device (2) does not exceed a deflection of the bed grating of about 3 cm from the horizontal position.

12. Device according to one of the preceding claims, characterized in that the drive device (2) is encased by a flexible sleeve following the movement of precision.