CN115137328A - Pressure control and blood pressure calculation device and method - Google Patents
Pressure control and blood pressure calculation device and method Download PDFInfo
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- 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
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- A61B5/02141—Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits
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- 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
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Abstract
The invention relates to a device and a method for pressure control and blood pressure calculation. The pressure control device according to the present invention includes: a pump for inflating a cuff for use with the apparatus; at least one valve for inflating or deflating the cuff; a pressure sensor for obtaining a pressure measurement representative of the pressure in the cuff; a controller for determining the type of the cuff from a change in the pressure measurement value within a predetermined time during inflation of the cuff, and controlling the pump and/or the at least one valve to inflate or deflate the cuff in dependence on the determined type of cuff.
Description
Technical Field
The invention relates to the technical field of blood pressure measurement, in particular to a pressure control device and method of a blood pressure measurement cuff and a device and method for blood pressure calculation.
Background
The non-invasive blood pressure measuring technology comprises a palpation method, an auscultation method, an ultrasonic measuring method, an oscillometric principle measuring method and the like.
Disclosure of Invention
According to a first aspect of the present application, there is provided a pressure control device comprising: a pump for inflating a cuff for use with the apparatus; at least one valve for inflating or deflating the cuff; a pressure sensor for obtaining a pressure measurement indicative of the pressure in the cuff; a controller for determining the type of the cuff from a change in the pressure measurement value within a predetermined time during inflation of the cuff, and controlling the pump and/or the at least one valve to inflate or deflate the cuff in dependence on the determined type of cuff.
According to a second aspect of the present application, there is provided an apparatus for blood pressure calculation, the apparatus for use with a blood pressure measurement cuff, the apparatus comprising: a pump for inflating the cuff; at least one valve for inflating or deflating the cuff; a pressure sensor for obtaining a pressure measurement indicative of the pressure in the cuff; and a processor. The processor is configured to: controlling the pump and the at least one valve to inflate the cuff until the pressure measurement reaches a predetermined inflation target value; controlling the at least one valve to deflate the cuff in series; recording a measured pressure value measured after each deflation is completed and before the next deflation is started and the amplitude of the oscillation of the measured pressure value; obtaining an amplitude-pressure curve from the pressure measurements and the amplitude of the oscillations of the pressure measurements; determining the maximum amplitude on the amplitude-pressure curve and the pressure corresponding to the maximum amplitude, namely the maximum amplitude pressure; and calculating the systolic pressure SBP and the diastolic pressure DBP according to the maximum amplitude pressure, the maximum amplitude and the amplitude of the sampling point adjacent to the maximum amplitude point.
According to a third aspect of the present application, there is provided a pressure control method including: inflating the cuff with a pump and at least one valve; obtaining a pressure measurement representative of a pressure in the cuff by a pressure sensor; determining a type of the cuff from a change in the pressure measurement value within a predetermined time during inflation of the cuff, and controlling the pump and/or the at least one valve to inflate or deflate the cuff in dependence on the determined type of cuff.
According to a fourth aspect of the present application, there is provided a method for blood pressure calculation, comprising: obtaining a pressure measurement value representing a pressure in the blood pressure measurement cuff using the pressure sensor; controlling a pump and at least one valve to inflate the cuff until the pressure measurement reaches a predetermined inflation target value; controlling the at least one valve to sequentially deflate the cuff; recording a measured pressure value measured after each deflation is completed and before the next deflation is started and the amplitude of the oscillation of the measured pressure value; obtaining an amplitude-pressure curve from the pressure measurements and the amplitude of the oscillations of the pressure measurements; determining the maximum amplitude on the amplitude-pressure curve and the pressure corresponding to the maximum amplitude, namely the maximum amplitude pressure; and calculating the systolic pressure SBP and the diastolic pressure DBP according to the maximum amplitude pressure, the maximum amplitude and the amplitude of the sampling point adjacent to the maximum amplitude point.
Other features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention.
Fig. 1 is a schematic diagram illustrating a pressure control device according to an embodiment of the present invention.
Fig. 2 is a block diagram of a blood pressure measuring instrument according to an embodiment of the present invention.
Fig. 3 is a flow chart for determination of the type of cuff in accordance with an embodiment of the present invention.
Fig. 4 is a flow chart for determining the type of cuff according to another embodiment of the present invention.
FIG. 5A is a schematic illustration of an inflation delay time applied during inflation in accordance with an embodiment of the present invention.
Fig. 5B shows a schematic of a pressure curve in which the inflation delay time is not applied during inflation and a pressure curve in which the inflation delay time is applied during inflation.
FIG. 6A is a schematic illustration of deflation delay time applied during deflation according to an embodiment of the present invention.
Fig. 6B shows a schematic of a pressure curve in which the deflation delay time is not applied during the deflation process and a pressure curve in which the deflation delay time is applied during the deflation process.
FIG. 7 shows a pressure control flow diagram of an inflation process in accordance with an embodiment of the invention.
FIG. 8 shows a pressure control flow diagram of a bleed process in accordance with an embodiment of the present invention.
FIG. 9 shows a general pressure control flow diagram according to an embodiment of the invention.
Fig. 10 is a block diagram of a blood pressure calculation apparatus according to an embodiment of the present invention.
Fig. 11 is a schematic diagram showing the deflation-by-deflation process for the cuff.
FIG. 12 is a graphical representation of pressure measurements versus oscillation amplitude during cuff deflation.
FIG. 13 is a schematic diagram of an amplitude versus pressure curve according to an embodiment of the present invention.
Fig. 14 is a flowchart of a blood pressure calculation method according to an embodiment of the present invention.
Detailed Description
Various exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers indicate functionally identical or similar elements. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present invention. It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In other instances, methods, procedures, components, and circuits that are well known to those skilled in the art have not been described in detail so as not to obscure the present invention.
The blood pressure measuring instrument based on the oscillometric principle consists of a pump, a pressure sensor and a valve. Wherein the pump is capable of inflating a cuff for use with the blood pressure meter and the valve is capable of opening or closing to inflate or deflate the cuff. A pressure measurement indicative of the pressure in the cuff can be obtained by the pressure sensor. During use of the blood pressure meter, the pump inflates the cuff to an expected systolic pressure above the blood pressure in the artery when the valve is closed, and when it is desired to reduce the cuff pressure, the valve is briefly opened to reduce the cuff pressure to a new desired level. When the blood pressure measurement process is over, the valve is continuously opened to evacuate the air circuit between the valve and the cuff and return the pressure in the cuff to atmospheric pressure.
When blood pressure measurement is initiated, the valve is closed, the pump is opened, the cuff is inflated, the cuff pressure is increased to the desired target pressure, once the cuff pressure reaches its target pressure, the blood pressure meter starts to deflate the cuff in small pressure steps one after the other, the amplitude of the oscillations of the pressure in the cuff is measured and recorded at each step as the cuff pressure decreases, and the procedure is continued until the cuff pressure is substantially below the estimated diastolic pressure. At this point, the blood pressure measurement cycle is complete, the valve is opened, and the cuff is fully deflated.
Conventional oscillometric blood pressure measurement techniques rely on empirical evidence. The amplitude of the measured pressure oscillations in the blood pressure cuff reaches a maximum when the cuff pressure approaches the mean arterial pressure (MBP) of the subject. Systolic and diastolic pressures are then obtained from the mean arterial pressure in dependence on clinical experience.
However, the conventional blood pressure measurement technology of the oscillometric principle has a limitation. For example, this technique does not consider the details of the subject and the blood pressure measurement hardware settings, and cannot ensure the accuracy of the blood pressure measurement value.
The above technical problems can be solved by the pressure control and blood pressure calculation device and method provided by the invention. In the pressure control and method provided herein, a pressure measurement indicative of the pressure in the cuff is obtained by a pressure sensor and the type of cuff is determined from the rate of change of increase of the pressure measurement in the cuff as inflation progresses. Once the cuff type is determined, the subsequent inflation and deflation processes can be adjusted accordingly, thereby improving the speed, accuracy and comfort of the overall blood pressure measurement.
FIG. 1 is a schematic diagram illustrating a pressure control device 100 according to an exemplary embodiment, including: a pump 101, a valve 102, a pressure sensor 103 and a controller 104, wherein the number of the valves 102 can be 1 or more. Controller 104 may be electrically connected to pump 101, valve 102, and pressure sensor 103, among other things. The controller 104 may receive pressure measurements from the pressure sensor 103, determine the type of the cuff from changes in the pressure measurements during a predetermined time during inflation of the cuff, and send control signals to the pump 101 and valve 102, respectively, to effect control of the pump 101 and valve 102 according to the determined type of cuff. The pump 101 may be connected, for example, by a hose, air-tightly to a cuff used with the pressure control device 100 for inflating the cuff under the control of the controller 104. The valve 102 can be placed in a manifold connecting the pump, the hose of the cuff, and the pressure sensor to open during inflation to allow the pumped flow of air into the cuff and close after inflation is complete to prevent the air in the cuff from flowing out; and/or valve 102 is positioned between the cuff and the atmosphere, which is closed during inflation to raise the pressure in the cuff, and opened during deflation to effect deflation. A pressure sensor 103, which may be disposed in the manifold (with a valve included in the manifold, the pressure sensor 103 is disposed between the valve and the cuff), or built into the cuff, or otherwise attached to the cuff, to obtain a pressure measurement representative of the pressure in the cuff and send it to the controller 104. The above exemplary constructions and connections are illustrative only and not limiting; other structures and connections may be used by those skilled in the art to perform the same function as the example pressure control device 100 described above.
Notably, the predetermined time is a predetermined length of time during inflation of the cuff. For example, the predetermined time may have a start equal to or later than a start of inflation of a cuff, and the predetermined time is entirely within the first two thirds of the inflation period.
Fig. 2 is a block diagram of a blood pressure meter 200 including the pressure control device 100, a memory 201 as a storage unit, an input device 202, a communication device 203, an output device 204, a power source 205, and a drive circuit 206 for driving the pump 101 and the valve 102.
The input device 202 is used for inputting a command to start or stop blood pressure measurement in the blood pressure measurement mode, switching between the setting mode and the blood pressure measurement mode, and a command to cancel determination, and the input device 202 is used for inputting a command to the subject, for example, a command to start blood pressure measurement, and a command to stop blood pressure measurement. Alternatively, a pressing type switch may be used as an example of the input device 202, and the input device 202 is not limited to the pressing type switch, and may be another touch input device such as a pressure-sensitive (resistive) or proximity (capacitive) touch panel. The input device 202 may be a voice input device having a microphone or a communication input device capable of performing wired or wireless communication with a computer, a smartphone, or the like. Alternatively, input device 202 may be any combination of a touch input device, a voice input device, and a communication input device.
The input device 202 may be used for inputting information to the subject, for example, for inputting biological information such as blood pressure measured by the blood pressure measuring instrument, a measured site, a circumference of a wrist of the subject, a physical condition of the subject, and a body fat percentage. The input device 202 outputs the input information and instruction to the controller 104. The user can input whether the subject is an adult or a minor using the input device 202. Alternatively, the user may input the cuff type directly into the pressure control apparatus 100 as an initial setting using the input apparatus 202.
The memory 201 stores, in a non-transitory manner, data of a program for controlling the blood pressure meter, data for controlling the blood pressure meter, setting data for setting various functions of the blood pressure meter, data of a measurement result of a blood pressure value, and the like. The memory 201 is used as a work memory or the like for executing a program. Here, the setting data for setting various functions of the blood pressure measurement instrument includes biological information input by the subject via the input device 202. In addition, the data for controlling the blood pressure measuring instrument includes: for calculating a predetermined inflation target value of the fluid to be supplied to the cuff, a predetermined deflation target value for each deflation in successive deflations, a time interval between two deflations in successive deflations, an initial inflation rate, a desired deflation rate, the predetermined time, and the like, based on the biological information.
The controller 104 functions as a control unit according to a program for controlling the blood pressure meter stored in the memory 201. For example, the controller 104 calculates a predetermined inflation target value of the fluid to be supplied to the cuff based on the biological information input by the subject via the input device 202. When the blood pressure measurement function is executed, if the controller 104 receives a blood pressure measurement start command via the input device 202, the controller controls the pump 101 and the valve 102 to be driven based on a signal from the pressure sensor 103. Also, the controller 104 calculates a blood pressure value based on the signal of the pressure sensor 103. For example, the amplitude-pressure curve, the maximum amplitude pressure, the base ratio, the first/second/third SBP ratio, and the first/second/third SBP ratio may be obtained from the signal of the pressure sensor 103 as described later, thereby obtaining the systolic pressure SBP and the diastolic pressure DBP.
The communication device 203 transmits predetermined information to an external device via a network under the control of the controller 104, or receives information from an external device via a network and transfers the information to the controller 104. The communication via the network may be either wireless or wired. In this embodiment, the network is the internet, but the network is not limited to this, and may be another type of network such as a local area network in a set area, or may be one-to-one communication using a USB cable or the like. The communication device 203 may comprise a micro USB connector.
An output device 204, which is typically a display, is used to provide feedback information to the subject. The output device 204 may also include one or more speakers for providing audible feedback, or other components for providing other types of feedback, such as tactile/haptic feedback. In general, suitable displays may be made from a variety of materials as described above. Additionally, the screen may be a touch screen display as a combination input/output device that enables user interaction of the blood pressure meter by touching the output device 204.
The power source 205 may be a battery or an alternating current power source (e.g., 220V utility). The power supply 205 supplies power to the main components on which the blood pressure measurement instrument is mounted, and in this example, supplies power to the respective components of the controller 104, the memory 201, the communication device 203, the pressure sensor 103, the pump 101, the valve 102, and the drive circuit 206.
The pump 101 is capable of adjusting the amount of inflation of the fluid entering the cuff. Alternatively, the pump 101 is driven by the drive circuit 206 in accordance with a control signal supplied from the controller 104. The pump 101 can be connected to the cuff in a fluid communication manner. The pump 101 can pressurize the pressure in the cuff.
Optionally, the blood pressure meter may further include additional components such as a microphone 220 to capture acoustic information of the subject (such as the sound of breathing or the sound of his heartbeat or the sound of blood flow in a blood vessel, etc.). Additionally or alternatively, the blood pressure meter may also include one or more microphones to capture voice commands from the subject.
It should be noted that the valve 102 in the present application includes a plurality of valves having different maximum allowable flow rates.
In order to obtain a more accurate blood pressure measurement value, stable control of the cuff pressure during the blood pressure measurement is required. The controller 104 may control the pump 101 by Pulse Width Modulation (PWM). PWM is a technique for controlling an analog circuit by using a digital signal, and encodes the analog signal by adjusting the duty ratio of high and low levels of the digital signal to control the analog circuit. Specifically, the controller 104 is configured to control the duty cycle of the PWM of the pump 101 according to the type of cuff, and the duty cycle may correspond to an operating characteristic of the pump, such as rotational speed or power. For example, when the duty cycle of the PWM is 100%, the pump can be controlled to rotate at full speed; and when the duty cycle of the PWM is 50%, the pump can be controlled to rotate at about half the speed, thereby reducing the flow rate of the delivered gas. The controller 104, in controlling the actuation of the valve 102, may select one or more valves from a plurality of valves for flow rate adjustment depending on the type of cuff.
Further, the controller 104 determines the type of cuff based on the rate of change of rise of the pressure measurement at a predetermined time or the age at which the pressure measurement reaches a threshold pressure.
In particular, the types of cuffs can be divided into adult and juvenile cuffs (e.g. selectable by the user via the input device 202), wherein an adult cuff can be subdivided by size into 4 different specifications, including: oversized (e.g., thigh strap), large size, average size, and small size. Juvenile cuffs are specifically subdivided by size into child sizes and infant sizes. It should be noted that the subdivision of the cuff types is only an optional classification manner, and the cuff types with more or less sizes may be divided according to actual situations.
Fig. 3 and 4 are flowcharts illustrating determination of the type of cuff. Fig. 3 is a flow chart of cuff type determination for a minor cuff; fig. 4 is a cuff type determination flowchart of an adult cuff. For example, the controller 104 may select to execute the flow shown in fig. 3 or fig. 4 according to information input by the user through the input device 202.
The cuff type determination flow of the minor cuff shown in fig. 3 is as follows:
s31, determining whether the size of the cuff is known, and if not, executing S32;
s32, inflating the cuff and measuring a pressure measurement value representing a pressure within the cuff by the pressure sensor;
s33, acquiring a first rising change rate of the pressure measurement value in a preset time or a first time when the pressure measurement value reaches a first threshold pressure;
s34, if the first ascending rate of change is not greater than the first set rate of change value or the first elapsed time is not less than the first set time period, determining the cuff type as a juvenile cuff of a child size, for example, the first set rate of change value may be set to 30mmHg/S, and the first set time period is set to 1000ms;
and S35, if the first ascending change rate is greater than a first set change rate value or the first time is less than a first set time length, determining that the type of the cuff is the infant-size minor cuff.
The above embodiments are merely exemplary. It will be appreciated by those skilled in the art that the first set rate of change value and the first set duration may be other values. For example, the first set rate of change value may also be between 18mmHg/s and 43 mmHg/s; and the first set time period may be between 700ms and 1700 ms.
The cuff type determination flow of the minor cuff shown in fig. 4 is as follows:
s41, determining whether the size of the cuff is known, and if not, executing S42;
s42, inflating the cuff and measuring a pressure measurement value representing the pressure in the cuff by a pressure sensor;
s43, acquiring a second rising change rate of the pressure measurement value in a preset time or a second time when the pressure measurement value reaches a second threshold pressure;
s44, if the second rate of change increase is not greater than a second set rate of change value or the second time period is not less than a second set time period, determining that the type of the cuff is an oversized adult cuff, for example, the second set rate of change value may be set to 10mmHg/S, and the second set time period is set to 5000ms;
s45, if the second ascending change rate is greater than the second set change rate value and not greater than the third set change rate value, or the second ascending change rate is less than the second set time period and not less than the third set time period, determining that the type of the cuff is a large-sized adult cuff, for example, the third set change rate value may be set to 25mmHg/S, and the third set time period is set to 2000ms;
s46, if the second ascending change rate is greater than the third set change rate value and not greater than the fourth set change rate value, or the second time is less than the third set time period and not less than the fourth set time period, determining the type of the cuff as an adult cuff with a common size, wherein the fourth set change rate value can be set to 50mmHg/S, and the fourth set time period is set to 1000ms;
and S47, if the second ascending change rate is greater than a fourth set change rate value or the second time is less than a fourth set time length, determining the type of the adult cuff as the small-size adult cuff.
The above embodiments are merely exemplary. It will be appreciated by those skilled in the art that the second, third and fourth set rate values and the second, third and fourth set time periods may have other values. For example, the second set rate of change value may also be between 7mmHg/s and 10mmHg/s, the third set rate of change value may also be between 12mmHg/s and 25mmHg/s, and the fourth set rate of change value may also be between 33mmHg/s and 50 mmHg/s; the second set time period may also be between 5000ms and 7100ms, the third set time period may also be between 2000ms and 4300ms, and the fourth set time period may also be between 1000ms and 1500 ms.
It should be noted that, in fig. 3 and 4, when determining the type of the cuff, the predetermined time and the threshold pressure related to the inflation process, and the respective set values compared with the ascending change rate and the elapsed time are empirical values determined according to an infinite number of tests; it is merely exemplary and a differentiated design is possible.
The change in the pressure measurement value in the predetermined time is shown by the rising rate of the pressure measurement value in the predetermined time in fig. 3 and 4, but may be shown by other parameter information (e.g., a specific section of the pressure measurement value, a second derivative of the pressure measurement value, etc.), and is not limited in this regard.
In addition, when the user initially sets the cuff type using the input device 202, the controller 104 may check the initial setting using the flow shown in fig. 3 and 4.
As previously described, the type of cuff is determined by the controller 104 during the pressure measurement, and the controller 104 may then control the duty cycle of the PWM of the pump 101 according to the type of cuff and select one or more valves from the plurality of valves for flow rate adjustment according to the type of cuff. In a particular implementation, the controller 104 collects information regarding the type of cuff and may determine, for example, from empirical values determined from an infinite number of experiments, a PWM and valve control scheme suitable for each type. Illustratively, as shown in FIG. 2, the valve 102 includes 2 valves for bleed air having different maximum allowable flow rates, referred to as a large flow rate valve and a small flow rate valve. For example, in the case where it is determined that the type of cuff has an oversized size, the PWM duty cycle of the pump may be increased during inflation to inflate as quickly as possible, and the large flow rate valve and the small flow rate valve may all be opened during deflation to deflate as quickly as possible. In the case where it is determined that the type of cuff has a large size, a general size, or a small size, the PWM duty ratio of the pump may be set to 70% or 80% during inflation to perform inflation at a reasonable speed, and only the large flow rate valve may be opened to deflate during deflation. Whereas in the case where it is determined that the type of cuff has a child size or an infant size, it may be desirable conversely that the speed of inflation/deflation is not too fast, so that the inflation/deflation process is controlled more accurately and smoothly, so that the PWM duty cycle of the pump can be reduced to 60% or 40% during inflation and only the small flow rate valve is opened during deflation.
Table 1 shows the selection of different pump PWM duty cycles and the selection of the valves to open according to different cuff types.
TABLE 1
| Type of subject | Type of cuff | Duty ratio of PWMRatio of | Valve selection |
| Adult | Oversize size | 100％ | High flow rate valve and low flow rate valve |
| Large size | 80％ | High flow rate valve | |
| General size | 80％ | High flow rate valve | |
| Small size | 70％ | High flow rate valve | |
| Minor age | Size of children | 60％ | Small flow rate valve |
| Infant size | 40％ | Small flow rate valve |
In order to ensure the accuracy of the pressure in the cuff during the blood pressure measurement, after the pressure in the cuff reaches the predetermined inflation target value during the inflation of the cuff, the inflation of the cuff needs to be continued within an inflation delay time so that the actual pressure in the cuff approaches the predetermined inflation target value. The predetermined inflation target value may be set according to the resulting cuff type, for example, it may be set to 250mmHg for a general-size, large-size, or oversized cuff, and to 180mmHg for an infant-size cuff.
Similarly, in each deflation of the cuff in the deflation process, after the measured pressure in the cuff reaches the corresponding predetermined deflation target value, the cuff needs to be continuously deflated for the deflation delay time so as to make the actual pressure in the cuff closer to the corresponding predetermined deflation target value, so as to make the blood pressure measurement more accurate. The deflation target value may be set by a person skilled in the art according to clinical experience and actual needs, for example, the corresponding deflation target value for each of successive deflations may be decremented by 10mmHg up to atmospheric ambient pressure.
FIG. 5A shows a schematic of inflation delay times applied in an inflation process according to an embodiment of the invention. Wherein the inflation is not stopped immediately after the pressure measurement reaches a predetermined inflation target value of 160 mmHg; but continues to inflate for an inflation delay time (in this example, about 300 ms) until the inflation delay time is over. Thereafter, the inflation of the cuff is completed and successive deflations and corresponding measurements may be made.
Fig. 5B shows a pressure curve 1 in which the inflation delay time is not applied during inflation and a pressure curve 2 in which the inflation delay time is applied during inflation. It can be seen that during inflation of curve 1, immediately after the pressure measurement reaches the predetermined inflation target value (160 mmHg in this example), the pressure in the cuff will slowly drop and fall below the predetermined inflation target value before the deflation process begins. In contrast, in the inflation process according to curve 2, the inflation is continued for an inflation delay time after the measured pressure value reaches the predetermined inflation target value, so that, for example, a more complete inflation can be achieved, so that the pressure in the cuff at the beginning of the deflation process is closer to the corresponding predetermined inflation target value.
FIG. 6A shows a schematic of deflation delay times applied during deflation according to an embodiment of the present invention, wherein two steps in the gradual deflation process are shown. Taking the first step as an example, the deflation is not stopped immediately after the pressure measurement reaches the corresponding predetermined deflation target value of 140 mmHg; but continues to bleed for a bleed delay time (in this example about 80 ms) until the end of the bleed delay time.
Fig. 6B shows a pressure curve 1 in which the deflation delay time is not applied during the deflation process and a pressure curve 2 in which the deflation delay time is applied during the deflation process. In each deflation of curve 1, the deflation is stopped immediately after the pressure measurement reaches the corresponding predetermined deflation target value; while in the deflation process of curve 2, deflation continues for a deflation delay time after the pressure measurement reaches the corresponding predetermined deflation target value. For example, when the respective predetermined deflation target value for each deflation is decreased by 10mmHg (e.g., 1.5 x 10 in the example of fig. 6B) 4 ms to 5 x 10 4 ms period), the stabilized pressure after only a few (in this example about 7) deflations in curve 1 approaches the respective predetermined deflation target value, while under-deflation occurs in the remaining few deflations, the stabilized pressure being significantly different from the respective predetermined deflation target value; by comparison, each deflation in curve 2 is more adequate, with the steady pressure after a greater number of deflates (10 in this example) approaching the respective predetermined deflation target value. And, without applying the deflation delay time, when the cuff pressure has been small (. About.10) 4 ms later), each deflation of curve 1 does not really allow the cuff pressure to continue to decrease; while curve 2, which applies the deflation delay time, does not have this problem.
Specifically, the controller 104 is configured to continue to control the pump 101 to inflate the cuff during inflation of the cuff for an inflation delay time from when the pressure measurement value reaches the predetermined inflation target value, wherein the inflation delay time is determined according to the type of the cuff; at each step in the deflation process of the cuff, the at least one valve 102 is continuously controlled to deflate the cuff for a deflation delay time from the pressure measurement value reaching the corresponding predetermined deflation target value, wherein the deflation delay time is determined according to the type of the cuff.
Specifically, the controller 104 is configured to determine a predetermined inflation target value in accordance with the subject type inferred from the determined cuff type, to control the pump 101 and the valve 102 to inflate the cuff to the predetermined inflation target value. Different preset inflation target values are designed according to different cuff types, so that the pressure measurement accuracy can be improved, and the physical discomfort of a testee can be reduced.
Further, for example as given in table 2, the controller 104 is configured to determine a corresponding inflation delay time based on the determined cuff type; and determining a corresponding deflation delay time based on the determined type of cuff and a corresponding predetermined deflation target value.
TABLE 2
| The person to be tested | Types of cuffs | Inflation delay time/ms | Deflation delay time/ms |
| Adult | Over |
600 | 100 |
| |
400 | 80 | |
| |
200 | 50 | |
| Small size | 150 | 30 | |
| Minor age | Size of children | 150 | 30 |
| Infant size | 40 | 10 |
From the above, the pressure control device or the pressure measuring instrument in the present application can achieve the smooth pressure measurement by controlling the parameter selection of the pump 101 and the valve 102 and controlling the inflation/deflation delay time during the pressure measurement process, and fig. 7 and 8 show the pressure control flow charts of the pressure control device and the pressure measuring instrument during the inflation process and the deflation process, respectively, and the specific flow charts are as follows:
inflating the cuff:
s51: the initial duty ratio of the pump 101 is determined according to the type of the subject. For example, if the subject is an adult then the pump 101 initial duty cycle is 100%; if the subject is a minor, the initial duty cycle of the pump 101 is 75%;
s52: determining the type of cuff according to the flow of fig. 3 or 4;
s53: adjusting a duty ratio of PWM for the pump 101 according to the determined type of the cuff, and determining a preset inflation delay time according to the type of the cuff;
s54: inflating the cuff, determining whether the pressure measurement value of the cuff is not less than a preset inflation target value, if so, executing S55, otherwise, continuing to inflate the cuff;
s55: determining whether the delay time of the current inflation is not less than the preset inflation delay time, if so, executing S56;
s56: and ending the inflation of the cuff.
As described above, the cuff is deflated in small pressure steps, during each step of deflation of the cuff:
the type of cuff has been determined during inflation and can be used directly during deflation of the cuff.
S61: determining the selection of the valve 102 according to the type of the cuff, and determining the preset corresponding deflation delay time according to the type of the cuff and each preset deflation target value;
s62: deflating the cuff, determining whether the pressure measurement value of the cuff is not greater than a preset deflation target value, if so, executing S63, otherwise, continuing to deflate the cuff;
s63: determining whether the current deflation delay time is not less than the preset corresponding deflation delay time, if so, executing S64;
s64: and ending the deflation of the cuff this time.
In one possible implementation, the PWM controlling the pump 101 may also be adjusted during the inflation delay time. For example, the PWM duty cycle may be reduced by half within the inflation delay time with respect to the PWM duty cycle used in the inflation process (i.e., the time from the start of inflation until the pressure measurement value reaches the predetermined inflation target value) before the inflation delay time.
The pressure control device and the blood pressure measuring instrument can drive and control the pump 101 and the valve 102 according to the type of the cuff, control the inflation delay time in the inflation process and control the deflation delay time in the deflation process, so that the pressure of the cuff can be stably and accurately controlled, the measuring time is further controlled, and the stability and the accuracy of blood pressure measurement are improved.
The embodiment of the present application further provides a pressure control method, which may be implemented by the pressure control device shown in fig. 1, the pressure measurement instrument shown in fig. 2, or other equipment with a pressure control device, and the present application does not limit this.
Specifically, the pressure control flow is shown in fig. 9, and the specific flow is as follows:
s71: the cuff is inflated by means of a pump 101 and at least one valve 102.
S72: a pressure measurement value representing the pressure in the cuff is obtained by the pressure sensor 103.
S73: the type of cuff is determined from a change in the pressure measurement value in a predetermined time during inflation of the cuff, and the pump 101 and/or the at least one valve 102 is controlled to inflate or deflate the cuff in dependence on the determined type of cuff.
With regard to the control method in the above-described embodiment, the specific manner in which the pressure control device or the blood pressure measuring instrument performs the operation has been described in detail in the embodiment related to the device, and will not be explained in detail here.
On the other hand, as described above, in the conventional measurement method, the systolic pressure and the diastolic pressure are obtained based on the mean arterial pressure MBP and according to clinical experience. In the art, mean arterial pressure MBP generally refers to the mean pressure in the patient's artery during one heart cycle of the patient. In practice, with the measurement method of the oscillometric principle, the pressure with the largest oscillation amplitude is often taken as the MBP; subsequent calculations regarding systolic and diastolic pressures are also made on the basis of the MBP without taking into account the specific physical condition of the subject. However, in practice, for example, when the physical condition of the subject is different, the actual systolic pressure and diastolic pressure may be different although the maximum oscillation amplitude or corresponding MBP may be the same. In this case, the conventional measurement method described above cannot obtain an accurate result. In addition, the hardware configuration of the device for blood pressure measurement may also have an influence on the measurement result.
In order to make the measurement result more accurate, the physical condition of the subject and the specific setting of hardware should be sufficiently considered in the blood pressure measurement. In the device and the method for calculating the blood pressure provided by the application, the systolic pressure and the diastolic pressure are not calculated by using MBP only, but are calculated based on the pressure corresponding to the maximum oscillation amplitude and considering the maximum amplitude and the amplitude of the sampling point adjacent to the maximum amplitude point, so that the accuracy of the calculation of the systolic pressure and the diastolic pressure is improved. Furthermore, the accuracy of the calculation of the systolic and diastolic blood pressures is further improved by calculating the systolic and diastolic blood pressures by introducing the base ratio, the first SBP/DBP ratio, the second SBP/DBP ratio and the third SBP/DBP ratio.
Fig. 10 is a block diagram illustrating a blood pressure computing device 800 for use with a blood pressure measurement cuff, according to an exemplary embodiment. In some embodiments, the blood pressure calculation device 800 may be the same as or form a part of the pressure control device 100 shown in fig. 1 or the blood pressure measurement instrument 200 shown in fig. 2. The blood pressure calculation apparatus 800 includes: a pump 801, a valve 802, a pressure sensor 803, and a processor (or controller) 804 as a control section, wherein:
a pump 801 for inflating the cuff.
The number of valves 802 may be 1, 2, or more, the valves 802 being used to inflate or deflate the cuff.
A pressure sensor 803 for obtaining a pressure measurement value representing the pressure in the cuff.
A processor 804 configured to: controlling the pump 801 and the at least one valve 802 to inflate the cuff until the pressure measurement reaches a predetermined inflation target value; controlling the at least one valve 802 to sequentially deflate the cuff; recording the pressure measurement value and the amplitude of oscillation of the pressure measurement value measured after each deflation is completed and before the next deflation is started; obtaining an amplitude-pressure curve from the pressure measurements and the amplitude of the oscillations of the pressure measurements; determining the maximum amplitude on the amplitude-pressure curve and the pressure corresponding to the maximum amplitude, namely the maximum amplitude pressure; and calculating the systolic pressure SBP and the diastolic pressure DBP according to the maximum amplitude pressure, the maximum amplitude and the amplitudes of the sampling points adjacent to the maximum amplitude point.
Specifically, the processor 804, when establishing the amplitude-pressure curve, may utilize existing NIBP techniques to deflate the cuff after the pressure within the cuff exceeds a predetermined inflation target value. For example, FIG. 11 shows the process of deflating the cuff in series, with the pressure measurement representing the pressure in the cuff substantially stabilized at the predetermined deflation target value for each deflation, but with oscillations. The amplitude of the oscillations is related to the corresponding pressure measurement. Specifically, as deflation occurs sequentially, the oscillation amplitude at the different pressure measurements increases and then decreases, and the maximum oscillation amplitude is reached at the mean arterial pressure (see fig. 12). Recording the measured pressure value and the amplitude of the oscillation of the measured pressure value measured after each deflation is completed and before the next deflation is started; an amplitude-pressure curve is obtained from the pressure measurements and the amplitude of the oscillations of the pressure measurements.
FIG. 13 is a schematic diagram illustrating an amplitude versus pressure curve in which the abscissa represents a pressure measurement and is in units of "0.1mmHg" and the ordinate represents an oscillation amplitude of the pressure measurement and is in units of a count value of an output voltage of the pressure sensor after analog-to-digital conversion, according to an exemplary embodiment. For example, in establishing the amplitude-pressure curve, the pressure measurement used may be an average of multiple measurements of the pressure sensor after each deflation is completed until the next deflation is initiated, or other characteristic of the measurements. For example, it is possible to wait a predetermined time after each deflation is completed, i.e. after the valve is completely closed (this may also be determined according to the cuff type, e.g. in case the cuff type is oversized, the predetermined time to wait is relatively long, and in case the cuff type is infant sized, the predetermined time to wait is relatively short), and then obtain a pressure measurement from the pressure sensor, thereby stabilizing the gas in the cuff to obtain a more accurate pressure measurement. As can be seen from fig. 13, as the pressure measurements are progressively reduced during deflation, the corresponding oscillation amplitude increases and then decreases. Here, the pressure corresponding to the point having the largest magnitude can be considered to be numerically equal to the mean arterial pressure MBP of the subject. The systolic pressure SBP is higher than MBP and thus to the left of the peak in the amplitude-pressure curve, and the diastolic pressure DBP is lower than MBP and thus to the right of the peak.
Further, in the embodiment of the present application, the processor 804 calculates the systolic pressures SBP and DBP according to the already established amplitude-pressure curve. As described above, in the conventional measurement method, only the pressure corresponding to the highest point on the curve is taken as the MBP, and the systolic and diastolic pressures are calculated based on only the MBP. However, the entire amplitude-pressure curve including the portion adjacent to the highest point can indirectly reflect the physical condition of the subject, and should be considered for measurement.
In a particular implementation, the processor 804 calculates the systolic SBP and the diastolic DBP based on pressure measurements, i.e., the maximum amplitude pressure, the maximum amplitude, and the amplitudes of the sample points adjacent to the maximum amplitude point, for the maximum amplitude point (i.e., the sample point having the largest amplitude) on the amplitude-pressure curve.
In one possible implementation, the processor 804 is configured to: calculating the systolic pressure SBP and the diastolic pressure DBP based on the product of the maximum amplitude and a base ratio, wherein the base ratio is calculated based on weighting the maximum amplitude and the amplitudes of the sample points adjacent to the maximum amplitude point, and the sample points adjacent to the maximum amplitude point include the nearest N sample points on the left side of the maximum amplitude point and the nearest M sample points on the right side of the maximum amplitude point on the amplitude-pressure curve, wherein N and M are integers greater than or equal to 1 respectively, that is, at least one adjacent point is taken on each of the left and right sides of the maximum amplitude point.
In calculating the base ratio, a number of sampling points (adjacent to the highest point) on the amplitude-pressure curve have been taken into account. Since the amplitudes of these adjacent sampling points can indirectly reflect the physical condition of the subject, the maximum amplitude or the maximum amplitude pressure is adjusted by the base ratio, and the calculation results of the systolic pressure and the diastolic pressure can be made more accurate. In addition, introducing the base ratio may also recover the distortion of the maximum amplitude or maximum amplitude pressure caused by the data acquisition method.
When adjacent sampling points are specifically selected, as shown in fig. 13, the sampling points optionally include the closest 2 sampling points on the left side of the maximum amplitude point and the closest 2 sampling points on the right side of the maximum amplitude point on the amplitude-pressure curve, where N and M are both 2. The value of N, M is only an exemplary choice, and other values may be also selected, for example, N, M may both be 3, 4 or 5, or other optional integers, and the values of N and M may be the same or different, which is not limited in this respect.
Optionally, when selecting the adjacent sampling points and setting both N and M to 2, the basic ratio is obtained by weighting the maximum amplitude, the amplitude of the closest sampling point on the left side of the maximum amplitude point, the amplitude of the next closest sampling point on the left side of the maximum amplitude point, the amplitude of the closest sampling point on the right side of the maximum amplitude point, and the amplitude of the next closest sampling point on the right side of the maximum amplitude point. In other words, as shown in fig. 13, the maximum amplitude point and the amplitudes of the two samples on the left and right sides that are circled, i.e., the amplitudes of a total of five samples, are used for weighting to obtain the base ratio. When N and M take other integer values, the base ratio is derived from weighting the maximum amplitude, the amplitudes of the nearest N samples to the left of the maximum amplitude point, and the amplitudes of the next nearest M samples to the right of the maximum amplitude point.
It should be noted that, when the base ratio is obtained, the weight assigned to the amplitude of each of the sampling points adjacent to the maximum amplitude point is related to the position of the sampling point on the amplitude-pressure curve with respect to the maximum amplitude point. For example, on the amplitude-pressure curve, the sampling point most adjacent to the maximum amplitude point is set with a larger weight, and the sampling point next to the sampling point most adjacent to the maximum amplitude point is set with a smaller weight. The specific numerical value of the weight can be flexibly set depending on actual situations such as the characteristics of the blood pressure measurement system used, the characteristics of the data acquisition system, or the physical characteristics of the subject, with reference to the clinical experience value. For example, the weight of the maximum magnitude is made positive and the corresponding weight of the magnitude of each adjacent sample point is made negative, and the weight of the maximum magnitude and the corresponding weight of the magnitude of each adjacent sample point are added to zero. The base ratio is then determined by dividing the weighted sum of the amplitudes by the sum of the amplitudes weighted by another set of weights to obtain a quotient and multiplying the quotient by an empirical factor. The above calculation manner of the basic ratio is only an example, and the embodiment is not limited thereto, and those skilled in the art should be able to adopt other related techniques to obtain the basic ratio, so as to correct the maximum amplitude or the maximum amplitude pressure, and further correct the systolic pressure SBP and the diastolic pressure DBP. In addition, the clinical experience value may be derived from clinical data representing a patient population, a patient type (e.g., minor or adult), a history of hypertension/hypotension in the patient.
In addition, when the processor 804 calculates the systolic pressure SBP and the diastolic pressure DBP according to the already established amplitude-pressure curve in the embodiment of the present application, the maximum amplitude may be corrected according to the amplitudes of the sampling points adjacent to the maximum amplitude point in other ways without introducing the basic ratio; and on the basis of the corrected maximum amplitude, the systolic pressure SBP and the diastolic pressure DBP may further be calculated, respectively. For example, the systolic blood pressure SBP may be calculated in combination with the first SBP ratio, the second SBP ratio, and the third SBP ratio as described below; and/or calculating the diastolic DBP ratio in combination with the first DBP ratio, the second DBP ratio and the third DBP ratio.
In an alternative embodiment, the processor 804 is further configured to calculate the corresponding amplitude of the systolic blood pressure SBP according to the following formula:
SBP amplitude = maximum amplitude basic ratio, first SBP ratio, wherein,the first SBP ratio is determined according to an arterial model. For example, according to the assumed specific artery model, the first SBP ratio =0.6-0.00003 × maximum amplitude pressure. Those skilled in the art may also derive specific values for the first SBP ratio based on various variables involved in the arterial model, such as the estimated young's modulus of the blood vessel, the estimated blood density, algorithms used for modeling, etc., as well as clinical experience or other variables contained in the gold standard. Then, the systolic pressure SBP is obtained from the calculated SBP amplitude versus amplitude-pressure curve. For example, an SBP amplitude of 1.7 x 10 may be calculated 6 The systolic blood pressure SBP of 100mmHg can be obtained by comparing the curves shown in fig. 13.
In experimental studies it was found that the slope of the curve to the left of the peak on the amplitude-pressure curve affects the determination of the first SBP ratio and the determination of the systolic pressure SBP, and therefore, in an alternative embodiment, the processor 804 is further configured to calculate the corresponding amplitude of the systolic pressure SBP according to the following formula:
SBP amplitude = maximum amplitude base ratio first SBP ratio second SBP ratio,
wherein the second SBP ratio is related to a rate of change of a first portion of the amplitude-pressure curve, the first portion being a portion of the amplitude-pressure curve to the left of a point of maximum amplitude. When the change rate of the first part is smaller than the SBP change rate threshold value, the second SBP ratio is a first change rate related set value; and when the change rate of the first part is greater than or equal to the SBP change rate threshold value, the second SBP ratio is a second change rate related set value. Then, the systolic pressure SBP is obtained from the calculated SBP amplitude versus amplitude-pressure curve.
In determining the second SBP ratio, the magnitude relationship between the change rate of the first portion and the SBP change rate threshold is compared, and the SBP change rate threshold is determined according to the physiological condition of the subject. For example, the SBP change rate threshold may be set to 10000 through experimental studies of large amounts of data. Note that, in the above example, the abscissa of the amplitude-pressure curve is in units of "0.1mmHg" and the ordinate is in units of count values of the output voltage of the pressure sensor after analog-to-digital conversion; those skilled in the art will appreciate that in other implementations the SBP rate of change threshold is also related to the particular manner in which the amplitude versus pressure curve is plotted.
The SBP change rate threshold may also be flexibly set according to actual situations, and is not particularly limited herein. For example, the SBP change rate threshold may be set to other values according to physiological conditions such as an arterial condition of the subject (e.g., whether the subject is an atherosclerotic patient), a cardiac output condition, and a subject blood volume. Alternatively, the physiological condition may be obtained by a blood pressure measurement device or other physiological monitoring device communicatively coupled to the blood pressure measurement device.
In the embodiment where the SBP change rate threshold is set to 10000, optionally, the first change rate related setting value is 1.2, and the second change rate related setting value is 1. The above embodiments are merely exemplary. Those skilled in the art will appreciate that the SBP rate of change threshold and the first rate of change related set point may be other values. For example, the SBP rate-of-change threshold may be between 8000 and 20000, and the first rate-of-change related setting may be between 1.05 and 1.5.
As shown in fig. 13, the average rate of change of the curve in the left part of the maximum amplitude point can be determined as the rate of change of the first part. For example, a portion of the curve on the left side of the maximum amplitude point (e.g., a portion from 122mmHg to the highest point) may be taken and the ratio of the variation of the amplitude of the portion to the variation of the pressure may be taken as the variation rate of the first portion, which is about 40000 and is greater than the SBP variation rate threshold 10000, so that the second SBP ratio may be taken as 1. The SBP amplitude was then calculated as 1.7 x 10 as described above 6 The systolic pressure SBP was 100mmHg compared to the amplitude-pressure curve.
In experimental studies it was found that different cuff type selections may affect the determination of the first SBP ratio and the determination of the systolic SBP, and therefore, in an alternative embodiment, the processor 804 is further configured to calculate the corresponding magnitude of the systolic SBP according to the following formula:
SBP amplitude = maximum amplitude basic ratio first SBP ratio third SBP ratio, wherein the third SBP ratio is determined according to the type of the cuff. Then, the systolic pressure SBP is obtained from the calculated SBP amplitude versus amplitude-pressure curve.
In this embodiment, optionally, the third SBP ratio is 1.03 when the type of cuff is an oversized band (e.g., thigh band), and is 1 otherwise. Of course, the third SBP ratio may also be set to other small values greater than 1, typically between 1 and 1.5, according to clinical experience.
It should be noted that, when the processor 804 calculates the systolic blood pressure SBP according to the basic ratio, any one of the 3 alternative embodiments may be adopted according to the actual situation of the human subject.
In an alternative embodiment, the processor 804 is further configured to calculate the corresponding amplitude of the diastolic pressure DBP according to the following formula:
DBP amplitude = maximum amplitude basic ratio-first DBP ratio, wherein the first DBP ratio is determined from an arterial model. For example, according to the assumed specific artery model, the first DBP ratio =0.7-0.00002 × maximum amplitude pressure. The skilled person may also derive specific values for the first DBP ratio based on various variables involved in the arterial model, such as the estimated young's modulus of the blood vessel, the estimated blood density, the algorithm used for the modeling, etc., as well as various variables contained in clinical experience or gold standards. The diastolic DBP is then obtained from the calculated DBP amplitude versus amplitude-pressure curve. For example, a DBP amplitude of 1.85 x 10 may be calculated 6 The diastolic pressure DBP was found to be 65mmHg by comparison of the amplitude-pressure curve shown in FIG. 13.
In experimental studies it was found that the slope of the curve to the right of the peak on the amplitude-pressure curve affects the determination of the first DBP ratio and the determination of the diastolic pressure DBP, and therefore, in an alternative embodiment, the processor 804 is further configured to calculate the corresponding amplitude of the diastolic pressure DBP according to the following formula:
DBP amplitude = maximum amplitude basic ratio first DBP ratio second DBP ratio,
wherein the second DBP ratio is related to a rate of change of a second portion of the amplitude-pressure curve, as shown in FIG. 13, the second portion being the portion of the amplitude-pressure curve to the right of the point of maximum amplitude, the second DBP ratio being a third rate-of-change related setting when the rate of change of the second portion is less than a DBP rate-of-change threshold; the second DBP ratio is a fourth rate-of-change related setting when the rate of change of the second portion is greater than or equal to the DBP rate-of-change threshold. The diastolic DBP is then obtained from the calculated DBP amplitude versus amplitude-pressure curve.
In specifically determining the second DBP ratio, it is necessary to compare the magnitude relationship between the rate of change of the second portion and a DBP rate of change threshold, which is determined according to the physiological condition of the subject. For example, through experimental studies of a large amount of data, the DBP change rate threshold may be set to 3500. Note that, in the above example, the abscissa of the amplitude-pressure curve is in units of "0.1mmHg" and the ordinate is in units of count values of the output voltage of the pressure sensor after analog-to-digital conversion; those skilled in the art will appreciate that in other implementations the DBP rate of change threshold is also related to the particular manner in which the amplitude versus pressure curve is plotted.
The DBP change rate threshold may also be flexibly set according to actual situations, and is not particularly limited herein. For example, the DBP rate-of-change threshold may be set to other values depending on physiological conditions of the subject such as arterial condition (e.g., whether the subject is an atherosclerotic patient), cardiac output condition, and the like.
In an embodiment where the DBP change rate threshold is set to 3500, optionally, the third change rate related set value is 1.1, and the fourth change rate related set value is 1. The above embodiments are merely exemplary. Those skilled in the art will appreciate that the DBP rate of change threshold and the third rate of change related setting described above may be other values. For example, the DBP rate-of-change threshold may be between 3000 and 5000 and the third rate-of-change related set point may be between 1.02 and 1.3.
As shown in fig. 13, the average rate of change of the curve in the portion to the right of the point of maximum amplitude may be determined as the rate of change of the second portion. For example, a portion of the curve to the right of the maximum amplitude point (e.g., a portion from the highest point to 50 mmHg) may be taken and dividedThe ratio of the amount of change in amplitude to the amount of change in pressure, taken as the rate of change in the first portion, is about 7000, which is greater than the DBP rate threshold 3500, so the second DBP ratio assumes a value of 1. The DBP amplitude was then calculated as 1.85 x 10 as described above 6 The diastolic DBP was found to be 65mmHg against the amplitude-pressure curve.
In experimental studies it was found that different cuff type selections may affect the determination of the first DBP ratio and the determination of the diastolic DBP, and therefore, in an alternative embodiment, the processor 804 is further configured to calculate the corresponding amplitude of the diastolic DBP according to the following formula:
DBP amplitude = maximum amplitude basic ratio first DBP ratio third DBP ratio,
wherein the third DBP ratio is determined according to a type of the cuff. The diastolic DBP is then obtained from the calculated DBP amplitude versus amplitude-pressure curve.
In this embodiment, optionally, the third DBP ratio is 1.05 when the type of cuff is an oversized band (e.g., a thigh band), and otherwise, the third DBP ratio is 1. Of course, the third DBP rate may also be set to other small values greater than 1, typically between 1 and 1.5, based on clinical experience.
It should be noted that, when the processor 804 calculates the diastolic pressure DBP according to the basic ratio, any one of the 3 optional embodiments may be adopted according to the actual condition of the subject.
It is noted that, when calculating the systolic pressure SBP and the diastolic pressure DBP, the processor 804 may calculate only the systolic pressure SBP or the diastolic pressure DBP, or may calculate both the systolic pressure SBP and the diastolic pressure DBP, in general, the systolic pressure SBP and the diastolic pressure DBP are calculated in pairs, for example, the systolic pressure SBP and the diastolic pressure DBP may be calculated by introducing a base ratio; the systolic SBP and the diastolic DBP may also be calculated without introducing a base ratio. Alternatively, in case the calculated systolic blood pressure SBP is above or below a predetermined criterion and/or the calculated diastolic blood pressure DBP is above or below a predetermined criterion, i.e. in case a too high or too low systolic and/or diastolic blood pressure is measured, the blood pressure calculation means 800 may give an audible or visual alarm accordingly.
Further, fig. 14 is a flowchart illustrating a blood pressure calculating method according to an exemplary embodiment, where the blood pressure calculating method may be implemented by the pressure calculating device shown in fig. 10, the pressure control device shown in fig. 1, or the pressure measuring instrument shown in fig. 2, and when the blood pressure calculating method is implemented by the device shown in fig. 1 or fig. 2, the pressure sensor 103 in fig. 1 or fig. 2 corresponds to the pressure sensor 804 in fig. 8, the controller 104 in fig. 1 or fig. 2 corresponds to the processor 804 in fig. 10, the pump 101 in fig. 1 or fig. 2 corresponds to the pump 801 in fig. 10, and the valve 102 in fig. 1 or fig. 2 corresponds to the valve 802 in fig. 10.
S1001: with the use of the pressure sensor 803, it is, a pressure measurement is obtained that represents the pressure in the blood pressure measurement cuff.
S1002: the pump 801 and the at least one valve 802 are controlled to inflate the cuff until the pressure measurement reaches a predetermined inflation target value.
S1003, carrying out: controlling the at least one 802 to deflate the cuff in series.
S1004: the measured pressure values and the amplitude of the oscillations of the pressure values measured after each deflation is completed until the next deflation is started are recorded.
S1005: an amplitude-pressure curve is obtained from the pressure measurements and the amplitude of the oscillations of the pressure measurements.
S1006: and determining the maximum amplitude on the amplitude-pressure curve and the pressure corresponding to the maximum amplitude, namely the maximum amplitude pressure.
S1007: and calculating the systolic pressure SBP and the diastolic pressure DBP according to the maximum amplitude pressure, the maximum amplitude and the amplitude of the sampling point adjacent to the maximum amplitude point.
Specifically, the detailed calculation process of the systolic pressure SBP and the diastolic pressure DBP in step 1007 can refer to the related description of the processor 804 in the embodiment of the apparatus shown in fig. 10, which is not repeated herein.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (60)
1. A pressure control device, comprising:
a pump for inflating a cuff for use with the apparatus;
at least one valve for inflating or deflating the cuff;
a pressure sensor for obtaining a pressure measurement indicative of the pressure in the cuff;
a controller for determining the type of the cuff from a change in the pressure measurement value within a predetermined time during inflation of the cuff, and controlling the pump and/or the at least one valve to inflate or deflate the cuff in dependence on the determined type of cuff.
2. The apparatus of claim 1, wherein the controller is configured to determine a predetermined inflation target value based on the determined type of cuff to control the pump and the at least one valve to inflate the cuff to the predetermined inflation target value.
3. The apparatus of claim 1 or 2, wherein the predetermined time is within the first two thirds of the time during inflation, and
the controller is configured to determine the type of cuff in accordance with at least one of: a rate of change of rise of the pressure measurement over the predetermined time, and a time at which the pressure measurement reaches a threshold pressure.
4. The apparatus according to claim 1 or 2, wherein the controller is configured to control a duty cycle of a Pulse Width Modulation (PWM) of the pump according to a type of the cuff.
5. The device of claim 1 or 2, wherein the at least one valve comprises a plurality of valves having different maximum allowable flow rates; the controller is configured to select one or more valves from the plurality of valves for flow rate adjustment based on the type of cuff.
6. The apparatus according to claim 2, wherein the controller is configured to continue to control the pump to inflate the cuff during inflation of the cuff for an inflation delay time from when the pressure measurement value reaches the predetermined inflation target value, wherein the inflation delay time is determined according to the type of the cuff.
7. The apparatus according to claim 1 or 2, wherein the controller is configured to continue to control the at least one valve to deflate the cuff during deflation of the cuff for a deflation delay time from the pressure measurement reaching a respective predetermined deflation target value, wherein the deflation delay time is determined in accordance with the respective predetermined deflation target value and the type of the cuff.
8. An apparatus for blood pressure calculation, for use with a blood pressure measurement cuff, the apparatus comprising:
a pump for inflating the cuff;
at least one valve for inflating or deflating the cuff;
a pressure sensor for obtaining a pressure measurement indicative of the pressure in the cuff;
a processor configured to:
controlling the pump and the at least one valve to inflate the cuff until the pressure measurement reaches a predetermined inflation target value;
controlling the at least one valve to deflate the cuff in series;
recording a measured pressure value measured after each deflation is completed and before the next deflation is started and the amplitude of the oscillation of the measured pressure value;
obtaining an amplitude-pressure curve from the pressure measurements and the amplitude of the oscillations of the pressure measurements;
determining the maximum amplitude on the amplitude-pressure curve and the pressure corresponding to the maximum amplitude, namely the maximum amplitude pressure; and
and calculating the systolic pressure SBP and the diastolic pressure DBP according to the maximum amplitude pressure, the maximum amplitude and the amplitude of the sampling point adjacent to the maximum amplitude point.
9. The apparatus of claim 8, wherein the processor is further configured to: calculating a Systolic Blood Pressure (SBP) and a Diastolic Blood Pressure (DBP) based on a product of the maximum amplitude and a base ratio calculated based on weighting of the maximum amplitude and amplitudes of the sample points adjacent to the maximum amplitude point, and the sample points adjacent to the maximum amplitude point include the nearest N sample points on the left side of the maximum amplitude point and the nearest M sample points on the right side of the maximum amplitude point on the amplitude-pressure curve, where N and M are integers of 1 or more, respectively.
10. The apparatus of claim 9, wherein the weight assigned to the magnitude of each of the sample points adjacent to the point of maximum magnitude is related to the position of that sample point on the magnitude-pressure curve relative to the point of maximum magnitude.
11. The apparatus of claim 9, wherein N and M are both 2, and wherein the base ratio is based on weighting of the maximum amplitude, the amplitude of the closest sample point to the left of the maximum amplitude point, the amplitude of the next closest sample point to the left of the maximum amplitude point, the amplitude of the closest sample point to the right of the maximum amplitude point, and the amplitude of the next closest sample point to the right of the maximum amplitude point.
12. The apparatus of claim 8, wherein the processor is further configured to: calculating a Systolic Blood Pressure (SBP) according to the maximum amplitude, the amplitudes of the sampling points adjacent to the maximum amplitude point and a first SBP ratio, wherein the first SBP ratio is determined according to an artery model.
13. The apparatus of claim 9, wherein the processor is further configured to:
calculating the amplitude corresponding to the systolic pressure SBP, namely the SBP amplitude according to the following formula:
SBP amplitude = maximum amplitude basic ratio first SBP ratio,
wherein the first SBP ratio is determined according to an arterial model, an
Obtaining the systolic SBP according to the calculated SBP amplitude and the amplitude-pressure curve.
14. The apparatus of claim 8, wherein the processor is further configured to: calculating a diastolic DBP from the maximum amplitude, amplitudes of sample points adjacent to the point of maximum amplitude, and a first DBP ratio, wherein the first DBP ratio is determined from an arterial model.
15. The apparatus of claim 9, wherein the processor is further configured to:
calculating a DBP amplitude corresponding to the diastolic DBP pressure according to the following formula:
DBP amplitude = maximum amplitude basic ratio first DBP ratio,
wherein the first DBP ratio is determined from an arterial model, an
The diastolic DBP is derived from the calculated DBP amplitude against the amplitude-pressure curve.
16. The apparatus of claim 12, wherein the processor is further configured to: calculating a systolic blood pressure SBP based on the maximum amplitude, the amplitudes of the sample points adjacent to the maximum amplitude point, the first SBP ratio and the second SBP ratio,
wherein the second SBP ratio is associated with a rate of change of a first portion of the amplitude-pressure curve, the first portion being a portion of the amplitude-pressure curve to the left of the point of maximum amplitude, the second SBP ratio being a first rate-of-change related setpoint when the rate of change of the first portion is less than an SBP rate-of-change threshold; when the change rate of the first part is larger than or equal to the SBP change rate threshold value, the second SBP ratio is a second change rate related set value.
17. The apparatus of claim 13, wherein the processor is further configured to:
calculating the amplitude corresponding to the systolic pressure SBP, namely the SBP amplitude according to the following formula:
SBP amplitude = maximum amplitude base ratio first SBP ratio second SBP ratio,
wherein the second SBP ratio is related to a rate of change of a first portion of the amplitude-pressure curve, the first portion being the portion of the amplitude-pressure curve to the left of the point of maximum amplitude, the second SBP ratio being a first rate-of-change related set point when the rate of change of the first portion is less than an SBP rate-of-change threshold; the second SBP ratio is a second rate-of-change related setting when the rate of change of the first portion is greater than or equal to the SBP rate-of-change threshold, an
Obtaining the systolic SBP according to the calculated SBP amplitude and the amplitude-pressure curve.
18. The apparatus of claim 16 or 17, wherein the SBP change rate threshold is determined based on a physiological condition of the subject.
19. The apparatus of claim 18 wherein the SBP rate of change threshold is between 8000 and 20000, the first rate of change related setting is between 1.05 and 1.5, and the second rate of change related setting is 1.
20. The apparatus of claim 14, wherein the processor is further configured to: calculating a diastolic DBP from the maximum amplitude, amplitudes of sample points adjacent to the point of maximum amplitude, the first DBP ratio, and a second DBP ratio,
wherein the second DBP ratio is related to a rate of change of a second portion of the amplitude-pressure curve, the second portion being a portion of the amplitude-pressure curve to the right of the point of maximum amplitude, the second DBP ratio being a third rate-of-change related setpoint when the rate of change of the second portion is less than a DBP rate-of-change threshold; and when the change rate of the second part is greater than or equal to the DBP change rate threshold value, the second DBP ratio is a fourth change rate related set value.
21. The apparatus of claim 15, wherein the processor is further configured to:
calculating the amplitude corresponding to the diastolic pressure DBP, namely the DBP amplitude, according to the following formula:
DBP amplitude = maximum amplitude basic ratio first DBP ratio second DBP ratio,
wherein the second DBP ratio is related to a rate of change of a second portion of the amplitude-pressure curve, the second portion being a portion of the amplitude-pressure curve to the right of the point of maximum amplitude, the second DBP ratio being a third rate-of-change related setpoint when the rate of change of the second portion is less than a DBP rate-of-change threshold; the second DBP ratio is a fourth rate-of-change related setting when the rate of change of the second portion is greater than or equal to the DBP rate-of-change threshold, an
The diastolic DBP is derived from the calculated DBP amplitude against the amplitude-pressure curve.
22. The apparatus of claim 20 or 21, wherein the DBP change rate threshold is determined based on a physiological condition of the subject.
23. The apparatus of claim 22 wherein the DBP rate-of-change threshold is between 3000 and 5000, the third rate-of-change related setting is between 1.02 and 1.3, and the fourth rate-of-change related setting is 1.
24. The apparatus of claim 12, wherein the processor is further configured to: calculating a Systolic Blood Pressure (SBP) according to the maximum amplitude, the amplitude of a sampling point adjacent to the maximum amplitude point, the first SBP ratio and a third SBP ratio, wherein the third SBP ratio is determined according to the type of the cuff.
25. The apparatus of claim 13, wherein the processor is further configured to:
calculating the SBP amplitude corresponding to the SBP according to the following formula:
SBP amplitude = maximum amplitude base ratio, first SBP ratio, third SBP ratio,
wherein the third SBP ratio is determined according to the type of the cuff, an
Obtaining the systolic SBP according to the calculated SBP amplitude and the amplitude-pressure curve.
26. The apparatus of claim 24 or 25, wherein the third SBP ratio is between 1 and 1.5 when the cuff is of the thigh band type, and otherwise the third SBP ratio is 1.
27. The apparatus of claim 14, wherein the processor is further configured to: calculating a diastolic DBP according to the maximum amplitude, amplitudes of sample points adjacent to the maximum amplitude point, the first DBP ratio, and a third DBP ratio, wherein the third DBP ratio is determined according to the type of the cuff.
28. The apparatus of claim 15, wherein the processor is further configured to:
calculating the amplitude corresponding to the DBP, namely the DBP amplitude according to the following formula:
DBP amplitude = maximum amplitude basic ratio first DBP ratio third DBP ratio,
wherein the third DBP ratio is determined according to a type of the cuff, an
The diastolic DBP is derived from the calculated DBP amplitude against the amplitude-pressure curve.
29. The apparatus of claim 27 or 28, wherein the third DBP ratio is between 1 and 1.5 when the cuff is of the thigh band type, and otherwise the third DBP ratio is 1.
30. The apparatus of claim 8, wherein recording pressure measurements taken after each deflation is complete and before the next deflation is initiated comprises:
waiting a predetermined time after the valve is fully closed; and
recording pressure measurements from the pressure sensor after waiting for the predetermined period of time,
wherein the predetermined time is determined according to a type of the cuff.
31. A pressure control method, characterized by comprising:
inflating the cuff with a pump and at least one valve;
obtaining a pressure measurement representative of a pressure in the cuff by a pressure sensor;
determining the type of the cuff from a change in the pressure measurement value during a predetermined time during inflation of the cuff, an
Controlling the pump and/or the at least one valve to inflate or deflate the cuff in accordance with the determined type of cuff.
32. The method of claim 31, further comprising determining a predetermined inflation target value based on the determined type of cuff to control the pump and the at least one valve to inflate the cuff to the predetermined inflation target value.
33. The method of claim 31 or 32, wherein the predetermined time is within the first two thirds of the time during inflation, and
the method further includes determining a type of the cuff based on at least one of: a rate of change of rise of the pressure measurement over the predetermined time, and a time at which the pressure measurement reaches a threshold pressure.
34. The method according to claim 31 or 32, further comprising controlling a duty cycle of a Pulse Width Modulation (PWM) of the pump according to the type of the cuff.
35. The method of claim 31 or 32, wherein the at least one valve comprises a plurality of valves having different maximum allowable flow rates; and is
The method also includes selecting one or more valves from the plurality of valves for flow rate adjustment based on the type of cuff.
36. The method of claim 32, further comprising: and during the inflation of the cuff, continuously controlling the pump to inflate the cuff within an inflation delay time from the pressure measured value reaching the preset inflation target value, wherein the inflation delay time is determined according to the type of the cuff.
37. The method of claim 31 or 32, further comprising: in the deflation process of the cuff, the at least one valve is continuously controlled to deflate the cuff within a deflation delay time from the pressure measurement value reaching a corresponding predetermined deflation target value, wherein the deflation delay time is determined according to the corresponding predetermined deflation target value and the type of the cuff.
38. A method for blood pressure calculation, comprising:
obtaining a pressure measurement value representing a pressure in the blood pressure measurement cuff using the pressure sensor;
controlling a pump and at least one valve to inflate the cuff until the pressure measurement reaches a predetermined inflation target value;
controlling the at least one valve to deflate the cuff in series;
recording a measured pressure value measured after each deflation is completed and before the next deflation is started and the amplitude of the oscillation of the measured pressure value;
obtaining an amplitude-pressure curve from the pressure measurements and the amplitude of the oscillations of the pressure measurements;
determining the maximum amplitude on the amplitude-pressure curve and the pressure corresponding to the maximum amplitude, namely the maximum amplitude pressure; and
and calculating the systolic pressure SBP and the diastolic pressure DBP according to the maximum amplitude pressure, the maximum amplitude and the amplitude of the sampling point adjacent to the maximum amplitude point.
39. The method of claim 38, further comprising: calculating a systolic pressure SBP and a diastolic pressure DBP based on a product of the maximum amplitude and a base ratio calculated based on weighting of the maximum amplitude and amplitudes of the sample points adjacent to the maximum amplitude point, and the sample points adjacent to the maximum amplitude point include the nearest N sample points on the left side of the maximum amplitude point and the nearest M sample points on the right side of the maximum amplitude point on the amplitude-pressure curve, where N and M are integers greater than or equal to 1, respectively.
40. The method of claim 39, wherein the weight assigned to the magnitude of each of the sample points adjacent to the point of maximum magnitude is related to the position of that sample point on the magnitude-pressure curve relative to the point of maximum magnitude.
41. The method of claim 39, wherein N and M are both 2, and wherein the base ratio is based on weighting the maximum amplitude, the amplitude of the closest sample point to the left of the maximum amplitude point, the amplitude of the next closest sample point to the left of the maximum amplitude point, the amplitude of the closest sample point to the right of the maximum amplitude point, and the amplitude of the next closest sample point to the right of the maximum amplitude point.
42. The method of claim 38, further comprising: calculating a Systolic Blood Pressure (SBP) according to the maximum amplitude, the amplitudes of the sampling points adjacent to the maximum amplitude point and a first SBP ratio, wherein the first SBP ratio is determined according to an artery model.
43. The method of claim 39, further comprising calculating the amplitude of the Systolic Blood Pressure (SBP) according to the formula:
SBP amplitude = maximum amplitude basic ratio first SBP ratio,
wherein the first SBP ratio is determined according to an arterial model, an
Obtaining the systolic SBP according to the calculated SBP amplitude and the amplitude-pressure curve.
44. The method of claim 38, further comprising: calculating a diastolic DBP from the maximum amplitude, amplitudes of sample points adjacent to the point of maximum amplitude, and a first DBP ratio, wherein the first DBP ratio is determined from an arterial model.
45. The method of claim 39, further comprising:
calculating the amplitude corresponding to the diastolic pressure DBP, namely the DBP amplitude, according to the following formula:
DBP amplitude = maximum amplitude basic ratio first DBP ratio,
wherein the first DBP ratio is determined from an arterial model, an
The diastolic DBP is derived from the calculated DBP amplitude against the amplitude-pressure curve.
46. The method of claim 42, further comprising: calculating a systolic blood pressure SBP based on the maximum amplitude, the amplitudes of the sample points adjacent to the maximum amplitude point, the first SBP ratio and the second SBP ratio,
wherein the second SBP ratio is related to a rate of change of a first portion of the amplitude-pressure curve, the first portion being the portion of the amplitude-pressure curve to the left of the point of maximum amplitude, the second SBP ratio being a first rate-of-change related set point when the rate of change of the first portion is less than an SBP rate-of-change threshold; when the change rate of the first part is larger than or equal to the SBP change rate threshold value, the second SBP ratio is a second change rate related set value.
47. The method of claim 43, further comprising:
calculating the amplitude corresponding to the systolic pressure SBP, namely the SBP amplitude according to the following formula:
SBP amplitude = maximum amplitude base ratio first SBP ratio second SBP ratio,
wherein the second SBP ratio is associated with a rate of change of a first portion of the amplitude-pressure curve, the first portion being a portion of the amplitude-pressure curve to the left of the point of maximum amplitude, the second SBP ratio being a first rate-of-change related setpoint when the rate of change of the first portion is less than an SBP rate-of-change threshold; the second SBP ratio is a second rate-of-change related setting when the rate of change of the first portion is greater than or equal to the SBP rate-of-change threshold, an
Obtaining the systolic SBP according to the calculated SBP amplitude and the amplitude-pressure curve.
48. The method of claim 46 or 47, wherein said SBP change rate threshold is determined according to a physiological condition of the subject.
49. The method of claim 48 wherein the SBP rate-of-change threshold is between 8000 and 20000, the first rate-of-change related setting is between 1.05 and 1.5, and the second rate-of-change related setting is 1.
50. The method of claim 44, further comprising: calculating a diastolic DBP from the maximum amplitude, amplitudes of sample points adjacent to the point of maximum amplitude, the first DBP ratio, and a second DBP ratio,
wherein the second DBP ratio is related to a rate of change of a second portion of the amplitude-pressure curve, the second portion being a portion of the amplitude-pressure curve to the right of the point of maximum amplitude, the second DBP ratio being a third rate-of-change related setpoint when the rate of change of the second portion is less than a DBP rate-of-change threshold; the second DBP ratio is a fourth rate-of-change related setting when the rate of change of the second portion is greater than or equal to the DBP rate-of-change threshold.
51. The method of claim 45, further comprising:
calculating a DBP amplitude corresponding to the diastolic DBP pressure according to the following formula:
DBP amplitude = maximum amplitude basic ratio first DBP ratio second DBP ratio,
wherein the second DBP ratio is related to a rate of change of a second portion of the amplitude-pressure curve, the second portion being a portion of the amplitude-pressure curve to the right of the point of maximum amplitude, the second DBP ratio being a third rate-of-change related setpoint when the rate of change of the second portion is less than a DBP rate-of-change threshold; the second DBP ratio is a fourth rate-of-change related set point when the rate of change of the second portion is greater than or equal to the DBP rate-of-change threshold, an
The diastolic DBP is derived from the calculated DBP amplitude against the amplitude-pressure curve.
52. The method of claim 50 or 51, wherein said DBP change rate threshold is determined based on a physiological condition of the subject.
53. The method of claim 52 wherein the DBP rate-of-change threshold is between 3000 and 5000, the third rate-of-change related setting is between 1.02 and 1.3, and the fourth rate-of-change related setting is 1.
54. The method of claim 42, further comprising: calculating a Systolic Blood Pressure (SBP) according to the maximum amplitude, the amplitudes of the sampling points adjacent to the maximum amplitude point, the first SBP ratio and a third SBP ratio, wherein the third SBP ratio is determined according to the type of the cuff.
55. The method of claim 43, further comprising: calculating the SBP amplitude corresponding to the SBP according to the following formula:
SBP amplitude = maximum amplitude basic ratio first SBP ratio third SBP ratio,
wherein the third SBP ratio is determined according to the type of the cuff, an
Obtaining the systolic SBP according to the calculated SBP amplitude and the amplitude-pressure curve.
56. The method of claim 54 or 55 wherein when the cuff is of the thigh strap type, the third SBP ratio is between 1 and 1.5, and otherwise the third SBP ratio is 1.
57. The method of claim 44, further comprising: calculating a diastolic DBP according to the maximum amplitude, amplitudes of sample points adjacent to the maximum amplitude point, the first DBP ratio, and a third DBP ratio, wherein the third DBP ratio is determined according to the type of the cuff.
58. The method of claim 45, further comprising:
calculating the amplitude corresponding to the DBP, namely the DBP amplitude according to the following formula:
DBP amplitude = maximum amplitude basic ratio first DBP ratio third DBP ratio,
wherein the third DBP ratio is determined according to a type of the cuff, an
The diastolic DBP is derived from the calculated DBP amplitude against the amplitude-pressure curve.
59. The method of claim 57 or 58 wherein when the cuff is of the thigh band type, the third DBP ratio is between 1 and 1.5, and otherwise the third DBP ratio is 1.
60. The method of claim 38, wherein recording pressure measurements taken after each deflation completion and before the next deflation initiation comprises:
waiting a predetermined time after the valve is fully closed; and
recording pressure measurements from the pressure sensor after waiting for the predetermined period of time,
wherein the predetermined time is determined according to a type of the cuff.
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| WO2024174236A1 (en) * | 2023-02-24 | 2024-08-29 | 上海英医达医疗器械用品有限公司 | Blood pressure measurement apparatus and blood pressure measurement method therefor |
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| WO2024174236A1 (en) * | 2023-02-24 | 2024-08-29 | 上海英医达医疗器械用品有限公司 | Blood pressure measurement apparatus and blood pressure measurement method therefor |
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