WO2021126615A1

WO2021126615A1 - Continuous non-invasive blood pressure measurement device

Info

Publication number: WO2021126615A1
Application number: PCT/US2020/063900
Authority: WO
Inventors: Blake W. Axelrod; Alexander H. Siemons
Original assignee: Edwards Lifesciences Corporation
Priority date: 2019-12-16
Filing date: 2020-12-09
Publication date: 2021-06-24
Also published as: EP4076165A1; CN114615929A

Abstract

Disclosed is a blood pressure measurement device to measure a patient's blood pressure from a patient's arm. The blood pressure measurement device may include an external brachial arm cuff mountable around the patient's arm to determine discrete absolute blood pressure (BP) measurements from the patient's brachial artery, and a sensor mountable near the external brachial arm cuff to measure a continuous pulsatility waveform from the patient' s brachial artery. The discrete absolute blood pressure measurements are combined with the measured continuous pulsatility waveform for pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking at the brachial location to provide continuous beat-to-beat non- invasive blood pressure monitoring.

Description

CONTINUOUS NON-INVASIVE BUOOD PRESSURE MEASUREMENT DEVICE

CROSS-REFERENCE TO REUATED APPUICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 62/948,458 filed December 16^th, 2019, which is incorporated by reference herein in its entirety.

BACKGROUND

Field

[0001] Embodiments of the invention relate to non-invasive blood pressure measurement. More particularly, embodiments relate to an external brachial arm cuff and a sensor that combine discrete absolute blood pressure measurements with a measured continuous pulsatility waveform for pulse wave analysis (PWA) blood pressure (BP) tracking to provide continuous beat-to-beat non-invasive blood pressure monitoring.

Relevant Background

[0002] Conventionally, absolute non-invasive blood pressure measurements are typically performed using external cuffs that apply pressure to one or more arteries and the response of the arteries is observed to determine the patient’s blood pressure. Auscultatory and oscillometric blood pressure cuffs typically use this technique to obtain discrete (non- continuous) blood pressure measurements. However, applying pressure to a patient’s arteries has downsides. For example, the large pressures required by auscultatory and oscillometric techniques are uncomfortable. Therefore, use of these techniques is typically limited to a single measurement every 3-5 minutes.

[0003] “Cuff-less” blood pressure measurement techniques that do not require applying an external force to the arteries or require very low forces have been developed. Pulse wave analysis (PWA) techniques that obtain an arterial pulsatility waveform, extract amplitude and timing features, and track changes in the those features over time that correlate with changes in blood pressure over time are the most successful class of cuff-less blood pressure measurement techniques. Examples of PWA techniques include photoplethysmogramy techniques developed by Centre Suisse d’Electronique et de Microtechnique (CSEM). However, these techniques are unable to obtain absolute blood pressure values from which to track changes. [0004] Despite the brachial artery being the most common location for absolute BP measurements, PWA techniques being applied to a pulsatility waveform obtained at the brachial artery have not been utilized to aid in continuous blood pressure measurement.

SUMMARY

[0005] In one example, disclosed is a blood pressure measurement device to measure a patient’s blood pressure from a patient’s arm. The blood pressure measurement device may comprise: an external brachial arm cuff mountable around the patient’s arm to determine discrete absolute blood pressure (BP) measurements from the patient’s brachial artery; and a sensor mountable near the external brachial arm cuff to measure a continuous pulsatility waveform from the patient’s brachial artery. The discrete absolute blood pressure measurements may be combined with the measured continuous pulsatility waveform for pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking at the brachial location to provide continuous beat-to-beat non-invasive blood pressure monitoring.

[0006] In one optional example, the sensor may be a flexible pressure sensor to measure artery pulsations by surface pressure induced by the movement of the patient’s brachial artery. In another optional example, the sensor may be a strain sensor to measure artery pulsations by strains induced by the movement of the patient’s brachial artery. As an optional example, the external brachial arm cuff may be an oscillometric cuff. Further, as an optional example, the absolute blood pressure measurements comprise systolic pressure, mean arterial pressure (MAP), and diastolic pressure. Further, the brachial location may be at approximately heart level, such that, compensation for hydrostatic changes is not required.

As an additional optional example, the continuous non-invasive blood pressure monitoring is displayed on a display device. It should be appreciated that the optional examples may be utilized independently from one another or in combination with one another.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a diagram of a blood pressure measurement device to measure a patient’s blood pressure from a patient’s arm, according to one example.

[0008] Figure 2 is a view of blood pressure measurement device attached to a patient’s arm to measure the patient’s blood pressure from the patient’s arm, according to one example.

[0009] Figure 3 is a flowchart illustrating a method for continuously monitoring the blood pressure of a patient, according to one example.

[0010] Figure 4 is a graph of a waveform illustrating a continuous pulsatility waveform of the patient’s brachial artery, according to one example. [0011] Figure 5 is a graph showing discrete absolute blood pressure measurements combined with the obtained pulsatility waveform for pulse wave analysis (PWA) blood pressure (BP) tracking to provide for continuous beat-to-beat non-invasive blood pressure monitoring, according to one example.

DETAILED DESCRIPTION

[0012] Various examples and aspects of the disclosures will be described with reference to details discussed below, and the accompanying drawings will illustrate the various examples. The following description and drawings are illustrative of the disclosure and are not to be construed as limiting the disclosure. Numerous specific details are described to provide a thorough understanding of various examples of the present disclosure. However, in certain instances, well-known or conventional details are not described in order to provide a concise discussion of examples of the present disclosures.

[0013] Reference in the specification to an example or an optional example means that a particular feature, structure, or characteristic described in conjunction with the example can be included in at least one example of the disclosure. The appearances of the phrase example or optional example in various places in the specification do not necessarily all refer to the same example.

[0014] Examples of the disclosure may relate to: combining a sensor to obtain pulsatility waveforms for pulse wave analysis (PWA) blood pressure (BP) tracking at a brachial location with a traditional oscillometric brachial arm cuff. This is beneficial in that it may combine both absolute blood pressure measurement and tracking into a single device. Further, this type of implementation of combining a traditional oscillometric brachial arm cuff with a sensor provides a type of form factor that is well understood and accepted in suitable medical environments (e.g., hospitals and other healthcare settings). Moreover, the brachial location is at heart level and does not require compensation for hydrostatic changes. In particular, examples of the disclosure relate to combining a sensor (e.g., a flexible pressure sensor or strain sensor) to obtain a pulsatility waveform from which changes in blood pressure (BP) may be tracked using PWA (Pulse Wave Analysis) techniques with a traditional external oscillometric brachial arm cuff that measures a discrete absolute blood pressure measurement from which the changes can be tracked. As an example, the flexible pressure sensor or strain sensor conforms to the subject’s arm in close proximity to the brachial artery. The sensor can measure the brachial artery pulsations by measuring either the surface pressure or strains induced by the movement of the artery within the arm. It should be appreciated that some of the examples may be utilized independently from one another or in combination with one another.

[0015] With reference to Figure 1, in one example, a diagram of a blood pressure measurement device 100 to measure a patient’s blood pressure from a patient’s arm is disclosed. The blood pressure measurement device 100 may comprise: an external brachial arm cuff 102 mountable around the patient’s arm to determine discrete absolute blood pressure (BP) measurements from the patient’s brachial artery; and a sensor 104 mountable near the external brachial arm cuff to measure a continuous pulsatility waveform from the patient’s brachial artery. The discrete absolute blood pressure measurements may be combined with the measured continuous pulsatility waveform from the sensor 104 for pulse wave analysis (PWA) blood pressure (BP) beat-to-beat tracking at the brachial location to provide continuous beat-to-beat non-invasive blood pressure monitoring.

[0016] Further, in one optional example, the blood pressure measurement device 100 may include the external brachial arm cuff 102 mountable around a patient’s arm; the sensor 104 mountable near the external brachial arm cuff; a display device 120; a memory 107; and a processor 106 coupled to the memory 107. The processor may process data to: determine discrete absolute blood pressure (BP) measurements from the patient’s brachial artery from the external brachial arm cuff 102; measure a continuous pulsatility waveform from the patient’s brachial artery from the sensor 104; combine the discrete absolute blood pressure measurements with the measured continuous pulsatility waveform for pulse wave analysis (PWA) blood pressure (BP) tracking at the brachial location to determine continuous beat-to- beat non-invasive blood pressure values; and display the continuous beat-to-beat non- invasive blood pressure values on the display device 120. As an optional example, a wireless or wired interface 108 may transmit the continuous beat-to-beat non-invasive blood pressure values for display on the display device 120. Therefore, continuous non-invasive blood pressure monitoring may be displayed on the display device 120.

[0017] In one optional example, the sensor 104 may be a flexible pressure sensor to measure artery pulsations by surface pressure on the patient’s skin induced by the movement of the patient’s brachial artery. In another optional example, the sensor 104 may be a strain sensor to measure artery pulsations by strains induced by the movement of the patient’s brachial artery on the patient’s skin. As an optional example, the external brachial arm cuff 102 may be an oscillometric cuff. As another optional example, the external brachial arm cuff 102 may be an auscultatory cuff. Further, as an optional example, the absolute blood pressure measurements may comprise systolic pressure, mean arterial pressure (MAP), and diastolic pressure. Additionally, the brachial location where the cuffs and sensor are located may be at approximately heart level, such that, compensation for hydrostatic changes is not required. Also, as has been described, the continuous non-invasive blood pressure monitoring may be displayed on a display device 120.

[0018] In one example, with additional reference to Figure 2, a view of the blood pressure measurement device 100 attached to a patient’s arm 130 to measure the patient’s blood pressure from the patient’s arm 130 is shown. As has been described, the blood pressure measurement device 100 may comprise: an external brachial arm cuff 102 mountable around the patient’s arm 130 to determine discrete absolute blood pressure (BP) measurements from the patient’s brachial artery 140; and a sensor 104 mountable near the external brachial arm cuff 102 to measure a continuous pulsatility waveform from the patient’s brachial artery. The discrete absolute blood pressure measurements may be combined with the measured continuous pulsatility waveform for pulse wave analysis (PWA) blood pressure (BP) beat-to-beat tracking at the brachial location to provide continuous non- invasive blood pressure monitoring.

[0019] In this example, as shown in Figure 2, the external brachial arm cuff 102 may be placed around a patient’s upper arm 132. The external brachial arm cuff 102 may be of conventional shape - approximately circular and conical shaped with a cavity to accept the patient’s arm 130. The external brachial arm cuff 102 may comprise components necessary for conventional oscillometric blood pressure measurement (e.g., pneumatic elements, pressure sensors, etc.). Arm cuffs to perform oscillometric blood pressure measurement are well known in the art. However, as another optional example, the external brachial arm cuff 102 may be an auscultatory cuff.

[0020] As can be seen in Figure 2, in this optional example, the external brachial arm cuff 102 may be wrapped around the patient’s upper arm 132. The external brachial oscillometric arm cuff 102 may be used to measure discrete absolute blood pressure from the brachial artery 140 (e.g., systolic pressure, diastolic pressure, mean arterial pressure (MAP), etc.). Further, a sensor 104 may be mounted on the patient’s inner arm 134. The sensor 104 may be a flexible pressure sensor or a strain sensor. The flexible pressure sensor 104 or strain sensor 104 may be used to obtain a pulsatility waveform from the brachial artery 140. The sensor 104 may conform to the subject’s inner arm 134 in close proximity to the brachial artery 140. The sensor 104 can measure the pulsations of the brachial artery 140. As one optional example, in a flexible pressure sensor implementation, the flexible pressure sensor 104 may measure the surface pressure of the inner arm 134 by the movement of the brachial artery 140. As another optional example, in a strain sensor implementation, the strain sensor 104 may measure strains induced by the movement of the brachial artery 140 within the inner arm 134. In particular, the flexible pressure sensor or strain sensor may measure a continuous pulsatility waveform. As will be described in more detail hereafter, the discrete absolute blood pressure measurements from the external brachial arm cuff 102 can be combined with the obtained pulsatility waveforms from the sensor 104 for pulse wave analysis (PWA) blood pressure (BP) tracking at the brachial location to provide for continuous non-invasive blood pressure monitoring. Further, the brachial location may be at approximately heart level 145, such that, compensation for hydrostatic changes is not required.

[0021] It should be appreciated that although a flexible pressure sensor or a strain sensor are provided as examples of a sensor 104 that may be utilized, it should be appreciated that any suitable digital or analog sensor may be utilized to perform the previously described functions. As examples, any suitable type of electronic pressure sensor, electromagnetic pressure sensor, mechanical pressure sensor, capacitive pressure sensor, optical pressure sensor, piezoelectric pressure sensor, strain gauge pressure sensor, piezoresistive strain gauge pressure sensor, etc., may be utilized, which are merely examples. Therefore, it should be appreciated that the optional examples (e.g., flexible pressure sensors, strain sensors, or other types of sensors) may be utilized independently from one another or in combination with one another.

[0022] Further, it should be appreciated that sensor 104 may be coupled to the external brachial arm cuff 102 by connection wires 150 such that the arm cuff and sensor are connectable to a patient in a suitable easy way with a proper form factor to be simply connectable to a patient by medical personnel in a medical environment or by any user (e.g., a personal home user). In this way, blood pressure measurement device 100 that includes both the arm cuff 102 and sensor 104 is an easily useable product. However, this is only one example of a connection type between the arm cuff 102 and sensor 104. The arm cuff 102 and sensor 104 may be connectable by any suitable means, such as, flexible polymers (natural or synthetic), plastics, metals, combinations thereof, VELCRO, adhesive, mechanical methods, etc., or any suitable means to keep the arm cuff 102 and sensor 104 connected together. However, in other optional examples, the arm cuff 102 and sensor 104 may each be separately connected to the patient’s arm 130 and not physically connected each other. Also, the sensor 104 and arm cuff 102 may be wirelessly connected by suitable electromagnetic signal transmission means to one another and/or other local or remote computing devices for the processing of obtained pulsatility waveforms from the sensor 104 for pulse wave analysis (PWA) blood pressure (BP) tracking at the brachial location to provide for continuous non- invasive blood pressure monitoring, as will be described in more detail hereafter. Therefore, it should be appreciated that optional examples may be utilized independently from one another or in combination with one another.

[0023] With brief additional reference to Figure 3, Figure 3 is a flowchart illustrating an optional example method 300. As shown in Figure 3, a method for continuously monitoring the blood pressure of a patient is shown. At process step 310, discrete absolute blood pressure (BP) measurements are determined from the patient’s brachial artery from an external brachial arm cuff. At process step 320, a continuous pulsatility waveform from the patient’s brachial artery from a sensor is measured. At process step 330, the discrete absolute blood pressure measurements are combined with the measured continuous pulsatility waveform for pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking at the brachial location to provide continuous non-invasive blood pressure monitoring.

[0024] With additional reference to Figures 4 and 5, examples of the disclosure related to discrete absolute blood pressure measurements being combined with the measured continuous pulsatility waveform for pulse wave analysis (PWA) blood pressure (BP) tracking to provide continuous non-invasive blood pressure monitoring, will be described. Figure 4 shows a graph of a waveform 400 (pulsatility versus time) illustrating the continuous pulsatility waveform of the patient’s brachial artery 140 as measured by the sensor 104. Figure 5 shows the discrete absolute blood pressure measurements combined with the obtained pulsatility waveforms for pulse wave analysis (PWA) blood pressure (BP) tracking to provide for continuous non-invasive blood pressure monitoring. Figure 5 illustrates blood pressure values versus time.

[0025] For example, for illustrative purposes, 501 shows discrete absolute blood pressure measurements 510 (e.g., systolic) from the external arm cuff 102 combined with the obtained continuous pulsatility waveform 400 from the sensor 104 that undergoes pulse wave analysis (PWA) blood pressure (BP) tracking to create beat-to-beat blood pressure values 500 to provide continuous non-invasive blood pressure monitoring. In particular, the intervals between the systolic discrete absolute blood pressure measurements 510 are calculated based upon the combination of the discrete systolic absolute blood pressure measurements 510 with the measured continuous pulsatility waveform 400 that provides for pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking to provide for the continuous beat-to-beat non-invasive blood pressure values 500 (e.g., including the intervals between the discrete absolute blood pressure measurements). Similarly, for illustrative purposes, 503 shows discrete absolute blood pressure measurements 520 (e.g., diastolic) from the external arm cuff 102 combined with the obtained continuous pulsatility waveform 400 from the sensor 104 that undergoes pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking to create beat-to-beat blood pressure values 502 to provide continuous non-invasive blood pressure monitoring. In particular, the intervals between the diastolic discrete absolute blood pressure measurements 520 are calculated based upon the combination of the discrete diastolic absolute blood pressure measurements 520 with the measured continuous pulsatility waveform 400 that provides for pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking to provide for the continuous beat-to-beat non-invasive blood pressure values 502 (e.g., including the intervals between the discrete absolute blood pressure measurements). It should be appreciated that mean arterial pressure (MAP) can be similarly calculated.

[0026] In one example, the blood pressure measurement device 100 may comprise: an external brachial arm cuff 102 mountable around the patient’s arm 130 to determine discrete absolute blood pressure (BP) measurements from the patient’s brachial artery 140; and a sensor 104 mountable near the external brachial arm cuff 102 to measure a continuous pulsatility waveform (e.g., the measured continuous pulsatility waveform 400 from Figure 4) from the patient’s brachial artery. The discrete absolute blood pressure measurements (e.g., 510, 520 from Figure 5) may be combined with the measured continuous pulsatility waveform (e.g., the measured continuous pulsatility waveform 400 from Figure 4) to provide for pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking at the brachial location to provide continuous non-invasive blood pressure monitoring (e.g., including the intervals between the discrete absolute blood pressure measurements). As an example, for illustrative purposes, as show in Figures 4 and 5, 501 shows discrete absolute blood pressure measurements 510 (e.g., systolic) from the external arm cuff 102 combined with the obtained continuous pulsatility waveform 400 from the sensor 104 that undergoes pulse wave analysis (PWA) blood pressure (BP) tracking to create beat-to-beat blood pressure values 500 to provide continuous non-invasive blood pressure monitoring. Similarly, 503 shows discrete absolute blood pressure measurements 520 (e.g., diastolic) from the external arm cuff 102 combined with the obtained continuous pulsatility waveform 400 from the sensor 104 that undergoes pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking to create beat-to-beat blood pressure values 502 to provide continuous non-invasive blood pressure monitoring. A variety of pulse wave analysis (PWA) techniques may be utilized to achieve these functions. This continuous non-invasive blood pressure monitoring may be displayed on an appropriate display device 120. [0027] In another optional example, the blood pressure measurement device 100 may include the external brachial arm cuff 102 mountable around a patient’s arm 130; the sensor 104 mountable near the external brachial arm cuff 102; a display device 102; a memory 107; and a processor 106 coupled to the memory 107. The processor may process data to: determine discrete absolute blood pressure (BP) measurements (e.g., 510, 520 from Figure 5) from the patient’s brachial artery 140 from the external brachial arm cuff 102; measure a continuous pulsatility waveform (e.g., 400 from Figure 4) from the patient’s brachial artery 140 from the sensor 104; combine the discrete absolute blood pressure measurements with the measured continuous pulsatility waveform for pulse wave analysis (PWA) blood pressure (BP) tracking at the brachial location to determine a continuous non-invasive blood pressure waveform (e.g., a waveform implementation that is similar to the values shown in Figure 5); and display the continuous non-invasive blood pressure waveforms on the display device 120.

[0028] Continuing with the current example, the discrete absolute blood pressure measurements (e.g., 510, 520 from Figure 5) may be combined with the measured continuous pulsatility waveform (e.g., measured continuous pulsatility waveform 400 from Figure 4) for pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking at the brachial location to provide continuous non-invasive blood pressure monitoring (e.g., including the intervals between the discrete absolute blood pressure measurements). As an example, for illustrative purposes, as shown in Figures 4 and 5, beat-to-beat values 500 shows discrete absolute blood pressure measurements 510 (e.g., systolic) from the external arm cuff 102 combined with the obtained continuous pulsatility waveform 400 from the sensor 104 that undergoes pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking to create beat-to-beat values 500 to provide continuous non-invasive blood pressure monitoring. Similarly, beat-to-beat values 502 shows discrete absolute blood pressure measurements 520 (e.g., diastolic) from the external arm cuff 102 combined with the obtained continuous pulsatility waveform 400 from the sensor 104 that undergoes pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking to create beat-to-beat values 502 to provide continuous non-invasive blood pressure monitoring. A variety of pulse wave analysis (PWA) techniques may be utilized to achieve these functions. Thus, the patient’s blood pressure can be continuously monitored, tracked, determined, and displayed based on the discrete baseline absolute blood pressures and the pulsatility waveform utilizing PWA techniques. Such PWA techniques may include any suitable PWA technique, such as techniques developed by Centre Suisse d’Electronique et de Microtechnique (CSEM). This continuous non-invasive blood pressure monitoring may be displayed on an appropriate display device 120. It should be appreciated that the various previously described optional examples: types of sensors - e.g., flexible pressure sensors, strain sensors, or other types of sensors; types of connections - e.g., wireless or wired; types of arm cuffs; and types of PWA techniques; may be utilized independently from one another or in combination with one another. Accordingly, it should be appreciated that a wide variety of the previously described optional examples may be utilized independently from one another or in combination with one another.

[0029] It should be appreciated that the processing functions to implement PWA blood pressure tracking to implement the continuous non-invasive blood pressure monitoring for calculation and display may be implemented utilizing appropriate hardware, firmware, and/or software at the arm cuff 102, sensor 104, display device 120, or by any suitable local or remote computing device, or combinations thereof, and these devices may be in suitable wired and/or wireless communication. Further, the display on the display device may be a local display at the device itself, at a local remote device, or at a remote device at any location.

[0030] Thus, the disclosure relates to combining a flexible pressure sensor or strain sensor to obtain a pulsatility waveform from which changes in blood pressure (BP) may be tracked using PWA (Pulse Wave Analysis) techniques with an external cuff that measures a discrete absolute blood pressure measurement from which changes can be tracked. In particular, examples of the disclosure may relate to: combining a sensor to obtain pulsatility waveforms for pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking at a brachial location with a traditional oscillometric brachial arm cuff. This is beneficial in that it may combine both absolute blood pressure measurement and tracking into a single device. Further, this type of implementation of combining a traditional oscillometric brachial arm cuff with a sensor provides a type of form factor that is well understood and accepted in suitable medical environments (e.g., hospitals and other healthcare settings). However, implementations may also be easily implemented in non-medical environments (e.g., home, work, etc.).

[0031] It should be appreciated that aspects of the disclosure previously described may be implemented in conjunction with the execution of instructions by processors, circuitry, controllers, control circuitry, etc. (e.g., processor 106 of Figure 1). As an example, a processor may operate under the control of a program, algorithm, routine, or the execution of instructions to execute methods or processes (e.g., method 300 of Figure 3) in accordance with embodiments previously described. For example, such a program may be implemented in firmware or software (e.g. stored in memory and/or other locations) and may be implemented by processors, control circuitry, and/or other circuitry, these terms being utilized interchangeably. Further, it should be appreciated that the terms processor, microprocessor, circuitry, control circuitry, circuit board, controller, microcontroller, etc., refer to any type of logic or circuitry capable of executing logic, commands, instructions, software, firmware, functionality, etc., which may be utilized to execute embodiments of the invention.

[0032] The various illustrative logical blocks, processors, modules, and circuitry described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a specialized processor, circuitry, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor may be a microprocessor or any conventional processor, controller, microcontroller, circuitry, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0033] The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module/firmware executed by a processor, or any combination thereof. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.

[0034] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. [0035] The disclosure also includes the following clauses:

1. A blood pressure measurement device to measure a patient’s blood pressure from a patient’s arm, comprising: an external brachial arm cuff mountable around the patient’ s arm to determine discrete absolute blood pressure (BP) measurements from the patient’s brachial artery; and a sensor mountable near the external brachial arm cuff to measure a continuous pulsatility waveform from the patient’s brachial artery, wherein, the discrete absolute blood pressure measurements are combined with the measured continuous pulsatility waveform for pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking at the brachial location to provide continuous non-invasive blood pressure monitoring.

2. The blood pressure measurement device of claim 1, wherein the sensor is a flexible pressure sensor to measure artery pulsations by surface pressure induced by the movement of the patient’s brachial artery.

3. The blood pressure measurement device of claim 1, wherein the sensor is a strain sensor to measure artery pulsations by strains induced by the movement of the patient’s brachial artery.

4. The blood pressure measurement device of any of the claims 1-3, wherein the external brachial arm cuff is an oscillometric cuff.

5. The blood pressure measurement device of any of the claims 1-4, wherein the absolute blood pressure measurements comprise systolic pressure, mean arterial pressure (MAP), and diastolic pressure.

6. The blood pressure measurement device of any of the claims 1-5, wherein the brachial location is at approximately heart level, such that, compensation for hydrostatic changes is not required.

7. The blood pressure measurement device of any of the claims 1-6, wherein the continuous non-invasive blood pressure monitoring is displayed on a display device. 8. The blood pressure measurement device of any of the claims 1-7, wherein the discrete blood pressure (BP) measurements are combined with the pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking and the continuous pulsatility waveform to estimate a continuous blood pressure waveform.

9. The blood pressure measurement device of claim 8, wherein the continuous blood pressure waveform is displayed on a display device.

10. A blood pressure measurement system, comprising: an external brachial arm cuff mountable around a patient’ s arm; a sensor mountable near the external brachial arm cuff; a display device; a memory; and a processor coupled to the memory, the processor configured to: determine discrete absolute blood pressure (BP) measurements from the patient’s brachial artery from the external brachial arm cuff; measure a continuous pulsatility waveform from the patient’s brachial artery from the sensor; combine the discrete absolute blood pressure measurements with the measured continuous pulsatility waveform for pulse wave analysis (PWA) blood pressure (BP) tracking at the brachial location to determine a continuous non-invasive blood pressure waveform; and display the continuous non-invasive blood pressure waveform on the display device.

11. The blood pressure measurement system of claim 10, wherein the sensor is a flexible pressure sensor to measure artery pulsations by surface pressure induced by the movement of the patient’s brachial artery.

12. The blood pressure measurement system of claim 10, wherein the sensor is a strain sensor to measure artery pulsations by strains induced by the movement of the patient’ s brachial artery. 13. The blood pressure measurement system of any of the claims 10-12, wherein the external brachial arm cuff is an oscillometric cuff.

14. The blood pressure measurement system of any of the claims 10-13, wherein the absolute blood pressure measurements comprise systolic pressure, mean arterial pressure (MAP), and diastolic pressure.

15. The blood pressure measurement system of any of the claims 10-14, wherein the brachial location is at approximately heart level, such that, compensation for hydrostatic changes is not required.

16. The blood pressure measurement system of any of the claims 10-15, wherein the discrete blood pressure (BP) measurements are combined with pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking and the continuous pulsatility waveform to estimate the continuous blood pressure waveform.

17. A method for continuously monitoring the blood pressure of a patient, comprising: determining discrete absolute blood pressure (BP) measurements from the patient’s brachial artery from an external brachial arm cuff; measuring a continuous pulsatility waveform from the patient’s brachial artery from a sensor; and combining the discrete absolute blood pressure measurements with the measured continuous pulsatility waveform for pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking at the brachial location to provide continuous non-invasive blood pressure monitoring.

18. The method of claim 17, wherein the sensor is a flexible pressure sensor to measure artery pulsations by surface pressure induced by the movement of the patient’s brachial artery.

19. The method of claim 17, wherein the sensor is a strain sensor to measure artery pulsations by strains induced by the movement of the patient’s brachial artery. 20. The method of any of the claims 17-19, wherein the external brachial arm cuff is an oscillometric cuff.

21. The method of any of the claims 17-20, wherein the absolute blood pressure measurements comprise systolic pressure, mean arterial pressure (MAP), and diastolic pressure.

22. The method of any of the claims 17-21, wherein the brachial location is at approximately heart level, such that, compensation for hydrostatic changes is not required.

23. The method of any of the claims 17-22, further comprising displaying the continuous non-invasive blood pressure monitoring on a display device.

24. The method of any of the claims 17-23, wherein the discrete blood pressure (BP) measurements are combined with the pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking and the continuous pulsatility waveform to estimate a continuous blood pressure waveform.

25. The method claim 24, further comprising displaying the continuous blood pressure waveform on a display device.

Claims

WHAT IS CLAIMED IS:

7. The blood pressure measurement device of any of the claims 1-6, wherein the continuous non-invasive blood pressure monitoring is displayed on a display device.

8. The blood pressure measurement device of any of the claims 1-7, wherein the discrete blood pressure (BP) measurements are combined with the pulse wave analysis (PWA) beat-to-beat blood pressure (BP) tracking and the continuous pulsatility waveform to estimate a continuous blood pressure waveform.

12. The blood pressure measurement system of claim 10, wherein the sensor is a strain sensor to measure artery pulsations by strains induced by the movement of the patient’ s brachial artery.

13. The blood pressure measurement system of any of the claims 10-12, wherein the external brachial arm cuff is an oscillometric cuff.

19. The method of claim 17, wherein the sensor is a strain sensor to measure artery pulsations by strains induced by the movement of the patient’s brachial artery.

20. The method of any of the claims 17-19, wherein the external brachial arm cuff is an oscillometric cuff.