Patient monitoring system employing array of force sensors on a bedsheet or similar substrate

• US 6,546,813 B2
• Filed: 02/22/2001
• Issued: 04/15/2003
• Est. Priority Date: 01/08/1997
• Status: Expired due to Term

• Current Assignee: Trustees of Boston University
• Original Assignee: Trustees of Boston University
• Inventors: Hubbard, James E. Jr.
• Primary Examiner(s): Noori, Max
• Application Number:
  US09/791,114
• Publication Number:
  US 20010020395A1
• Time in Patent Office: 782 Days
• Field of Search: 738/620.41, 738/620.42, 738/620.43, 738/620.46, 731/72
• US Class Current: 73/862.041
• CPC Class Codes: A43B 3/00 Footwear characterised by the shape or the use
• CPC Class Codes: A43B 3/34 with electrical or electronic arrangements
• CPC Class Codes: A61B 2562/0252 Load cells
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/1115 Monitoring leaving of a patient support, e.g. a bed or a wheelchair
• CPC Class Codes: A61B 5/112 Gait analysis
• CPC Class Codes: A61B 5/1126 using a particular sensing technique
• CPC Class Codes: A61B 5/6892 Mats
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/01526 using piezoelectric elements
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015
• CPC Class Codes: G01G 19/44 for weighing persons
• CPC Class Codes: G01G 19/445 in a horizontal position
• CPC Class Codes: G01G 23/3728 with wireless means
• CPC Class Codes: G01L 1/205 using distributed sensing elements
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
• CPC Class Codes: G06V 40/25 Recognition of walking or running movements, e.g. gait recognition

Abstract

A patient monitoring system includes a replaceable laminar sensor to be placed on a bed, the sensor including distributed force sensing elements providing output signals to processing apparatus including a near-bed processor and a central processor coupled to the near-bed processor by a wireless communication link. The processing apparatus applies spatial weighting to the sensor output signals to derive the force distribution across the sensor, and processes the force distribution over time to generate patient status information such as patient presence, position, agitation, seizure activity, respiration, and security. This information can be displayed at a central monitoring station, provided to a paging system to alert attending medical personnel, and used to update medical databases. The sensor may be manufactured from layers of olefin film and conductive ink to form capacitive sensing elements.

Claims

1. A system for sensing status of a patient in a bed comprising:

a replaceable laminar sensor on said bed;

said laminar sensor having a plurality of force sensing elements distributed two-dimensionally throughout said sensor;

processing apparatus responsive to forces sensed by said sensor for forming a spatially-weighted sum of the forces sensed by said sensor to provide a distribution of the forces throughout said laminar sensor, said processing apparatus including a near-bed processor and a central processor in communication with said near-bed processor through a communication link;

said processing apparatus providing an indication over time of a patient status in response to said weighted average;

wherein said communication link is a wireless link having interfaces at said near-bed processor and said central processor.

2. A system for sensing status of a patient in a bed comprising:

a replaceable laminar sensor on said bed;

said laminar sensor having a plurality of force sensing elements distributed two-dimensionally throughout said sensor;

processing apparatus responsive to forces sensed by said sensor for forming a spatially-weighted sum of the forces sensed by said sensor to provide a distribution of the forces throughout said laminar sensor;

said processing apparatus providing an indication over time of a patient status in response to said weighted average;

wherein said processing apparatus provides patient status information including information regarding patient presence, patient position, patient agitation, patient seizures, patient respiration, and patient security.

3. A system for sensing status of a patient in a bed comprising:

a replaceable laminar sensor on said bed;

said laminar sensor having a plurality of force sensing elements distributed two-dimensionally throughout said sensor;

processing apparatus responsive to forces sensed by said sensor for forming a spatially-weighted sum of the forces sensed by said sensor to provide a distribution of the forces throughout said laminar sensor;

said processing apparatus providing an indication over time of a patient status in response to said weighted average;

wherein said processing apparatus provides patient status information relative to sleep disorders.

4. A system for sensing status of a patient in a bed comprising:

a replaceable laminar sensor on said bed;

said laminar sensor having a plurality of force sensing elements distributed two-dimensionally throughout said sensor;

processing apparatus responsive to forces sensed by said sensor for forming a spatially-weighted sum of the forces sensed by said sensor to provide a distribution of the forces throughout said laminar sensor;

said processing apparatus providing an indication over time of a patient status in response to said weighted average;

wherein said processing apparatus provides patient status information relative to patient drug reactions.

5. A system for sensing status of a patient in a bed comprising:

a replaceable laminar sensor on said bed;

said laminar sensor having a plurality of force sensing elements distributed two-dimensionally throughout said sensor;

processing apparatus responsive to forces sensed by said sensor for forming a spatially-weighted sum of the forces sensed by said sensor to provide a distribution of the forces throughout said laminar sensor;

said processing apparatus providing an indication over time of a patient status in response to said weighted average;

wherein said processing apparatus provides information relative to the presence or absence of patient activity sufficient to avoid bed sores.

6. A patient monitoring system, comprising:

a plurality of patient-specific sensing sub-systems, each sub-system including a sensing sheet and a sensor signal processing unit electrically coupled to the sensing sheet, the sensing sheet including an insulative substrate having a plurality of sensing elements arranged two-dimensionally thereon so as to define a sensing area, the sensor signal processing unit being operative to (i) apply spatial weights to sensor output signals from the sensing elements, (ii) perform a predetermined analysis procedure using the spatially-weighted sensor output signals, and (iii) generate an analysis results signal including information reflecting results of performing the analysis procedure; and

a centralized sub-system communicatively coupled with the sensor signal processing units of the patient-specific sensing sub-systems, the centralized sub-system including receiver circuitry and processing circuitry collectively operative to (i) receive the respective analysis results signals from the sensor signal processing units, (ii) detect certain predetermined clinically significant patterns of the analysis results signals, and (iii) respond to the detection of such patterns by generating corresponding notification signals alerting attending medical personnel to the possible existence of clinically significant conditions.

7. A patient monitoring system according to claim 6, wherein the sensor signal processing unit is portable.

8. A patient monitoring system according to claim 6, wherein (i) the patient-specific sub-systems are coupled to the centralized sub-system via wireless communications links, (ii) each sensor signal processing unit includes a radio-frequency modem operative to transmit the analysis results signal to the centralized sub-system, and (iii) the receiver circuitry of the centralized sub-system includes a radio-frequency modem operative to receive the analysis results signal from the patient-specific sub-systems.

9. A patient monitoring system according to claim 6, wherein the centralized sub-system further includes a paging system operative to transmit the attendant-alerting notification signals.

10. A patient monitoring system according to claim 6, wherein the centralized sub-system further includes an interface to a computer network for transferring data obtained from the analysis results signals to other locations at which the obtained data is used.

11. A patient monitoring system according to claim 10, wherein the computer network is an inter-departmental network of a medical facility.

12. A patient monitoring system according to claim 10, wherein the computer network is a wide-area network.