Pressure-relieving wheelchair seating apparatus

A seating apparatus for supporting a lower body region of an immobilized person for avoidance and relief of decubitus ulcers which provides regular intervals of seating pressure reduction below a predetermined seating pressure for a predetermined relief period. The seating apparatus includes a plurality of slats/cushions which may be displaced between a first support position wherein each of the slats/cushions is co-planar with a defined plane and a second displaced position wherein each of the slats/cushions is displaced a distance D from the defined plane for the predetermined relief period whereby capillary blood pressure is reduced below the predetermined seating pressure in the unsupported portion of the lower body region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view, in partial section, of a wheelchair incorporating the seating apparatus of the present invention;

FIG. 2 is a front elevational view, in partial section, of the wheelchair of FIG. 1;

FIG. 3 is an isometric view of the seating apparatus of FIG. 1;

FIG. 4 is a plan view, in partial section, of the seating apparatus/wheelchair arrangement of FIG. 1;

FIG. 5 is a graphical depiction of seating pressure versus time under the ischial tuberosities of a 56 year old male quadriplegic patient weighing approximately 160 lbs.; and

FIG. 6 is a graphical depiction of ulcer length versus cumulative seated hours for the patient of FIG.

5.

1. A seating apparatus for supporting a lower body region of an immobilized person for avoidance and relief of decubitus ulcers, the seating apparatus providing regular intervals of seating pressure reduction below a predetermined seating pressure for at least a predetermined relief period, comprising:

2. The seating apparatus according to claim 1, further comprising a number of slats N wherein N ranges from 5 to 7;

3. The seating apparatus according to claim 2, wherein said cycle interval time CI is selected to maintain said peak seating pressure P

p below accepted pressure guidelines for the selected number of slats N.

4. The seating apparatus according to claim 3, wherein the number of slats N equals 6, and wherein said predetermined seating pressure is approximately 32 mm Hg and said predetermined relief period is at least about 5 seconds.

5. The seating apparatus according to claim 4, wherein said thickness T of said cushion is equal to or less than said width W of said cushion.

6. The seating apparatus according to claim 5, wherein said thickness T of said cushion is approximately 1.5 to about 2.5 inches.

7. The seating apparatus according to claim 3, wherein said cycle interval time CI ranges from about 2½ minutes to about 4½ minutes.

8. The seating apparatus according to claim 1, further comprising a pressure gauge to monitor seating pressure under the lower body region of the person.

9. The seating apparatus accordingly to claim 1, wherein said cage has a front side and a back side; and

10. A method of retrofitting a wheelchair, comprising the steps of:

11. The method according to claim 10, further comprising the steps of:

12. A method of treating decubitus ulcers, comprising:

13. The seating apparatus according to claim 12, further comprising a number of slats N wherein N ranges from 5 to 7;

14. The seating apparatus according to claim 13, wherein said cycle interval time CI is selected to maintain said peak seating pressure P

p below accepted pressure guidelines for the selected number of slats N.

15. The seating apparatus according to claim 14, wherein the number of slats N equals 6, and wherein said predetermined seating pressure is approximately 32 mm Hg and said predetermined relief period is at least about 5 seconds.

16. The seating apparatus according to claim 15, wherein said thickness T of said cushion is equal to or less than said width W of said cushion.

17. The seating apparatus according to claim 16, wherein said thickness T of said cushion is approximately 1.5 to about 2.5 inches.

18. The seating apparatus according to claim 13, wherein said cycle interval time CI ranges from about 2½ minutes to about 4½ minutes.

19. The seating apparatus according to claim 12, wherein said cushion has a thickness T, a width W, a stiffness S, a maximum compression C and a recovery rate R, said thickness T and stiffness S being selected to allow said cushion to conform to the lower body region of the immobilized person to provide support therefor while minimizing an initial seating pressure P

i, and wherein said displacement D exceeds said maximum compression C, said maximum compression C being a function of thickness T, stiffness S and the body weight of the immobilized person, said recovery rate R of said cushion being no greater than said predetermined relief period whereby said cushion substantially regains its original shape during said predetermined relief period.