Necklace-shaped physiological monitor

摘要

The invention provides a neck-worn sensor (referred to herein as the ‘necklace’) that is a single, body-worn system that measures the following parameters from an ambulatory patient: heart rate, pulse rate, pulse oximetry, respiratory rate, temperature, thoracic fluid levels, stroke volume, cardiac output, and a parameter sensitive to blood pressure called pulse transit time. From stroke volume, a first algorithm employing a linear model can estimate the patient's pulse pressure. And from pulse pressure and pulse transit time, a second algorithm, also employing a linear algorithm, can estimate systolic blood pressure and diastolic blood pressure. Thus, the necklace can measure all five vital signs along with hemodynamic parameters. It also includes a motion-detecting accelerometer, from which it can determine motion-related parameters such as posture, degree of motion, activity level, respiratory-induced heaving of the chest, and falls.

主权项

1. A necklace system for measuring a blood pressure value and configured to be worn around a patient's neck, comprising:
an electrocardiogram (ECG) system comprising an analog ECG circuit in electrical contact with at least two ECG electrodes, the ECG system configured to generate an analog ECG waveform; an impedance system comprising an analog impedance circuit in electrical contact with at least two impedance electrodes, the impedance system configured to generate an analog impedance waveform; a wireless system comprising a wireless transceiver configured to receive a blood pressure calibration value; a digital processing system comprising a microprocessor and an analog-to-digital converter and configured to receive the analog ECG and impedance waveforms, the analog-to-digital converter configured to digitize the analog ECG waveform to generate a digital ECG waveform and digitize the analog impedance waveform to generate a digital impedance waveform, and the microprocessor configured to process the digital ECG waveform to determine a first time point, process the digital impedance waveform to determine a second time point, and analyze the first and second time points to determine pulse transit time (PTT), and then process the PTT and the blood pressure calibration value to determine the blood pressure value; and, a cable configured to be worn around the patient's neck, the cable housing the analog ECG circuit, the analog impedance circuit, the wireless system, and the digital processing system.