Floormat physiological sensor
A stand-on physiological sensor (e.g. floormat) measures vital signs and various hemodynamic parameters, including blood pressure and ECG waveforms. The sensor is similar in configuration to a common bathroom scale and includes electrodes that take electrical measurements from a patient's feet to generate bioimpedance waveforms, which are analyzed digitally to extract various other parameters, as well as a cuff-type blood pressure system that takes physical blood pressure measurements at one of the patient's feet. Blood pressure can also be calculated/derived from the bioimpedance waveforms. Measured parameters are transmitted wirelessly to facilitate remote monitoring of the patient for heart failure, chronic heart failure, end-stage renal disease, cardiac arrhythmias, and other degenerative diseases.
1. A system for measuring a blood pressure value from a patient, comprising:
a base comprising a bottom surface configured to rest on a substantially horizontal surface, and a top surface configured to receive at least one of the patient's feet;
a pressure-delivery system connected to the top surface and comprising an opening which receives a portion of at least one of the patient's feet when the patient is in contact with the top surface, the pressure-delivery system comprising a bladder formed as a strap, with a first distal end of the strap connected to the top surface, and a second distal end of the strap connected to the top surface and comprising an inlet configured to receive air from a pump, the strap configured to apply pressure to a portion of at least one of the patient's feet, and a pressure sensor connected to the bladder and configured to measure the applied pressure; and
a processing system in electrical contact with the pressure sensor, and configured to receive signals from the pressure sensor and convert them into a set of pressure values, the processing system further configured to analyze the set of pressure values to determine the blood pressure value.
2. The system of claim 1 , wherein the pump connects to the bladder and is configured to pump air into the bladder when the pump is powered on.
3. The system of claim 2 , wherein the pressure-delivery system further comprises a valve connected to the pump.
4. The system of claim 3 , wherein the valve connects to the bladder and is configured to pass air into the bladder when the pump is powered on.
5. The system of claim 1 , wherein the pressure sensor is configured to measure a pressure within the bladder.
6. The system of claim 1 , wherein the processing system is configured to analyze the set of pressure values to determine the blood pressure value.
7. The system of claim 6 , wherein the processing system is further configured to filter the pressure values to determine a set of pressure-dependent oscillations that is dependent on the patient's blood pressure.
8. The system of claim 7 , wherein each pressure-dependent oscillation in the set of pressure-dependent oscillations is characterized by a pressure value and an amplitude value.
9. The system of claim 8 , wherein the processing system is further configured to determine the pressure-dependent oscillation having a maximum amplitude value.
10. The system of claim 9 , wherein the processing system is further configured to determine a mean arterial pressure (MAP) from the pressure-dependent oscillation having the maximum amplitude value.
11. The system of claim 9 , wherein the processing system is further configured to determine a systolic blood pressure (SYS) from a first pressure-dependent oscillation characterized by an amplitude that, when divided by the maximum amplitude of the pressure-dependent oscillations, is substantially equivalent to a first pre-determined ratio.
12. The system of claim 11 , wherein the first pre-determined ratio is between 0.4 and 0.8.
13. The system of claim 9 , wherein the processing system is further configured to determine a diastolic blood pressure (DIA) from a second pressure-dependent oscillation characterized by an amplitude that, when divided by the maximum amplitude of the pressure-dependent oscillations, is substantially equivalent to a second pre-determined ratio.
14. The system of claim 13 , wherein the second pre-determined ratio is between 0.4 and 0.8.
15. The system of claim 7 , wherein the system measures the set of pressure-dependent oscillations while the pressure-delivery system inflates the bladder.
16. The system of claim 7 , wherein the system measures the set of pressure-dependent oscillations while the pressure-delivery system deflates the bladder.
17. A system for measuring a blood pressure value from a patient, comprising:
a base comprising a bottom surface configured to rest on a substantially horizontal surface, and a top surface configured to receive at least one of the patient's feet;
a pressure-delivery system connected to the top surface and comprising an opening which receives a portion of at least one of the patient's feet when the patient is in contact with the top surface, the pressure-delivery system comprising a bladder formed as a strap, with a first distal end of the strap connected to the top surface, and a second distal end of the strap connected to the top surface and comprising an inlet configured to receive air from a pump when the pump is powered on, the strap configured to apply pressure to a portion of at least one of the patient's feet, and a pressure sensor connected to the bladder and configured to measure the applied pressure;
a weight-measuring system connected to the top surface, the weight-measuring system comprising an electrical system that measures a set of voltages that correlates with a force applied to the top surface; and
a processing system in electrical contact with the pressure sensor, and configured to receive signals from the pressure sensor and convert them into a set of pressure values, the processing system further configured to analyze the set of pressure values to determine the blood pressure value.
18. The system of claim 17 , wherein the electrical system comprises a Wheatstone Bridge.
19. The system of claim 18 , wherein the Wheatstone Bridge connects electrically with an amplifier system.
20. The system of claim 19 , wherein the processing system is further configured to receive the set of voltages, and analyze them to determine a value of weight corresponding to the force applied on the top surface.
21. The system of claim 17 , wherein the pressure-delivery system further comprises a valve connected to the pump.
22. The system of claim 21 , wherein the valve connects to the bladder and is configured to pass air into the bladder when the pump is powered on.
23. The system of claim 17 , wherein the pressure sensor is configured to measure a pressure within the bladder.
24. The system of claim 17 , wherein the processing system is configured to analyze a set of pressure-dependent oscillations to determine the blood pressure value.
25. The system of claim 24 , wherein the processing system is further configured to filter the pressure values to determine a set of pressure-dependent oscillations that is dependent on the patient's blood pressure.
26. The system of claim 25 , wherein each pressure-dependent oscillation in the set of pressure-dependent oscillations is characterized by a pressure value and an amplitude value.
27. The system of claim 26 , wherein the processing system is further configured to determine the pressure-dependent oscillation having a maximum amplitude value.
28. The system of claim 27 , wherein the processing system is further configured to determine a mean arterial pressure (MAP) from the pressure-dependent oscillation having the maximum amplitude value.
29. The system of claim 28 , wherein the processing system is further configured to determine a systolic blood pressure (SYS) from a first pressure-dependent oscillation characterized by an amplitude that, when divided by the maximum amplitude of the pressure-dependent oscillations, is substantially equivalent to a first pre-determined ratio.
30. The system of claim 29 , wherein the first pre-determined ratio is between 0.4 and 0.8.
31. The system of claim 30 , wherein the processing system is further configured to determine a diastolic blood pressure (DIA) from a second pressure-dependent oscillation characterized by an amplitude that, when divided by the maximum amplitude of the pressure-dependent oscillations, is substantially equivalent to a second pre-determined ratio.
32. The system of claim 31 , wherein the second pre-determined ratio is between 0.4 and 0.8.
33. The system of claim 28 , wherein the processing system is configured to measure the set of pressure-dependent oscillations while the pressure-delivery system inflates the bladder.
34. The system of claim 31 , wherein the processing system is configured to measure the set of pressure-dependent oscillations while the pressure-delivery system deflates the bladder.