Abstract: Methods and apparatus for measuring arterial compliance using combined noninvasive arterial tonometry and cuff oscillometry. Some embodiments include a calibration method using an oscillometric signal to calibrate the pressures of tonometric signals in a contralateral arterial site. The times at which two of the three oscillometric blood pressures (systolic pressure, mean pressure, diastolic pressure) are acquired are identified with times of uncalibrated tonometric pressure waveform. These blood pressures are then used to calibrate the tonometric pressure waveform along (optionally) with adjustments for head pressure. For example, a left brachial arterial cuff oscillometric signal is acquired coincidentally with an uncalibrated right radial arterial pressure tonometric signal. The time points of mean arterial pressure and diastolic pressure are determined from the oscillometric signal and identified with coinciding time points on the tonometric signal to produce a calibration.

Abstract: Methods and apparatus for measuring arterial compliance using combined noninvasive arterial tonometry and cuff oscillometry. Some embodiments include a calibration method using an oscillometric signal to calibrate the pressures of tonometric signals in a contralateral arterial site. The times at which two of the three oscillometric blood pressures (systolic pressure, mean pressure, diastolic pressure) are acquired are identified with times of un-calibrated tonometric pressure waveform. These blood pressures are then used to calibrate the tonometric pressure waveform along (optionally) with adjustments for head pressure. For example, a left brachial arterial cuff oscillometric signal is acquired coincidentally with an un-calibrated right radial arterial pressure tonometric signal. The time points of mean arterial pressure and diastolic pressure are determined from the oscillometric signal and identified with coinciding time points on the tonometric signal to produce a calibration.

Abstract: Methods and apparatus for processing an arterial blood pressure waveform to extract clinically useful information on the state of the cardiovascular system are disclosed herein. In order to obtain the parameters of the modified Windkessel model, the diastolic portion of a subject's blood pressure waveform is scanned over a plurality of ranges and the range that produces the best fit of data and lowest error estimates are selected. In addition, multiple empirically determined starting values of the ‘A’ parameters are used to find the best fit of the model data to the actual arterial blood pressure waveform data.

Abstract: Methods and apparatus for non-invasively measuring arterial compliance using the combination of noninvasive arterial tonometry and noninvasive cuff oscillometry. Some embodiments include an accurate calibration method using an oscillometric signal to calibrate the pressures of tonometric signals in a contralateral arterial site. The exact time at which two of the three oscillometric blood pressures (systolic pressure, mean pressure, diastolic pressure) are acquired are identified with precise locations on the un-calibrated tonometric pressure waveform. These two blood pressures are then used to calibrate the tonometric pressure waveform along (optionally) with adjustments for head pressure. For example, a left brachial arterial cuff osciilometric signal is acquired coincidentally with an un-calibrated right radial arterial pressure tonometric signal.

Abstract: A method for fabricating a pressure-waveform sensor with a leveling support element. One embodiment provides a pressure-waveform sensor having a housing, a support element, and a piezoelectric element having a first end secured between the support element and the housing, and a second end in a cantilevered orientation. The support element and the piezoelectric element together form a plurality of support regions to level the piezoelectric element and relative to the housing. In some embodiments, the support element includes a ring having three slots spaced apart on one face of the ring, or one or more support regions formed with a shim having a thickness equal to a thickness of the piezoelectric device, or support regions that are integral to the support element. Another aspect provides a method for fabricating a pressure-waveform sensor.

Abstract: A vascular impedance measurement instrument includes a transducer to obtain a digitized arterial blood pressure waveform. The digitized data is used to determine cardiac output, and to subsequently obtain measurements of impedance parameters using the modified Windkessel model of the arterial system. The instrument is used as an aid in diagnosing, treating and monitoring patients with cardiovascular disease.

Abstract: A method and an apparatus for fabricating a pressure-waveform sensor with a leveling support element. One embodiment provides a pressure-waveform sensor having a housing, a support element, and a piezoelectric element having a first end secured between the support element and the housing, and a second end in a cantilevered orientation. The support element and the piezoelectric element together form a plurality of support regions to level the piezoelectric element and relative to the housing. In some embodiments, the support element includes a ring having three slots spaced apart on one face of the ring, or one or more support regions formed with a shim having a thickness equal to a thickness of the piezoelectric device, or support regions that are integral to the support element. Another aspect provides a method for fabricating a pressure-waveform sensor.

Abstract: Method and apparatus for acquiring and analyzing signals to generate medical data pertinent to one or more individuals and storing the data in a local machine, then collecting the medical data to a centralized system for further analysis and/or creation of invoices for billing. Some embodiments include a medical-data collection apparatus for processing an arterial blood pressure waveform to extract clinically useful information on the state of the cardiovascular system of an individual. After storing medical data for one or more individuals, the medical-data collection apparatus establishes communications with a centralized information-processing system, uploads its data, and is re-enabled to collect further data. The information-processing system optionally generates bills or invoices for the services based on usage of each of the medical-data collection apparatus, and optionally aggregates the data from a plurality of individuals for further analysis.

Abstract: A method and a sensor holding and positioning device. In one embodiment, the device includes a sensor base having two feet, the base forming a raised bridge between the two feet. The bridge has one or more cross members spanning all or part of the space between the two feet. A sensor suspension including a sensor holder and sensor-height-adjustment mechanism is coupled by a pivot-arm axle to the sensor base, such that the sensor suspension is able to rotate in an arc about the long axis of the axle. In one such embodiment, the device further includes a pressure sensor attached to the sensor holder of the sensor suspension. In another such embodiment, the sensor suspension is able to slide back and forth along a line parallel to the long axis of the axle. Another aspect is a method for positioning a sensor over the radial artery, for example in a human's wrist. Yet another aspect is a pulse-waveform acquisition system.

Abstract: Methods and apparatus for processing an arterial blood pressure waveform to extract clinically useful information on the state of the cardiovascular system are disclosed herein. In order to obtain the parameters of the modified Windkessel model, the diastolic portion of a subject's blood pressure waveform is scanned over a plurality of ranges and the range that produces the best fit of data and lowest error estimates are selected. In addition, multiple empirically determined starting values of the ‘A’ parameters are used to find the best fit of the model data to the actual arterial blood pressure waveform data.

Abstract: Methods and apparatus for processing an arterial blood pressure waveform to extract clinically useful information on the state of the cardiovascular system are disclosed herein. In order to obtain the parameters of the modified Windkessel model, the diastolic portion of a subject's blood pressure waveform is scanned over a plurality of ranges and the range that produces the best fit of data and lowest error estimates are selected. In addition, multiple empirically determined starting values of the ‘A’ parameters are used to find the best fit of the model data to the actual arterial blood pressure waveform data.

Abstract: A vascular impedance measurement instrument includes a transducer to obtain a digitized arterial blood pressure waveform. The digitized data is used to determine cardiac output, and to subsequently obtain measurements of impedance parameters using the modified Windkessel model of the arterial system. The instrument is used as an aid in diagnosing, treating and monitoring patients with cardiovascular disease.

Abstract: A method and an apparatus for fabricating a pressure-waveform sensor with a leveling support element. One embodiment provides a pressure-waveform sensor having a housing, a support element, and a piezoelectric element having a first end secured between the support element and the housing, and a second end in a cantilevered orientation. The support element and the piezoelectric element together form a plurality of support regions to level the piezoelectric element and relative to the housing. In some embodiments, the support element includes a ring having three slots spaced apart on one face of the ring, or one or more support regions formed with a shim having a thickness equal to a thickness of the piezoelectric device, or support regions that are integral to the support element. Another aspect provides a method for fabricating a pressure-waveform sensor.

Abstract: A vascular impedance measurement instrument includes a transducer to obtain a digitized arterial blood pressure waveform. The digitized data is used to determine cardiac output, and to subsequently obtain measurements of impedance parameters using the modified Windkessel model of the arterial system. The instrument is used as an aid in diagnosing, treating and monitoring patients with cardiovascular disease.

Abstract: A method and a pulse pressure sensor for sensing an arterial pulse pressure waveform. In one embodiment, the pulse pressure sensor includes a housing, a diaphragm, a piezoelectric device, and a self-contained amplifier. The skin-contact diaphragm is attached across a recess or opening in the housing. The piezoelectric device has a first portion mounted in a fixed relationship to the housing and a second portion displacementally coupled to the diaphragm. The solid-state amplifier has a signal input coupled to the piezoelectric device, wherein the piezoelectric device and amplifier together have a frequency response at least including a range from below approximately 0.1 hertz to above approximately 250 hertz. In one such embodiment, the housing and the skin-contact diaphragm of the sensor are stainless steel. In one such embodiment, the diaphragm has a skin-contact surface with a skin-contact dimension of between approximately 0.4 inch and 0.6 inch.

Abstract: A sensor holding and positioning device. In one embodiment, the device includes a sensor base having two feet, the base forming a raised bridge between the two feet. The bridge has one or more cross members spanning all or part of the space between the two feet. A sensor suspension including a sensor holder and sensor-height-adjustment mechanism is coupled by a pivot-arm axle to the sensor base, such that the sensor suspension is able to rotate in an arc about the long axis of the axle. In one such embodiment, the device further includes a pressure sensor attached to the sensor holder of the sensor suspension. In another such embodiment, the sensor suspension is able to slide back and forth along a line parallel to the long axis of the axle. Another aspect is for positioning the sensor over the radial artery, for example in a human's wrist. Yet another aspect is a pulse-waveform acquisition system.

Abstract: A vascular impedance measurement instrument includes a transducer to obtain a digitized arterial blood pressure waveform. The digitized data is used to determine cardiac output, and to subsequently obtain measurements of impedance parameters using the modified Windkessel model of the arterial system. The instrument is used as an aid in diagnosing, treating and monitoring patients with cardiovascular disease.

Abstract: Methods and apparatus for processing an arterial blood pressure waveform to extract clinically useful information on the state of the cardiovascular system are disclosed herein. In order to obtain the parameters of the modified Windkessel model, the diastolic portion of a subject's blood pressure waveform is scanned over a plurality of ranges and the range that produces the best fit of data and lowest error estimates are selected. In addition, multiple empirically determined starting values of the `A` parameters are used to find the best fit of the model data to the actual arterial blood pressure waveform data.

Abstract: Apparatus for Measuring Stroke Volume/Cardiac Output includes a transducer for measuring arterial blood pressure waveform, a digitizer for digitizing the analog signal generated by the transducer and a digital signal processor for determining ejection time and heart rate. Processor circuitry determines cardiac output using the ejection time, heart rate, the body surface area and age of the patient, with the cardiac output measure being displayed by the meter.