Hospital bed control apparatus

• US 20050268401A1
• Filed: 03/18/2003
• Published: 12/08/2005
• Est. Priority Date: 03/18/2002
• Status: Active Grant

• Current Assignee: Hill-Rom Services Incorporated (Baxter International Inc.)
• Original Assignee: Hill-Rom Services Incorporated (Baxter International Inc.)
• Inventors: Skinner, Andrew F., Dixon, Steven A., Stolpmann, James R., Welling, Jeffrey R.
• Granted Patent: US 7,500,280 B2
• Time in Patent Office: Days
• US Class Current: 5/655.300
• CPC Class Codes: A61B 5/1115 Monitoring leaving of a patient support, e.g. a bed or a wheelchair
• CPC Class Codes: A61G 2203/32 for force
• CPC Class Codes: A61G 2203/34 for pressure
• CPC Class Codes: A61G 2203/42 for inclination
• CPC Class Codes: A61G 2203/44 for weight
• CPC Class Codes: A61G 2203/74 for anti-shear when adjusting furniture
• CPC Class Codes: A61G 7/00 Beds specially adapted for nursing; Devices for lifting patients or disabled persons stretchers with facilities for picking up patients or disabled persons A61G1/003
• CPC Class Codes: A61G 7/002 having adjustable mattress frame
• CPC Class Codes: A61G 7/005 tiltable around transverse horizontal axis, e.g. for Trendelenburg position rocking beds for physical therapy A61H1/003; hanging patient inclined downwardly for drawing him out A61H2203/0493
• CPC Class Codes: A61G 7/008 tiltable around longitudinal axis, e.g. for rolling
• CPC Class Codes: A61G 7/012 raising or lowering of the whole mattress frame A61G7/005, A61G7/008 take precedence
• CPC Class Codes: A61G 7/015 divided into different adjustable sections, e.g. for Gatch position
• CPC Class Codes: A61G 7/018 Control or drive mechanisms
• CPC Class Codes: A61G 7/05 Parts, details or accessories of beds devices for prevention against falling out A47C21/08, A47D7/00 ; mattresses A47C27/00
• CPC Class Codes: A61G 7/0504 Harnesses or restraining devices in order to evacuate a patient with the mattress, e.g. in situations of emergency, disaster or fire restraining in general A61F5/37
• CPC Class Codes: A61G 7/0506 Head or foot boards head or foot boards for comfort or ergonomics A47C19/022
• CPC Class Codes: A61G 7/0507 Side-rails
• CPC Class Codes: A61G 7/0509 sliding or pivoting downwards
• CPC Class Codes: A61G 7/051 pivoting sideward
• CPC Class Codes: A61G 7/0514 mounted to individual mattress supporting frame sections
• CPC Class Codes: A61G 7/0527 : Weighing devices
• CPC Class Codes: A61G 7/05715 : with modular blocks, or inserts, with layers of different material
• CPC Class Codes: A61G 7/05769 : with inflatable chambers
• CPC Class Codes: B60B 33/0002 : assembling to the object, e.g. furniture
• CPC Class Codes: B60B 33/0021 : in the form of a mounting pin
• CPC Class Codes: B60B 33/0042 : Double or twin wheels
• CPC Class Codes: B60B 33/0049 : the rolling axle being horizontal
• CPC Class Codes: B60B 33/0057 : the rolling axle being offset from swivel axis
• CPC Class Codes: B60B 33/0068 : the swivel axis being vertical
• CPC Class Codes: B60B 33/0073 : the swivel axis being symmetrical to wheel or wheels
• CPC Class Codes: B60B 33/021 : combined with braking of castor wheel
• CPC Class Codes: G01G 19/445 : in a horizontal position
• CPC Class Codes: G01G 19/52 : Weighing apparatus combined with other objects, e.g. furniture with walking sticks A45B3/08
• CPC Class Codes: G01G 23/36 : Indicating the weight by electrical means, e.g. using photoelectric cells
• CPC Class Codes: G01G 5/006 : with pneumatic means
• CPC Class Codes: G08B 3/10 : using electric transmission; using electromagnetic transmission
• CPC Class Codes: G08B 5/36 : using visible light sources

Abstract

The present invention provides a hospital bed (10) including a force sensor (24) or scale apparatus configured to detect the weight of a patient (42).

Claims

1. Apparatus for supporting a patient, the patient producing weight force having a vertical direction, the weight force including a first force vector having a first magnitude, and a second force vector having a second magnitude, the first force vector having a first direction aligned at angle relative to the direction of the weight force, the second force vector having a second direction perpendicular to the first direction, the apparatus comprising:

a supply configured to receive a control signal and supply a compressible medium in response to the control signal;

a patient support including an inflatable portion coupled to the supply to receive the compressible medium therefrom, the inflatable portion being configured to be pressurized by the compressible medium;

a pressure sensor coupled to the inflatable portion of the patient support to be exposed to the pressure therein, the pressure sensor being configured to generate a pressure signal in response to the pressure;

a force sensor positioned to detect the first magnitude of the first force vector, the force sensor being configured to generate a force signal in response to the first magnitude; and

a controller coupled to the pressure sensor to receive the pressure signal therefrom and coupled to the force sensor to receive the force signal therefrom, the controller being configured to generate the control signal in response to the pressure signal and the force signal.

2. The apparatus of claim 1, further comprising:

an angle sensor positioned to detect the angle between the first direction of the first force vector and the direction of the weight force, the angle sensor being configured to generate an angle signal in response to the angle, the controller being further configured to generate the control signal in response to the angle signal.

3. The apparatus of claim 2, wherein:

the patient support includes a plurality of individually pressurizable zones;

the supply is further configured to distribute the compressible medium to the plurality of zones in response to a plurality of control signals; and

the controller is further configured to generate the plurality of control signals.

4. The apparatus of claim 3, wherein the zones of the patient support include a head zone, a seat zone, and a foot zone.

5. The apparatus of claim 2, wherein the controller is further configured to generate the control signal in response to a cosine function of the angle signal.

6. The bed apparatus of claim 2, wherein the angle sensor is a dual-axis accelerometer.

7. A method for supporting a patient on a patient support, the method comprising:

pressurizing at least a portion of the patient support with a compressible medium in response to a control signal;

generating a pressure signal in response to a pressure of the compressible medium within the patient support;

measuring a weight of the patient on the patient support; and

generating the control signal in response to the pressure signal and the measured patient weight.

8. An apparatus for supporting a patient, the apparatus comprising:

a base;

a frame;

a patient support coupled to the frame;

a lift mechanism coupled to the base and the frame;

the lift mechanism being configured to selectably elevate a first end of the patient support relative to a second end of the patient support;

a force sensor coupled to the patient support, the force sensor being configured to generate a force signal in response to a detected force;

an angle sensor coupled to one of the frame and the patient support, the angle sensor being configured to generate an angle signal in response to an angle of the force sensor;

a controller coupled to the angle sensor to receive the angle signal therefrom and coupled to the force sensor to receive the force signal therefrom, the controller being configured to generate a weight signal in response to the angle signal and the force signal; and

an output device coupled to the controller to receive the weight signal therefrom, the output device being configured to indicate a weight of the patient based on the weight signal.

9. The apparatus of claim 8, wherein the output device provides a visual indication of the weight signal.

10. The apparatus of claim 8, wherein the output device provides a printout of the weight signal.

11. The apparatus of claim 8, wherein the output device provides an audible indication of the weight signal.

12. The apparatus of claim 8, further comprising:

a supply configured to receive a control signal and supply a compressible medium in response to the control signal; and

wherein the patient support includes an inflatable portion coupled to the supply to receive the compressible medium therefrom so that the inflatable portion is pressurized by the compressible medium.

13. The apparatus of claim 12, further comprising:

a pressure sensor coupled to the inflatable portion of the patient support to be exposed to the pressure therein, the pressure sensor being configured to generate a pressure signal in response to the pressure;

wherein the controller is coupled to the pressure sensor to receive the pressure signal therefrom and the controller is configured to generate the control signal in response to the pressure signal and the weight signal.

14. The apparatus of claim 13, wherein:

the patient support includes a plurality of individually pressurizable zones;

the supply is further configured to distribute the compressible medium to the plurality of zones in response to a plurality of control signals; and

the controller is further configured to generate the plurality of control signals.

15. The apparatus of claim 14, wherein the zones of the patient support include a head zone, a seat zone, and a foot zone.

16. The apparatus of claim 8, wherein the controller is further configured to generate the weight signal in response to a cosine function of the angle signal.

17. The apparatus of claim 8, wherein the angle sensor includes a dual-axis accelerometer.

18. A method for supporting a patient on a patient support, the patient support including a first end and a second end, the patient producing a weight force having a vertical direction, the weight force including a first force vector and a second force vector, the first force vector having a first magnitude directed in a first direction at an angle relative to the direction of the weight force, the second force vector having a second magnitude directed in a second direction perpendicular to the first direction, the method comprising the steps of:

supporting the patient on the patient support;

selectably elevating the first end of the patient support relative to the second end of the patient support;

measuring an angle of the patient support;

generating a weight signal in response to the angle of the first force vector and the first magnitude; and

providing an indication of the weight signal.

19. The method of claim 18, wherein the step of indicating the weight signal includes providing a visual indication of the weight signal.

20. The method of claim 19, wherein providing the visual indication of the weight signal includes providing a printout of the weight signal.

21. The method of claim 18, wherein the step of indicating the weight signal includes providing an audible indication of the weight signal.

22. The method of claim 18, further comprising the step of pressurizing at least a portion of the patient support in response to a control signal.

23. The method of claim 22, further comprising the step of generating the control signal in response to the pressure within the portion of the patient support and the weight signal.

24. The method of claim 18, further comprising the steps of:

pressurizing a plurality of individually pressurizable portions of the patient support in response to a plurality of control signals; and

generating the plurality of control signals in response to the pressures within the portions of the patient support and the weight signal.

25. The method of claim 18, wherein the step of generating the weight signal includes calculating a cosine.

26. A method of supporting a patient on a patient support having at least one fluid-filled zone, the method comprising the steps of:

detecting an actual pressure within the fluid-filled zone;

measuring a weight of the patient on the patient support;

comparing the actual pressure within the fluid-filled zone to an optimum pressure of the fluid-filled zone based upon the measured patient weight; and

adjusting the pressure within the fluid-filled zone, if necessary, based on the patient weight.

27. The method of claim 26, wherein the adjusting step occurs automatically based on the measuring step.

28. The method of claim 27, wherein the measuring step occurs continuously while the patient is on the patient support.

29. A method of determining a weight of a patient located on a movable patient support, the method comprising the steps of:

providing a scale to determine a weight value of the patient;

determining an angle of the patient support; and

adjusting the weight value detected by the scale based on the angle of the patient support.

30. The method of claim 29, wherein the patient support is movable about an axis transverse to the patient support, and the step of determining the angle of the patient support comprises the step of determining an angle of movement of the patient support about the transverse axis relative to a horizontal position.

31. The method of claim 29, wherein the patient support is rotatable about a longitudinal axis of the patient support, and the step of determining the angle of the patient support includes the step of determining an angle of rotation of the patient support about its longitudinal axis relative to a horizontal position.

32. The method of claim 29, wherein the step of adjusting the weight value of the patient includes the step of calculating a cosine of the angle of the patient support in at least one direction, and dividing the measured weight value by the cosine of the angle or angles.

33. A method of determining and setting pressures for a patient support including a head section and a seat section, the method comprising the steps of:

measuring force exerted upon the patient support,

measuring an angle that a head section of the patient support assumes relative to horizontal,

calculating patient weight from the force measurement and the head section angle measurement, and

setting baseline pressures in the sections of the patient support in response to the calculated patient weight.

34. The method of claim 33 wherein the setting step comprises the step of:

providing a fluid supply and a plurality of valves fluidly coupled to the fluid supply; and

controlling the fluid supply and the plurality of valves.

35. The method of claim 33 further comprising the steps of:

recording the calculated patient weight,

re-measuring the force exerted upon the patient support, and

selectively adjusting the pressure in at least one of the sections of the patient support based upon the re-measured force.

36. The method of claim 35 further comprising the steps of:

comparing the re-measured force exerted upon the patient support to defined limits,

determining if the re-measured force is outside the defined limits, and

if the re-measured force is outside the limits, recalculating the patient weight by re-measuring the force and the head section angle, and re-setting the baseline pressures for the sections.

37. The method of claim 33 wherein the calculating step comprises the steps of:

comparing the force measurement and the angle measurement comparison to a table including a plurality of associated force measurements and angle measurements, and

generating baseline pressure values from the comparison table.

38. The method of claim 33 wherein the calculating step comprises the steps of:

inputting the force measurement and the angle measurement to a predefined algorithm; and

generating baseline pressure values from the algorithm.

39. A method of determining and setting pressures for a patient support including a head section and a seat section, the method comprising the steps of:

measuring force exerted upon the patient support,

measuring an angle that a head section of the patient support assumes relative to horizontal,

comparing the force measurement and the angle measurements to a set of predetermined values in a comparison table,

determining weight of a patient from the comparison table,

determining baseline pressure values in the sections of the patient support based upon the determined weight of the patient, and

setting baseline pressures in the sections of the patient support to the determined baseline pressure values.

40. The method of claim 39 further comprising the steps of:

recording the determined weight of the patient,

re-measuring the force exerted upon the patient support, and

selectively adjusting the pressures in the sections of the patient support based upon the re-measured force.

41. The method of claim 40 further comprising the steps of:

comparing the re-measured force exerted upon the patient support to defined limits,

determining if the re-measured force is outside the defined limits, and

if the re-measured force is outside the limits, recalculating the patient weight by re-measuring the seat force and the head section angle, and resetting the baseline pressures for the sections.

42. A patient support comprising:

a frame,

a deck supported by the frame including a head section, a seat section, and a foot section, each of the sections being configured to articulate relative to each other,

an inflatable mattress supported on the deck and including a head section, a seat section, and a foot section,

a force sensor configured to sense the force applied to the mattress,

an angle sensor configured to sense the angle of the head section of the deck relative to horizontal, and

a controller configured to receive input from the force sensor and the angle sensor and in response thereto determine the weight of a patient upon the patient support, the controller further configured to determine baseline pressures for the sections of the mattress.

43. The patient support of claim 42, wherein the controller is further configured to, at defined intervals, re-measure the force exerted upon the mattress of the patient support and adjust the pressures in the sections of the mattress based upon the re-measured force.

44. The patient support of claim 43 wherein the controller is further configured to determine whether the re-measured seat section force is outside defined limits and if the re-measured force is outside the defined limits, the controller is configured to recalculate the patient weight by re-measuring the force and the head section angle and re-setting the baseline pressures for the sections of the mattress.

45. The patient support of claim 42 wherein the controller operates independently of human impetus.

46. The patient support of claim 42 wherein the controller is comprised of an EPROM.

47. The patient support of claim 42 wherein the controller utilizes a look up table with the force and angle input to generate output.

48. A method of controlling a patient support having at least one fluid-filled zone, the method comprising the steps of:

detecting an actual pressure within the fluid-filled zone;

providing a first force sensor configured to measure force applied to the patient support;

determining a first measured weight of a patient supported on the patient support from the first force sensor;

setting a baseline pressure within the fluid-filled zone based upon the first measured weight;

providing a second force sensor configured to measure force applied to the patient support;

determining a second measured weight of the patient from the second force sensor;

comparing the first measured weight to the second measured weight; and

providing a diagnostic output if a differential between the first measured weight and the second measured weight exceeds a predetermined value.

49. The method of claim 48, further comprising the step of adjusting the pressure within the fluid-filled zone in response to changes in output from the first force sensor.

50. The method of claim 48, wherein the first force sensor comprises a bed scale.

51. The method of claim 50, wherein the patient support comprises a mattress operably coupled to the bed scale and including a head section, a seat section, and a foot section, the second force sensor being operably coupled to the seat section of the mattress.

52. The method of claim 48, further comprising the step of activating an alarm in response to the diagnostic output.

53. The method of claim 48, further comprising the step of establishing a new baseline pressure within the fluid filled zone independent of the first measured weight in response to the diagnostic output.

54. A patient support comprising:

a frame;

a deck supported by the frame;

a first force sensor operably coupled to the deck and configured to provide a first force output indicative of force applied to the deck;

a mattress supported by the deck and including a fluid-filled seat section;

a second force sensor operably coupled to the seat section of the mattress and configured to provide a second force output indicative of force applied to the seat section; and

a controller configured to receive the first force output and the second force output, the controller including a processor configured to determine a first measured weight of the patient in response to the first force output and to determine a second measured weight of the patient in response to the second force output, the processor further configured to provide a diagnostic output if a differential between the first measured weight and the second measured weight exceeds a predetermined value.

55. The patient support of claim 54, wherein the first force sensor comprises a scale including a plurality of load cells operably coupled to the deck.

56. The patient support of claim 54, further comprising a fluid supply coupled to the mattress, the controller being configured to set a baseline pressure within the seat section based upon the first measured weight.

57. The patient support of claim 56, wherein the controller is further configured to establish a new baseline pressure within the seat section independent of the first measured weight in response to the diagnostic output.

58. The patient support of claim 54, further comprising an alarm operably coupled to the controller and configured to be activated in response to the diagnostic output.

59. The patient support of claim 54, wherein the deck includes pivotably coupled head, seat, and foot sections, and a head elevation sensor is operably coupled to the head section to sense an angle of the head section relative to horizontal and provide an elevation output indicative thereof.

60. The patient support of claim 59, wherein the controller is configured to receive the elevation output and to utilize the elevation output to determine at least one of the first and second measured weights.

61. The patient support of claim 56, further comprising a pressure sensor operably coupled to the seat section of the mattress, the pressure sensor being configured to measure fluid pressure within the seat section of the mattress and provide a pressure output indicative thereof.

62. The patient support of claim 61, wherein the controller is configured to receive the pressure output and to control the fluid supply in response to the pressure output.

63. A patient support comprising:

at least one deck section;

at least one fluid receiving cushion coupled to the at least one deck section;

a weight sensor configured to detect the weight of a patient supported by the at least one fluid receiving cushion;

an angle sensor configured to determine an angle of the at least one deck section;

a controller configured to receive input from the weight sensor and the angle sensor and to set an inflation pressure for the at least one fluid receiving cushion.

64. The patient support of claim 63, wherein the weight sensor includes a first force sensor operably coupled to the deck and configured to provide a first force output indicative of force applied to the deck and a second force sensor operably coupled to a seat section of the deck and configured to provide a second force output indicative of force applied to the seat section.

65. The patient support of claim 64, wherein the controller includes a processor configured to determine a first measured weight of the patient in response to the first force sensor output and to determine a second measured weight of the patient in response to the second force sensor output, the processor further configured to provide a diagnostic output if a differential between the first measured weight and the second measured weight exceeds a predetermined value.