Warning system for excessive orthopedic pressures

• US 4,858,620 A
• Filed: 09/15/1987
• Issued: 08/22/1989
• Est. Priority Date: 02/28/1986
• Status: Expired due to Fees

• Current Assignee: Walgen Corporation
• Original Assignee: Walgen Corporation
• Inventors: Sugarman, Edward D., D'Antonio, Nicholas F., D'Antonio, Nicholas J.
• Primary Examiner(s): Howell, Kyle E.
• Assistant Examiner(s): Hanley, John C.
• Application Number:
  US07/096,667
• Time in Patent Office: 707 Days
• Field of Search: 128/694, 128/774, 128/748, 73/172, 73/700, 73/715, 73/716, 73/717, 73/720, 73/723, 73/729
• US Class Current: 600/587
• CPC Class Codes: A61B 5/1036 Measuring load distribution, e.g. podologic studies
• CPC Class Codes: A61B 5/6892 Mats

Abstract

A small, inexpensive, but reliable pressure warning system includes a plurality of pressure sensors which are disposed between an orthopedic restraining member and an injured portion of a patient'"'"'s body, and a processor and alarm unit coupled to the pressure sensor and providing a warning when the pressure reaches a danger level (i.e. 30 mm) in which medical assistance is required. If the pressure goes above a critical value (i.e. 35 mm), another warning is provided that immediate medical attention is needed. The processor and alarm unit can be mounted directly on the patient'"'"'s cast and are disposable, one-use items.

Claims

1. An apparatus for monitoring pressure beneath an orthopedic restraining member that has been applied to a person'"'"'s body, said apparatus comprising:

sensing means for sensing a pressure level at a plurality of compartments beneath a restraining member, said sensing means includes a plurality of electrical pressure sensors, whereby at least one of said sensors can be situated at each of the compartments,

means, coupled to the plurality of electrical pressure sensors of said sensing means, for generating an electrical output signal that is proportional to the algebraic sum of said pressure levels sensed at a plurality of compartments, and

warning means, coupled to said generating means and responsive to the output signal, for warning when said output signal reaches a predetermined danger level.

2. The apparatus of claim 1 wherein said warning means includes a display, responsive to said output signal, for providing a numerical indication of said output signal.

3. The apparatus of claim 1 wherein said generating means further comprises adjusting means for adjusting said output signal to a predetermined initial value.

4. The apparatus of claim 3 that includes means for activating said warning means when the value of said electrical output signal is less than zero.

5. The apparatus of claim 1 wherein said warning means includes an audible alarm that provides an audible signal when said electrical output signal reaches a predetermined value.

6. The apparatus of claim 1 wherein said warning means includes a first light indicator that is actuated when the value of the electrical output signal is within a first range of values, a second light indicator that is actuated when the value of the electrical output signal is within a second range of values, and a third light indicator that is actuated when the value of the electrical output signal is within a third range of values.

7. The apparatus of claim 1 that further includes means, coupled to said generating means, for measuring the value of said electrical output signal at predetermined time intervals to produce a plurality of value measurements, means for storing the value measurements, means, coupled to said measurement means and said storage means, for latching said value measurements into said storage means, means coupled to said storage means, for comparing one of said value measurements with another of said value measurements, and means, connected to said comparing means, for activating an alarm if the difference between the compared value measurements exceeds a given value.

8. The apparatus of claim 1 that further includes a self-contained power supply comprising a battery having an electrical potential, and switch means, connected to said battery and said generating means, for closing an electrical circuit that includes said battery and said generating means.

9. An apparatus as recited in claim 8, further comprising a housing of small dimension relative to a restraining member, said housing being configured to mount on the restraining member and containing said generating means, said warning means, said self-contained power supply, and said switch means.

10. An apparatus as recited in claim 1, further comprising means, coupled to said generating means, for determining a rate of change in pressure level beneath a retraining member;

and alarm means, coupled to said determining means, for providing a patient sensible warning as soon as the rate of change in pressure level exceeds a predetermined value.

11. An apparatus for detecting a pressure level beneath an orthopedic restraining member that has been applied to a person'"'"'s body, said apparatus comprising,

non-invasive pressure sensor means, disposed externally on a portion of a body encircled by a restraining member, for providing pressure signals representing the pressure sustained by said portion of the body at a plurality of compartments beneath the orthopedic restraining member, said signals together indicating attempted changes in volume of the affected portion of the body encircled by the restraining member, said sensing means including a plurality of pressure sensitive fluid-filled pads, whereby at least one of said pads can be situated at each of the compartments;

processor means, coupled to the plurality of fluid-filled pads of said pressure sensor means, for processing said pressure signals to provide at least one output signal having a value that substantially corresponds to the combination of the pressure signals; and

warning means, coupled to said processor means and responsive to the output signal, for warning when said output signal reaches a predetermined danger level.

12. An apparatus as recited in claim 11, further comprising means, coupled to said processor means, for determining a rate of change in pressure level beneath a restraining member.

13. An apparatus as recited in claim 12, further comprising display means coupled to said processor means for providing a numerical indication of the instantaneous pressure level beneath a restraining member.

14. A method of monitoring pressure beneath an orthopedic restraining member that has been applied to a person'"'"'s body, said method includes the steps of

placing a plurality of pressure sensors at a plurality of compartments beneath an orthopedic restraining member,

sensing a pressure level at a plurality of compartments beneath an orthopedic restraining member,

generating an electrical output signal having a value that substantially corresponds to the combination of the pressure levels sensed, and providing a warning signal in response to a predetermined warning value of said electrical output signal.

15. The method of claim 14 that includes the step of providing a display indicative of the electrical output signal value.

16. The method of claim 14 that includes the step of adjusting said output signal to a predetermined initial value.

17. The method of claim 14 that further includes the step of sounding an audible alarm when said electrical output signal reaches said warning value.

18. The method of claim 14 that includes the further steps of measuring the value of said electrical output signal at predetermined time intervals to produce a plurality of value measurements, storing the value measurements, comparing one of said value measurements with another of said value measurements, and activating an alarm if the difference between the compared measured values exceeds a given level.

19. The method of claim 14, that further includes the step of providing a warning signal when the value of said electrical output signal is less than zero.

20. The method of claim 14, that further includes the steps of actuating a first light indicator when the value of the electrical output signal is within a first range of values;

actuating a second light indicator when the value of the electrical output signal is within a second range of values; and

actuating a third light indicator when the value of the electrical output signal is within a third range of values.