WO2009130635A1

WO2009130635A1 - Adaptive blood pressure system and cuff hose

Info

Publication number: WO2009130635A1
Application number: PCT/IB2009/051570
Authority: WO
Inventors: Joseph Fallon
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2008-04-23
Filing date: 2009-04-15
Publication date: 2009-10-29

Abstract

A blood pressure monitoring system including components allowing the system to connect to a blood pressure cuff having a single hose and a dual hose. The blood pressure monitoring system further including a control element that configures the blood pressure monitoring system to operate with the connected cuff having either the single hose or the dual hose.The blood pressure monitoring system determining a blood pressure value of a patient.

Description

Adaptive blood pressure system and cuff hose

BACKGROUND

Non- invasive blood pressure (NIBP) monitors generally use an oscillometric method in order to determine arterial pressure. The oscillometric method entails measuring a mean arterial pressure to estimate the systolic and diastolic pressures, the peak pressure and the lowest pressure in the arteries, respectively. NIBP monitors are fitted with an electronic pressure sensor to detect blood flow. An air- filled cuff is wrapped around the patient's arm and is inflated to a pressure usually in excess of the systolic arterial pressure, and then reduced to below a diastolic pressure over a period. As the cuff is allowed to deflate, pressure data is recorded by the device.

SUMMARY OF THE INVENTION

A blood pressure monitoring system including components allowing the system to connect to a blood pressure cuff having a single hose and a dual hose. The blood pressure monitoring system further including a control element that configures the blood pressure monitoring system to operate with the connected cuff having either the single hose or the dual hose. The blood pressure monitoring system determining a blood pressure value of a patient.

A method for determining a number of hoses connected from a blood pressure cuff to a blood pressure system, the cuff including one of a single hose and a dual hose. Configuring the blood pressure system to operate with either the single hose cuff or the dual hose cuff. Detecting a pressure in the cuff and determining a blood pressure value as a function of the pressure in the cuff.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a schematic diagram of an exemplary embodiment of a Non-

Invasive Blood Pressure (NIBP) system.

Fig. 2 shows a flow diagram of an exemplary method performed by the exemplary NIBP system of Fig. 1. Figure 3 shows an exemplary embodiment of a pressure manifold implemented in an exemplary NIBP system.

DETAILED DESCRIPTION The following description provides exemplary embodiments and related appended drawings, wherein like elements are provided with the same reference numerals. The exemplary embodiments are related to a system, which is capable of connecting to both a single hose cuff and dual hose cuff for measuring a non- invasive blood pressure.

NIBP monitors use either single or dual hose pressure cuffs. A single hose pressure cuff allows the cuff to be both inflated and deflated via a single hose. A dual hose pressure cuff allows the cuff to be inflated via one hose and deflated via the other. A user (e.g., hospital, clinic, doctor, patient, etc.) may purchase blood pressure cuffs from a medical supplier either in bulk or through a contract such that the user is locked- in to a particular blood pressure cuff type, either single or dual hose. This may hinder the patient from being able to change NIBP monitors since current monitors only support one cuff type, either the single hose or the dual hose, but not both.

Fig. 1 shows an exemplary embodiment of a NIBP system 100 that is compatible with both a single hose cuff and a dual hose cuff. The NIBP system 100 comprises a NIBP control software 110, which communicates with a pressure sensor 120 a pump 140 and a valve 142. The pressure sensor 120 may be connected to a pressure manifold 130, which may be connected to a cuff 10. The inflation/deflation of the cuff 10 is controlled by the pump 140 and the valve 142, which may also be connected to the pressure manifold 130. The NIBP system 100 may further comprise input and/or output means such as a display 150 and a control 152. The NIBP control software 110 may run on either a local or a host processor.

That is, it is not necessary for all the components of the NIBP system 100 to be implemented as a single stand-alone device. It will be understood by those of skill in the art that the NIBP control software 110 is implemented, for example, as lines of code that are executed by a processor, controller, microcontroller, etc. Thus, the NIBP control software 110 (via input/output mechanisms of a processor executing the NIBP control software 110) may read cuff pressure measurements, via the pressure sensor 120, to determine a blood pressure value. Additionally, the NIBP control software may indicate to the pump 140 and the valve 142, to inflate and deflate the cuff 10, respectively. It will be understood by those of skill in the art, that the pump 140 and the valve 142 may also be operated manually. The pump 140 and the valve 142 may be connected to the pressure manifold 130, which is adapted to connect to the cuff 10, which may be either a single hose or a dual hose cuff. The pump 140 inflates the cuff 10 to an appropriate cuff pressure. The valve 142 is able to control the cuff pressure by maintaining the pressure or deflating the cuff 10 at a particular rate, which may be done manually or by the NIBP control software 110. If the cuff 10 is a single hose cuff, the cuff 10 connects to the pressure manifold 130 via a single hose 12a. If the cuff 10 is a dual hose cuff, the cuff 10 connects to the pressure manifold 130 via both the hose 12a and a hose 12b, which is shown in broken lines to indicate that the hose 12b is not required for a single hose connection. The pressure manifold 130 and/or the NIBP control software 110 may be capable of determining whether the cuff 10 is a single hose or a dual hose cuff by detecting the number of connections. For example, the hoses 12 a-b and/or a connector for the hoses 12 a-b may include an electrical and/or mechanical sensor (e.g. , conductance sensor, switch, etc.) indicating that an actual connection to a cuff 10 has been made. In another example, the pressure manifold 130 may allow air to flow to a connection for the hoses 12 a-b and the pressure sensor 120 may measure the pressure of the air flow, the NIBP control software 110 may then determine if a cuff 10 is attached to one or both connections based on the pressure data. In a further exemplary embodiment, a user may enter an indication via the control input 152 of whether the attached cuff 10 is a single hose or dual hose cuff. If the pressure manifold 130 detects that the cuff 10 is a single hose cuff, the pressure manifold 130 may direct the single hose 12a to alternately connect with both the pump 140 and the valve 142 such that the cuff 10 may be inflated and deflated via the single hose 12a. If the pressure manifold 130 detects that the cuff 10 is a dual hose cuff, the pressure manifold 130 may direct the first hose 12a to connect with the pump 140 and the second hose 12b to connect with the valve 142 such that the cuff 10 may be inflated via one of the hoses 12a and deflated via the other hose 12b. It will be understood by those of skill in the art that the pressure manifold 130 may be a connector that supports both cuff types or may include a connector that supports both cuff types.

The pressure sensor 120 may also be connected to the pressure manifold 130. As the cuff 10 is deflating, the pressure sensor 120 detects a pressure in the cuff to determine a blood flow. The cuff pressure may vary periodically in synchrony with the cyclic expansion and contraction of the artery such that the cuff pressure oscillates. When there is no blood flow, such that the cuff pressure exceeds the systolic pressure, or when there is unimpeded blood flow, such that the cuff pressure is below diastolic pressure, the cuff pressure will remain substantially constant. Thus, the systolic and diastolic pressure may be calculated using the cuff pressure values detected by the pressure sensor 120. The values detected by the pressure sensor 120 are inputted to the NIBP control software 110 such that the blood pressure value may be calculated. Once the blood pressure is calculated, the blood pressure value may be outputted to a display 150. It will be understood by those of skill in the art that the display 150 may also show other information such as the cuff pressure according to the pressure sensor 120 while the system 100 is measuring the blood pressure or a status of the measurement of the blood pressure value. In a further embodiment, the system 100 may also include the control means 152 for inputting control information, which may include means for powering on and powering off of the system 100 or initiating or stopping of the blood pressure monitoring. The control means 152 may also include options for printing and storing the blood pressure value. Thus, it will be understood by those of skill in the art that the NIBP system 100 may be connected to a printer and/or memory such that the NIBP pressure data may be printed or stored. Information may be stored for record-keeping purposes and may be retrieved at a later time for further analysis. It will also be understood by those of skill in the art that the display 150 and the control means 152 may be substituted for other input and/or output means and may include other inputting/outputting options that may be utilized by the system 100. Figure 3 shows an exemplary embodiment of a pressure manifold 130. Those skilled in the art will understand that there may be many examples of interconnections and valves within the pressure manifold 130 to accomplish the purposes described herein and that the arrangement shown and described in Fig. 3 is only an example. In the exemplary arrangement of Fig. 3, the pressure manifold 130 includes five (5) valves 305-325 that may be controlled by the NIBP control software 110 based on whether the attached cuff 10 is a single hose or dual hose cuff.

Initially, it may be considered that the cuff 10 is a single hose cuff. Thus, in such an embodiment, the valve 320 that is connected to the hose 12b will be normally closed and will remain closed throughout the entire operation because the hose 12b is not connected to the cuff 10. To begin single cuff operation, the valve 310 (connected to the pump 140) and the valve 325 (connected to the cuff 10 via the hose 12a) will be opened to allow air from the pump 140 to inflate the cuff 10, e.g., air flow in the direction of arrow 350 from the pump and arrow 352 to the cuff 10. The valve 305 (connected to the pressure sensor 120) may be opened to measure the cuff 10 pressure as the cuff is inflated (e.g., air flow in the direction of arrow 354 to the pressure sensor 120) or the valve 305 may remain closed and a fixed amount of air may be supplied to the cuff 10. When the cuff 10 is inflated, the valve 310 may be closed and the valve 305 may be opened (or remain opened) so the pressure sensor 120 may measure the pressure. In addition, the valve 325 may remain open. The valve 315 (connected to the valve 142) may then be opened to allow the cuff 10 to be deflated, e.g., allowing air flow in the direction of arrow 356 away from the cuff 10 and in the direction of arrow 358 toward the valve 142. The valve 305 may remain open during this time so that the pressure sensor 120 may take pressure readings as the cuff 10 is deflated.

To continue with the example, it may now be considered that the pressure manifold 130 is connected to a dual hose cuff 10. Again, to inflate the cuff 10, the valves 310 and 325 may be opened, while the valves 315 and 320 remain closed, e.g., air flow in the direction of arrow 350 from the pump and arrow 352 to the cuff 10. When inflation is complete, the valves 310 and 325 are closed. Then, the valves 320 and 315 may be opened to allow the cuff 10 to be deflated, e.g., allowing air flow in the direction of arrow 360 away from the cuff 10 and in the direction of arrow 358 toward the valve 142.

As described above, the arrangement shown in Fig. 3 is only exemplary and any number of other possible arrangements exists. For example, it may be assumed that the pressure sensor 120 is always connected to the pressure manifold 130. Thus, the valve 305 may not be used, i.e., the connection between the pressure manifold 130 and pressure sensor 120 is always open. In another example, the valve 315 may not be used because the valve

142 is sufficient to control the air flow for deflation. That is, if the valve 142 is open, the cuff 10 is being deflated and if the valve 142 is closed, the cuff 10 is not being deflated. In another example, the valve 315 may replace the valve 142. For example, the valve 315 may be a control valve (a valve that has a known flow characteristic) rather than a simple open/close valve and the NIBP software 110 may control the control valve 315 to deflate the cuff 10 and the desired rate, thereby making the valve 142 superfluous. In a further example, the valve 310 may be a valve that is controlled {e.g., a open/close or control valve) or it may simply be a check valve {e.g., a valve that is open when the pump 140 is pumping air to the pressure manifold 130, but closes on its own when the air flow from the pump 140 falls below a certain flow value). Thus, as can be seen from the plurality of examples above, there are many arrangements and types of components {e.g., open/close valves, control valves, check valves, etc.) that may be used to implement the pressure manifold 130.

In a further exemplary embodiment, it may be possible to connect a first pressure sensor {e.g., pressure sensor 120) directly to the hose 12a and to connect a second pressure sensor (not shown) directly to the hose 12b. In such an exemplary embodiment, those skilled in the art will understand that some of the valves 305-325 may not be needed. The cost of an additional pressure sensor may be offset by the corresponding savings in reducing the number of valves in the system. It is also noted that such an arrangement may make the pressure readings more stable. For example, when the pump 140 is operating, it may introduce a certain amount of noise into the system 100. However, by attaching the pressure sensor(s) to hoses, the hoses may act to muffle or damp some or all of the noise in the system.

Moreover, the dual pressure sensors being located on the hoses 12a-b may also be used to determine whether the cuff 10 is a single hose or dual hose cuff. For example, as the cuff 10 is inflated, if the first pressure sensor connected to the hose 12a indicates an increasing pressure and the second pressure sensor connected to the hose 12b indicates an increasing pressure, the NIBP control software 110 may determine that the cuff 10 is a dual hose cuff and operate the system 100 in an appropriate manner. In a further example, as the cuff 10 is inflated, if the first pressure sensor connected to the hose 12a indicates an increasing pressure and the second pressure sensor connected to the hose 12b indicates little or no increase in pressure, the NIBP control software 110 may determine that the cuff 10 is a single hose cuff and operate the system 100 in an appropriate manner.

Those skilled in the art will understand that the NIBP system 100 of Fig. 1 is only exemplary and that an NIBP system may employ more or less components than those illustrated in Fig. 1. For example, an NIBP system may incorporate a secondary or tertiary pressure sensor that is used for safety purposes in case the primary pressure sensor(s) and/or the NIBP control software fail. For example, a safety pressure sensor may be set to automatically (e.g., through mechanical or electrical means) open valve 142 to reduce the pressure of the cuff 10 if the pressure exceeds 350 mm Hg.

Fig. 2 shows an exemplary method 200 of the system 100, as described above. In step 210, the cuff 10 is connected to the system 100 such that a pressure of the cuff may be detected by the pressure sensor 120 and read by the NIBP software 110. The system 100 is configured to be connectable to both a single hose cuff and a dual hose cuff via a connector, which may be included in the pressure manifold 130. In step 220, the type of cuff 10 (single or dual hose) that has been connected pressure manifold 130 is determined. As described above, the detection of the type of cuff 10 may be performed automatically by the NIBP system 100 or may be entered manually by a user of the NIBP system 100. Based on the determination of the type of cuff 10, the pressure manifold 130 (and/or other components of the NIBP system 100) may be properly configured, e.g., the hoses(s) 12a and/or 12b connected to the pump 140 and the valve 142, as necessary. For example, if the cuff 10 includes the single hose 12a, the pressure manifold 130 may direct the hose 12a to alternately connect with both the pump 140 and the valve 142. Alternatively, if the cuff 10 includes dual hoses 12a and 12b, the pressure manifold 130 may direct the hose 12a to connect to the pump 140 and the hose 12b to connect to the valve 142, or vice versa.

The user may place the cuff 10 in an appropriate position on the patient's body. Once the cuff 10 is in the appropriate position a NIBP measuring process may be initiated, in step 230. It will be understood by those of skill in the art that the measuring process may be initiated via the control means 152, which transmits the user input to the

NIBP control software 110. The NIBP software may signal the pump 140 to inflate the cuff 10. The cuff 10 is inflated such that the pressure in the cuff exceeds systolic pressure, to approximately 180 mm/Hg, such that the brachial artery is compressed and collapses so there is no flow of blood through the brachial artery. After the appropriate level of inflation has been achieved, the NIBP control software 110 may signal the valve 142 to begin deflation of the cuff 10. It will also be understood by those of skill in the art that the pump 140 and the valve 142 may be used to inflate and deflate the pump manually. Once the diastolic pressure is reached, the brachial artery opens. The blood flow increases steadily until the cuff pressure falls below the diastolic pressure. Thus, based on the changes in the cuff pressure, the NIBP software is able to determine the NIBP value.

In step 240, the pressure sensor 120 detects the cuff pressure. The cuff pressure may be monitored during the inflation and deflation process to ensure that the cuff 10 is inflated to the appropriate pressure and that the cuff 10 is being deflated at the appropriate rate. During deflation, the pressure sensor 120 detects the cuff pressure, which is transmitted to the NIBP control software 110 such that the NIBP control software 110 may determine the blood pressure value of the user based on the cuff pressure, in step 250. The NIBP control software 110 is able to determine the NIBP value based on the changes in cuff pressure, which indicates blood flow. The measured NIBP value may then be displayed in step 260. In a further embodiment, the status of the measurement of the blood pressure value may also be displayed.

In an even further embodiment, the system 100 may receive control information inputted by the user via control means 152, in step 270. The control means 152 may include powering on or powering off of the system 100. The control means 152 may also include options for printing and storing the blood pressure value. Thus, based upon the user input, the system 100 may print, store, power on/off or initiate/cancel measurement. It will, however, be understood in the art that a variety of other input/output options may be available.

It will be apparent to those skilled in the art that various modifications may be made in the present invention, without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

It is also noted that the claims may include reference signs/numerals in accordance with PCT Rule 6.2(b). However, the present claims should not be considered to be limited to the exemplary embodiments corresponding to the reference signs/numerals.

Claims

CLAIMS:

1. A blood pressure monitoring system (100), comprising: a connector (130) adapted to connect a blood pressure cuff (10) to the blood pressure monitoring system, the connector (130) adapted to connect a blood pressure cuff (10) having one of a single hose and a dual hose; and a control element (110) configuring the blood pressure monitoring system

(100) to operate with the one of the single hose cuff and dual hose cuff to determine a blood pressure value.

2. The system of claim 1, further comprising: a pressure sensor (120) coupled to the cuff (10) via the connector (130), the pressure sensor (120) measuring a pressure in the cuff (10), the blood pressure being determined based on the pressure in the cuff.

3. The system of claim 1, wherein the system determines whether the cuff (10) is the one of the single hose cuff and the dual hose cuff.

4. The system of claim 3, wherein the determination is based on one of i) a detection of connections by the connector, ii) a detection of one of a pressure and flow of air through the connector, and iii) a manual input by a user.

5. The system of claim 1, wherein the control element (110) configures the system in a first configuration when the cuff is determined to be the single hose cuff and the cuff is being inflated, in a second configuration when the cuff is determined to be the single hose cuff and the cuff is being deflated, in a third configuration when the cuff is determined to be the dual hose cuff and the cuff is being inflated, in a fourth configuration when the cuff is determined to be the dual hose cuff and the cuff is being deflated.

6. The system of claim 1, further comprising: a pump (140) generating an inflation air flow to inflate the cuff (10), the inflation air flow being directed via the connector (130) to the cuff (10); and a control valve (142) allowing a deflation air flow to deflate the cuff.

7. The system of claim 6, wherein, when the cuff (10) is a dual hose cuff, the inflation air flow is directed via a first connection to the cuff and the deflation air flow is directed via a second connection from the cuff.

8. The system of claim 1, wherein the control element (110) includes a processor executing lines of code to configure the system.

9. The system of claim 1, wherein the connector (130) includes a plurality of valves and the configuring includes setting an operating position of the plurality of valves.

10. A method, comprising : determining a number of hoses connected from a blood pressure cuff to a blood pressure system (220), the cuff including one of a single hose and a dual hose; configuring the blood pressure system to operate with the one of the single hose cuff and dual hose cuff (230); detecting a pressure in the cuff (240); and determining a blood pressure value as a function of the pressure in the cuff

(250).

11. The method of claim 10, wherein the configuring the blood pressure system to operate with the single hose cuff includes: directing a connection between a first hose and both a pump and a valve, wherein the pump inflates the cuff and the valve deflates the cuff.

12. The method of claim 10, wherein the configuring the blood pressure system to operate with the dual hose cuff includes: directing a connection between a first hose and a pump and a second hose and a valve wherein the pump inflates the cuff and the valve deflates the cuff.

13. The method of claim 10, wherein the determining includes one of i) detecting connections, ii) detecting one of a pressure and air flow, and iii) receiving a manual input by a user.

14. The method of claim 10, wherein the configuring includes setting an operating position of a plurality of valves for a connector, the connector connecting the blood pressure system to the cuff.

15. A system, comprising: means (130) for connecting a blood pressure cuff (10) to a blood pressure monitoring system (100), the means adapted to connect blood pressure cuffs having one of a single hose and a dual hose; and a means (110) for configuring the blood pressure monitoring system to operate with the one of the single hose cuff and dual hose cuff to determine a blood pressure value.