Patient position monitor

• US 6,129,686 A
• Filed: 06/03/1999
• Issued: 10/10/2000
• Est. Priority Date: 06/12/1996
• Status: Expired due to Term

• Current Assignee: Mark M. Friedman
• Original Assignee: Mark M. Friedman
• Inventors: Friedman, Mark B.
• Primary Examiner(s): MULCAHY, JOHN M
• Application Number:
  US09/324,548
• Time in Patent Office: 495 Days
• Field of Search: 600/595, 200/DIG. 2, 200/61.45 R, 200/61.52, 200/52 R, 340/573.1, 340/573.7, 340/689, 340/575, 340/573.4, 356/138, 356/139.1, 73/514.26
• US Class Current: 600/595
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/1126 using a particular sensing technique
• CPC Class Codes: A61B 5/447 specially adapted for aiding the prevention of ulcer or pressure sore development, i.e. before the ulcer or sore has developed
• CPC Class Codes: A61B 5/6828 Leg
• CPC Class Codes: G01C 2009/066 optical
• CPC Class Codes: G01C 9/10 by using rolling bodies , e.g. spheres, cylinders, mercury droplets
• CPC Class Codes: Y10S 200/02 Body attached switches

Abstract

A patient position monitor is disclosed. The patient position monitor includes an inclinometer and a microprocessor connected to the output of the inclinometer. The inclinometer is a body axis orientation sensor having a light impermeable capsule including a cylindrical body. The longitudinal axis of the cylindrical body is parallel to the patient'"'"'s body axis. The cylindrical body includes a first end portion having a circuit board with a radial array of sequentially illuminated LEDs. A light sensor is mounted on a second end portion of the cylindrical body. A light impermeable sphere disposed in the capsule between the array of LEDs and the light sensor is sized to block light emitted from a portion of the LEDs. The detection of light from the unblocked LEDs is indicative of the position of the sphere and of the orientation of the patient'"'"'s body axis relative to gravity.

Claims

1. A patient position monitor for monitoring the orientation of a part of a patient'"'"'s body with respect to gravity comprising:

(1) a body axis orientation sensor for repeatedly measuring an arbitrary orientation of a part of a patient'"'"'s body with respect to gravity; and

(2) means for determining the time elapsed between a time when a patient is in one said arbitrary orientation and a time when a patient moves to another said arbitrary orientation based on an output of said body axis orientation sensor,

wherein said body axis orientation sensor includes;

a nonconductive housing;

a conductive sphere surrounded by a plurality of wires disposed parallel to the body axis of the patient and arranged in a circle within said housing, said wires comprising an even numbered plurality of output wires and a same number of input wires, said output wires each separated by one of said input wires;

a plurality of input leads connecting each one of said input wires to said determining means; and

a pair of output leads, every other one of said output wires connected to one of said output leads and the others of said output wires connected to the other of said output leads, wherein said ball is sized to contact one of said output wires and one of said input wires adjacent said one of said output wires such that the contact between the wires is indicative of the orientation of the body axis of the patient relative to gravity.

2. A method of monitoring the orientations of the body axis of a patient lying down comprising the steps of:

(a) attaching a patient position monitor to the torso or thigh of a patient, said patient position monitor comprising a body axis orientation sensor and a microprocessor which receives output from said body axis orientation sensor;

(b) repeatedly measuring an arbitrary orientation of the body axis of the patient with respect to gravity using an accelerometer; and

(c) measuring the time elapsed between a time when the patient is in one said arbitrary orientation and a time when the patient moves to another said arbitrary orientation.

3. The method of claim 2 wherein a change in the orientation of the patient'"'"'s body axis is accomplished by the patient.

4. The method of claim 2 wherein a change in the orientation of the patient'"'"'s body axis is accomplished with assistance by another person.

5. The method of claim 2 wherein said body axis orientation sensor comprises:

a light impermeable capsule comprising a cylindrical body having a longitudinal axis parallel to the patient'"'"'s body axis and having a first end portion and a second end portion, said first end portion comprising a circuit board having a radial array of sequentially illuminated light emitting diodes;

a light sensor mounted on said second end portion of said capsule; and

a light impermeable sphere disposed in said capsule between said array of light emitting diodes and said light sensor, wherein said sphere is sized to block light emitted from a portion of the light emitting diodes, whereby the detection by said light sensor of light emitted from said light emitting diodes and not blocked by said sphere is indicative of the orientation of the body axis of the patient relative to gravity.

6. A method of preventing pressure ulcers in a bed bound patient comprising performing the method of claim 2 further comprising rotating the body axis of the patient within a prescribed repositioning period such that the time measured in each of step (c) is within said prescribed repositioning period.

7. The method of claim 2, further comprising:

monitoring the verticality of the patient by

(a) attaching the patient position monitor to the thigh of the patient, said patient position monitor further comprising a verticality sensor, the microprocessor receiving output from said verticality sensor;

(b) repeatedly measuring the orientation of the patient'"'"'s thigh relative to vertical; and

(c) measuring the time spent in said orientation.

8. The method of claim 7 wherein said verticality sensor comprises:

a light impermeable capsule comprising a cylindrical body having a longitudinal axis orthogonal to the patient'"'"'s body axis disposed medially-laterally to the patient, said cylindrical body further having a first end portion and a second end portion, said second end portion comprising a circuit board having a radial array of sequentially illuminated light emitting diodes;

a light sensor mounted on said second end portion of said capsule; and

a light impermeable sphere disposed in said capsule between said array of light emitting diodes and said light sensor, wherein said sphere is sized to block light emitted from a portion of the light emitting diodes, whereby the detection by said light sensor of light emitted from said light emitting diodes and not blocked by said sphere is indicative of the orientation of the patient'"'"'s thigh relative to vertical.

9. A method for determining compliance with a patient repositioning regimen comprising the steps of:

(a) attaching a patient position monitor to a body part of a patient, said patient position monitor comprising an inclinometer, a microprocessor which receives output from said inclinometer and a recorder which records data from said microprocessor;

(b) repeatedly measuring an arbitrary orientation of the body axis of the patient with respect to gravity using said inclinometer; and

(c) measuring the time elapsed between a time when the patient is in one said arbitrary orientation and a time when the patient moves to another said arbitrary orientation;

(d) recording the measurements of the orientations of said body part of the patient relative to gravity and the time spent in said orientations; and

(e) comparing the measurements recorded in step (d) to orientation and time parameters of a prescribed repositioning regimen.

10. The method of claim 9 further comprising the step of sounding an alarm when the measurements compared in step (e) do not conform with parameters of said prescribed repositioning regimen.

11. The method of claim 9 further comprising transmitting the measurements recorded in step (d) to a remote receiver.

12. The method of claim 11 wherein said remote receiver displays the measurements recorded in step (d).

13. A method of diagnosing a patient'"'"'s need for a repositioning regimen comprising the steps of:

(a) attaching a patient position monitor to a body part of a patient, said patient position monitor comprising an inclinometer, a microprocessor which receives output from said inclinometer and a recorder which records data from said microprocessor;

(b) repeatedly measuring an arbitrary orientation of said body part of the patient relative to gravity using said inclinometer; and

(c) measuring the time elapsed between a time when the patient is in one said arbitrary orientations and a time when the patient moves to another said arbitrary orientation;

(d) recording the measurements of the orientations of said body part of the patient relative to gravity and the time spent in said orientations; and

(e) comparing the measurements recorded in step (d) to a set of predetermined minimal repositioning orientation and time parameters.