| 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 system for measuring pulse transit time (PTT) and configured to be worn around a patient's neck, comprising:
an 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 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 PTT; and, a cable configured to be worn around the patient's neck, the cable housing the analog ECG circuit, the analog impedance circuit, and the digital processing system. |
