Bed load cell based physiological sensing systems and methods
A system for determining a physiological signal of a person supported by a person support apparatus using signals from force transducers is described herein. Force transducers communicate with a controller to transmit signals indicative of weight acting on them. The controller determines blood volume pulse information from the signals received from the force transducers. Heart rate and respiratory rate information is derived from the blood volume pulse information.
1. A system comprising:
a person support apparatus embodied as a hospital bed comprising a lower frame supported on wheels, a weigh frame supported by supports for variable elevation relative to the lower frame, at least one deck section supported on the weigh frame, and a set of siderails movable with respect to the weigh frame and the at least one deck section between raised and lowered positions;
at least two force transducers configured to mount on said person support apparatus, said at least two force transducers configured to generate signals indicative of forces acting on said at least two force transducers by a person supported on the hospital bed; and
a controller carried by the hospital bed and comprising a processor configured to receive signals from said at least two force transducers, said controller configured to process the signals received from said at least two force transducers to determine the person's weight and to determine blood volume pulse based only on the signals from said at least two force transducers by causing the signals to undergo blind source separation analysis including an independent component analysis (ICA) transform to identify source signals indicative of forces produced by the person onto the hospital bed, the source signals being indicative of varying flow through the person's blood vessels during the person's cardiac cycle, wherein after the ICA transform the controller performs artifact suppression on the source signals, wherein the controller is also operable to control movement of the at least one deck section and weigh frame relative to the lower frame, wherein each force transducer of the at least two force transducers detects a mixture of the blood volume pulse and the person's weight, wherein weight detected by the at least two force transducers is used by the controller to determine if the person is supported on the hospital bed and, if it is determined by the controller that the person is not supported on the hospital bed, the operation to determine blood volume pulse is terminated and a message displayed on a touch screen display of the hospital bed.
2. The system of claim 1 , further comprising a memory wherein said memory is configured to store at least one of signals received from said at least two force transducers and processed signals.
3. The system of claim 1 , further comprising a remote controller comprising a remote processor, said remote controller in communication with said controller.
4. The system of claim 1 , further comprising a user interface in communication with said controller, said user interface comprising a display configured to display messages received from said controller.
5. The system of claim 4 , wherein said user interface further comprises an audio output configured to output an audio signal.
6. The system of claim 1 , wherein said controller is configured to determine heart rate from said blood volume pulse.
7. The system of claim 1 , wherein said controller is configured to determine respiratory rate from said blood volume pulse.
8. A person support apparatus embodied as a hospital bed comprising:
a lower frame supported on wheels;
a weigh frame supported by supports for variable elevation relative to the lower frame;
at least one deck section supported on the weigh frame;
a set of siderails movable with respect to the weigh frame and the at least one deck section between raised and lowered positions;
a mattress supported by the at least one deck section and configured to support a person;
at least two force transducers configured to generate signals indicative of components of weight of a person supported by said mattress acting on said at least two force transducers; and
a controller carried by the hospital bed and comprising a processor configured to receive signals from said at least two force transducers, said controller configured to process the signals received from said at least two force transducers to determine the person's weight and to determine blood volume pulse based only on the signals from said at least two force transducers by causing the signals to undergo blind source separation analysis including an independent component analysis (ICA) transform to identify source signals indicative of forces produced by the person onto the hospital bed, the source signals being indicative of varying flow through the person's blood vessels during the person's cardiac cycle, wherein after the ICA transform the controller performs artifact suppression on the source signals, wherein the controller is also operable to control movement of the at least one deck section and weigh frame relative to the lower frame, wherein each force transducer of the at least two force transducers detects a mixture of the blood volume pulse and the person's weight, wherein weight detected by the at least two force transducers is used by the controller to determine if the person is supported on the hospital bed and, if it is determined by the controller that the person is not supported on the hospital bed, the operation to determine blood volume pulse is terminated and a message displayed on a touch screen display of the hospital bed.
9. The person support apparatus of claim 8 , further comprising a remote controller comprising a remote processor, said remote controller in communication with said controller.
10. The person support apparatus of claim 8 , further comprising a user interface in communication with said controller, said user interface comprising a display configured to display information received from said controller.
11. The person support apparatus of claim 8 , wherein said controller is configured to determine heart rate from said blood volume pulse.
12. The person support apparatus of claim 8 , wherein said controller is configured to determine respiratory rate from said blood volume pulse.
13. A physiological signal sensing system for use with a person support apparatus embodied as a hospital bed comprising a lower frame supported on wheels, a weigh frame supported by supports for variable elevation relative to the lower frame, at least one deck section supported on the weigh frame, and a set of siderails movable with respect to the weigh frame and the at least one deck section between raised and lowered positions, the system comprising:
at least two force transducers configured to generate signals in response to a person's weight supported by said at least two force transducers; and
a controller carried by the hospital bed and comprising a processor configured to receive signals from said at least two force transducers, said controller configured to process the signals received from said at least two force transducers to determine the person's weight to determine blood volume pulse based only on the signals from said at least two force transducers by causing the signals to undergo blind source separation analysis including an independent component analysis (ICA) transform to identify source signals indicative of forces produced by the person onto the hospital bed, the source signals being indicative of varying flow through the person's blood vessels during the person's cardiac cycle, wherein after the ICA transform the controller performs artifact suppression on the source signals, wherein the controller is also operable to control movement of the at least one deck section and weigh frame relative to the lower frame, wherein each force transducer of the at least two force transducers detects a mixture of the blood volume pulse and the person's weight, wherein weight detected by the at least two force transducers is used by the controller to determine if the person is supported on the hospital bed and, if it is determined by the controller that the person is not supported on the hospital bed, the operation to determine blood volume pulse is terminated and a message displayed on a touch screen display of the hospital bed.
14. The system of claim 13 , wherein said controller is configured to determine heart rate from said blood volume pulse.
15. The system of claim 14 , further comprising a display device configured to display heart rate.
16. The system of claim 13 , wherein said controller is configured to determine respiratory rate from said blood volume pulse.
17. The system of claim 16 , further comprising a display device configured to display respiratory rate information.
18. A system comprising:
a person support apparatus embodied as a hospital bed comprising a lower frame supported on wheels, a weigh frame supported by supports for variable elevation relative to the lower frame, at least one deck section supported on the weigh frame, and a set of siderails movable with respect to the weigh frame and the at least one deck section between raised and lowered positions;
means to generate signals indicative of components of weight acting said person support apparatus by a person; and
means carried by the hospital bed to determine blood volume pulse from said signals indicative of components of weight acting on said person support apparatus based only on the signals from said means to generate signals by causing the signals to undergo blind source separation analysis including an independent component analysis (ICA) transform to identify source signals indicative of forces produced by the person onto the hospital bed, the source signals being indicative of varying flow through the person's blood vessels during the person's cardiac cycle, wherein the controller is also operable to control movement of the at least one deck section and weigh frame relative to the lower frame, wherein after the ICA transform the means to determine blood volume pulse performs artifact suppression on the source signals, wherein the means to generate signals detects a mixture of the blood volume pulse and the person's weight, wherein weight detected by the means to generate signals is used by the means to determine blood volume pulse to determine if the person is supported on the hospital bed and, if it is determined by the means to determine blood volume pulse that the person is not supported on the hospital bed, the operation to determine blood volume pulse is terminated and a message displayed on a touch screen display of the hospital bed.
19. The system of claim 18 , further comprising means to display heart rate derived from said blood volume pulse.
20. The system of claim 18 , further comprising means to display respiratory rate derived from said blood volume pulse.
21. A method of sensing a physiological signal of a person supported by a person support apparatus embodied as a hospital bed comprising a lower frame supported on wheels, a weigh frame supported by supports for variable elevation relative to the lower frame, at least one deck section supported on the weigh frame, and a set of siderails movable with respect to the weigh frame and the at least one deck section between raised and lowered positions, the method comprising:
generating signals indicative of components of forces acting on said person support apparatus by a person using at least two force transducers;
transmitting said signals to a controller carried by the hospital bed; and
with the controller, processing signals indicative of components of forces acting on said person support apparatus to determine blood volume pulse based only on the signals from said at least two force transducers by causing the signals to undergo blind source separation analysis including an independent component analysis (ICA) transform to identify source signals indicative of forces produced by the person onto the hospital bed, the source signals being indicative of varying flow through the person's blood vessels during the person's cardiac cycle, wherein after the ICA transform the controller performs artifact suppression on the source signals, wherein the controller is also operable to control movement of the at least one deck section and weigh frame relative to the lower frame, wherein each force transducer of the at least two force transducers detects a mixture of the blood volume pulse and the person's weight, wherein weight detected by the at least two force transducers is used by the controller to determine if the person is supported on the hospital bed and, if it is determined by the controller that the person is not supported on the hospital bed, the operation to determine blood volume pulse is terminated and a message displayed on a touch screen display of the hospital bed.
22. The method of claim 21 , further comprising the operation of determining heart rate from said blood volume pulse.
23. The method of claim 22 , further comprising the operation of displaying heart rate on a display device.
24. The method of claim 21 , further comprising the operation of determining respiratory rate from said blood volume pulse.
25. The method of claim 24 , further comprising the operation of displaying respiratory rate on a display device.
26. The method of claim 21 , further comprising the operation of normalizing operation of at least one of a mattress supported by said person support apparatus and said person support apparatus.