Abstract: A method and apparatus for continuous measurement of blood pressure, based on pulse transit time, which does not require any external calibration. This technique, referred to herein as the ‘composite technique’, is carried out with a body-won sensor that measures blood pressure and other vital signs, and wirelessly transmits them to a remote monitor. A network of disposable sensors, typically placed on the patient's right arm and chest, connect to the body sensor and measure a time-dependent electrical waveform, optical waveform, and pressure waveform. The disposable sensors typically include an armband that features an inflatable bladder coupled to a pressure sensor, at least 3 electrical sensors (e.g. electrodes), and an optical sensor (e.g., a light source and photodiode) attached to a wrist-worn band.

Abstract: A system is described that continuously measures a patient's blood pressure over a length of time. The system features a sensor assembly featuring a flexible cable configured to wrap around a portion of a patient's arm. The flexible cable features a back surface that includes at least two electrodes that are positioned to contact the patient's skin to generate electrical signals. It additionally features an optical sensor that includes at least one light source and at least one photodetector. These components form an optical sensor that is configured to generate an optical signal by detecting optical radiation emitted by the at least one light source and reflected from a blood vessel underneath the patient's skin.

Abstract: The invention features a monitoring device that measures a patient's vital signs (e.g. blood pressure). The device features a first sensor configured to attach to a first portion of the patient's body that includes: i) a first electrode configured to generate a first electrical signal from the first portion of the patient's body; ii) a first light-emitting component; and iii) a first photodetector configured to receive radiation from the first portion of the patient's body after the radiation is emitted by the first light-emitting component and in response generate a first optical waveform. The device also features a second sensor that includes essentially the same components. An amplifier system, in electrical contact with the first and second electrodes, receives first and second electrical signals from the two sensors to generate an electrical waveform.

Abstract: The invention features a monitoring device that measures a patient's vital signs (e.g.). The device features a first sensor configured to attach to a first portion of the patient's body that includes: i)a first electrode configured to generate a first electrical signal fron the first portion of the patient's body; ii)a first light-emitting component; and iii)a first photodetector configured to receive radiation from the first portion of the patient's body after the radiation is emitted by the first light-emiting component and in response generate a first optical waveform. The device also features a second sensor that includes essentially the same components. An amplifier system, in electrical contact with the first and second electrodes, receives first and second electrical signal from the two sensors to generate an electrical waveform. A processor, in electrical contact with the amplifier system, receives the electrical waveform, the first optical waveform, and the second optical waveform.

Abstract: A system for measuring a blood pressure value from a patient features a sensor configured to be worn on the patient's thumb. The sensor includes one or two light sources that emit optical radiation, and a photodetector that detects the optical radiation after it passes through a portion of a vessel (e.g. an artery or capillary) in the patient's thumb to generate a first time-dependent signal (e.g. a PPG waveform). In embodiments the sensor is made from a flexible material that wraps around a portion of the patient's thumb (e.g. the base) while leaving the thumb's tip uncovered. This configuration is less awkward than most finger-worn sensors, and allows the patient to comfortably go about their day-to-day activities (e.g. reading, eating) with little obstruction. The system also includes at least two electrodes that are configured to be worn on the patient's body and detect electrical signals that are processed by an electrical circuit to generate a second time-dependent signal (e.g. an ECG waveform).

Abstract: A method and apparatus for continuous measurement of blood pressure, based on pulse transit time, which does not require any external calibration. This technique, referred to herein as the ‘composite technique’, is carried out with a body-won sensor that measures blood pressure and other vital signs, and wirelessly transmits them to a remote monitor. A network of disposable sensors, typically placed on the patient's right arm and chest, connect to the body sensor and measure a time-dependent electrical waveform, optical waveform, and pressure waveform. The disposable sensors typically include an armband that features an inflatable bladder coupled to a pressure sensor, at least 3 electrical sensors (e.g. electrodes), and an optical sensor (e.g., a light source and photodiode) attached to a wrist-worn band.

Abstract: A body-worn sensor that measures respiratory rate and other vital signs using an acoustic sensor (e.g., a small-scale sensor). The body-worn sensor features a chest-worn patch sensor that combines both the acoustic sensor and an ECG electrode into a single adhesive patch. To measure blood pressure, the device additionally performs a ‘composite’ PTT-based measurement that features both pressure-dependent and pressure-free measurements. The acoustic sensor measures respiration rate by recording sounds related to the patient's inspiration and expiration. The acoustic sensor is typically placed near the patient's trachea, but can also be placed on the middle right and left side of the chest, and the middle right and left side of the back.

Abstract: A method and apparatus for measuring a patient's blood pressure featuring the following steps: 1) measuring a time-dependent optical waveform with an optical sensor; 2) measuring a time-dependent electrical signal with an electrical sensor; 3) estimating the patient's arterial properties using the optical waveform; 4) determining a pulse transit time (PTT) from the time-dependent electrical signal and the time-dependent optical waveform; and 5) calculating a blood pressure value using a mathematical model that includes the PTT and the patient's arterial properties.

Abstract: A system is described that continuously measures a patient's blood pressure over a length of time. The system features a sensor assembly featuring a flexible cable configured to wrap around a portion of a patient's arm. The flexible cable features a back surface that includes at least two electrodes that are positioned to contact the patient's skin to generate electrical signals. It additionally features an optical sensor that includes at least one light source and at least one photodetector. These components form an optical sensor that is configured to generate an optical signal by detecting optical radiation emitted by the at least one light source and reflected from a blood vessel underneath the patient's skin.

Abstract: A sensor for monitoring a patient's blood pressure, the sensor including a housing unit with a back surface and which includes: a pair of electrodes mounted on the back surface; an optical system mounted on the back surface and including at least one light source that emits optical radiation near 570 nm and at least one photodetector; a first amplifier which generates an analog electrical waveform from the electrical signals from the electrodes; a second amplifier that generates an analog optical waveform from the optical signal from the photodetector; analog-to-digital converter circuitry configured to receive the analog electrical waveform and generate a digital electrical waveform therefrom and to receive the analog optical waveform and generate a digital optical waveform therefrom; and a processor programmed to receive the digital electrical and optical waveforms and determine a pulse transit time for the patient which is a measure of a separation in time of a first feature of the digital electrical wavef