WO2010057565A2

WO2010057565A2 - Method for carrying out a zero point comparison in a patient monitoring system and corresponding patient monitoring system

Info

Publication number: WO2010057565A2
Application number: PCT/EP2009/007729
Authority: WO
Inventors: Bernd Beck; Marko Pavlin
Original assignee: Hyb D.O.O.
Priority date: 2008-11-18
Filing date: 2009-10-29
Publication date: 2010-05-27
Also published as: EP2346393A2; EP2346393B1; WO2010057565A3; DE102008058101A1

Abstract

The invention relates to a method for carrying out a zero point comparison in a patient monitoring system (50) with measured data taken from a patient by means of a transmission unit (58), transmitting over a radio path and at least one receiver (60) for receiving the measured data sent from the transmitter unit (58), wherein the measured data taken from the patient are pressure signals, which are supplied through a fluid-filled line (52) to a pressure transducer (56) which converts the pressure signal into electrical signals and forwards the same to the transmitter unit (58). The measured data received by the receiver unit is displayed on a monitor (62). In order to carry out the zero point comparison the fluid-filled line (52) to the patient is interrupted and subjected to ambient pressure, the offset voltage Vofs generated by the pressure transducer (56) resulting from the ambient pressure Po is determined in the transmitter unit and the measured data sent from the transmitter (58) in normal operation is corrected for the value of the off-set voltage and sent to the receiver (60). The invention further relates to a corresponding patient monitoring system.

Description

Title: Method of Performing a Zeroing of a Patient Monitoring System and Related Patient Monitoring System

description

The invention relates to a method for performing a zero point adjustment of a patient monitoring system with a measured data transmitted to the patient via a radio link sending unit and at least one receiving unit for receiving the measured data emitted by the transmitting unit, wherein the measured data taken at the patient pressure signals are via a liquid-filled pressure measuring line a pressure transducer converting the pressure signals into electrical signals and forwarding them to the transmitting unit, and wherein the measured data received by the receiving unit are displayed in particular on a monitor.

Such patient monitoring systems are previously known, for example, from EP 1 574 164 A1. In practice, performing a zero point adjustment of the patient monitoring system has proven to be problematic. A zero point adjustment is necessary because each pressure transducer has a different, so-called offset voltage V _O f _Ξ , which falsifies the absolute value of the measurement result. In this respect, it is necessary, after establishing the connection between the pressure transducer and the monitor, to adjust the zero line of the monitor such that an input signal corresponding to the ambient pressure of the monitor lies on a zero line of the monitor.

The present invention is intended to simplify the implementation of such a zero point adjustment. This object is achieved by a method having the features of claim 1. The method is thus characterized by the fact that the liquid-filled pressure measuring line is interrupted towards the patient to perform the zero point adjustment and the ambient air pressure that determined from the ambient air pressure po, generated by the pressure transducer offset voltage V _O f _{S determined} in the transmitting unit and optionally is stored, and that in normal operation, the measured data sent by the transmitting unit by the value V _O f _{S be} sent to the receiving unit.

Carrying out the method has the advantage that the measured data sent by the transmitting unit are already sent to the receiving unit, adjusted by the offset voltage V _O fs. The consideration of the offset voltage V _O f _S thus does not take place on the part of the receiver or the monitor, but takes place on the transmitting side. Since the signal sent by the transmitting unit to the receiving unit has correct absolute values due to the correction of the offset voltage of the measuring transducer, these can be received as such by the receiving unit and graphically displayed on the monitor. If necessary, it is only necessary to carry out a one-off comparison between the receiving unit and the monitor.

In the case of the invention, it is also advantageous if a base signal for matching the signals displayed on the monitor can be generated with the receiving unit, as a result of which the zero line of the monitor can be set to a base value. Advantageously, the base signal generated by the receiving unit corresponds to a signal of the transmitting unit resulting from the ambient air pressure po, in which case the base value corresponds to a zero value. In this case, consequently, due to the receiving unit side generated Base signal set the zero line of the monitor to the zero value. However, according to the invention, it is not necessarily required that the base signal corresponds to a zero value signal; For example, the base signal can also correspond to an X value, and the zero line of the monitor can then be correspondingly adjusted as a function of the X value signal.

In particular, it is conceivable that due to the base signal of the receiving unit, the zero line of the monitor is manually set to the appropriate value. For this purpose, on the monitor side, for example, a corresponding rotary control or a corresponding button can be provided.

In a further advantageous embodiment of the invention, it is provided that the zero line of the monitor is set automatically on the basis of a zero offset signal generated by the receiving unit. Consequently, a zero point adjustment signal is generated in the receiving unit when zeroing, which is detected by the monitor. Due to this zero point adjustment signal, the zero line of the monitor is then automatically shifted to the value zero via a corresponding monitor-side unit.

It is conceivable that during or after the determination and in particular the storage of the offset voltage V _O f _S in the transmitting unit, a zero adjustment command is sent to the receiving unit, due to which the zero point adjustment signal generated by the receiving unit and the zero line of the monitor according to manually adjustable is and / or automatically set.

Advantageously, the method is carried out fully automatically, that is, during the determination or storage of the offset voltage V _O f _S, the zero line of Monitor is automatically set based on the zero trim command and the zero trim signal.

The object mentioned at the outset is also achieved by a patient monitoring system according to the invention. Such a patient monitoring system provides, in addition to a transmitting unit and a receiving unit in or on the pressure measuring line before a valve which establishes a connection between the patient and the pressure transducer in an operating position and which for performing the zero point adjustment in an adjustment position, a connection between a liquid at ambient pressure and the pressure transducer manufactures. In this

Zero point adjustment of the valve can thus be carried out the zero point adjustment according to the inventive method. The transmitting unit here comprises evaluation means, which determine in the adjustment position of the valve from the ambient air pressure po resultant generated by the pressure transducer offset voltage V _O f _S and which the sent from the transmitting unit to the receiving unit measurement data by the value of the offset voltage V _O f _S purge.

The transmitting unit can in particular have a memory function which can be actuated to store the offset voltage V _O fs. Consequently, after the valve has been placed in the adjustment position, the memory function is carried out to perform the zero point adjustment, for example by pressing a transmitter-side memory button. It is also conceivable that after switching the valve within a certain period of time, the offset voltage V _O f _{S is} automatically stored.

Furthermore, it is advantageous if the receiving unit has a balancing function which can be actuated to generate the base signal. After the operation of Calibration key can be set to the actual zero value within a specified period of time the zero line of the monitor. The setting can, as already mentioned, either manually or automatically.

According to the invention, it is further conceivable that the transmitting unit has a balancing function and the receiving unit has means for generating a zero adjustment command such that a zero adjustment signal is sent to the receiving unit by actuation of the balancing function by the transmitting unit and a zero adjustment signal is generated in the receiving unit due to the zero adjustment command. The adjustment function can be performed, for example, by pressing a corresponding button on the transmitting unit and / or the receiving unit.

According to the invention, it can also be provided that the receiving unit has means for automatically setting the zero position of the monitor such that the zero line of the monitor is set automatically on the basis of the zero point adjustment signal.

A further advantageous embodiment of the invention provides when the monitor is integrated in the receiving unit. As a result, a receiving unit is provided which can be made compact and, in particular, mobile.

In another embodiment of the invention, it is conceivable that the monitor is formed separately from the receiving unit and has a connection via which the zero-point adjustment signal generated by the receiving unit can be fed to the monitor. Due to the corresponding connection or a corresponding interface, consequently, the zero point adjustment signal can be supplied to the monitor. Due to the zero point adjustment signal, such as already described, the zero line of the monitor will be set automatically.

Further details and advantageous embodiments of the invention will become apparent from the following description, the basis of which the invention is described and explained.

Show it:

Figure 1 is a schematic representation of a zero point calibration in prior art patient monitoring systems, ^•

Figure 2 is a schematic representation of a performance of a zero point adjustment system in a patient monitoring system according to the invention; and

FIG. 3 shows the patient monitoring system according to FIG. 3 in operation, and FIG

4 shows the implementation of the zero point adjustment in a patient monitoring system with multiple receivers.

FIG. 1 shows a known patient monitoring system 10, which is a liquid-filled patient

Pressure measuring line 12, a valve 14, a pressure transducer 16 and a monitor 18 includes. The pressure transducer 16 converts the analog pressure signals into electrical signals and forwards them via a cable connection 20 to the monitor. The pressure signals picked up by the patient may in particular be intravenous blood pressure signals.

Since each pressure transducer Beaubedingt has a different offset voltage V _O f _S , which is usually at a Zero bar reference pressure; is not equal to zero volts, it is necessary to clean up the measurement signal displayed on the monitor 18 by this voltage V _O f _S. Only at the monitor 18 are correct absolute values displayed.

The following shows a typical relationship between the pressure signal p measured at the pressure transducer 16 and the associated output voltage V _{out of} the pressure transducer.

pressure (mmHg)

It can be clearly seen that at a pressure p equal to zero an output voltage V _{out is} present, which is not equal to zero. This offset from the value of zero offset voltage V _O f _S falsifies the signal displayed on the monitor 18.

In order to obtain an output voltage V _ou t adjusted by the value V _O f _S , the output voltage V _ou t is to be reduced by the offset voltage V _O fs:

pofs = 0 pressure (mmHg)

The output voltage V _{out of} the pressure transducer 16 can be represented as:

v <, ut = <y _B s) (p + Pof _S ) (D.

Here, V _{B is} the bridge excitation voltage, s the sensitivity of the pressure transducer and p _O f _S the offset pressure. With a value p equal to zero, the offset voltage V _O f _S thus results:

Vofs = (YβΦofs (2;

The sensitivity s corresponds for example

s = SμV / V / mmHg: 3).

On the monitor 18, the output voltage V _ou t must be reduced by the value V _O f _S , so that correct absolute values can be read on the monitor.

In an arrangement according to Figure 1, in which the pressure transducer 16 is connected directly to the monitor, it is true that the monitor _input voltage V _{mon is} equal to the output voltage V _ou t of the pressure transducer 16, ie: ^V mor. = Vout. (4)

Consequently one obtains

(V _B s) (j) + p _ofs ) = (V _B s) (p _mon + ρ _mofs ) ₍₅ j _

Where p _{mon is} the current pressure value displayed on the monitor and p _m ofs is the internal offset compensation value. By changing the equation (5), one obtains the following:

Pmon - P + Pofs ~ Pmofs / g \

In order for the correct absolute values to be read out on the monitor, the following must apply:

Pmon = P (7) or

Pmofs = Pofs (8)

Since each pressure transducer has a different value p _O f _S , the value p _m ofs for each individual pressure transducer on the monitor 18 must be set such that ultimately p _{mon is} equal to p.

For FIG. 1, the following procedure results for performing a zero point adjustment:

At time ti, the valve 14 is switched to a balancing position, in which the pressure measuring line 12 is interrupted toward the patient and the liquid column standing between the valve 14 and the pressure transducer 16 is exposed to the ambient air pressure. The pressure in mmHg displayed on monitor 18 should now be at a zero line of the monitor. Due to the different offset Voltages V _OfS of different pressure transducers 16 this is usually not the case. Consequently, at a time t2, a person 22 operating the system 10 must move from the patient side A to the monitor B, and there manually adjust the zero line of the monitor 18 to a value of zero. This ensures that in the zero point adjustment position of the valve 14 on the monitor 18 actually zero mmHg are displayed. At a time t3, the person 22 then has to switch back to the patient side A in order to adjust the valve 14 to the operating position there, so that the liquid-filled pressure measuring line 12 is connected to the pressure transducer 16. The pending on the pressure transducer 16 pressure signals are then displayed with correct absolute values on the monitor 18.

In the described, previously known method for performing a zero point adjustment, it is therefore necessary that the person 22 operating the system 10 must change from the patient side A to the monitor side B at the time t2, and then again to the patient side A at the time T3 Procedure comparatively complex and takes a comparatively long time.

FIG. 2 shows a zero point adjustment according to the invention in a patient monitoring system 50 according to the invention.

On the patient side A, a pressure measuring line 52 is provided, corresponding to the system 10, with which pressure signals taken from the patient are fed via a valve 54 to a pressure transducer 56. The pressure transducer 56, which converts the pressure signals into electrical signals, is connected to a transmitting unit 58. The transmitting unit 58 communicates wirelessly, in particular via radio or Bluetooth, with a receiving unit 60, which is connected to a monitor 62. Since the Patient monitoring system 50, unlike the patient monitoring system 10 of Figure 1, the monitor 62 is not directly connected to the pressure transducer 56 is not a mandatory requirement that the output voltage V _{out of} the pressure transducer 56 is equal to the monitor input voltage V _mon , ie

(8th) .

According to the invention, it is provided that the measured data transmitted by the transmitting unit are already adjusted by the offset voltage V _O f _s ; that is to say, the measurement data sent by the transmission unit 58 are measurement data with correct absolute values. In this respect applies here:

and consequently too

(V _B s) (p + 0) = (V _B sXp _mσκ + 0) ₍ ! O ₎ .

Since no compensation of the offset voltage V _O f _{S is to be} performed on the monitor, as it has to be done according to the prior art of Figure 1, also applies

Pm = P (H).

In detail, the zero point adjustment according to the invention according to FIG. 2 is carried out as follows:

At time ti, the valve 54 is set to the adjustment position, that is, the liquid present between the valve 54 and the pressure transducer 56 is exposed to the ambient pressure po. The resulting offset voltage V _OfS produced by the pressure transducer 56 becomes measured and buffered in the transmitting unit 58. Thereafter, at the time t ₂ by the operator 22, the valve 54 is placed in the operating position. The operator 22 thereby does not have to change the location A.

In operation, the transmitting unit 58 then sends measured data to the receiving unit 60, which are adjusted by the value of the offset voltage Vofs, or in which the offset voltage V _O fs was subtracted. In this respect, the transmitting unit 58 sends measurement data with correct absolute values.

To ensure that the correct absolute values are also displayed on the monitor 62, it is necessary that, at a time t3, which may, however, also lie before the time ti, on the side B of the monitor 62 or of the receiver 60, the zero line of the monitor 62 is set once. For this purpose, a base signal, which is generated for example by pressing a corresponding key on the receiving unit, is sent to the monitor 62 by the receiving unit 60. The base signal corresponds in particular to a signal sent by the transmitting unit, which results from the ambient air pressure po.

Thus, while the base signal is being sent from the receiving unit 60 to the monitor 62, the monitor 62 can set the zero line of the monitor to the value of zero mmHg. As long as the receiving unit 60 remains connected to the monitor 62, this adjustment need not be repeated. In this respect, the path of the operator from the patient side A to the monitor side B must be covered only once.

FIG. 3 shows the invention

Patient monitoring system then in operation after performing the zero point adjustment. In the case of the patient monitoring system 50, provision can advantageously be made for a function or key to be provided at the transmitting unit 58 with which a zero-point adjustment command can be sent to the receiving unit 60. Due to the zero point adjustment command, the receiving unit 60 then generates a zero point adjustment signal, which is sent to the monitor 62. The monitor 62, which can provide a special interface for this, can then make an automatic adjustment of the zero line to the value of zero mmHg due to the zero point adjustment signal. In such a system, therefore, the zero point adjustment takes place fully automatically from the patient side A, merely by actuating a function or key provided there.

The receiving unit 60 and the monitor 62 can also be designed as an assembly according to the invention, that is to say that the monitor 62 on the one hand can be integrated in the receiving unit 60 and / or that the receiving unit 60 can be integrated in the monitor 62.

In the figure 4 is the invention

Monitoring device 50 shown in Figure 2, wherein not only a receiving unit 60 is provided, but in addition two further receiving units 60.2 and 60.3 with associated other monitors 62.2 and 62.3.

The receiving unit 60 together with the monitor 62 can be arranged, for example, in a preparation room of an operating room. The receiving unit 60.2 including the monitor 62.2 may be arranged, for example, in an operating room. The receiving unit 60.3 including monitor 62.3 can be provided in particular in a recovery room. To carry out the zero point adjustment, the valve 54, as already described, can be adjusted to the zero-point adjustment position on the patient side, and thus the offset unit in the transmitter unit 58 can be adjusted. Voltage V _O f _{S are} measured and stored. Within a selectable time, the valve 54 can be switched to the operating position. Thereafter, if this has not already been done, base signals can be generated at the receiving units 60, 60.2 and 60.3, for a one-time zero-line adjustment on the monitors 62, 62.2 and 62.3.

As described, this monitor-side adjustment is only carried out once, since the consideration of the offset voltage V _ofs not on the receiving unit side, but sendereinheitsseitig takes place.

Claims

claims

1. A method for performing a zero point adjustment of a patient monitoring system (50) with a measured data transmitted to the patient via a radio link sending unit (58) and at least one receiving unit (60) for receiving the transmission unit (58) emitted measurement data, wherein the patient measured data are pressure signals which are fed via a fluid-filled pressure measuring line (52) to a pressure transducer (56) converting the pressure signals into electrical signals and forwarded to the transmitting unit (58), and wherein the measurement data received by the receiving unit (60) is displayed on a monitor ( 62), characterized in that for performing the zero point adjustment, the liquid-filled pressure measuring line (52) towards the

Patients interrupted and exposed to the ambient air pressure, that resulting from the ambient air pressure po, generated by the pressure transducer (56)

Offset voltage V _O f _S in the transmitting unit (58) is determined, and that in normal operation, the measured data sent by the transmitting unit (58) by the value of the offset voltage

V _O f _S to be sent to the receiving unit (60).

2. The method according to claim 1, characterized in that with the receiving unit (60) a base signal for adjusting the signals displayed on the monitor (62) can be generated, due to which the zero line of the monitor (62) is adjustable to a base value.

3. The method according to claim 1 or 2, characterized in that the base signal one of the Send unit (58) signal emitted, which results from the ambient air pressure: po, and that the base value corresponds to a zero value.

4. The method of claim 1, 2 or 3, characterized in that the zero line of the monitor (62) is manually adjustable.

5. The method of claim 1, 2 or 3, characterized in that the zero line of the monitor (62) is set automatically due to a generated by the receiving unit (60) Zero adjustment signal.

6. The method according to claim 5, characterized in that during or after the storage of the off-voltage V _O f _S in the transmitting unit (58) a

Zero adjustment command is sent to the receiving unit (60), due to which the

Zero adjustment signal generated by the receiving unit (60) and the zero line of the monitor (62) is manually adjustable and / or adjusted automatically.

7. Patient monitoring system (50) with a measurement data transmitted to the patient via a radio link transmitting unit (58) and with at least one receiving unit (60) for receiving the transmission unit (58) emitted measurement data, suitable and / or provided for performing the method according to at least one of the preceding claims, wherein in or on the pressure measuring line (52) a valve (54) is provided, which establishes a connection between the patient and the pressure transducer (56) in an operating position and which for performing a zero point adjustment in a balancing position a connection between a pending on the ambient air pressure and the liquid Pressure transducer (56) manufactures, and wherein the transmitting unit (58) comprises evaluation means which determine the in the adjustment position of the valve (54) from the ambient air pressure po resulting from the pressure transducer (56) generated offset voltage V _O f _S and which the the transmission unit (58) to the receiving unit (60) sent measurement data by the value of the offset voltage V _OfS clean up.

8. System (50) according to claim 7, characterized in that the transmitting unit (58) has a memory function which is _operable to store the offset voltage V _OfS .

9. System (50) according to claim 7 or 8, characterized in that the receiving unit (60) has a balancing function, which is operable to generate a base signal for adjusting the signals displayed on the monitor (62), wherein due to the base signal, the zero line of the monitor (62) is adjustable to a base value.

10. System (50) according to claim 7, 8 or 9, characterized in that the transmitting unit (58) has a balancing function and the receiving unit (60) comprises means for generating a zero adjustment command such that actuation of the balancing function of the transmitting unit to a zero adjustment command the receiving unit (60) is transmitted and, based on the zero point adjustment command in the receiving unit (60), a zero point adjustment signal is generated.

11. System (50) according to claim 10, characterized in that the receiving unit (60) comprises means for automatically adjusting the zero position of the monitor such that the zero line of the monitor is set automatically due to the zero point adjustment signal.

12. System (50) according to claim 7, 8 or 9, characterized in that the monitor is integrated in the receiving unit.

13. System (50) according to at least one of claims 7 to 10, characterized in that the monitor (62) is formed separately from the receiving unit (60) and has a connection, via which the receiving unit (60) generated zero point adjustment signal Monitor can be fed.