WO2011051822A1 - Apparatus and methods for enhancing and analyzing signals from a continous non-invasive blood pressure device - Google Patents
Apparatus and methods for enhancing and analyzing signals from a continous non-invasive blood pressure device Download PDFInfo
- Publication number
- WO2011051822A1 WO2011051822A1 PCT/IB2010/003325 IB2010003325W WO2011051822A1 WO 2011051822 A1 WO2011051822 A1 WO 2011051822A1 IB 2010003325 W IB2010003325 W IB 2010003325W WO 2011051822 A1 WO2011051822 A1 WO 2011051822A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signal
- ppg
- ppg signal
- pressure
- cuff
- Prior art date
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/021—Measuring pressure in heart or blood vessels
- A61B5/022—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/021—Measuring pressure in heart or blood vessels
- A61B5/022—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
- A61B5/02233—Occluders specially adapted therefor
- A61B5/02241—Occluders specially adapted therefor of small dimensions, e.g. adapted to fingers
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7203—Signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal
Definitions
- the invention relates generally to a method of measuring blood pressure, and more particularly to a continuous non-invasive arterial pressure (CNAP) measurement where the blood pressure signal is enhanced.
- CNAP non-invasive arterial pressure
- PC A Pulse contour analysis
- BP blood pressure
- Blood pressure may be measured in a number of ways.
- a standard non-invasive sphygmomanometer NBP
- the NBP applies pressure to the arteries, causing them to constrict and limit blood flow.
- NBP measures BP intermittently and not continuously, so it cannot be used for PCA.
- Another device for measuring blood pressure is a finger cuff having an infrared light source and a light detector for measuring a photo-plethysmographic (PPG) signal that is known also from pulse oximetry.
- PPG photo-plethysmographic
- This PPG-signal is fed into a control system, which produces a counter pressure in the finger cuff. It is well known that the counter pressure equals intra-arterial pressure when the PPG-signal is kept constant. Thus, the counter pressure, which is indirect equivalent to intra-arterial pressure, is measured.
- This method is known as "Vascular Unloading Technique," and the continuous pressure signal can be used for PCA.
- Intra-arterial transducers have relatively high frequency transmission (up to 200Hz) and can therefore be used for PCA.
- Some example parameters that may be calculated from the contour of the pulse wave include stroke volume (SV), cardiac output (CO), stroke volume variation (SVV), pulse pressure variation (PPV), and total peripheral resistance (TPR).
- SV stroke volume
- CO cardiac output
- SVV stroke volume variation
- PV pulse pressure variation
- TPR total peripheral resistance
- PCA can be used for other measurements which give insight to the human vascular properties, for example arterial stiffness.
- Invasive devices have the disadvantage of being overly disturbing and painful to the patient, whereas signals from non-invasive devices have problems with the fidelity or accuracy of the signal.
- a method for determining a blood pressure contour curve includes placing a photo-plesthysmographic (PPG) system over an artery in a human finger, the PPG system producing a PPG signal based on volume of the artery, the PPG system including at least one light source and at least one light detector, modifying a component of the PPG signal having a frequency higher than a predefined threshold frequency, and calculating a blood pressure signal using the modified PPG signal.
- PPG photo-plesthysmographic
- a computing device for determining a blood pressure contour curve.
- the computing device includes a pressure cuff adapted to be placed over an artery in a human finger, the cuff including a PPG system having at least one light source and at least one light detector, a pressure sensor, and a controller for controlling the pressure in the cuff.
- the PPG system produces a PPG signal based on volume of the artery, and a pressure signal is calculated using the PPG signal and this pressure signal is applied to cuff and finger.
- the computing device modifies a component of the PPG signal having a frequency higher than a predefined threshold frequency and calculates a blood pressure signal using the cuff pressure and the modified PPG signal.
- a method for eliminating undesired signal content of a continuous non-invasive arterial blood pressure device includes placing cuff having a photo-plesthysmographic (PPG) system over an artery in a human finger, the PPG system producing a PPG signal based on volume of the artery, eliminating from the PPG signal an undesired portion of the PPG signal, and reconstructing the PPG signal from the remaining portion of the PPG signal.
- PPG photo-plesthysmographic
- FIG. 1 shows a prior art Vascular Unloading Technique (VUT) control system using a photo-plesthysmographic (PPG) system controlling the cuff pressure for measuring blood pressure;
- FIG 2 describes the transfer function between PPG-signal v(t) at different constant cuff pressures;
- Figure 3 shows an example pulse of the remaining PPG-signal v(t) in search (open loop) and measuring (closed loop) mode
- Figure 4 shows a block diagram using different frequency ranges with different control gains and concepts
- Figure 5 is a block diagram of the calibration method
- Figure 6 shows the change in the remaining PPG-signal v(t) caused due to vasoconstriction of the artery
- Figure 7 describes prior art Pulse Contour Analysis (PC A) having one time varying input signal and several input parameters;
- Figure 8 is a block diagram of the new PCA-method and device.
- Figure 9 shows an example computing device that may be used with the system and method of the present application.
- a system and method of measuring and enhancing blood pressure (BP) signals is described. These modified, more accurate signals may then be used to more accurately calculate a variety of parameters for a patient, such as stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), and arterial stiffness, for example.
- the method extracts the AC-component of the photo-plethysmographic (PPG) signal of known "Vascular Unloading Technique" (VUT). In combination with the measured pressure signal, this signal is used as a second input for Pulse Contour Analysis (PCA).
- PPG photo-plethysmographic
- PCA Pulse Contour Analysis
- the VUT system 100 is used to obtain a PPG signal, which can then be used to control the cuff pressure, which is equivalent to the continuous arterial blood pressure.
- the VUT system 100 includes a "photo-plethysmographic" (PPG) system located within a finger cuff 102 and having one or more light sources 104 and one or more light detectors 106.
- PPG photo-plethysmographic
- the PPG-signal is fed into a control system 114 that produces a pressure in the cuff 102.
- a human finger 108 is placed in the finger cuff 102.
- the finger cuff 102 measures blood volume in an artery 110 of the finger 108.
- a controller 114 increases the pressure of the finger cuff 102, p cu ff(t), until the excess blood volume is squeezed out by pressure of the cuff.
- the controller 114 decreases p cu ff(t) so the overall blood volume in the artery remains constant.
- p art (t) is equal to cuff pressure p cu ff(t), which can easily be measured by means of a manometer (pressure measuring instrument), for example.
- intra-arterial pressure p art (t) itself is measured indirectly, and a PPG-signal v(t), which reflects the arterial blood volume changes in the measuring area (e.g. the finger) is obtained.
- the PPG signal is kept constant, the counter pressure eliminates the arterial blood volume changes and the diameter of the artery is also constant.
- VAc(t) alternating current-like component
- VUT methods rely on their valve systems as they are producing the pressure signal. Typically these valves systems are limited to upper cut-of frequencies of 15- 40Hz. Thus, the counter pressure in the cuff p cu ff(t) is often slower than the signal origin, which produces VAc(t). Additional factors like pressure coupling from cuff to tissue, air supply from pump to valve system and from valve system to cuff etc. limit the control system. These factors limit VUT and lead to remaining VAc(t).
- pulse pressure depends on the control loop gain(s) that are either calculated from the maximum PPG signal amplitude v max (t) according to the "PhysioCal” criteria or chosen empirically. These gains cannot be infinity, which would be necessary for zero VAc(t). When calculated from v max (t), the controller gain could be suboptimal.
- T is the pulse interval [sec] and N is the number of samples p ⁇ of the beat.
- a constant p cu ff is used in search modes of the VUT device for detecting mean BP before the actual measurement starts.
- p cu ff where PPG amplitude Ac(t) is at maximum, represents mean BP.
- This starting p cu ff is the so called starting setpoint p T0 .
- Figure 3 shows the mechanism p cu ff that is alternating around setpoint px and is controlled by v(t).
- the control condition is to keep v(t), and therefore blood volume in the finger, constant. This can only be done to a minimum amplitude of VAc(t)- Note the inverted characteristic of the control system.
- An increase of v(t) lowers p cu ff and a decrease of v(t) increases p cu ff due to the inverted characteristic of the PPG signal.
- Fig. 4 shows a block diagram of such a control system.
- v(t) is split into different frequency ranges. Pulsatile VACC , 1° w frequency VLF and very low frequency VVLF ⁇ are obtained with filters having cutoff frequencies at f V LF and fn?. It is a further advantage that the three frequency ranges have different gains gAc, gLF and gvLF- This allows for optimal gain application to v(t).
- Equation (2) is a more general formula, when using n control loops:
- ⁇ ++ ( ⁇ ) ⁇ ( + ⁇ [ ⁇ 1 ( ⁇ ), ⁇ 2 ( ⁇ )... ⁇ ) ⁇ ( ⁇ > fcvfci -fc n ] (2)
- Equation (2) for the embodiment described in Fig. 4 will be simplified as follows, because only VAc(t) and VLF ⁇ contribute to a meaningful signal:
- pulse wave form is different when measured at different sites (e.g. finger, upper arm, wrist, leg, etc.).
- sites e.g. finger, upper arm, wrist, leg, etc.
- finger arterial pressure devices lack accuracy in comparison to standard devices.
- One method of enhancing the VUT pressure signal p cu ff(t), and thus increasing accuracy of the signal is to calibrate the signal v that is measured at the finger to a standard upper arm sphygmomanometer (NBP).
- NBP standard upper arm sphygmomanometer
- One reason for doing this is that there are inherent physiological and hydrostatic differences of BP measured at the finger artery as opposed to the upper arm, since the upper arm is almost close to heart level whereas the finger can be anywhere.
- pulse pressure (PP) of BP depends on the control-loop gain(s) and these gains are parameters from the control system and not physiological.
- the gain is determined from the maximum VAC ⁇ amplitude according to the "physiocal” criteria, this amplitude depends on the actual vascular tone (vasoconstriction or vasodilatation). This has no information about BP.
- the gain(s) are chosen empirically by increasing the gain until the system start to swing with resonance frequency, these gain(s) also depends on vascular tone and system conditions. Again, this has no information about BP.
- the maximum VAC ⁇ amplitude indicates only that the constant cuff pressure in search mode is equal to mean BP.
- the value itself is more or less a "house number" as it depends on the actual vascular tone (vasoconstriction or vasodilatation) and therefore depends on the state of the autonomic nervous system of the patient to be measured.
- SBP and DBP are systolic and diastolic values measured from the NBP calibration device (e.g., the upper arm blood pressure cuff) and sBP and dBP are systolic and diastolic values measured from the uncalibrated finger cuff.
- This method lacks accuracy because slope k is not only scaling BP- pulse, but also hypo- and hypertensive episodes.
- This BP-trend does not need an artificial amplification as mean BP is correctly detected by the improved VUT system.
- this method amplifies natural rhythms of BP, e.g., the 0.1 Hz Traube-Hering- Mayer waves, and makes them look very non-physiological.
- Figure 5 shows a method that further improves the accuracy of the signal measured by the PPG system.
- the method includes only multiplying the component of the signal that has a frequency content higher than some threshold value, e.g., 0.3 Hz., by slope k. Signal components lower than the cut off frequency remain unamplified.
- the offset d is added.
- the amplification formula reads as follows:
- p A c(t) is the component of the measured pressure that has a frequency greater than the threshold frequency
- pn?(t) is the component of the measured pressure that has a frequency less than the threshold frequency
- Pulse wave frequency content is per se higher than the actual pulse rate or pulse frequency. For a normal pulse rate of 60 beats per minute, the pulse frequency is 1 Hz and this frequency will come down to 0.5 Hz in humans (30 beats per minute). [0042] When a transfer function is applied in order to transfer the wave form of the pulses (e.g., from finger to upper arm wave forms) this transfer function starts with its frequency range at the lowest possible beat frequency, which is at
- the transfer function can be constant. It would be of further advantage if that transfer function depends on pulse frequency. This can be achieved by normalization to heart beats instead of seconds.
- VUT signals Another problem with known methods of detecting and enhancing VUT signals is that the underlying PPG system cannot detect changes in the blood volume due to vasoconstriction or vasodilatation (vasomotoric changes), which may be caused by drugs, for example. In other words, present systems cannot distinguish between the change of v(t) caused by vasoactivity as opposed to actual blood pressure changes.
- an algorithm may be used to detect changes in the blood vessel (e.g. in the finger artery) due to vasomotoric changes. The algorithm enhances the BP frequency band, where vasomotoric activities are active - in the very low frequency (VLF) band below 0.02 Hz.
- VLF very low frequency
- This VLF-band is below Traube-Hering- Mayer waves (0.1 Hz) and breathing frequency (appr. 0.2 Hz). Note that in this document both Traube-Hering- Mayer waves and breathing frequency are called LF-band as both physiological frequencies are treated within the so-called LF-loop.
- the VLF-band is disturbed by vasomotoric changes coming from physiological- or drug-induced vasoconstriction or vasodilatation.
- Fig. 6 shows typical changes of v(t) due to vasoconstriction which is indicated with a new S-shaped transfer function.
- p cu ff stays at setpoint p T1 , although setpoint p T2 would be correct.
- the amplitude is decreased, but vasoconstrction produces also a more remarkable change in waveform. This behavior is used for reconstructing the VLF-band.
- vasoactivities may cause physiological BP-changes.
- the BP- signal is enhanced by elimination and reconstruction of VLF-band.
- the algorithm starts with its functionality when the control loop is closed after finding the starting setpoint pxo and determining at least one gain factor for at least one control loop in searching mode, pTM is equal to the actual mean BP.
- VAc(t) the gain of the control system cannot be infinity and therefore VAc(t) is not zero.
- p cu ff is not exactly equal to p art . If VAC ⁇ is negative (systolic part), p cuff is following p art (p cu ff ⁇ part)- When VAc(t) is in its positive (diastolic) halfwave, p cu ff is leading p art (p cu ff > part)-
- Fig. 2 describes this phenomenon: 2a shows that the positive and negative half-waves of VAc(t) are equal, 2b shows the signal with low setpoint and a greater negative half-wave, and 2c with high setpoint and greater positive half- wave.
- Equation (10) calculates control deviation P réelle for the n th beat that indicates setpoint changes:
- Proportional control deviation P is now used for reconstruction of the VLF-band. For that, it needs also an integral part / and the new setpoint for the n th beat is as follows:
- PTn PT0 + gl - ⁇ P n + gp - P n (12)
- Control loop gains gi and g P are determined in accordance with the gain g A c for the pulsatile part and in accordance to physiological rhythms.
- This tracking (or reconstruction) algorithm allows for the elimination of the VLF-band with a high pass filter (e.g. digital filter). All frequencies content below 0.02 Hz (for example) are eliminated - only the LF-band and the pulsatile AC- component is used. Note that VACO) is calculated by subtracting VVLF ⁇ from the measured PPG signal v(t) and not by subtracting the DC-component of the signal VDC- [0056]
- Fig. 7 shows a prior art PCA having one single time varying input signal, either an intra-arterial catheter or a non-invasive device, and several input parameters. When using VUT for PCA, p cu ff is not equal to p art . This is indicated by the remaining PPG-signal VAC ⁇ . I n addition, state variables of the control system indicate vasomotoric changes. The remaining information may also be used to enhance PCA-algorithms.
- Standard PCA methods cannot be used as they must be extended with additional input signal(s) like VAc(t) but also signals for determining setpoint p T (which is equal to mean BP).
- a meaningful signal could be P n that indicates if the setpoint must be corrected due to vasomotoric changes.
- Further state variables can be used for determining vascular properties.
- Fig. 8 represents the block diagram of the PCA-method and device.
- the VUT-part provides pressure p cu ff(t), VAc(t) and P n as well as state variables.
- the method can also include the method for calculating the enhanced pressure signal p ++ . Further, the method calculates PCA parameters like CO, SV, SW, PPV, arterial stiffness, etc and provides and displays these parameters and p ++ . In addition, the method can obtain intermittent BP-readings (like systolic BP, mean BP and diastolic BP) from a standard NBP. Further, the method can be provided with an excitation voltage from another device having an IBP-input in order to know the scaling factor of such device.
- intermittent BP-readings like systolic BP, mean BP and diastolic BP
- the PCA method is now a multiport network or algorithm due to multiple input signals in comparison to prior PCA with only one pressure or PPG input.
- the PCA method handles these multiple inputs.
- One embodiment of the method is sequential mode, where p ++ is calculated first and then used for standard PCA. With that method information regarding vasomotoric changes may be lost.
- the preferred embodiment uses linear and non-linear multiport algorithms.
- these algorithms can compute signal markers from the input time series, which can be for example, areas under curves or part of the curves, duty cycles of the signals, ratios (e.g. (mean BP - dia BP)/(sys BP - dia BP)), diastolic decay, linear regressions of the signals and of the logarithmic signal statistical moments, etc. These markers can be used for the computation of PCA-parameters along with
- anthropometric patient information like height, weight, age, sex, etc.
- the computation can be made out of multivariate polynomial equations.
- the weights of such multivariate equations can be either determined from physiological a-priori information or be trained with machine learning methods using a training set.
- a height correcting system may also be used in conjunction with the method for enhancing the blood pressure signal.
- a height correcting system may include a fluid-filled tube where the density of the fluid corresponds to the density of blood. One end of the tube is placed at heart level and the other end is placed on the finger cuff. A free-floating membrane, which prevents the fluid from escaping, could be attached at the heart end of the tube. A pressure sensor at the finger end and connected directly to the fluid measures the hydrostatic pressure difference.
- the pressure sensor of the height correcting system can be constructed so that a frequency or digital signal at the sensor site is produced and submitted to the overall control system.
- the non-invasive signal can be displayed on a screen and can be distributed to other monitoring devices.
- Most patient monitors have an interface for a pressure transducer in order to measure intraarterial blood pressure (IBP).
- IBP intraarterial blood pressure
- the IBP interface provides excitation voltage that is used for scaling the blood pressure signal to voltage.
- the enhanced signal may also be digitally distributed to further devices or computers, such as that described with respect to Fig. 9. The same applies for all calculated values like SV, CO, SW, PPV, TPR, arterial stiffness, etc. as well as for the enhanced systolic, diastolic and mean BP values.
- the patient monitor In order to determine the scaling range and factor, the patient monitor provides an excitation voltage. Minimum and maximum pressures are known from the specification.
- the excitation voltage can act as an input into the present method and can transform p ++ (t) or pbrach(t) to a voltage a ++ (t) that emulates the output voltage of an intra-arterial transducer.
- the transformed and enhanced signal is transmitted to the other device.
- a ++ (t) can be supplied by the analogue output of the
- mircoprocessor/computer of the present device an external DAC or by using a PWM- output followed by a RC filter.
- Fig. 9 is a block diagram illustrating an example computing device 200 that may be associated with the system and method of the present application.
- the computing device 200 may perform the methods of the present application, including the modification of signals, calculation of values, and execution of algorithms.
- computing device 200 typically includes one or more processors 210 and system memory 220.
- a memory bus 230 can be used for communicating between the processor 210 and the system memory 220.
- processor 210 can be of any type including but not limited to a microprocessor ( ⁇ ), a microcontroller ( ⁇ ), a digital signal processor (DSP), or any combination thereof.
- processor 210 can include one more levels of caching, such as a level one cache 211 and a level two cache 212, a processor core 213, and registers 214.
- the processor core 213 can include an arithmetic logic unit (ALU), a floating point unit (FPU), a digital signal processing core (DSP Core), or any combination thereof.
- a memory controller 215 can also be used with the processor 210, or in some implementations the memory controller 215 can be an internal part of the processor 210.
- system memory 220 can be of any type including but not limited to volatile memory (such as RAM), nonvolatile memory (such as ROM, flash memory, etc.) or any combination thereof.
- System memory 220 typically includes an operating system 221, one or more applications 222, and program data 224.
- an application 222 may be designed to receive certain inputs from the PPG system and base decisions off of those inputs.
- the application may be designed to receive inputs from the PPG system, the NBP, and potentially other systems.
- the application 222 may carry out any of the methods described herein above and provide a higher fidelity BP signal.
- Computing device 200 can have additional features or functionality, and additional interfaces to facilitate communications between the basic configuration 201.
- a bus/interface controller 240 can be used to facilitate
- the data storage devices 250 can be removable storage devices 251, non-removable storage devices 252, or a combination thereof.
- removable storage and non-removable storage devices include magnetic disk devices such as flexible disk drives and hard-disk drives (HDD), optical disk drives such as compact disk (CD) drives or digital versatile disk (DVD) drives, solid state drives (SSD), and tape drives to name a few.
- Example computer storage media can include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data.
- System memory 220, removable storage 251 and non-removable storage 252 are all examples of computer storage media.
- Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computing device 200. Any such computer storage media can be part of device 200.
- Computing device 200 can also include an interface bus 242 for facilitating communication from various interface devices to the basic configuration 201 via the bus/interface controller 240.
- Example output interfaces 260 include a graphics processing unit 261 and an audio processing unit 262, which can be configured to communicate to various external devices such as a display or speakers via one or more A/V ports 263.
- Example peripheral interfaces 260 include a serial interface controller 271 or a parallel interface controller 272, which can be configured to communicate with external devices such as input devices (e.g., keyboard, mouse, pen, voice input device, touch input device, etc.) or other peripheral devices (e.g., printer, scanner, etc.) via one or more I/O ports 273.
- An example communication interface 280 includes a network controller 281, which can be arranged to facilitate communications with one or more other computing devices 290 over a network communication via one or more communication ports 282.
- the communication connection is one example of a communication media.
- Communication media may typically be embodied by computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and includes any information delivery media.
- a "modulated data signal" can be a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal.
- communication media can include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency (RF), infrared (IR) and other wireless media.
- RF radio frequency
- IR infrared
- computer readable media can include both storage media and communication media.
- Computing device 200 can be implemented as a portion of a small- form factor portable (or mobile) electronic device such as a cell phone, a personal data assistant (PDA), a personal media player device, a wireless web-watch device, a personal headset device, an application specific device, or a hybrid device that include any of the above functions.
- a small- form factor portable (or mobile) electronic device such as a cell phone, a personal data assistant (PDA), a personal media player device, a wireless web-watch device, a personal headset device, an application specific device, or a hybrid device that include any of the above functions.
- PDA personal data assistant
- Computing device 200 can also be implemented as a personal computer including both laptop computer and non-laptop computer configurations.
- the physician is used to blood pressure values that are obtained at heart level.
- the difference between finger and heart level could be corrected with a water filled tube between these two sites.
- a height correcting system may be applied in order to eliminate hydrostatic difference of the finger sensor and heart level.
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- General Health & Medical Sciences (AREA)
- Veterinary Medicine (AREA)
- Biophysics (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Medical Informatics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- Physics & Mathematics (AREA)
- Public Health (AREA)
- Pathology (AREA)
- Cardiology (AREA)
- Vascular Medicine (AREA)
- Physiology (AREA)
- Ophthalmology & Optometry (AREA)
- Signal Processing (AREA)
- Dentistry (AREA)
- Artificial Intelligence (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Psychiatry (AREA)
- Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
Abstract
A system and method of enhancing a blood pressure signal is disclosed. The volume of an artery in a finger is measured by a photo-plesthysmographic (PPG) system, which produces a PPG signal. This PPG system is placed inside a cuff, and the cuff pressure is controlled by the PPG signal. The portion or component of the PPG signal having a frequency higher than a predefined threshold frequency is then modified or enhanced, such as by multiplying the high frequency component by a calibration factor. A blood pressure signal is then calculated using the cuff pressure and the modified PPG signal. A blood pressure contour curve may then be generated, and a variety of parameters may be calculated using the curve.
Description
APPARATUS AND METHOD FOR ENHANCING AND ANALYZING SIGNALS FROM A CONTINUOUS NON-INVASIVE BLOOD PRESSURE
DEVICE
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. provisional patent application serial no. 61/256,081 filed October 29, 2009, and from U.S. provisional patent application serial no. 61/256,110, the entire contents of which are incorporated herein by reference. BACKGROUND
1. Field
[0002] The invention relates generally to a method of measuring blood pressure, and more particularly to a continuous non-invasive arterial pressure (CNAP) measurement where the blood pressure signal is enhanced.
2. Description of Related Art
[0003] Pulse contour analysis (PC A) is the process of calculating parameters from a blood pressure pulse, especially from the contour of the pulse wave. PCA begins with measuring blood pressure (BP).
[0004] Blood pressure may be measured in a number of ways. As one example, a standard non-invasive sphygmomanometer (NBP) may be placed on the upper arm or wrist. The NBP applies pressure to the arteries, causing them to constrict and limit blood flow. As the pressure is released, blood flow is restored in the artery, and the systolic and diastolic blood pressures may be measured. NBP measures BP intermittently and not continuously, so it cannot be used for PCA.
[0005] Another device for measuring blood pressure is a finger cuff having an infrared light source and a light detector for measuring a photo-plethysmographic (PPG) signal that is known also from pulse oximetry. This PPG-signal is fed into a
control system, which produces a counter pressure in the finger cuff. It is well known that the counter pressure equals intra-arterial pressure when the PPG-signal is kept constant. Thus, the counter pressure, which is indirect equivalent to intra-arterial pressure, is measured. This method is known as "Vascular Unloading Technique," and the continuous pressure signal can be used for PCA.
[0006] Invasive devices may also be used to measure blood pressure, such as an intra-arterial catheter, for example. Intra-arterial transducers have relatively high frequency transmission (up to 200Hz) and can therefore be used for PCA.
[0007] Some example parameters that may be calculated from the contour of the pulse wave include stroke volume (SV), cardiac output (CO), stroke volume variation (SVV), pulse pressure variation (PPV), and total peripheral resistance (TPR). In addition, PCA can be used for other measurements which give insight to the human vascular properties, for example arterial stiffness. Thus, it is desirable that the measured blood pressure signals be as accurate as possible.
[0008] Invasive devices have the disadvantage of being overly disturbing and painful to the patient, whereas signals from non-invasive devices have problems with the fidelity or accuracy of the signal.
SUMMARY
[0009] A system and method of enhancing the blood pressure signal fidelity is disclosed. In one embodiment, a method for determining a blood pressure contour curve includes placing a photo-plesthysmographic (PPG) system over an artery in a human finger, the PPG system producing a PPG signal based on volume of the artery, the PPG system including at least one light source and at least one light detector, modifying a component of the PPG signal having a frequency higher than a
predefined threshold frequency, and calculating a blood pressure signal using the modified PPG signal.
[0010] In another embodiment, a computing device for determining a blood pressure contour curve is disclosed. The computing device includes a pressure cuff adapted to be placed over an artery in a human finger, the cuff including a PPG system having at least one light source and at least one light detector, a pressure sensor, and a controller for controlling the pressure in the cuff. The PPG system produces a PPG signal based on volume of the artery, and a pressure signal is calculated using the PPG signal and this pressure signal is applied to cuff and finger. The computing device modifies a component of the PPG signal having a frequency higher than a predefined threshold frequency and calculates a blood pressure signal using the cuff pressure and the modified PPG signal.
[0011] In yet another embodiment, a method for eliminating undesired signal content of a continuous non-invasive arterial blood pressure device is disclosed. The method includes placing cuff having a photo-plesthysmographic (PPG) system over an artery in a human finger, the PPG system producing a PPG signal based on volume of the artery, eliminating from the PPG signal an undesired portion of the PPG signal, and reconstructing the PPG signal from the remaining portion of the PPG signal.
BRIEF DESCRIPTION OF THE FIGURES
[0012] An exemplary embodiment of the present invention is described herein with reference to the drawings, in which:
[0013] Figure 1 shows a prior art Vascular Unloading Technique (VUT) control system using a photo-plesthysmographic (PPG) system controlling the cuff pressure for measuring blood pressure;
[0014] Figure 2 describes the transfer function between PPG-signal v(t) at different constant cuff pressures;
[0015] Figure 3 shows an example pulse of the remaining PPG-signal v(t) in search (open loop) and measuring (closed loop) mode;
[0016] Figure 4 shows a block diagram using different frequency ranges with different control gains and concepts;
[0017] Figure 5 is a block diagram of the calibration method;
[0018] Figure 6 shows the change in the remaining PPG-signal v(t) caused due to vasoconstriction of the artery;
[0019] Figure 7 describes prior art Pulse Contour Analysis (PC A) having one time varying input signal and several input parameters;
[0020] Figure 8 is a block diagram of the new PCA-method and device; and
[0021] Figure 9 shows an example computing device that may be used with the system and method of the present application.
DETAILED DESCRIPTION
[0022] A system and method of measuring and enhancing blood pressure (BP) signals is described. These modified, more accurate signals may then be used to more accurately calculate a variety of parameters for a patient, such as stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), and arterial stiffness, for example. The method extracts the AC-component of the photo-plethysmographic (PPG) signal of known "Vascular Unloading Technique" (VUT). In combination with the measured pressure signal, this signal is used as a second input for Pulse Contour Analysis (PCA).
[0023] Figure 1 shows a typical VUT system 100 and its control principle. The VUT system 100 is used to obtain a PPG signal, which can then be used to control the cuff pressure, which is equivalent to the continuous arterial blood pressure. The VUT system 100 includes a "photo-plethysmographic" (PPG) system located within a finger cuff 102 and having one or more light sources 104 and one or more light detectors 106. The PPG-signal is fed into a control system 114 that produces a pressure in the cuff 102.
[0024] In operation, a human finger 108 is placed in the finger cuff 102. The finger cuff 102 measures blood volume in an artery 110 of the finger 108. During systole, when blood volume increases in the finger 108, a controller 114 increases the pressure of the finger cuff 102, pcuff(t), until the excess blood volume is squeezed out by pressure of the cuff. On the other hand during diastole, the blood volume in the finger is decreased, and therefore the controller 114 decreases pcuff(t) so the overall blood volume in the artery remains constant. As blood volume and thus v(t) is held constant over time, the pressure difference between cuff pressure pcuff(t) and intraarterial pressure, Part(t), is zero. Thus, part(t) is equal to cuff pressure pcuff(t), which can easily be measured by means of a manometer (pressure measuring instrument), for example. Thus, intra-arterial pressure part(t) itself is measured indirectly, and a PPG-signal v(t), which reflects the arterial blood volume changes in the measuring area (e.g. the finger) is obtained. As the PPG signal is kept constant, the counter pressure eliminates the arterial blood volume changes and the diameter of the artery is also constant. Thus, arterial influx is guaranteed during measurement, whereas venous return from the fingertip is slightly reduced.
[0025] This indirect measurement may not be accurate for a number of reasons. For example, v(t) is not truly constant since the pressure in the cuff may not
instantly track the pressure in the artery. Thus, as the cuff pressure tracks the pressure in the artery, v(t) takes on an alternating current (AC)-like component (referred to as VAc(t)). VUT methods rely on their valve systems as they are producing the pressure signal. Typically these valves systems are limited to upper cut-of frequencies of 15- 40Hz. Thus, the counter pressure in the cuff pcuff(t) is often slower than the signal origin, which produces VAc(t). Additional factors like pressure coupling from cuff to tissue, air supply from pump to valve system and from valve system to cuff etc. limit the control system. These factors limit VUT and lead to remaining VAc(t).
[0026] Additionally, pulse pressure depends on the control loop gain(s) that are either calculated from the maximum PPG signal amplitude vmax(t) according to the "PhysioCal" criteria or chosen empirically. These gains cannot be infinity, which would be necessary for zero VAc(t). When calculated from vmax(t), the controller gain could be suboptimal.
[0027] The underlying mechanism between pcuff(t), Part(t) and VAC© is shown in Figure 2 for constant cuff pressures (pci, ρτ, pc2) (lines 2b, 2a, 2c, respectively). A typical S-shaped p-v transmission curve produces different PPG-signals v(t) depending on pcuff. It is well known that the amplitude of VAC© depends on pcuff and is highest at pcuff = mean BP. There are different shapes of v(t) at different pcuff.
[0028] Note the inverted characteristic of the PPG signal. The light from light source 104 is absorbed by blood. The more blood that is inside the finger (e.g. during systole), the less light is shone through the finger and detected by the light detector 106.
[0029] True mean BP is calculated as follows (for analog signals and time series): meanBP = (1)
[0030] A constant pcuff is used in search modes of the VUT device for detecting mean BP before the actual measurement starts. pcuff, where PPG amplitude Ac(t) is at maximum, represents mean BP. This starting pcuff is the so called starting setpoint pT0.
[0031] During measuring mode the loop of the control system is closed, which means that pcuff is alternating with respect to v(t) and depending on controller gain g. According to the VUT-principle, the amplitude of VAc(t) is decreasing to a minimum. Ideally VAC© is zero, but this is not possible since the gain is a real value and not infinity, and the valve cut-off frequency.
[0032] Figure 3 shows the mechanism pcuff that is alternating around setpoint px and is controlled by v(t). The control condition is to keep v(t), and therefore blood volume in the finger, constant. This can only be done to a minimum amplitude of VAc(t)- Note the inverted characteristic of the control system. An increase of v(t) lowers pcuff and a decrease of v(t) increases pcuff due to the inverted characteristic of the PPG signal.
[0033] In some embodiments, it may be advantageous to have more than one control loop. Fig. 4 shows a block diagram of such a control system. In this typical embodiment, v(t) is split into different frequency ranges. Pulsatile VACC , 1°w frequency VLF and very low frequency VVLF© are obtained with filters having cutoff frequencies at fVLF and fn?. It is a further advantage that the three frequency ranges have different gains gAc, gLF and gvLF- This allows for optimal gain application to v(t).
[0034] The remaining pulsatile PPG signal VAC( ), but also other frequency bands of v(t), and the state variables of the control system (e.g. gains, cut-off
frequencies, etc.) can be used for a multivariate transfer function T, which can be used for enhancing the measured pcuff(t) to p++(t). Equation (2) is a more general formula, when using n control loops:
ρ++(ί) = ρ( + Τ[ν1 (ί),ν2(ί)...ν)Ι (ί> fcvfci -fcn ] (2)
It has been shown that frequency ranges below 0.1 Hz do not contribute to p++(t). Equation (2) for the embodiment described in Fig. 4 will be simplified as follows, because only VAc(t) and VLF© contribute to a meaningful signal:
P++(t) = p(t) + T[vAC(t),vLF(t);
A linear function can be used when the correct setpoint is applied. As can be seen in Figures 2-4, at the correct setpoint, px is the point of maximal slope and therefore maximal pulsatile VAc(t), low frequency VLF and very low frequency VVLFO) is reached. Linear interpolation can be approximated: p++{t) = p{t) +
gAC vLF(t} gLF] (4) where T indicates the remaining transfer function after linear interpolation. In one example, T can be a vector of different scaling factors between the different linearized v(t) * gain multiples.
[0035] Due to physiological reasons, pulse wave form is different when measured at different sites (e.g. finger, upper arm, wrist, leg, etc.). Thus, because blood pressure measurement in the finger artery 1 10 is different from blood pressure measured at other areas of the human body, finger arterial pressure devices lack accuracy in comparison to standard devices.
[0036] One method of enhancing the VUT pressure signal pcuff(t), and thus increasing accuracy of the signal, is to calibrate the signal v that is measured at the
finger to a standard upper arm sphygmomanometer (NBP). One reason for doing this is that there are inherent physiological and hydrostatic differences of BP measured at the finger artery as opposed to the upper arm, since the upper arm is almost close to heart level whereas the finger can be anywhere. Additionally, pulse pressure (PP) of BP depends on the control-loop gain(s) and these gains are parameters from the control system and not physiological. When the gain is determined from the maximum VAC© amplitude according to the "physiocal" criteria, this amplitude depends on the actual vascular tone (vasoconstriction or vasodilatation). This has no information about BP. When the gain(s) are chosen empirically by increasing the gain until the system start to swing with resonance frequency, these gain(s) also depends on vascular tone and system conditions. Again, this has no information about BP.
[0037] The maximum VAC© amplitude indicates only that the constant cuff pressure in search mode is equal to mean BP. The value itself is more or less a "house number" as it depends on the actual vascular tone (vasoconstriction or vasodilatation) and therefore depends on the state of the autonomic nervous system of the patient to be measured.
[0038] Calibration methods include transforming the signal along a straight line: p++(t) = k*pcuff(t) + d (5) where k and d can be calculated from NBP-values as follows:
SBP -DBP
k =
sBP - dBP (6)
d = SBP - k sBP (V)
where SBP and DBP are systolic and diastolic values measured from the NBP calibration device (e.g., the upper arm blood pressure cuff) and sBP and dBP are systolic and diastolic values measured from the uncalibrated finger cuff.
[0039] This method lacks accuracy because slope k is not only scaling BP- pulse, but also hypo- and hypertensive episodes. This BP-trend does not need an artificial amplification as mean BP is correctly detected by the improved VUT system. High k values overestimate BP trend, e.g., with a k=2, a drop of BP of 40mmHg would be displayed as 80mmHg. Even negative values could be displayed with such method. In addition, this method amplifies natural rhythms of BP, e.g., the 0.1 Hz Traube-Hering-Mayer waves, and makes them look very non-physiological.
[0040] Figure 5 shows a method that further improves the accuracy of the signal measured by the PPG system. The method includes only multiplying the component of the signal that has a frequency content higher than some threshold value, e.g., 0.3 Hz., by slope k. Signal components lower than the cut off frequency remain unamplified. In addition, the offset d is added. Thus, the amplification formula reads as follows:
p++(t) = k*pAC(t) + pLF(t) + d (8)
where pAc(t) is the component of the measured pressure that has a frequency greater than the threshold frequency, and pn?(t) is the component of the measured pressure that has a frequency less than the threshold frequency.
[0041] Pulse wave frequency content is per se higher than the actual pulse rate or pulse frequency. For a normal pulse rate of 60 beats per minute, the pulse frequency is 1 Hz and this frequency will come down to 0.5 Hz in humans (30 beats per minute).
[0042] When a transfer function is applied in order to transfer the wave form of the pulses (e.g., from finger to upper arm wave forms) this transfer function starts with its frequency range at the lowest possible beat frequency, which is at
approximately 0.3 Hz. Below that, the transfer function can be constant. It would be of further advantage if that transfer function depends on pulse frequency. This can be achieved by normalization to heart beats instead of seconds.
Pbrach(t) = Tnorm(p++(t)) =
Pbrach(t) = Tnorm(k*pAc(t) + LF( + d) =
Pbrach(t) = pLF(t) + d + T„orm(k*PAc(t)) (9)
[0043] As can be seen from equation (9), only the pulse frequency content pAc(t) has to be transform as Tnorm is constant (e.g. 1) for lower frequencies. This algorithm could be part of the PCA-method and computed within the invented device.
[0044] Another problem with known methods of detecting and enhancing VUT signals is that the underlying PPG system cannot detect changes in the blood volume due to vasoconstriction or vasodilatation (vasomotoric changes), which may be caused by drugs, for example. In other words, present systems cannot distinguish between the change of v(t) caused by vasoactivity as opposed to actual blood pressure changes. Thus, to further enhance the BP-waveform, an algorithm may used to detect changes in the blood vessel (e.g. in the finger artery) due to vasomotoric changes. The algorithm enhances the BP frequency band, where vasomotoric activities are active - in the very low frequency (VLF) band below 0.02 Hz. This VLF-band is below Traube-Hering-Mayer waves (0.1 Hz) and breathing frequency (appr. 0.2 Hz). Note that in this document both Traube-Hering-Mayer waves and breathing frequency are called LF-band as both physiological frequencies are treated within the so-called LF-loop.
[0045] The VLF-band is disturbed by vasomotoric changes coming from physiological- or drug-induced vasoconstriction or vasodilatation. Fig. 6 shows typical changes of v(t) due to vasoconstriction which is indicated with a new S-shaped transfer function. pcuff stays at setpoint pT1, although setpoint pT2 would be correct. The amplitude is decreased, but vasoconstrction produces also a more remarkable change in waveform. This behavior is used for reconstructing the VLF-band.
[0046] These vasoactivities may cause physiological BP-changes. The BP- signal is enhanced by elimination and reconstruction of VLF-band. The algorithm starts with its functionality when the control loop is closed after finding the starting setpoint pxo and determining at least one gain factor for at least one control loop in searching mode, p™ is equal to the actual mean BP.
[0047] As already described, the gain of the control system cannot be infinity and therefore VAc(t) is not zero. Thus, pcuff is not exactly equal to part. If VAC© is negative (systolic part), pcuff is following part (pcuff < part)- When VAc(t) is in its positive (diastolic) halfwave, pcuff is leading part (pcuff > part)-
[0048] Consider an example in which gain(s) were set to zero. In this situation, which can be seen in Fig. 2a, pT0 and pcuff are at mean BP and VACO) nas its maximum amplitude. The area under the negative curve equals the area under the positive half wave of the beat. Thus, part is as often greater as lower in comparison to pcuff that indicates mean BP. This indicates that the setpoint pT0 is correct. Therefore, this phenomenon can be used for setpoint tracking.
[0049] When the negative and the positive half wave of an alternating signal are equal the following formula is true:
i=0
[0050] When this integral of VAc(t) over a beat is not zero, the waveform is changing. Fig. 2 describes this phenomenon: 2a shows that the positive and negative half-waves of VAc(t) are equal, 2b shows the signal with low setpoint and a greater negative half-wave, and 2c with high setpoint and greater positive half- wave.
[0051] Equation (10) calculates control deviation P„ for the nth beat that indicates setpoint changes:
Pn = ) vAC(t)dt (11) where: P„ =0 -> setpoint correct
Pn <0 -> setpoint to low
Pn >0 -> setpoint to high
[0052] This phenomenon is also true when gain(s) are not zero, pcuff leads and follows part and VAc(t) is minimized. This phenomenon is also true when the s-shaped p-v transfer function is changed due to vasomotoric changes.
[0053] Proportional control deviation P is now used for reconstruction of the VLF-band. For that, it needs also an integral part / and the new setpoint for the nth beat is as follows:
n
PTn = PT0 + gl -∑Pn + gp - Pn (12)
0
[0054] Control loop gains gi and gP are determined in accordance with the gain gAc for the pulsatile part and in accordance to physiological rhythms.
[0055] This tracking (or reconstruction) algorithm allows for the elimination of the VLF-band with a high pass filter (e.g. digital filter). All frequencies content below 0.02 Hz (for example) are eliminated - only the LF-band and the pulsatile AC- component is used. Note that VACO) is calculated by subtracting VVLF© from the measured PPG signal v(t) and not by subtracting the DC-component of the signal VDC-
[0056] Fig. 7 shows a prior art PCA having one single time varying input signal, either an intra-arterial catheter or a non-invasive device, and several input parameters. When using VUT for PCA, pcuff is not equal to part. This is indicated by the remaining PPG-signal VAC©. In addition, state variables of the control system indicate vasomotoric changes. The remaining information may also be used to enhance PCA-algorithms.
[0057] Standard PCA methods cannot be used as they must be extended with additional input signal(s) like VAc(t) but also signals for determining setpoint pT (which is equal to mean BP). A meaningful signal could be Pn that indicates if the setpoint must be corrected due to vasomotoric changes. Further state variables can be used for determining vascular properties.
[0058] Fig. 8 represents the block diagram of the PCA-method and device. The VUT-part provides pressure pcuff(t), VAc(t) and Pn as well as state variables.
[0059] The method can also include the method for calculating the enhanced pressure signal p++. Further, the method calculates PCA parameters like CO, SV, SW, PPV, arterial stiffness, etc and provides and displays these parameters and p++. In addition, the method can obtain intermittent BP-readings (like systolic BP, mean BP and diastolic BP) from a standard NBP. Further, the method can be provided with an excitation voltage from another device having an IBP-input in order to know the scaling factor of such device.
[0060] The PCA method is now a multiport network or algorithm due to multiple input signals in comparison to prior PCA with only one pressure or PPG input.
[0061] The PCA method handles these multiple inputs. One embodiment of the method is sequential mode, where p++ is calculated first and then used for standard
PCA. With that method information regarding vasomotoric changes may be lost. Thus, the preferred embodiment uses linear and non-linear multiport algorithms. In addition, these algorithms can compute signal markers from the input time series, which can be for example, areas under curves or part of the curves, duty cycles of the signals, ratios (e.g. (mean BP - dia BP)/(sys BP - dia BP)), diastolic decay, linear regressions of the signals and of the logarithmic signal statistical moments, etc. These markers can be used for the computation of PCA-parameters along with
anthropometric patient information (like height, weight, age, sex, etc.) and
information obtained by the VUT-control system and its state variables. The computation can be made out of multivariate polynomial equations. The weights of such multivariate equations can be either determined from physiological a-priori information or be trained with machine learning methods using a training set.
[0062] A height correcting system may also be used in conjunction with the method for enhancing the blood pressure signal. Such a height correcting system may include a fluid-filled tube where the density of the fluid corresponds to the density of blood. One end of the tube is placed at heart level and the other end is placed on the finger cuff. A free-floating membrane, which prevents the fluid from escaping, could be attached at the heart end of the tube. A pressure sensor at the finger end and connected directly to the fluid measures the hydrostatic pressure difference. The pressure sensor of the height correcting system can be constructed so that a frequency or digital signal at the sensor site is produced and submitted to the overall control system.
[0063] Providing the enhanced or modified signals described above to other devices, e.g. commercially available patient monitors, would be desirable, as all of them have an input for the standard IBP pressure. Thus, the non-invasive signal can
be displayed on a screen and can be distributed to other monitoring devices. Most patient monitors have an interface for a pressure transducer in order to measure intraarterial blood pressure (IBP). The IBP interface provides excitation voltage that is used for scaling the blood pressure signal to voltage. The enhanced signal may also be digitally distributed to further devices or computers, such as that described with respect to Fig. 9. The same applies for all calculated values like SV, CO, SW, PPV, TPR, arterial stiffness, etc. as well as for the enhanced systolic, diastolic and mean BP values.
[0064] In order to determine the scaling range and factor, the patient monitor provides an excitation voltage. Minimum and maximum pressures are known from the specification. The excitation voltage can act as an input into the present method and can transform p++(t) or pbrach(t) to a voltage a++(t) that emulates the output voltage of an intra-arterial transducer. The transformed and enhanced signal is transmitted to the other device. a++(t) can be supplied by the analogue output of the
mircoprocessor/computer of the present device, an external DAC or by using a PWM- output followed by a RC filter.
[0065] Fig. 9 is a block diagram illustrating an example computing device 200 that may be associated with the system and method of the present application. The computing device 200 may perform the methods of the present application, including the modification of signals, calculation of values, and execution of algorithms.
[0066] In a very basic configuration 201, computing device 200 typically includes one or more processors 210 and system memory 220. A memory bus 230 can be used for communicating between the processor 210 and the system memory 220.
[0067] Depending on the desired configuration, processor 210 can be of any type including but not limited to a microprocessor (μΡ), a microcontroller (μθ), a digital signal processor (DSP), or any combination thereof. Processor 210 can include one more levels of caching, such as a level one cache 211 and a level two cache 212, a processor core 213, and registers 214. The processor core 213 can include an arithmetic logic unit (ALU), a floating point unit (FPU), a digital signal processing core (DSP Core), or any combination thereof. A memory controller 215 can also be used with the processor 210, or in some implementations the memory controller 215 can be an internal part of the processor 210.
[0068] Depending on the desired configuration, the system memory 220 can be of any type including but not limited to volatile memory (such as RAM), nonvolatile memory (such as ROM, flash memory, etc.) or any combination thereof. System memory 220 typically includes an operating system 221, one or more applications 222, and program data 224. For example, an application 222 may be designed to receive certain inputs from the PPG system and base decisions off of those inputs. For instance, the application may be designed to receive inputs from the PPG system, the NBP, and potentially other systems. As an output, the application 222 may carry out any of the methods described herein above and provide a higher fidelity BP signal.
[0069] Computing device 200 can have additional features or functionality, and additional interfaces to facilitate communications between the basic configuration 201. For example, a bus/interface controller 240 can be used to facilitate
communications between the basic configuration 201 and one or more data storage devices 250 via a storage interface bus 241. The data storage devices 250 can be removable storage devices 251, non-removable storage devices 252, or a combination
thereof. Examples of removable storage and non-removable storage devices include magnetic disk devices such as flexible disk drives and hard-disk drives (HDD), optical disk drives such as compact disk (CD) drives or digital versatile disk (DVD) drives, solid state drives (SSD), and tape drives to name a few. Example computer storage media can include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data.
[0070] System memory 220, removable storage 251 and non-removable storage 252 are all examples of computer storage media. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computing device 200. Any such computer storage media can be part of device 200.
[0071] Computing device 200 can also include an interface bus 242 for facilitating communication from various interface devices to the basic configuration 201 via the bus/interface controller 240. Example output interfaces 260 include a graphics processing unit 261 and an audio processing unit 262, which can be configured to communicate to various external devices such as a display or speakers via one or more A/V ports 263. Example peripheral interfaces 260 include a serial interface controller 271 or a parallel interface controller 272, which can be configured to communicate with external devices such as input devices (e.g., keyboard, mouse, pen, voice input device, touch input device, etc.) or other peripheral devices (e.g., printer, scanner, etc.) via one or more I/O ports 273. An example communication
interface 280 includes a network controller 281, which can be arranged to facilitate communications with one or more other computing devices 290 over a network communication via one or more communication ports 282. The communication connection is one example of a communication media. Communication media may typically be embodied by computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and includes any information delivery media. A "modulated data signal" can be a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media can include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency (RF), infrared (IR) and other wireless media. The term computer readable media (or medium) as used herein can include both storage media and communication media.
[0072] Computing device 200 can be implemented as a portion of a small- form factor portable (or mobile) electronic device such as a cell phone, a personal data assistant (PDA), a personal media player device, a wireless web-watch device, a personal headset device, an application specific device, or a hybrid device that include any of the above functions. Computing device 200 can also be implemented as a personal computer including both laptop computer and non-laptop computer configurations.
[0073] The physician is used to blood pressure values that are obtained at heart level. As the finger could be on a different hydrostatic level, the difference between finger and heart level could be corrected with a water filled tube between these two sites. Thus, a height correcting system may be applied in order to eliminate hydrostatic difference of the finger sensor and heart level.
[0074] While the invention has been described herein with relation to certain embodiments and applications, those with skill in the art will recognize changes, modifications, alterations, and the like which still come within the spirit of the inventive concept, and such are intended to be within the scope of the invention as expressed in the following claims.
Claims
1. A method for determining a blood pressure contour curve comprising:
placing a photo-plethysmographic (PPG) system over an artery in a human finger, the PPG system producing a PPG signal based on volume of the artery, the PPG system including at least one light source and at least one light detector;
modifying a component of the PPG signal having a frequency higher than a predefined threshold frequency; and
calculating a blood pressure signal using at least the modified component of the PPG signal.
2. The method of claim 1 wherein a cuff is applied to the artery of the finger, pressure in the cuff is controlled by the PPG signal, and a new blood pressure is calculated using the cuff pressure and the modified PPG signal.
3. The method of claim 2 wherein modifying a component of the PPG signal having a frequency higher than a predefined threshold frequency comprises:
separating the PPG signal into a first component having a frequency higher than the predefined threshold frequency and a second component having a frequency lower than the predefined threshold frequency;
modifying the first component; and
adding the modified first component to the second component to create a modified PPG signal;
using the modified PPG signal and the cuff pressure to calculate the blood pressure signal.
4. The method of claim 2 wherein the modification includes calibrating a component of the blood pressure signal having a frequency higher than a predefined threshold frequency using a value obtained for blood pressure by a sphygmomanometer placed on an artery in a human upper arm.
5. The method of claim 2 wherein the modification includes multiplying a component of the blood pressure signal having a frequency higher than a predefined threshold frequency by a calibration factor, the calibration factor being calculated from a blood pressure measurement from a sphygmomanometer placed on an artery in a human upper arm.
6. The method according to claim 2, wherein the threshold frequency is about .3 Hz.
7. The method of claim 1 wherein the modification includes eliminating from the PPG signal an undesired portion of the PPG signal and reconstructing the PPG signal from the remaining portion of the PPG signal.
8. The method according to claim 2, wherein the calculation uses anthropometric parameters.
9. The method according to claim 2, further comprising calculating physiological parameters from the blood pressure contour curve.
10. The method according to claim 9, wherein the parameters are calculated by using multiport algorithms.
11. The method according to claim 9, wherein the parameters are calculated by using one or more markers of input signals.
12. A computing device for determining a blood pressure contour curve comprising: a pressure cuff adapted to be placed over an artery in a human finger, the cuff including a PPG system having at least one light source and at least one light detector;
a pressure sensor;
a controller for controlling the pressure in the cuff;
wherein the PPG system produces a PPG signal based on volume of the artery, a pressure signal is calculated using the PPG signal, and the pressure signal is applied to the cuff and finger; and
wherein the computing device modifies a component of the PPG signal having a frequency higher than a predefined threshold frequency and calculates a blood pressure signal using the cuff pressure and the modified PPG signal.
13. The computing device according to claim 12, wherein the computing device receives control state information from the controller.
14. The computing device according to claim 12, wherein the computing device receives information from a calibration device.
15. The computing device according to claim 12, wherein the computing device receives scaling information from another device.
16. The computing device according to claim 12, where the computing device receives information from a hydrostatic correction system.
17. The computing device according to claim 12, wherein the computing device receives anthropometric information from the patient.
18. The computing device according to claim 12, wherein the computing device calculates physiological parameters from one or more input signals.
19. A method for eliminating undesired signal content of a continuous noninvasive arterial blood pressure device comprising: placing a cuff having a photo-plesthysmographic (PPG) system over an artery in a human finger, the PPG system producing a PPG signal based on volume of the artery, the cuff pressure being controlled by the PPG-signal;
eliminating from the PPG signal an undesired portion of the PPG signal; and reconstructing the PPG signal from the remaining portion of the PPG signal.
20. The method according to claim 19, wherein the reconstruction is calculated from the pulsatile part of the remaining portion of the PPG signal.
21. The method according to claim 20, wherein the reconstructed PPG signal is n t
PT„ = PT0 + gi -∑P„+ gp - P„ P„ = \ VAC {t)dt
o and
22. The method according to claim 18, wherein the part of the PPG signal having the undesired portion of the PPG signal is below a predetermined frequency.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201080048387.8A CN102791192B (en) | 2009-10-29 | 2010-10-29 | Apparatusfor enhancing and analyzing signals from a continuous non-invasive blood pressure device |
EP10807720.7A EP2493373B1 (en) | 2009-10-29 | 2010-10-29 | Apparatus and methods for enhancing and analyzing signals from a continuous non-invasive blood pressure measurement device |
JP2012535959A JP6058397B2 (en) | 2009-10-29 | 2010-10-29 | Apparatus and method for enhancing and analyzing signals from continuous non-invasive blood pressure devices |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US25611009P | 2009-10-29 | 2009-10-29 | |
US25608109P | 2009-10-29 | 2009-10-29 | |
US61/256,081 | 2009-10-29 | ||
US61/256,110 | 2009-10-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2011051822A1 true WO2011051822A1 (en) | 2011-05-05 |
Family
ID=43663783
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2010/003274 WO2011051819A1 (en) | 2009-10-29 | 2010-10-29 | Digital control method for measuring blood pressure |
PCT/IB2010/003325 WO2011051822A1 (en) | 2009-10-29 | 2010-10-29 | Apparatus and methods for enhancing and analyzing signals from a continous non-invasive blood pressure device |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2010/003274 WO2011051819A1 (en) | 2009-10-29 | 2010-10-29 | Digital control method for measuring blood pressure |
Country Status (5)
Country | Link |
---|---|
US (2) | US8814800B2 (en) |
EP (2) | EP2493373B1 (en) |
JP (3) | JP6058397B2 (en) |
CN (2) | CN102647940B (en) |
WO (2) | WO2011051819A1 (en) |
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102613966A (en) * | 2012-02-01 | 2012-08-01 | 香港应用科技研究院有限公司 | Blood pressure measuring device and adjusting method thereof |
WO2013178475A1 (en) | 2012-05-31 | 2013-12-05 | Cnsystems Medizintechnik Gmbh | Method and device for continuous, non-invasive determination of blood pressure |
US8977348B2 (en) | 2012-12-21 | 2015-03-10 | Covidien Lp | Systems and methods for determining cardiac output |
US9060745B2 (en) | 2012-08-22 | 2015-06-23 | Covidien Lp | System and method for detecting fluid responsiveness of a patient |
US9241646B2 (en) | 2012-09-11 | 2016-01-26 | Covidien Lp | System and method for determining stroke volume of a patient |
US9357937B2 (en) | 2012-09-06 | 2016-06-07 | Covidien Lp | System and method for determining stroke volume of an individual |
WO2017143366A1 (en) | 2016-02-22 | 2017-08-31 | Cnsystems Medizintechnik Ag | Method and measuring system for continuously determining the intra-arterial blood pressure |
DE202019004899U1 (en) | 2019-12-01 | 2019-12-09 | Pulsion Medical Systems Se | measuring device |
WO2020043726A1 (en) | 2018-08-29 | 2020-03-05 | Pulsion Medical Systems Se | Multi-part appliance for non-invasive detection of vital parameters |
WO2020043724A1 (en) | 2018-08-29 | 2020-03-05 | Pulsion Medical Systems Se | Method and device for correcting a blood pressure measurement carried out at a measurement location |
WO2020043725A1 (en) | 2018-08-29 | 2020-03-05 | Pulsion Medical Systems Se | Noninvasive blood-pressure measuring device |
WO2021110601A1 (en) | 2019-12-01 | 2021-06-10 | Pulsion Medical Systems Se | Sleeve part and measuring device |
WO2021110603A1 (en) | 2019-12-01 | 2021-06-10 | Pulsion Medical Systems Se | Device for measuring vital parameters with advantageous radiation guidance |
WO2021110599A1 (en) | 2019-12-01 | 2021-06-10 | Pulsion Medical Systems Se | Cuff cushion, cuff part, method for the production thereof and measuring device |
WO2021110598A1 (en) | 2019-12-01 | 2021-06-10 | Pulsion Medical Systems Se | Apparatus for measuring vital parameters, having advantageous seal arrangement |
US11058303B2 (en) | 2012-09-14 | 2021-07-13 | Covidien Lp | System and method for determining stability of cardiac output |
DE102020202590A1 (en) | 2020-02-28 | 2021-09-02 | Pulsion Medical Systems Se | DEVICE FOR MEASURING VITAL PARAMETERS WITH ADVANTAGEOUS LENS DEVICE |
US11298086B2 (en) | 2018-10-05 | 2022-04-12 | Samsung Electronics Co., Ltd. | Apparatus and method for estimating blood pressure |
Families Citing this family (61)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9549678B2 (en) | 2008-07-08 | 2017-01-24 | The Johns Hopkins University | Non-invasive methods and systems for assessing cardiac filling pressure |
EP2319408A1 (en) * | 2009-10-15 | 2011-05-11 | Finapres Medical Systems B.V. | Device for controlling the pressure in an inflatable pressure pad |
US8814800B2 (en) * | 2009-10-29 | 2014-08-26 | Cnsystems Medizintechnik Ag | Apparatus and method for enhancing and analyzing signals from a continuous non-invasive blood pressure device |
WO2012155133A2 (en) * | 2011-05-12 | 2012-11-15 | The Johns Hopkins University | Automated process for assessing cardiac filling pressure non-invasively |
GB2494622A (en) * | 2011-08-30 | 2013-03-20 | Oxitone Medical Ltd | Wearable pulse oximetry device |
US8731649B2 (en) | 2012-08-30 | 2014-05-20 | Covidien Lp | Systems and methods for analyzing changes in cardiac output |
US9615756B2 (en) | 2012-10-31 | 2017-04-11 | Cnsystems Medizintechnik Ag | Device and method for the continuous non-invasive measurement of blood pressure |
CN103349545A (en) * | 2013-05-21 | 2013-10-16 | 深圳市理邦精密仪器股份有限公司 | Device and method for simulating invasive blood pressure |
WO2014197257A1 (en) * | 2013-06-05 | 2014-12-11 | Northern Fields, Llc | Methods, systems, and devices for measuring information related to blood pressure |
US9239619B2 (en) | 2013-11-08 | 2016-01-19 | Applied Invention, Llc | Use of light transmission through tissue to detect force |
ES2951290T3 (en) | 2014-02-25 | 2023-10-19 | Icu Medical Inc | Patient monitoring system with gatekeeper signal and corresponding procedure |
WO2015131065A1 (en) * | 2014-02-28 | 2015-09-03 | Valencell, Inc. | Method and apparatus for generating assessments using physical activity and biometric parameters |
US10610113B2 (en) | 2014-03-31 | 2020-04-07 | The Regents Of The University Of Michigan | Miniature piezoelectric cardiovascular monitoring system |
EP3160337B1 (en) * | 2014-06-30 | 2022-04-06 | Scint B.V. | Body worn measurement device |
NL2013091B1 (en) * | 2014-06-30 | 2016-07-11 | Scint B V | Body worn measurement device. |
US9408541B2 (en) | 2014-08-04 | 2016-08-09 | Yamil Kuri | System and method for determining arterial compliance and stiffness |
KR102299361B1 (en) | 2014-09-03 | 2021-09-07 | 삼성전자주식회사 | Apparatus and method for monitoring blood pressure, wearable device having function of blood pressure monitoring |
CN104188643B (en) * | 2014-09-17 | 2016-08-24 | 上海工程技术大学 | A kind of pressure control circuit for blood pressure measurement and control method |
AU2015367622B2 (en) * | 2014-12-16 | 2020-01-23 | Lmd Ip, Llc | Personal health data collection |
WO2016110781A1 (en) * | 2015-01-08 | 2016-07-14 | Cnsystems Medizintechnik Ag | Wearable hemodynamic sensor |
KR102411658B1 (en) | 2015-01-15 | 2022-06-21 | 삼성전자주식회사 | Apparatus for detecting information of the living body |
KR102384225B1 (en) | 2015-03-06 | 2022-04-07 | 삼성전자주식회사 | System and method for sensing blood pressure |
US11298035B2 (en) | 2015-03-17 | 2022-04-12 | Koninklijke Philips N.V. | Method and apparatus for measuring blood pressure |
KR102486700B1 (en) * | 2015-08-11 | 2023-01-11 | 삼성전자주식회사 | Apparatus and method for estimating blood pressure |
KR102434701B1 (en) | 2015-09-01 | 2022-08-22 | 삼성전자주식회사 | Apparatus and method for acquiring bio- information and apparatus for detecting bio- information |
EP3364860A4 (en) | 2015-10-19 | 2019-09-18 | ICU Medical, Inc. | Hemodynamic monitoring system with detachable display unit |
FR3043539B1 (en) * | 2015-11-17 | 2017-11-24 | Moreau Guillaume | DEVICE AND METHOD FOR MEASURING ARTERIAL RIGIDITY OF A PATIENT |
WO2017152098A1 (en) * | 2016-03-03 | 2017-09-08 | Board Of Trustees Of Michigan State University | Method and apparatus for cuff-less blood pressure measurement |
US10398324B2 (en) | 2016-03-03 | 2019-09-03 | Board Of Trustees Of Michigan State University | Method and apparatus for cuff-less blood pressure measurement in a mobile device |
US11350837B2 (en) | 2016-03-30 | 2022-06-07 | Elfi-Tech Ltd. | Method and apparatus for optically measuring blood pressure |
US11134901B2 (en) | 2016-03-30 | 2021-10-05 | Elfi-Tech Ltd. | Method and apparatus for optically measuring blood pressure |
CN106026978B (en) * | 2016-05-11 | 2018-11-27 | 广州视源电子科技股份有限公司 | PWM circuit duty ratio adjusting method and system of blood pressure measuring device |
US11166643B2 (en) * | 2016-06-07 | 2021-11-09 | Michael F. O'Rourke | Non-invasive method of estimating intra-cranial pressure (ICP) |
KR102655671B1 (en) | 2016-10-12 | 2024-04-05 | 삼성전자주식회사 | Apparatus and method for estimating bio-information |
US10874307B2 (en) * | 2017-01-24 | 2020-12-29 | Verily Life Sciences Llc | Digital artery blood pressure monitor |
US20180289271A1 (en) * | 2017-04-11 | 2018-10-11 | Edwards Lifesciences Corporation | Blood pressure measurement device wearable by a patient |
US20180325396A1 (en) * | 2017-05-09 | 2018-11-15 | Edwards Lifesciences Corporation | Finger cuff connector |
US20180338694A1 (en) * | 2017-05-23 | 2018-11-29 | Edwards Lifesciences Corporation | Method for correcting cuff pressure in a non-invasive blood pressure measurement |
KR102407094B1 (en) | 2017-07-25 | 2022-06-08 | 삼성전자주식회사 | Apparatus and method for measuring bio-information |
CN109480805B (en) | 2017-09-13 | 2023-08-15 | 三星电子株式会社 | Biological information measuring apparatus and biological information measuring method |
US20190082982A1 (en) * | 2017-09-20 | 2019-03-21 | Edwards Lifesciences Corporation | Finger cuff utilizing multiple sensors for blood pressure measurement |
US11382522B2 (en) | 2017-09-29 | 2022-07-12 | Fitbit, Inc. | Position detection of blood pressure device |
US11013421B2 (en) | 2017-10-10 | 2021-05-25 | Verily Life Sciences Llc | Blood pressure estimation using finger-wearable sensor array |
US20190133465A1 (en) * | 2017-11-03 | 2019-05-09 | Edwards Lifesciences Corporation | Device for a non-invasive blood pressure measurement |
RU2682474C1 (en) * | 2018-01-16 | 2019-03-19 | Непубличное акционерное общество "Институт кардиологической техники" (ИНКАРТ) | Finger photoplethysographic system device for continuous non-invasive measurement of arterial pressure |
US11357416B2 (en) * | 2018-02-27 | 2022-06-14 | Edwards Lifesciences Corporation | Adaptive tuning for volume clamp blood pressure measurement |
US11576583B2 (en) * | 2018-03-27 | 2023-02-14 | Samsung Electronics Co., Ltd. | Noninvasive blood pressure measurement method and device |
US20190357786A1 (en) * | 2018-05-22 | 2019-11-28 | Edwards Lifesciences Corporation | Finger cuff for non-invasive hemodynamic measurements |
CN108478204B (en) * | 2018-06-07 | 2024-05-10 | 深圳市德力凯医疗设备股份有限公司 | Noninvasive continuous blood pressure measuring equipment |
CN108784742B (en) * | 2018-06-07 | 2024-03-12 | 深圳市德力凯医疗设备股份有限公司 | Cerebral blood flow automatic regulating and monitoring equipment |
WO2020077363A1 (en) | 2018-10-12 | 2020-04-16 | ViviPulse, LLC | Blood pressure measuring device and method |
KR102677448B1 (en) | 2018-11-13 | 2024-06-20 | 삼성전자주식회사 | Electronic device, method for estimating bio-information using the same |
KR20200087567A (en) | 2019-01-11 | 2020-07-21 | 삼성전자주식회사 | Apparatus and method for estimating blood pressure |
AT522324B1 (en) | 2019-05-22 | 2020-10-15 | Cnsystems Medizintechnik Gmbh | METHOD AND DEVICE FOR VALIDATING A BLOOD PRESSURE MONITORING SYSTEM |
WO2021247300A1 (en) | 2020-06-01 | 2021-12-09 | Arc Devices Limited | Apparatus and methods for measuring blood pressure and other vital signs via a finger |
CN112168161B (en) * | 2020-11-06 | 2023-12-15 | 深圳市汇顶科技股份有限公司 | Blood pressure detection method, device, equipment and storage medium |
AT524040B1 (en) * | 2020-11-12 | 2022-02-15 | Cnsystems Medizintechnik Gmbh | METHOD AND MEASURING DEVICE FOR THE CONTINUOUS, NON-INVASIVE DETERMINATION OF AT LEAST ONE CARDIAC CIRCULATORY PARAMETER |
AT524039B1 (en) | 2020-11-12 | 2022-02-15 | Cnsystems Medizintechnik Gmbh | METHOD AND MEASURING SYSTEM FOR CONTINUOUS, NON-INVASIVE DETERMINATION OF ARTERIAL BLOOD PRESSURE |
CN112998674B (en) * | 2021-02-22 | 2022-03-22 | 天津工业大学 | Continuous blood pressure measuring device and self-calibration method |
EP4052641A1 (en) * | 2021-03-02 | 2022-09-07 | Murata Manufacturing Co., Ltd. | Vital-sign detection device |
CN113509160A (en) * | 2021-08-04 | 2021-10-19 | 天津工业大学 | Continuous non-invasive blood pressure monitoring method and device |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000072750A1 (en) * | 1999-06-01 | 2000-12-07 | Massachusetts Institute Of Technology | Cuffless continuous blood pressure monitor |
US7740591B1 (en) * | 2003-12-01 | 2010-06-22 | Ric Investments, Llc | Apparatus and method for monitoring pressure related changes in the extra-thoracic arterial circulatory system |
Family Cites Families (123)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4105021A (en) * | 1976-08-13 | 1978-08-08 | Joseph H. Allen | Method and arrangement for measuring blood pressure |
US4099589A (en) * | 1976-12-20 | 1978-07-11 | Trans Research Development Corporation | DC electric car with auxiliary power and AC drive motor |
NL8005145A (en) | 1980-09-12 | 1982-04-01 | Tno | DEVICE FOR INDIRECT, NON-INVASIVE, CONTINUOUS MEASUREMENT OF BLOOD PRESSURE. |
NL8104879A (en) | 1981-10-28 | 1983-05-16 | Tno | METHOD AND APPARATUS FOR CONTROLLING THE CUFF PRESSURE WHEN MEASURING THE FINGER BLOOD PRESSURE WITH A PHOTO-ELECTRICAL PLETHYSMOGRAPH. |
NL8105381A (en) | 1981-11-27 | 1983-06-16 | Tno | METHOD AND APPARATUS FOR CORRECTING THE CUFF PRESSURE IN MEASURING THE BLOOD PRESSURE IN A BODY PART USING A PLETHYSMOGRAPH. |
JPS59156325A (en) | 1983-02-25 | 1984-09-05 | 株式会社 ウエダ製作所 | Indirect blood pressure measuring apparatus |
US4592364A (en) | 1984-05-10 | 1986-06-03 | Pinto John G | Apparatus for the diagnosis of heart conditions |
US4676330A (en) * | 1985-04-12 | 1987-06-30 | Roberts Jerry G | Auxiliary propulsion system on trailer |
JPS61247431A (en) * | 1985-04-25 | 1986-11-04 | 株式会社エー・アンド・ディ | Method for correcting blood non-observing type continuous blood pressure measurement and blood non-observing type continuous hemomanometer using said method |
DE3522062C2 (en) * | 1985-06-20 | 1993-10-14 | Man Nutzfahrzeuge Ag | Hybrid vehicle |
US4685527A (en) * | 1985-09-05 | 1987-08-11 | Standard Manufacturing Co., Inc. | System for powering a trailer |
US4705047A (en) | 1985-09-30 | 1987-11-10 | Camino Laboratories, Inc. | Output circuit for physiological measuring instruments |
US5054493A (en) | 1986-01-31 | 1991-10-08 | Regents Of The University Of Minnesota | Method for diagnosing, monitoring and treating hypertension |
US4899758A (en) | 1986-01-31 | 1990-02-13 | Regents Of The University Of Minnesota | Method and apparatus for monitoring and diagnosing hypertension and congestive heart failure |
US4726382A (en) | 1986-09-17 | 1988-02-23 | The Boc Group, Inc. | Inflatable finger cuff |
CS272057B1 (en) | 1987-03-27 | 1991-01-15 | Jan Doc Mudr Csc Penaz | Blood pressure automatic non-invasive meter |
JPH01214340A (en) * | 1988-02-24 | 1989-08-28 | Koorin Denshi Kk | Blood pressure monitor apparatus |
FI84690C (en) * | 1988-05-20 | 1992-01-10 | Instrumentarium Oy | Method and apparatus for regulating the pressure of a blood pressure monitor |
JPH0213507U (en) * | 1988-07-12 | 1990-01-29 | ||
US4969466A (en) * | 1988-09-15 | 1990-11-13 | Spacelabs, Inc. | Inflation rate control circuit for blood pressure cuffs |
US5265011A (en) | 1989-04-03 | 1993-11-23 | Eastern Medical Testing Services, Inc. | Method for ascertaining the pressure pulse and related parameters in the ascending aorta from the contour of the pressure pulse in the peripheral arteries |
FR2653718A1 (en) * | 1989-10-26 | 1991-05-03 | Sita | METHOD OF DIFFERENTIATED TRANSPORT AND VEHICLES FOR THEIR PRODUCTION. |
JPH0763450B2 (en) * | 1989-10-31 | 1995-07-12 | テルモ株式会社 | Photoplethysmograph |
SE465551B (en) * | 1990-02-16 | 1991-09-30 | Aake Oeberg | DEVICE FOR DETERMINING A HEART AND RESPIRATORY FREQUENCY THROUGH PHOTOPLETISMOGRAPHICAL SEATING |
US5211177A (en) | 1990-12-28 | 1993-05-18 | Regents Of The University Of Minnesota | Vascular impedance measurement instrument |
NL9100150A (en) | 1991-01-29 | 1992-08-17 | Tno | METHOD FOR DETERMINING THE BATTLE VOLUME AND THE HEART MINUTE VOLUME OF THE HUMAN HEART. |
EP0591289B1 (en) * | 1991-05-16 | 1999-07-07 | Non-Invasive Technology, Inc. | Hemoglobinometers and the like for measuring the metabolic condition of a subject |
EP0537383A1 (en) | 1991-10-15 | 1993-04-21 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | Inflatable finger cuff for use in non-invasive monitoring of instaneous blood pressure |
US5327987A (en) * | 1992-04-02 | 1994-07-12 | Abdelmalek Fawzy T | High efficiency hybrid car with gasoline engine, and electric battery powered motor |
US5485838A (en) * | 1992-12-07 | 1996-01-23 | Nihon Kohden Corporation | Non-invasive blood pressure measurement device |
US5533511A (en) | 1994-01-05 | 1996-07-09 | Vital Insite, Incorporated | Apparatus and method for noninvasive blood pressure measurement |
US5575284A (en) | 1994-04-01 | 1996-11-19 | University Of South Florida | Portable pulse oximeter |
US5535753A (en) | 1994-10-04 | 1996-07-16 | Rutgers University | Apparatus and methods for the noninvasive measurement of cardiovascular system parameters |
GB9503787D0 (en) | 1995-02-24 | 1995-04-12 | Monitoring Tech Ltd | A method of and apparatus for analysing a signal |
AUPN179895A0 (en) | 1995-03-17 | 1995-04-13 | Pwv Medical Pty Ltd | Non-invasive determination of aortic flow velocity waveforms |
NL1001309C2 (en) | 1995-09-28 | 1997-04-03 | Tno | Method and device for the determination of brachial artery pressure wave on the basis of non-invasively measured finger blood pressure wave. |
US5687733A (en) | 1995-10-26 | 1997-11-18 | Baxter International Inc. | System and method for estimating cardiac output |
GB9600209D0 (en) | 1996-01-05 | 1996-03-06 | Monitoring Tech Ltd | Improved method and apparatus for the measurement of cardiac output |
DE69728031T2 (en) * | 1996-09-10 | 2004-11-11 | Seiko Epson Corp. | ORGANISM STATUS MEASURING DEVICE AND RELAXATION STATUS INDICATOR |
GB9714550D0 (en) | 1997-07-10 | 1997-09-17 | Lidco Ltd | Improved method and apparatus for the measurement of cardiac output |
US6367570B1 (en) * | 1997-10-17 | 2002-04-09 | Electromotive Inc. | Hybrid electric vehicle with electric motor providing strategic power assist to load balance internal combustion engine |
US6017313A (en) | 1998-03-20 | 2000-01-25 | Hypertension Diagnostics, Inc. | Apparatus and method for blood pressure pulse waveform contour analysis |
AU3104399A (en) | 1998-03-20 | 1999-10-11 | Hypertension Diagnostics, Inc. | Sensor and method for sensing arterial pulse pressure |
US6155365A (en) * | 1998-05-12 | 2000-12-05 | Chrysler Corporation | Brake blending strategy for a hybrid vehicle |
AT407949B (en) | 1998-06-09 | 2001-07-25 | Cnsystems Medizintechnik Gmbh | Haemodynamic patient monitor |
US6892839B2 (en) * | 1998-10-14 | 2005-05-17 | James W. Cooper | Multi-combination vehicle incorporating a power trailer |
AT408066B (en) * | 1999-03-30 | 2001-08-27 | Juergen Dipl Ing Fortin | CONTINUOUS NON-INVASIVE BLOOD PRESSURE GAUGE |
US6315735B1 (en) | 1999-03-31 | 2001-11-13 | Pulsion Medical Systems Ag | Devices for in-vivo determination of the compliance function and the systemic blood flow of a living being |
US6431298B1 (en) * | 1999-04-13 | 2002-08-13 | Meritor Heavy Vehicle Systems, Llc | Drive unit assembly for an electrically driven vehicle |
AU3955500A (en) * | 1999-04-21 | 2000-11-02 | Jie Kan | A noninvasive blood pressure measuring method and apparatus |
IT1315206B1 (en) | 1999-04-27 | 2003-02-03 | Salvatore Romano | METHOD AND APPARATUS FOR MEASURING HEART RATE. |
US6725955B2 (en) * | 1999-10-08 | 2004-04-27 | John L. Bidwell | Powered trailer to propel a two wheeled vehicle |
JP2001112728A (en) * | 1999-10-15 | 2001-04-24 | Advanced Medical Kk | Pulsimeter |
AUPQ420599A0 (en) | 1999-11-24 | 1999-12-16 | Duncan Campbell Patents Pty Ltd | Method and apparatus for determining cardiac output or total peripheral resistance |
US6616613B1 (en) * | 2000-04-27 | 2003-09-09 | Vitalsines International, Inc. | Physiological signal monitoring system |
US6419037B1 (en) * | 2000-07-19 | 2002-07-16 | Meritor Heavy Vehicle Systems, Llc | Multi-unit articulated road train propulsion system |
US6516925B1 (en) * | 2000-09-28 | 2003-02-11 | Ford Global Technologies, Inc. | System and method for braking a towed conveyance |
JP4462257B2 (en) * | 2000-11-14 | 2010-05-12 | オムロンヘルスケア株式会社 | Electronic blood pressure monitor |
US7338335B1 (en) * | 2001-01-23 | 2008-03-04 | Frank Messano | Hybrid electric heavy-duty vehicle drive system |
ES2220607T3 (en) | 2001-03-01 | 2004-12-16 | Pulsion Medical Systems Ag | APPARATUS, INFORMATIC PROGRAM AND SET OF CENTRAL VENOUS CATHETER FOR HEMODINAMIC CONTROL. |
ATE520341T1 (en) | 2001-06-22 | 2011-09-15 | Nellcor Puritan Bennett Ie | WAVELET-BASED ANALYSIS OF PULSE OXIMETRY SIGNALS |
US6471646B1 (en) | 2001-07-19 | 2002-10-29 | Medwave, Inc. | Arterial line emulator |
DE10146386A1 (en) * | 2001-09-20 | 2003-04-17 | Gkn Automotive Gmbh | drive unit |
US7317409B2 (en) | 2002-01-30 | 2008-01-08 | Tensys Medical, Inc. | Apparatus and method for interfacing time-variant signals |
AU2003217564A1 (en) * | 2002-02-22 | 2003-09-09 | Datex-Ohmeda, Inc. | Monitoring physiological parameters based on variations in a photoplethysmographic signal |
US6733461B2 (en) | 2002-08-01 | 2004-05-11 | Hypertension Diagnostics, Inc. | Methods and apparatus for measuring arterial compliance, improving pressure calibration, and computing flow from pressure data |
CN1394546A (en) * | 2002-08-08 | 2003-02-05 | 天津市先石光学技术有限公司 | Blood pressure measuring device and method |
SG152019A1 (en) | 2003-01-29 | 2009-05-29 | Healthstats Int Pte Ltd | Noninvasive blood pressure monitoring system |
CA2418686A1 (en) * | 2003-02-07 | 2004-08-07 | Gaetan Leclerc | Motorized semi-trailer |
US7815578B2 (en) | 2003-02-10 | 2010-10-19 | Massachusetts Institute Of Technology | Methods and apparatus for determining cardiac output |
US8255029B2 (en) | 2003-02-27 | 2012-08-28 | Nellcor Puritan Bennett Llc | Method of analyzing and processing signals |
EP2392257A3 (en) * | 2003-03-12 | 2012-02-29 | Yale University | Method of assessing blood volume using photoelectric plethysmography |
AT412613B (en) * | 2003-04-01 | 2005-05-25 | Cnsystems Medizintechnik Gmbh | DEVICE AND METHOD FOR CONTINUOUS, NON-INVASIVE MEASUREMENT OF BLOOD PRESSURE |
CN100346741C (en) * | 2003-05-29 | 2007-11-07 | 香港中文大学 | Blood pressure measuring method and device based on heart sound signal |
AT412702B (en) * | 2003-10-21 | 2005-06-27 | Cnsystems Medizintechnik Gmbh | DEVICE AND METHOD FOR CONTROLLING THE PRESSURE IN AN INFLATABLE CUFF OF A BLOOD PRESSURE METER |
US7422562B2 (en) | 2003-12-05 | 2008-09-09 | Edwards Lifesciences | Real-time measurement of ventricular stroke volume variations by continuous arterial pulse contour analysis |
US7220230B2 (en) | 2003-12-05 | 2007-05-22 | Edwards Lifesciences Corporation | Pressure-based system and method for determining cardiac stroke volume |
US7452333B2 (en) | 2003-12-05 | 2008-11-18 | Edwards Lifesciences Corporation | Arterial pressure-based, automatic determination of a cardiovascular parameter |
US6991571B2 (en) * | 2003-12-09 | 2006-01-31 | Arvinmeritor Technology, Llc | Variable ratio drive system |
WO2005058155A1 (en) | 2003-12-17 | 2005-06-30 | Atcor Medical Pty Ltd | Method and apparatus for determination of central aortic pressure |
US7442169B2 (en) | 2004-03-05 | 2008-10-28 | Atcor Medical Pty Limited | Methods of distinguishing between vasoconstriction and vasodilation as a cause of hypotension |
JP2007526040A (en) | 2004-03-05 | 2007-09-13 | アトコー メディカル ピーティーワイ リミテッド | Method and apparatus for determining cardiac output from arterial pressure pulse waveform |
US7238159B2 (en) * | 2004-04-07 | 2007-07-03 | Triage Wireless, Inc. | Device, system and method for monitoring vital signs |
DE102004024334A1 (en) | 2004-05-17 | 2005-12-22 | Pulsion Medical Systems Ag | Device for determining a hemodynamic parameter |
DE102004024335A1 (en) | 2004-05-17 | 2005-12-15 | Pulsion Medical Systems Ag | Device for determining the transition between systole and diastole |
US7115057B2 (en) * | 2004-06-03 | 2006-10-03 | Arvinmeritor Technology Llc | Drive axle assembly for hybrid electric vehicle |
JP4760246B2 (en) * | 2004-09-30 | 2011-08-31 | トヨタ自動車株式会社 | Hydraulic brake device |
JP4412659B2 (en) * | 2004-10-06 | 2010-02-10 | 日本電信電話株式会社 | Blood pressure measurement device |
US20060108866A1 (en) * | 2004-11-22 | 2006-05-25 | Hunter Scott A | Apparatus which is a self contained trailer axle assembly that collects, stores and uses momentum energy |
JP4453529B2 (en) * | 2004-11-24 | 2010-04-21 | パナソニック電工株式会社 | Arterial stiffness measurement device |
US7186198B2 (en) * | 2005-02-24 | 2007-03-06 | Selva Jr Efrain A | Transaxle |
US7651466B2 (en) | 2005-04-13 | 2010-01-26 | Edwards Lifesciences Corporation | Pulse contour method and apparatus for continuous assessment of a cardiovascular parameter |
JP5399602B2 (en) * | 2005-04-22 | 2014-01-29 | フクダ電子株式会社 | Biological information output device and method, and biological information report |
US7514803B2 (en) * | 2005-08-18 | 2009-04-07 | Wilks Paul L | Trailer with integral axle-mounted generator and battery charger |
US7325638B1 (en) * | 2005-11-21 | 2008-02-05 | Belloso Gregorio M | Motor vehicle with a primary engine for acceleration and secondary engine augmented by an electric motor for cruising |
EP1954187A1 (en) | 2005-12-01 | 2008-08-13 | Atcor Medical Pty Ltd | A method of estimating pulse wave velocity |
US7666144B2 (en) | 2006-02-21 | 2010-02-23 | Board Of Trustees Operating Michigan State University | Methods and apparatus for determining cardiac output and left atrial pressure |
US8282569B2 (en) | 2006-03-15 | 2012-10-09 | Board Of Trustees Of Michigan State University | Method and apparatus for determining ejection fraction |
US7476840B2 (en) | 2006-05-08 | 2009-01-13 | Slicex, Inc. | Sensing light and sensing the state of a memory cell an aid of a switch controlled by a schmidt trigger |
JP2007330431A (en) * | 2006-06-14 | 2007-12-27 | Mitsuba Corp | Biological information determining system, biological information determining method, and biological information determining program |
US20080015451A1 (en) | 2006-07-13 | 2008-01-17 | Hatib Feras S | Method and Apparatus for Continuous Assessment of a Cardiovascular Parameter Using the Arterial Pulse Pressure Propagation Time and Waveform |
JP4702216B2 (en) * | 2006-08-03 | 2011-06-15 | オムロンヘルスケア株式会社 | Electronic blood pressure monitor and control method thereof |
US8679025B2 (en) | 2006-08-31 | 2014-03-25 | Atcor Medical Pty Ltd | Method for determination of cardiac output |
CN100407993C (en) * | 2006-09-05 | 2008-08-06 | 西安交通大学 | Digital signal process method for light- frequency conversion type pulse blood oxygen instrument |
JP4789203B2 (en) * | 2006-10-02 | 2011-10-12 | フクダ電子株式会社 | Blood pressure reflex function measuring device |
JP5193224B2 (en) | 2006-12-11 | 2013-05-08 | ツェーエンシステムズ・メディツィーンテヒニーク・ゲー・エム・ベー・ハー | Apparatus for continuous noninvasive measurement of arterial pressure and its use |
US20080174174A1 (en) * | 2007-01-22 | 2008-07-24 | James S. Burns | Passive Truck Trailer Braking Regeneration and Propulsion System and Method |
US8435184B2 (en) | 2007-01-31 | 2013-05-07 | Aortic Wrap Pty Ltd. | Characterisation of ageing effect and cardiovascular risk |
CN201033073Y (en) * | 2007-02-07 | 2008-03-12 | 深圳市科瑞康实业有限公司 | Sphygmus blood oxygen test apparatus |
DE102007020038A1 (en) * | 2007-04-27 | 2008-10-30 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Evidence of apnea with blood pressure dependent detected signals |
US20100198088A1 (en) | 2007-05-01 | 2010-08-05 | Michael Ortenberg | Method, apparatus and system for detection of arterial stiffness and artery tonus by pulse curve geometry analysis |
US8282564B2 (en) | 2007-05-16 | 2012-10-09 | Massachusetts Institute Of Technology | Systems and methods for model-based estimation of cardiac output and total peripheral resistance |
JP4971041B2 (en) * | 2007-06-11 | 2012-07-11 | 株式会社デンソー | Blood pressure measuring device, program, and recording medium |
WO2009014420A1 (en) | 2007-07-20 | 2009-01-29 | Bmeye B.V. | A method, a system and a computer program product for determining a beat-to beat stroke volume and/or a cardiac output |
US20090270739A1 (en) | 2008-01-30 | 2009-10-29 | Edwards Lifesciences Corporation | Real-time detection of vascular conditions of a subject using arterial pressure waveform analysis |
CA2713675C (en) | 2008-02-15 | 2017-08-22 | Assistance Publique-Hopitaux De Paris | Device and process for calculating new indices of arterial stiffness, and/or for stroke volume monitoring |
JP5098721B2 (en) * | 2008-03-14 | 2012-12-12 | オムロンヘルスケア株式会社 | Blood pressure measurement device, blood pressure derivation program, and blood pressure derivation method |
JP5045514B2 (en) * | 2008-03-19 | 2012-10-10 | オムロンヘルスケア株式会社 | Electronic blood pressure monitor |
US20100076326A1 (en) | 2008-09-22 | 2010-03-25 | Richard Jonathan Cohen | Method for estimating changes of cardiovascular indices using peripheal arterial blood pressure waveform |
US20100204591A1 (en) | 2009-02-09 | 2010-08-12 | Edwards Lifesciences Corporation | Calculating Cardiovascular Parameters |
US8491487B2 (en) | 2009-02-11 | 2013-07-23 | Edwards Lifesciences Corporation | Detection of parameters in cardiac output related waveforms |
US20100241013A1 (en) | 2009-03-18 | 2010-09-23 | Edwards Lifesciences Corporation | Direct Measurements of Arterial Pressure Decoupling |
US8814800B2 (en) * | 2009-10-29 | 2014-08-26 | Cnsystems Medizintechnik Ag | Apparatus and method for enhancing and analyzing signals from a continuous non-invasive blood pressure device |
-
2010
- 2010-10-29 US US12/915,496 patent/US8814800B2/en active Active
- 2010-10-29 EP EP10807720.7A patent/EP2493373B1/en active Active
- 2010-10-29 WO PCT/IB2010/003274 patent/WO2011051819A1/en active Application Filing
- 2010-10-29 CN CN201080048391.4A patent/CN102647940B/en not_active Expired - Fee Related
- 2010-10-29 JP JP2012535959A patent/JP6058397B2/en active Active
- 2010-10-29 CN CN201080048387.8A patent/CN102791192B/en active Active
- 2010-10-29 JP JP2012535957A patent/JP2013509225A/en active Pending
- 2010-10-29 US US12/915,572 patent/US8343062B2/en active Active
- 2010-10-29 WO PCT/IB2010/003325 patent/WO2011051822A1/en active Application Filing
- 2010-10-29 EP EP10805828.0A patent/EP2493370B1/en active Active
-
2015
- 2015-09-24 JP JP2015187209A patent/JP2016025935A/en active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000072750A1 (en) * | 1999-06-01 | 2000-12-07 | Massachusetts Institute Of Technology | Cuffless continuous blood pressure monitor |
US7740591B1 (en) * | 2003-12-01 | 2010-06-22 | Ric Investments, Llc | Apparatus and method for monitoring pressure related changes in the extra-thoracic arterial circulatory system |
Cited By (30)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102613966A (en) * | 2012-02-01 | 2012-08-01 | 香港应用科技研究院有限公司 | Blood pressure measuring device and adjusting method thereof |
CN104822314B (en) * | 2012-05-31 | 2017-10-31 | Cn 体系药物技术股份公司 | The method and apparatus that blood pressure is determined for continuous, non-invasive |
WO2013178475A1 (en) | 2012-05-31 | 2013-12-05 | Cnsystems Medizintechnik Gmbh | Method and device for continuous, non-invasive determination of blood pressure |
US10098554B2 (en) | 2012-05-31 | 2018-10-16 | Cnsystems Medizintechnik Ag | Method and device for continuous, non-invasive determination of blood pressure |
JP2015521071A (en) * | 2012-05-31 | 2015-07-27 | ツェーエンシステムズ・メディツィーンテヒニーク・アー・ゲーCnsystems Medizintechnik Ag | Method and apparatus for continuous noninvasive measurement of blood pressure |
CN104822314A (en) * | 2012-05-31 | 2015-08-05 | Cn体系药物技术股份公司 | Method and device for continuous, non-invasive determination of blood pressure |
US9402573B2 (en) | 2012-08-22 | 2016-08-02 | Covidien Lp | System and method for detecting fluid responsiveness of a patient |
US9060745B2 (en) | 2012-08-22 | 2015-06-23 | Covidien Lp | System and method for detecting fluid responsiveness of a patient |
US9357937B2 (en) | 2012-09-06 | 2016-06-07 | Covidien Lp | System and method for determining stroke volume of an individual |
US9241646B2 (en) | 2012-09-11 | 2016-01-26 | Covidien Lp | System and method for determining stroke volume of a patient |
US10448851B2 (en) | 2012-09-11 | 2019-10-22 | Covidien Lp | System and method for determining stroke volume of a patient |
US11445930B2 (en) | 2012-09-11 | 2022-09-20 | Covidien Lp | System and method for determining stroke volume of a patient |
US11058303B2 (en) | 2012-09-14 | 2021-07-13 | Covidien Lp | System and method for determining stability of cardiac output |
US8977348B2 (en) | 2012-12-21 | 2015-03-10 | Covidien Lp | Systems and methods for determining cardiac output |
WO2017143366A1 (en) | 2016-02-22 | 2017-08-31 | Cnsystems Medizintechnik Ag | Method and measuring system for continuously determining the intra-arterial blood pressure |
US11426087B2 (en) | 2016-02-22 | 2022-08-30 | Cnsystems Medizintechnik Ag | Method and measuring system for continuously determining the intra-arterial blood pressure |
WO2020043726A1 (en) | 2018-08-29 | 2020-03-05 | Pulsion Medical Systems Se | Multi-part appliance for non-invasive detection of vital parameters |
WO2020043725A1 (en) | 2018-08-29 | 2020-03-05 | Pulsion Medical Systems Se | Noninvasive blood-pressure measuring device |
US11974836B2 (en) | 2018-08-29 | 2024-05-07 | Pulsion Medical Systems Se | Multi-part appliance for non-invasive detection of vital parameters |
WO2020043724A1 (en) | 2018-08-29 | 2020-03-05 | Pulsion Medical Systems Se | Method and device for correcting a blood pressure measurement carried out at a measurement location |
US11744526B2 (en) | 2018-10-05 | 2023-09-05 | Samsung Electronics Co., Ltd. | Apparatus and method for estimating blood pressure |
US11298086B2 (en) | 2018-10-05 | 2022-04-12 | Samsung Electronics Co., Ltd. | Apparatus and method for estimating blood pressure |
WO2021110599A1 (en) | 2019-12-01 | 2021-06-10 | Pulsion Medical Systems Se | Cuff cushion, cuff part, method for the production thereof and measuring device |
WO2021110598A1 (en) | 2019-12-01 | 2021-06-10 | Pulsion Medical Systems Se | Apparatus for measuring vital parameters, having advantageous seal arrangement |
WO2021110601A1 (en) | 2019-12-01 | 2021-06-10 | Pulsion Medical Systems Se | Sleeve part and measuring device |
DE202019004899U1 (en) | 2019-12-01 | 2019-12-09 | Pulsion Medical Systems Se | measuring device |
WO2021110597A1 (en) | 2019-12-01 | 2021-06-10 | Pulsion Medical Systems Se | Photoplethysmographic blood pressure measuring device with removable finger cuff |
WO2021110603A1 (en) | 2019-12-01 | 2021-06-10 | Pulsion Medical Systems Se | Device for measuring vital parameters with advantageous radiation guidance |
DE102020202590A1 (en) | 2020-02-28 | 2021-09-02 | Pulsion Medical Systems Se | DEVICE FOR MEASURING VITAL PARAMETERS WITH ADVANTAGEOUS LENS DEVICE |
WO2021170818A1 (en) | 2020-02-28 | 2021-09-02 | Pulsion Medical Systems Se | Apparatus for measuring vital parameters comprising an advantageous lens device |
Also Published As
Publication number | Publication date |
---|---|
CN102647940A (en) | 2012-08-22 |
US20110105917A1 (en) | 2011-05-05 |
JP2013509225A (en) | 2013-03-14 |
CN102791192A (en) | 2012-11-21 |
JP2016025935A (en) | 2016-02-12 |
EP2493373A1 (en) | 2012-09-05 |
EP2493370B1 (en) | 2016-03-16 |
JP2013509226A (en) | 2013-03-14 |
US8343062B2 (en) | 2013-01-01 |
CN102791192B (en) | 2015-02-25 |
CN102647940B (en) | 2015-02-04 |
US8814800B2 (en) | 2014-08-26 |
JP6058397B2 (en) | 2017-01-11 |
WO2011051819A1 (en) | 2011-05-05 |
US20110105918A1 (en) | 2011-05-05 |
EP2493370A1 (en) | 2012-09-05 |
EP2493373B1 (en) | 2016-03-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2493373B1 (en) | Apparatus and methods for enhancing and analyzing signals from a continuous non-invasive blood pressure measurement device | |
US20160302678A1 (en) | Evaluation of aortic blood pressure waveform using an adaptive peripheral pressure transfer function | |
US20120157791A1 (en) | Adaptive time domain filtering for improved blood pressure estimation | |
JP2018511391A (en) | Method and apparatus for measuring blood pressure | |
JP2000512875A (en) | Non-invasive high-speed blood pressure measurement device | |
WO2003034916A2 (en) | Methods, apparatus and sensor for hemodynamic monitoring | |
KR20150082401A (en) | Improved blood pressure monitor and method | |
US10390712B2 (en) | Blood pressure measurement device, blood pressure measurement method, and non-transitory recording medium | |
US6440080B1 (en) | Automatic oscillometric apparatus and method for measuring blood pressure | |
KR100804454B1 (en) | Superior-and-inferior-limb blood-pressure index measuring apparatus | |
Mukkamala et al. | Photoplethysmography in noninvasive blood pressure monitoring | |
WO2013061765A1 (en) | Measuring device, evaluation method, and evaluation program | |
ZA200106578B (en) | Method and device for continuous analysis of cardiovascular activity of a subject. | |
KR101918577B1 (en) | Blood Pressure Meter And Method For Measuring Blood Pressure Using The Same | |
RU2281687C1 (en) | Method for monitoring arterial pressure | |
US11020010B2 (en) | Blood pressure/pulse wave measurement device | |
JP5887836B2 (en) | Measuring device, index calculation method, and index calculation program | |
WO2023072730A1 (en) | Device, system and method for calibrating a blood pressure surrogate for use in monitoring a subject's blood pressure | |
JP2023539358A (en) | Method and apparatus for estimating reliability of cardiac output measurements | |
JP2007044261A (en) | Blood vessel hardness measuring instrument | |
Gupta | Blood Pressure Monitoring | |
Chellathurai | Development of a new device to measure finger's mean arterial pressure |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 201080048387.8 Country of ref document: CN |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 10807720 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2012535959 Country of ref document: JP |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2010807720 Country of ref document: EP |