Body-worn system for continuous, noninvasive measurement of cardiac output, stroke volume, cardiac power, and blood pressure
The invention provides a system for measuring stroke volume (SV), cardiac output (CO), and cardiac power (CP) from a patient that features: 1) an impedance sensor connected to at least two body-worn electrodes and including an impedance circuit that processes analog signals from the electrodes to measure an impedance signal (e.g. a TBEV waveform); 2) an ECG sensor connected to at least two chest-worn electrodes and including an ECG circuit that processes analog signals from the electrodes to measure and ECG signal; 3) an optical sensor connected to a body-worn optical probe and including an optical circuit that processes signals from the probe to measure at least one optical signal (e.g. a PPG waveform) from the patient; 4) processing system, typically worn on the patient's wrist and connected through a wired interface to the optical sensor, and through either a wired or wireless interface to the TBEV and ECG sensors.
1. A body-worn system for measuring a stroke volume value from a patient, comprising:
a TBEV module worn on the patient's body and comprising: i) an electrical circuit configured to inject a current proximal to the patient's brachium; ii) a pair of electrical connectors located on a bottom portion of the module, the electrical connectors configured to snap into a pair of mated connectors comprised by a first electrode, with a first connector configured to inject the current into a first portion of the electrode, and a second connector configured to measure signals from a second portion of the electrode that relate to a voltage; iii) an analog circuit configured to process the signals from the second connector to generate a voltage value; and iv) a processor configured to convert the voltage value, or a value calculated therefrom, into a time-dependent resistance value, and then convert the time-dependent resistance value into a stroke volume value.
2. The system of claim 1 , wherein the first portion of the first electrode comprises a first conductive portion.
3. The system of claim 2 , wherein the first conductive portion comprises a conductive gel disposed on an Ag/AgCl film.
4. The system of claim 1 , wherein the second portion of the first electrode comprises a second conductive portion.
5. The system of claim 4 , wherein the second conductive portion comprises a conductive gel disposed on an Ag/AgCl film.
6. The system of claim 1 , wherein the pair of mated connectors comprises a first metal post and a second metal post.
7. The system of claim 6 , wherein both the first and second metal posts are a metal rivet.
8. The system of claim 6 , wherein the electrical connectors located on a bottom portion of the TBEV module are female connectors, each configured to receive a metal post.
9. The system of claim 1 , further comprising an ECG module.
10. The system of claim 9 , wherein the ECG module is configured to be worn on the patient's body.
11. The system of claim 10 , wherein the ECG module comprises i) an ECG circuit configured to measure an ECG waveform from the patient; ii) a second pair of electrical connectors located on a bottom portion of the ECG module, the electrical connectors configured to snap into a pair of mated connectors comprising a second electrode, with a first connector configured to receive current injected by the first electrode, and a second connector configured to measure signals from a second portion of the electrode that relate to the voltage; iii) a conducting wire configured to transmit signals measured by the second electrode to the analog circuit in the TBEV module; and iv) a second serial port configured to transmit a heart rate value to the body-worn TBEV module.
12. The system of claim 11 , wherein the first portion of the second electrode comprises a first conductive portion.
13. The system of claim 12 , wherein the first conductive portion comprises a conductive gel disposed on an Ag/AgCl film.
14. The system of claim 11 , wherein the second portion of the second electrode comprises a second conductive portion.
15. The system of claim 14 , wherein the second conductive portion comprises a conductive gel disposed on an Ag/AgCl film.
16. The system of claim 11 , wherein the pair of mated connectors comprises a first metal post and a second metal post.
17. The system of claim 16 , wherein both the first and second metal posts are a metal rivet.
18. The system of claim 16 , wherein the electrical connectors located on a bottom portion of the TBEV module are female connectors, each configured to receive a metal post.
19. The system of claim 1 , further comprising a harness comprising: i) the TBEV module; ii) a collection of conductive wires that receive and transmit digitized versions of the stroke volume value and the time-dependent resistance value; and iii) a connector configured to detachably connect to a controller worn on the patient's body that receives and analyzes the digitized versions of the stroke volume value and the time-dependent resistance value.
20. A body-worn system for measuring a cardiac output value from a patient, comprising:
a TBEV module worn on the patient's body and comprising: i) an electrical circuit configured to inject a current proximal to the patient's brachium; ii) a first pair of electrical connectors located on a bottom portion of the TBEV module, the electrical connectors configured to snap into a pair of mated connectors comprised by a first electrode, with a first connector configured to inject the current into a first portion of the electrode, and a second connector configured to measure signals from a second portion of the electrode that relate to a voltage; iii) an analog circuit configured to process the signals from the second connector to generate a voltage value; iv) a first processor configured to convert the voltage value into a time-dependent resistance value, and then convert the time-dependent resistance value into a stroke volume value; and v) a first serial port configured to receive a heart rate value from a body-worn ECG module; and,
the body-worn ECG module, comprising i) an ECG circuit configured to measure an ECG waveform from the patient; ii) a second pair of electrical connectors located on a bottom portion of the ECG module, the electrical connectors configured to snap into a pair of mated connectors comprising (N.B.: Accepted syntax prefers “comprising”, rather than “comprised by) a second electrode, with a first connector configured to receive current injected by the first electrode, and a second connector configured to measure signals from a second portion of the electrode that relate to the voltage; iii) a conducting wire configured to transmit signals measured by the second electrode to the analog circuit in the TBEV module; and iv) a second serial port configured to transmit a heart rate value to the body-worn TBEV module.
21. A body-worn system for measuring a stroke volume value from a patient, comprising:
a TBEV module worn on the patient's body and comprising: i) an electrical circuit configured to inject a current proximal to the patient's brachium; ii) a pair of electrical connectors located on a bottom portion of the module, the electrical connectors configured to snap into a pair of mated connectors comprising a first electrode, with a first connector configured to inject the current into a first portion of the electrode, and a second connector configured to measure signals from a second portion of the electrode that relate to a voltage; iii) an analog circuit configured to process the signals from the second connector to generate a voltage value; and iv) a processor configured to convert the voltage value into a time-dependent resistance value, and then convert the time-dependent resistance value into a stroke volume value; and,
a harness comprising the TBEV module, a collection of conductive wires that receive and transmit digitized versions of the stroke volume value and the time-dependent resistance value, and a connector configured to detachably connect to a controller worn on the patient's body that receives and processes the digitized versions of the stroke volume value and the time-dependent resistance value.
22. A body-worn system for measuring a cardiac output value, comprising:
an ECG module attached to a patient's body using a first two-part electrode, the ECG module configured to generate a heart rate value;
an impedance module attached to the patient's body with a second two-part electrode, the impedance module configured to generate a stroke volume value from signals collected by the first and second two-part electrodes; and
a processor configured to receive the heart rate and stroke volume values, and from these calculate a cardiac output value.
23. A body-worn system for measuring a cardiac power value, comprising:
an ECG module attached to a patient's body, using a first two-part electrode, the ECG module configured to generate a heart rate value and an ECG waveform;
an impedance module attached to the patient's body with a second two-part electrode, the impedance module configured to generate a stroke volume value and an impedance waveform from signals collected by the first and second two-part electrodes; and,
a processor configured to receive the heart rate and stroke volume values, and the ECG and impedance waveforms, and from these calculate a cardiac power value.