Abstract: Apparatus and methods for calculating cardiac output (CO) of a living subject using applanation tonometry measurements. In one embodiment, the apparatus and methods build a nonlinear mathematical model to correlate physiologic source data vectors to target CO values. The source data vectors include one or more measurable or derivable parameters such as: systolic and diastolic pressure, pulse pressure, beat-to-beat interval, mean arterial pressure, maximal slope of the pressure rise during systole, the area under systolic part of the pulse pressure wave, gender (male or female), age, height and weight. The target CO values are acquired using various methods, across a plurality of individuals. Multidimensional nonlinear optimization is then used to find a mathematical model which transforms the source data to the target CO data. The model is then applied to an individual by acquiring physiologic data for the individual and applying the model to the collected data.

Abstract: An improved method and apparatus for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises a method of measuring a hemodynamic parameter (e.g., arterial blood pressure) by applanating or compressing portions of tissue proximate to the blood vessel of concern until a desired condition is achieved, and then measuring the hemodynamic parameter. Such applanation effectively mitigates transfer and other losses created by the tissue proximate to the blood vessel, thereby facilitating accurate and robust tonometric measurement. An algorithm adapted to maintain optimal levels of applanation is also described. Methods and apparatus for scaling such hemodynamic parameter measurements based on subject physiology, and providing treatment to the subject based on the measured parameters, are also disclosed.

Abstract: Improved apparatus and methods for non-invasively assessing one or more physiologic (e.g., hemodynamic) parameters associated with a living organism. In one embodiment, the invention comprises an apparatus adapted to automatically and accurately place and maintain a sensor (e.g., tonometric pressure sensor) with respect to the anatomy of the subject. The apparatus is comprised of a sensor device removably coupled to a host device which is used to position the sensor during measurements. Methods for positioning the alignment apparatus and sensor, and operating the apparatus, are also disclosed.

Abstract: Improved apparatus and methods for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises spatially compact “bracelet” embodiment adapted to accurately place and maintain a sensor (e.g., tonometric pressure sensor) with respect to the anatomy of the subject, including an optional alignment apparatus which moveably captures the sensor to, inter alia, facilitate coupling thereof to an actuator used to position the sensor during measurements. The alignment apparatus also advantageously allows the sensor position to be maintained when the fixture is removed from the subject, such as during patient transport. A completely autonomous variant of the bracelet apparatus having internal power supply and wireless interfaces is also disclosed. Methods for positioning the alignment apparatus and sensor and providing treatment to the subject are also described.

Abstract: Improved apparatus and methods for non-invasively assessing one or more parameters associated with systems such as fluidic circulating systems (e.g., the circulatory system of a living organism). In a first aspect, an improved method of continuously measuring pressure from a compressible vessel is disclosed, wherein a substantially optimal level of compression for the vessel is achieved and maintained using dynamically applied dither perturbations (e.g., modulation) on the various axes associated with the vessel. In a second aspect, an improved apparatus and method are provided for monitoring hemodynamic parameters, such as blood pressure, in a continuous and non-invasive manner while operating under a single unifying scheme. One variant of this scheme using a simulated annealing (SA) type approach to determining and maintaining an optimal operating state.

Abstract: Improved methods and apparatus for non-invasively assessing one or more parameters associated with fluidic systems such as the circulatory system of a living organism, when such parameters are potentially affected by other concurrent events. In one exemplary embodiment, apparatus and methods for compensating for occlusive events (e.g., pressure cuff inflation) occurring ipsilateral to the location of parameter measurement are disclosed. Upon passive detection of signal degradation resulting from the event, the apparatus selectively enters a “wait state” wherein further processing of the hemodynamic data is suspended until the degrading event subsides. This behavior mitigates any adverse effects the event might have on the accuracy of the representation of the measured hemodynamic parameter generated by the system. In another exemplary embodiment, the measured data is analyzed in order to classify the type of event (e.g.

Abstract: Improved methods and apparatus for non-invasively assessing one or more parameters associated with fluidic systems such as the circulatory system of a living organism. In a first aspect, an improved method of continuously measuring pressure from a compressible vessel is disclosed, wherein a substantially optimal level of compression for the vessel is achieved and maintained using perturbations (e.g., modulation) of the compression level of the vessel. In one exemplary embodiment, the modulation is conducted according to a pseudo-random binary sequence (PBRS). In a second aspect, an improved apparatus for determining the blood pressure of a living subject is disclosed, the apparatus generally comprising a pressure sensor and associated processor with a computer program defining a plurality of operating states related to the sensed pressure data. Methods for pressure waveform correction and reacquisition, as well as treatment using the present invention, are also disclosed.

Abstract: An improved apparatus and method for interfacing a time variant waveform between two hardware environments. In one aspect, the invention comprises a circuit for accurately simulating the output of one or more types of sensing device (e.g., passive bridge pressure transducer) for use with a plurality of different monitoring and/or analysis devices, thereby obviating the need for specialized interface circuitry adapted to each different monitor/analyzer. In one exemplary embodiment, the sensing device comprises a non-invasive blood pressure monitor (NIBPM), which universally interfaces with prior art patient monitors via the interface circuit of the invention. In a second aspect of the invention, an improved NIBPM device incorporating the interface circuit is disclosed. An improved disconnect circuit adapted to sense the status of the electrical connection between the sensing device and monitor is also described.

Abstract: Improved apparatus and methods for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises an apparatus adapted to automatically and accurately place and maintain a sensor (e.g., tonometric pressure sensor) with respect to the anatomy of the subject. The apparatus comprised of a sensor device removably coupled to an actuator which is used to position the sensor during measurements. Methods for positioning the alignment apparatus and sensor, and operating the apparatus, are also disclosed.

Abstract: An improved method and apparatus for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises a method of measuring a hemodynamic parameter (e.g., arterial blood pressure) by applanating or compressing portions of tissue proximate to the blood vessel of concern until a desired condition is achieved, and then measuring the hemodynamic parameter. Such applanation effectively mitigates transfer and other losses created by the tissue proximate to the blood vessel, thereby facilitating accurate and robust tonometric measurement. An algorithm adapted to maintain optimal levels of applanation is also described. Methods and apparatus for scaling such hemodynamic parameter measurements based on subject physiology, and providing treatment to the subject based on the measured parameters, are also disclosed.

Abstract: An improved method and apparatus for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises a method of measuring a hemodynamic parameter (e.g., arterial blood pressure) by applanating or compressing portions of tissue proximate to the blood vessel of concern until a desired condition is achieved, and then measuring the hemodynamic parameter. Such applanation effectively mitigates transfer and other losses created by the tissue proximate to the blood vessel, thereby facilitating accurate and robust tonometric measurement. An algorithm adapted to maintain optimal levels of applanation is also described. Methods and apparatus for scaling such hemodynamic parameter measurements based on subject physiology, and providing treatment to the subject based on the measured parameters, are also disclosed.

Abstract: Improved apparatus and methods for non-invasively assessing one or more parameters associated with systems such as fluidic circulating systems (e.g., the circulatory system of a living organism). In a first aspect, an improved method of continuously measuring pressure from a compressible vessel is disclosed, wherein a substantially optimal level of compression for the vessel is achieved and maintained using dynamically applied dither perturbations (e.g., modulation) on the various axes associated with the vessel. In a second aspect, an improved apparatus and method are provided for monitoring hemodynamic parameters, such as blood pressure, in a continuous and non-invasive manner while operating under a single unifying scheme. One variant of this scheme using a simulated annealing (SA) type approach to determining and maintaining an optimal operating state.

Abstract: An improved method and apparatus for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises a method of measuring a hemodynamic parameter by measuring a non-calibrated value of the parameter non-invasively, and inducing a stress of the circulatory system while measuring a second parameter. The response of the circulatory system to the stress is determined directly from the subject, and a calibration function is derived from the response and applied to the non-calibrated measured value to produce a calibrated measure of the actual value of the hemodynamic parameter. Methods of using backscattered acoustic energy for determination of hemodynamic markers are also disclosed.

Abstract: Improved methods and apparatus for non-invasively assessing one or more parameters associated with fluidic systems such as the circulatory system of a living organism, when such parameters are potentially affected by other concurrent events. In one exemplary embodiment, apparatus and methods for compensating for occlusive events (e.g., pressure cuff inflation) occurring ipsilateral to the location of parameter measurement are disclosed. Upon passive detection of signal degradation resulting from the event, the apparatus selectively enters a “wait state” wherein further processing of the hemodynamic data is suspended until the degrading event subsides. This behavior mitigates any adverse effects the event might have on the accuracy of the representation of the measured hemodynamic parameter generated by the system. In another exemplary embodiment, the measured data is analyzed in order to classify the type of event (e.g.

Abstract: Improved apparatus and methods for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises spatially compact “bracelet” embodiment adapted to accurately place and maintain a sensor (e.g., tonometric pressure sensor) with respect to the anatomy of the subject, including an optional alignment apparatus which moveably captures the sensor to, inter alia, facilitate coupling thereof to an actuator used to position the sensor during measurements. The alignment apparatus also advantageously allows the sensor position to be maintained when the fixture is removed from the subject, such as during patient transport. A completely autonomous variant of the bracelet apparatus having internal power supply and wireless interfaces is also disclosed. Methods for positioning the alignment apparatus and sensor and providing treatment to the subject are also described.

Abstract: An improved method and apparatus for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises a method of measuring a hemodynamic parameter (e.g., arterial blood pressure) by applanating or compressing portions of tissue proximate to the blood vessel of concern until a desired condition is achieved, and then measuring the hemodynamic parameter. Such applanation effectively mitigates transfer and other losses created by the tissue proximate to the blood vessel, thereby facilitating accurate and robust tonometric measurement. An algorithm adapted to maintain optimal levels of applanation is also described. Methods and apparatus for scaling such hemodynamic parameter measurements based on subject physiology, and providing treatment to the subject based on the measured parameters, are also disclosed.

Abstract: A method and apparatus for determining the mean arterial blood pressure (MAP) of a subject during tonometric conditions. In one embodiment, the apparatus comprises one or more pressure and ultrasound transducers placed over the radial artery of a human subject's wrist, the latter transmitting and receiving acoustic energy so as to permit the measurement of blood velocity during periods of variable compression of the artery. In another aspect of the invention, a wrist brace useful for measuring blood pressure using the aforementioned apparatus is disclosed. In yet another aspect of the invention, backscattered acoustic energy is used to identify the location of the blood vessel of interest, and optionally control the position of measurement or treatment equipment with respect thereto.

Abstract: An improved apparatus and method for interfacing a time variant waveform between two hardware environments. In one aspect, the invention comprises a circuit for accurately simulating the output of one or more types of sensing device (e.g., passive bridge pressure transducer) for use with a plurality of different monitoring and/or analysis devices, thereby obviating the need for specialized interface circuitry adapted to each different monitor/analyzer. In one exemplary embodiment, the sensing device comprises a non-invasive blood pressure monitor (NIBPM), which universally interfaces with prior art patient monitors via the interface circuit of the invention. In a second aspect of the invention, an improved NIBPM device incorporating the interface circuit is disclosed. An improved disconnect circuit adapted to sense the status of the electrical connection between the sensing device and monitor is also described.

Abstract: Improved methods and apparatus for non-invasively assessing one or more parameters associated with fluidic systems such as the circulatory system of a living organism, when such parameters are potentially affected by other concurrent events. In one exemplary embodiment, apparatus and methods for compensating for occlusive events (e.g., pressure cuff inflation) occurring ipsilateral to the location of parameter measurement are disclosed. Upon passive detection of signal degradation resulting from the event, the apparatus selectively enters a “wait state” wherein further processing of the hemodynamic data is suspended until the degrading event subsides. This behavior mitigates any adverse effects the event might have on the accuracy of the representation of the measured hemodynamic parameter generated by the system. In another exemplary embodiment, the measured data is analyzed in order to classify the type of event (e.g.

Abstract: An improved method and apparatus for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises a method of measuring a hemodynamic parameter by measuring a non-calibrated value of the parameter non-invasively, and inducing a stress of the circulatory system while measuring a second parameter. The response of the circulatory system to the stress is determined directly from the subject, and a calibration function is derived from the response and applied to the non-calibrated measured value to produce a calibrated measure of the actual value of the hemodynamic parameter. Methods of using backscattered acoustic energy for determination of hemodynamic markers are also disclosed.