BODY-WORN SYSTEM FOR CONTINUOUS, NONINVASIVE MEASUREMENT OF CARDIAC OUTPUT, STROKE VOLUME, CARDIAC POWER, AND BLOOD PRESSURE
First Claim
1. A system for measuring at least one of stroke volume and cardiac output from a patient, comprising:
- an impedance sensor connected to at least two electrodes attached to the patient and comprising an impedance circuit, the impedance circuit configured to process signals from the at least two electrodes to measure an impedance signal from the patient;
an optical sensor connected to an optical probe attached to the patient and comprising an optical circuit, the optical circuit configured to process signals from the optical probe to measure at least one optical signal from the patient; and
a processing system configured to;
i) be worn on the body;
ii) operably connect to both the impedance sensor and the optical sensor;
iii) receive the impedance signal from the impedance sensor and process it to determine a first value of at least one of stroke volume and cardiac output;
iv) receive the optical signal from the optical sensor and process it to determine a second value of at least one of stroke volume and cardiac output; and
v) collectively process both the first and second values of at least one of stroke volume and cardiac output to determine a third value of at least one of stroke volume and cardiac output.
1 Assignment
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Accused Products
Abstract
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) a processing system, typically worn on 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.
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Citations
22 Claims
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1. A system for measuring at least one of stroke volume and cardiac output from a patient, comprising:
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an impedance sensor connected to at least two electrodes attached to the patient and comprising an impedance circuit, the impedance circuit configured to process signals from the at least two electrodes to measure an impedance signal from the patient; an optical sensor connected to an optical probe attached to the patient and comprising an optical circuit, the optical circuit configured to process signals from the optical probe to measure at least one optical signal from the patient; and a processing system configured to;
i) be worn on the body;
ii) operably connect to both the impedance sensor and the optical sensor;
iii) receive the impedance signal from the impedance sensor and process it to determine a first value of at least one of stroke volume and cardiac output;
iv) receive the optical signal from the optical sensor and process it to determine a second value of at least one of stroke volume and cardiac output; and
v) collectively process both the first and second values of at least one of stroke volume and cardiac output to determine a third value of at least one of stroke volume and cardiac output. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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2. A system for measuring stroke volume from a patient, comprising:
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an impedance sensor connected to at least two electrodes attached to the patient and comprising an impedance circuit, the impedance circuit configured to process signals from the at least two electrodes to measure an impedance signal representing time-dependent blood flow in a first region of the patient; an optical sensor connected to an optical probe attached to the patient and comprising an optical circuit, the optical circuit configured to process signals from the optical probe to measure at least one optical signal representing time-dependent blood flow in a second region of the patient; and a processing system configured to;
i) be worn on the body;
ii) operably connect to both the impedance sensor and the optical sensor;
iii) receive the impedance signal from the impedance sensor and process it to determine a calibration value of stroke volume;
iv) receive the optical signal from the optical sensor and process it to determine a relative value of stroke volume; and
v) calibrate the relative value of stroke volume with the calibration value of stroke volume to determine a first value of stroke volume.
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3. A system for determining a stroke volume for a patient, comprising:
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a first sensor, configured to worn proximal to the patient'"'"'s brachium, comprising an impedance sensor; a second sensor, configured to be worn proximal the patient'"'"'s hand, comprising an optical sensor; and a processing system, configured to be worn on the patient'"'"'s body and operably connect to both the first and second sensors, the processing system configured to determine the stroke volume by collectively processing time-domain properties of signals from both the first and second sensors.
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4. A system for measuring stroke volume from a patient, comprising:
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an impedance sensor connected to at least two electrodes attached proximal to the patient'"'"'s brachium and comprising an impedance circuit, the impedance circuit configured to process signals measured by the at least two electrodes to generate an impedance signal comprising a first pulsatile component indicative of blood flow proximal to the brachium; an optical sensor connected to an optical probe attached to the patient'"'"'s hand and comprising an optical circuit, the optical circuit configured to process signals from the optical probe to generate an optical signal comprising a second pulsatile component indicative of blood flow proximal to the hand; and a processing system configured to;
i) be operably connected to both the impedance sensor and the optical sensor;
ii) receive the impedance signal from the impedance sensor and process it to determine a derivative indicating blood flow;
iii) receive the optical signal from the optical sensor and process it to determine an ejection time; and
iv) determine the stroke volume by collectively processing the derivative and ejection time.
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Specification