US 3866606 A
Apparatus for and method of cyclically forming a precisely contoured support for a patient requiring a fixed position, as for example, undergoing traction, by means of periodically fluidizing granular material disposed within a container which upon successive fluidization forms the contoured support to distribute pressure over a substantial portion of the body of a patient in avoidance of concentrated pressure on restricted areas thereof.
Description (OCR text may contain errors)
United States Patent [191 Hargest [451 Feb. 18, 1975 CYCLllCALLY PRODUCED CONTOURED SUPPORT  Inventor: Thomas s. Hargest, 1078 Winston 52 us. or. 128/71, 5/347  Int. Cl. A6lf 5/00  Field of Search 128/71, 70, 75, 84, 33; 5/345, 347, 348
 References Cited UNITED STATES PATENTS 2,660,999 12/1953 Thornton 128/71 X 2,915,057 12/1959 Ammon 128/71 X 2,934,063 4/1960 Elsasser 128/71 2,999,496 9/1961 Parson 128/71 X 3,148,391 9/1964 Whitney 5/348 3,428,973 2/1969 Hargest et al 128/33 X 3,644,950 2/1972 Lindsay, Jr. 1. 5/347 3,653,083 4/1972 Lupidus 5/347 X Primary ExaminerRichard A. Gaudet Assistant Examiner-J. Yasko Attorney, Agent, or Firm-Woodcock, Washburn, Kurtz & Mackiewicz 57] ABSTRACT Apparatus for and method of cyclically forming a precisely contoured support for a patient requiring a fixed position, as for example, undergoing traction, by means of periodically fluidizing granular material dis posed within a container which upon successive fluidization forms the contoured support to distribute pres sure over a substantial portion of the body of a patient in avoidance of concentrated pressure on restricted areas thereof.
6 Claims, 3 Drawing Figures CYCLICALLY PRODUCED CONTOUREI) SUPPORT SUMMARY OF THE INVENTION the patient under tensional forces developed by the traction, but also provides, for each cycle of operation, uniform support over all parts of a substantial portion of the body of the patient in avoidance of concentrated pressure on restricted areas thereof.
In general, patients who require traction on any limb, and including the neck, are subjected to tensional forces which tend to move them along the bedsheet of a hospital bed not noted for its softness or accommodation to the contour of the patients anatomy. Such tensional movements cause shear forces which tend to abrade and degrade the health of the skin at pressure points. These give rise not only to areas of abrasion, but sometimes including as well areas which become infected or are slow healing, as bedsores.
In accordance with the present invention, advantage is taken of the fluidized supporting apparatus disclosed and claimed in [1.8. Pat. No. 3,428,973, I-Iargest, et al., dated Feb. 25, 1969. In accordance with said patent, a fluidized mass of granular material is utilized to support a patient on a porous covering sheet which not only distributes pressure on a large portion of the body but aerates the outer surface of the patient, a requirement important to the healing of burned areas of the body. When flow of the aerating gas in the bed of said patient is terminated, the granular material gradually settles and conforms to the shape of the patient, thus forming a natural contour bed.
In accordance with the present invention, the contoured support of the patients body is cyclically produced to permit change of position and at the same time to prevent movement of the patient in the direction of application of tensional forces. In order fully to achieve the advantages of the present invention, the fluidization part of the cycle is short, of the order of three (3) seconds in every cycle of around ten (10) minutes duration. Were it not for cyclical reforming of the contoured support, any change of position by the patient or any appearance of edema and the like, would give rise to pressure points to the detriment of the health of the skin tissue in the pressure areas.
DESCRIPTION OF THE DRAWINGS FIG. 1 diagrammatically illustrates an apparatus and system embodying a preferred form of the invention;
FIG. 2 is a fractional sectional view taken on the lines 2-2 of FIG. 3; and
FIG. 3 is an exploded perspective view of the contour-support of FIG. ll.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, an open-top tank or container 10 of material which can be fiberglass, steel or epoxy-coated wood, has near its lower portion an expanded metal grate l1 suitably supported above the lower wall 10A of the container to provide a plenum chamber 12. The grate 11 is covered with porous sheet material 13. It acts as a diffuser permitting upward flow of air and preventing passage of the granular material into the plenum chamber 12. The container 10 above grate 11 is partly filled with granular material 14. To the plenum chamber 12, there is connected a pipe 15 through which gas, such as air, is driven under pressure by a fan or air pump 16 driven by a motor 17. Disposed over the bed or mass of granular material 14, is a loosely fitting impervious vinyl sheet 10 affixed to the container. To provide for exit of :air from the mass of granular material 14, the vinyl sheet is provided with a plurality of openings 19 distributed along opposite side portions of the sheet 18. Though. these openings can vary as to number, size and location, in one form of the invention four round openings of about 2 inches in diameter have been found to be satisfactory. Beneath each opening is a layer of perforate material 20 suitably bonded to the vinyl sheet 18 as by adhesive or thermal bonding. Thus the granular material cannot escape through the openings 19 and air flow encounters low resistance. Besides affording protection to the granular material 14 from fluids from or applied to the patient, a real saving is realized over a porous sheet coextensive with the length and breadth of the container 10.
As shown in FIG. 1, a patient 21 is lying on the imperforate vinyl sheet 18. His right leg, as shown, is attached as by a pin 22 to a cord 23, passing over a pulley 24. The cord 23 terminates in a platform 25 to which there may be applied one or more of the weights 26 to apply the desired degree of traction to the right leg. If the patient were supported on a normal hospital bed, the degree of traction would be limited to that amount which would not cause the patient to be moved along the bed in the direction of application of the tensional forces. In accordance with the present invention, a much higher traction-al force can be applied without causing the patient to slide along the supporting sheet 18, as will soon be explained.
A control system has been diagrammatically illustrated in FIG. 1 with the parts in position corresponding to the beginning of a cycle, i.e., with line switch 30 closed. Thus the motor 17 drives the fan 16 to fluidize the bed. It has been found that the granular material 14 will take on the characteristics of a fluid of high specific gravity when the pressure within pipe 15 rises to within the range of between 18 inches of water and 21 inches of water, (corresponding respectively with pressures of 0.65 pounds per square inch and 0.76 pounds per square inch gauge). The pressure within pipe 15 is measured by conventional means such as a manometer or pressure gauge 31 which closes contacts 32 when a selected pressure is attained. That pressure within the foregoing range will be selected in terms of the weight of the patient and will be high enough to assure that degree of fluidization which will to a slight degree, about 1 to linch, float the patient. This is adequate for the reformation of the contour support to relieve pressure points and to permit some change of position.
With the fluidization, the granular material moves the vinyl sheet 18 upwardly about the patients body throughout the length and breadth thereof and forms the supporting surface precisely contoured to the body. It is, in effect, three-dimensional since it has length, width and depth. As fluidization terminates, the granular material is closely compacted to form a relatively rigid patient-restraining three-dimensional support of great value in treating patients where body constraint is essential to treatment or convalescence from surgical or other medical procedures.
When contacts 32 close, a relay 34 is energized from the source of supply to open the energizing circuit of the motor 17, which it will be observed includes the contacts 35 of a timer 36. The motor and fan 16 slow down, the pressure falls and the contacts 32 open. This occurs in a few seconds, a time interval long enough for the granular material to re-shape itself and as a relatively rigid mass (absent fluidization) form the contoured supporting surface coextensive with the backside of the patient from head to foot.
Though not critical, experience has shown that the reforming of the contoured support should take place every 8 to 10 minutes. To this end, the timer motor of timer 36 through suitable gearing opens its contacts after each cycle of operation of the motor 17 and maintains them open for the selected time of about 8 to 10 minutes. The time required to fluidize the mass 14 is relatively short. Because the on-time of motor 17 is very short relative to its off-time, there is realized real economy in the operation.
For details of the choice of the granular material 14 and for other aspects of the present invention embodying features of said l-largest, et al. U.S. Pat. No. 3,428,973, reference is to be made to that patent, the disclosure of which is embodied herein by this reference thereto.
From the foregoing description, it will be seen that if a patient is healthy except for the disability of a portion of the body which requires immobilization as a whole, he is quite likely to wish to change position and may, in any event, endeavor to do so even if supported by a mold forming to the shape of his body, thus creating pressure points. In accordance with this invention, the patient is provided with a precisely contoured support which accommodates changed positions, contributing greatly to the comfort of the patient. When traction produces pain by use of normal equipment, it has been found that in accordance with this invention, much less pain if any, is experienced. The patient is more relaxed and pressure points are avoided. Healing is thus aided with greater comfort to the patient.
Referring again to FIG. 3, it is emphasized again that while the structural features of earlier U.S. Pat. No. 3,428,973 have, in part, been illustrated, nevertheless, in accorance with the present invention, the container 10' is about half the depth of the earlier invention notwithstanding there have been retained a grate 37 over which there is disposed the intermediate or sheet material 13. The granular material, while illustrated as a rectangular block 14, comprises a loose mass of such material, for example silicone-coated glass beads, in the range of 0.002 inch to 0.05 inch which are not coherent one to another, and which are fluidized by a passage therethrough of air. In accordance with the present invention, some forty-odd cubic feet per minute of air at 18 inches to 21 inches of water pressure per square inch can be used to fluidize the granular material 14 to achieve the repeated formation of the precisely contoured support for the patient. Above the mass of granular material is disposed the supporting sheet 18 which, as earlier stated, may be imperforate vinyl which may be readily washed and sterilized,
though it is to be understood that there can also be utilized the perforate covering disclosed in said Hargest, et al., patent. However, with the vinyl sheet, it becomes possible to utilize as well as interposed thin blanket for greater warmth and a softer feel to the body of the patient.
Because the periods of each cycle are relatively short, of the order of ten minutes, and the principal function is to produce the contoured support, the fluidization part of the cycle is measured in terms of a few seconds. Thus, not only is there a saving in quantity of fluidized material needed, but also the container is smaller. Thus, for one embodiment of the air bed, glass spheres were required having a total weight of about 2,600 pounds. For the present invention, only about 1,000 pounds of the granular fluidized material the glass spheres are required. The motor 15 need be operated only long enough to cause fluidization which causes a rise in the fluidized material. It need be but of the order of only about A inch to 7% inch, this being sufficient indication that fluidization has taken place to the degree needed for the formation of the second and subsequently precisely contoured supports.
At the same time, there are retained the advantages of the fluidized bed of said l-largest, et al., patent in permitting body care with minimum disturbance and manipulation of the patient. Thus, the timing controls may be disabled by closure of the switch 40. This then connects the motor 17 directly to the source of supply. As soon as the granular material 14 has been fluidized, the blanket interposed between the vinyl sheet 18 and the patient may be replaced by simply pressing downwardly on the fluidized mass and then moving it lengthwise of the patient in a progressive manner. Thus the blanket is removed without change of position of the patient. A fresh blanket is placed in position by reversing the just described steps. In a similar manner, should the patient require a bedpan or the like, then it is pressed downwardly into the fluidized mass and then moved into the required position again without change of position of the patient. By then opening switch 30, the contoured support will include the bedpan, thus holding it in position. Automatic cyclical operation is resumed by operating switches 30 and 40 to their illustrated positions.
What is claimed is:
1. The method of repeatedly forming a precisely contoured support for a patient undergoing traction, which comprises:
supporting the patient upon a mass of granular material disposed within a container,
applying traction to a selected part of the body of the patient, while said traction is being applied fluidizing said granular material during a short period of time for movement of the patient into a position of alignment with tensional forces produced by said traction,
forming said precisely contoured support as said fluidization is terminated for prevention of movement of said patient in the direction of said tensional forces, and
for short periods of time, of the order of three seconds in every cycle of the order of 8 to 10 minutes, again fluidizing said bed of granular material to establish for each said cycle a modified precisely contoured support for the patient.
2. In a fluidized bed for support of a person said bed having:
a gas impermeable base portion, a supporting cover affixed to said base portion and closing said base portion to define an enclosure, a mass of granular material disposed within said enclosure, and an air pump and driving motor for forcing a flow of gas through said mass of granular material of sufficient volume to fluidize said mass and to reduce the specific gravity thereof to a value determined by that necessary to support the person on said supporting cover, the improvement which comprises: control means for cyclically energizing said motor to drive said pump to fluidize said mass for a short interval of time to provide in each cycle of said operation a three-dimensional uniform support over all parts of a substantial portion of the body of a patient in avoidance of concentrated pressure on restricted areas thereof, said control means after expiration of said short interval deenergizing said motor to terminate said flow of gas, said granular material then forming a relatively rigid, patient-restraining, precisely contoured, three-dimensional support over which the pressure thereon of the patient is evenly distributed in avoidance of said concentrated pressure on restricted areas thereof, and said control means after an interval of time which is long compared with said short intervals again energizing said motor to initiate a further cycle of operation for reforming said threedimensional contoured support.
3. The fluidized bed of claim 2 in which said control means energizes said motor to produce said fluidization of said bed during a time interval of about 3 seconds in every said cycle of duration of the order of 10 minutes.
4. The fluidized bed of claim 3 in which there are provided:
over riding control means for selectively operating said motor continuously to drive said air pump to fluidize said mass of granular material during periods of time long enough to permit body care of the patient, as for example, replacement of bedding by movement thereof downwardly in the fluidized mass and progressively lengthwise of the patient and including similar downward movement into the fluidized mass of a bedpan which is then held in place by said granular material upon termination of said flow of gas.
5. The fluidized bed of claim 2 in which said control means includes pressure responsive means operating in response to the pressure of the gas producing said fluidization for deenergizing said motor when said gas pressure rises to a value indicative of fluidization of said mass of granular material.
6. The fluidized bed of claim 2 in which said supporting cover is impermeable to gas flow, said cover having a plurality of openings distributed about its periphery for a flow of air therethrough, each said opening being covered by a gas-permeable element secured to said sheet for exit of gas therethrough and for restraining said granular material within said enclosure.