WO2008128673A1

WO2008128673A1 - Ecg monitoring module, ecg monitoring system and method for monitoring cardiac patients

Info

Publication number: WO2008128673A1
Application number: PCT/EP2008/002961
Authority: WO
Inventors: Bernd Falter; Joachim-Michael Knörig
Original assignee: Brandenburgisch Technische Universität Cottbus
Priority date: 2007-04-24
Filing date: 2008-04-09
Publication date: 2008-10-30
Also published as: DE102007020241A1

Abstract

The invention relates to an ECG monitoring system having an ECG monitoring module (1), having a number of spatially distributed receivers (13) designed to receive output signals forwarded wirelessly from the transmitting unit (9) and to transmit them to a control station (19), and having a control station (19) connected to the receivers (13), the station comprising a position determination module, which is designed to determine the position of the sending ECG monitoring module (1) from the data transmitted by the receivers (13). The ECG monitoring module (1) is equipped with a number of electrodes (3) that are suitable for being placed on the body of a patient for reading electrical biosignals, with an evaluation unit (7) connected to the electrodes (3) and designed such that it can provirde information about the frequency, amplitude, and rhythm of cardiac activity based on the read electrical biosignals and can generate output signals representing the information, and with a transmitting unit (9) connected to the evaluation unit (7) for receiving an output signal and designed such that it can wirelessly forward the received output signal to a receiver (13).

Description

ECG monitoring module, ECG monitoring system and method for monitoring cardiac patients

The present invention relates to an ECG monitoring module, an ECG monitoring system and methods for monitoring cardiac patients.

Systems for monitoring cardiac patients are known in the art and are distributed by various companies. For example, Vitaphone offers two devices for monitoring patients after cardiac surgery (Vitaphone 3100 BT loop recorder and Vitaphone 100 IR ECG monitoring card). The Vitaphone 3100 BT loop recorder makes it possible to detect pathological ECG changes using a 1-channel ECG. The device can be easily worn by the patient on the chest. If pathological ECG deviations occur, the recorder contacts a Bluetooth-enabled mobile phone via a Bluetooth interface and transmits the ECG to the Vitaphone Service Center. For the sensible use of the device, a Bluetooth-enabled mobile phone must be in the immediate vicinity (10 m). Only in this case the functionality of the product is guaranteed. In addition, no positioning of the patient by the loop recorder Vitaphone 3100 BT is possible.

The company anandic offers a telemetry monitoring system with simultaneous localization of the patient in the hospital. The system provides a wealth of information, such as 2- to 12-lead ECG,

Oxygen saturation measurements and various others. In addition, all transmitted data including the current position of the patient displayed in a central workstation, which offers a variety of representation options for the raw data. Due to the large number of display options of the raw data on the PC, however, the manageability effort for the medical personnel increases considerably. In addition, a location of the patient is only possible within the clinic.

The Fraunhofer Institute for Photonic Microsystems is developing a foil ECG as part of a telemetric system based on Bluetooth. The ECG is transmitted to the doctor by telephone or mobile phone network and thus requires the active participation of the patient. It can be used both in the clinical area as well as in the domestic area. However, in the latter case, a considerable time interval arises between the occurrence of physiological changes of the biosignal and the analysis by the attending physician. In addition, no location of the patient is provided even in the clinical area.

The object of the present invention is therefore to provide an EKG monitoring module that is advantageous over this prior art, an EKG monitoring system that is advantageous over this prior art, and a method for monitoring cardiac patients which is advantageous over this prior art.

This object is achieved by an ECG monitoring module according to claim 1, an ECG monitoring system according to claim 3 and a method for monitoring cardiac patients according to claim 6. The dependent claims contain advantageous embodiments of the invention.

An ECG monitoring module according to the invention comprises a number of electrodes, an evaluation unit connected to the electrodes and a transmitting unit. The electrodes, which are suitable for being attached to the body of a patient for the purpose of accepting electrical biosignals, are connected to the evaluation unit. This is designed in such a way that, on the basis of the removed electrical biosignals, it can make statements about the frequency, the amplitude and the rhythmicity of the heart activity and can generate the output signals representing the statements. The Transmitting unit is connected to receive an output signal to the evaluation unit. It is designed such that it can forward the received output signal wirelessly to a receiver.

As statements about the frequency, the amplitude and the rhythm of the heart activity, the evaluation unit on the basis of the removed electrical biosignals in particular between the following

Distinguish heart conditions: a) normal heart rate, b) too high / too low heart rate, c) asystole (cardiac arrest), d) ventricular fibrillation. The

In this case, the evaluation unit can create different output signals, which represent the respective heart condition.

The ECG monitoring module according to the invention reduces the parameters to be sent only to a rough characterization of the patient's condition (eg normal heart rate, too high / too low heart rate, asystole, or ventricular fibrillation). Shifting much of the patient's diagnosis to the ECG monitoring modules eliminates the need to submit extensive raw data (such as a complete ECG). This reduces the radio load in the sensitive hospital area as well as the complexity of the software to be used by the staff. Due to the much smaller range of functions of the product according to the invention, in addition to the necessary hardware components of the ECG monitoring modules logically also their size and any effort for commissioning reduced. The concept of functionality limitation can increase the practicality considerably. In most medical emergencies, the trained personnel will re-diagnose onsite with more suitable equipment anyway. Against this background, the increased functionality of existing telemetry systems seems doubtful.

An ECG monitoring system according to the invention comprises an ECG monitoring module according to the invention, a number of spatially distributed receivers and a control station connected to the receivers. The receivers are designed in such a way that they can receive the output signals transmitted wirelessly by the transmitting unit and transmit them to a control station. The control station comprises a positioning module, which is configured such that it can determine the position of the transmitting ECG monitoring module from the data transmitted by the receivers.

The ECG monitoring system according to the invention serves to monitor the cardiac activity of patients in the postoperative environment and at the same time localization possibility for the "indoor" and the "outdoor" area. For the continuous analysis of the electrical biosignal, an ECG monitoring module, also called ECG monitor module, is available for each patient to be monitored. This allows, for example, a simple arrhythmia analysis of the heart activity and contains a radio module which transmits the medical data to stationary receivers (LNA). The receivers collect the data from all the ECG monitoring modules within reach and transmit them via the in-house intranet to a control station, for example a central computer. Here, in addition to the appropriate representation of the patient data and the actual location is performed. Should the evaluation result in a critical condition (e.g., cardiac arrest), the attending physician can be promptly alerted. Examples include messages on computers in the network or wirelessly via a "beeper." In addition to the medical data, the patient's whereabouts are also transferred so that the doctor receives all the information needed for rapid treatment which is configured to monitor temporally successive positions of the transmitting ECG monitoring module and detect unrealistic position changes, thereby optimizing the location of the transmitting ECG monitoring module.

The receivers of the ECG monitoring system can be designed as network switches with two cable network connections: They can then be designed as communication adapters which are switched between a PC and a PC connection to the intranet connecting the network. In this case, no separate network connection is required for the receiver. In the method according to the invention for monitoring cardiac patients with the aid of an ECG monitoring module that generates diagnostic data, only the diagnostic data from the ECG monitoring module are sent wirelessly to at least one of a number of localized receivers. The data is then forwarded by the receiving receiver (s) to a control station, where the position of the transmitting ECG monitoring module is determined from the location (s) of the receiving receiver (s). In an advantageous embodiment of the method, the position of the ECG monitoring module is displayed visually and / or acoustically together with the diagnostic data transmitted by it in the control station. The inventive method can be excellently implemented in particular with the ECG monitoring system according to the invention.

In the context of the method according to the invention, the position of the transmitting ECG monitoring module can also be continuously monitored and unrealistic position changes can be eliminated with the aid of a tracking algorithm.

The method according to the invention and the ECG monitoring system according to the invention have in particular the following advantages:

- It is not an "online" transmission but only an "online"

Monitoring of the electrical biosignal (ECG signal) necessary.

Signal pre-processing on site (ECG monitor module) only requires the transmission of the current patient status.

The construction of a hospital-compatible radio network low transmission power for the monitoring of cardiac patients and to avoid disturbing effects within the 2.4 GHz ISM band is possible.

There is no need to use additional radio systems (GPS / GSM) to realize a location in the immediate vicinity of the hospital. - There is a location possibility of the patient in the clinic and its immediate environment. In addition, the cause of the alarm can be conveyed by specifying the patient's condition.

- A time saving can be realized by parallel alerting of qualified specialists and thus a more efficient treatment.

Compared with the systems according to the prior art, the installation effort is reduced by using already existing wired communication systems (intranet).

- A modular system structure is possible, which allows a deliberate increase / decrease of the positioning accuracy / radio load.

The technical challenge underlying the invention consists in the establishment of a cost-effective, simple, interference-insensitive and reliable system for patient monitoring and location. The system according to the invention or the method according to the invention alerts, in the case of the occurrence of pathological ECG changes, promptly the medical staff. Shifting the biosignal analysis by the on-duty nurse to the ECG monitoring module adds extra time and simplifies results.

The system according to the invention or the method according to the invention differs from the systems and methods according to the prior art in several points.

Telemetry is an integral part of the system according to the invention or of the method according to the invention. It therefore does not rely on services (e.g., GSM) of additional providers. It also allows symbolic location both inside and outside buildings.

The product according to the invention reduces the transmitted parameters only to a rough characterization of the patient's condition and the associated location. By transferring much of the patient's diagnosis to the ECG monitoring modules, the Transmission of extensive raw data (eg complete ECG). This reduces the radio load in the sensitive hospital area as well as the complexity of the software to be used by the staff.

Due to the much lower functionality of the product according to the invention compared to the prior art, in addition to the necessary hardware components of the ECG monitoring modules, their size as well as any costs for commissioning are reduced. The concept of functionality limitation can increase the practicality considerably. In most medical emergencies, healthcare professionals are re-diagnosing onsite with more suitable equipment anyway. Against this background, the increased functionality of existing telemetry systems seems doubtful.

Further features, properties and advantages of the present invention will become apparent from the following description of an embodiment with reference to the accompanying figures.

FIG. 1 shows a block diagram of the ECG monitoring system.

FIG. 2 shows an ECG monitoring module and its system components.

FIG. 3 shows the system components of a communication adapter of the ECG monitoring system.

FIG. 4 shows the connection of a communication adapter from FIG. 2.

FIG. 5 shows the possible representation of the events in the ECG monitoring system.

The ECG monitoring system according to the invention serves to monitor the cardiac activity of patients in the postoperative environment and at the same time localization possibility for the "indoor" and the "outdoor" area. To ensure this range of functions, the overall system, as shown in FIG. 1, is composed of different subsystems. For the constant analysis of the electrical biosignal is for everyone an ECG monitoring module or ECG monitor module in the form of an ECG vest 1. It allows a simple arrhythmia analysis of cardiac activity and includes a radio module which transmits the medical data to stationary communication adapters 13 (LNA) as a receiver. These collect the data from all the ECG modules in range and transmit them via the in-house intranet 15 to a central computer, which represents the control station 19 of the ECG monitoring system. Here, in addition to the appropriate representation of the patient data and the actual location is performed. If the evaluation results in a critical condition (eg cardiac arrest), the attending physician can be alerted promptly. Examples of this are messages on computers 21 located in the network or wirelessly via "Pieper 23." In addition to the medical data, the patient's whereabouts are also transmitted so that the doctor receives all the information necessary for rapid treatment.

Description of the individual system components:

1. ECG monitor module (ECG vest)

The ECG monitor module 1 is shown in more detail in FIG. It represents the mobile subsystem for detecting relevant biosignals and is carried by the patient to be monitored.

When putting on the vest, electrodes 3 (max 3-4) are placed on the chest, which allow a decrease of the electrical bio-signal. A downstream analogue electronics 5 receives and amplifies the biosignal in such a way that statements about the frequency, amplitude and rhythmicity of the cardiac activity are already possible by means of the following digital signal preprocessing 7. This information is summarized after appropriate coding in a state for the patient and a radio module 9 (transceiver) provided. Only a few possible situations are distinguished for the determination of the current patient condition.

a) Determination of normal heart rate (frequency 50-100 / min). b) Determination of high / low heart rate.

c) finding asystole (cardiac arrest).

d) Ventricular fibrillation (irregular curve).

In addition, the ECG monitor module 1 can detect system conditions (eg: loose electrodes, manual triggering, low battery voltage, etc.).

The ECG monitor module 1 also has an independent power supply in the form of a rechargeable battery 11. Due to the low energy requirement and the low transmission power, a service life of a few months is assumed. A special criterion in addition to the running time is the size. Here, dimensions of approx. 85mm x 55 mm (base area of a commercially available chip card) with a height of not more than 25 mm can be realized.

The measurement data are transmitted wirelessly to communication adapter 13 (see FIG. 3), provided that a corresponding request has been made.

2. Communication adapter

The communication adapter 13 forms the interface between the in-house intranet 15 (see Figure 1) and the wireless communication to the ECG monitor modules. They are installed at selected points in or on the building and form the basis for the "indoor" and "outdoor" location to be carried out in the control center. The basic structure of such a stationary communication adapter is shown in FIG. 2.

The communication adapter 13 essentially comprises three components, namely a radio module 17, a network switch 31 and a central processing unit 33. The radio module 17 is available for communication with the patient ECGs. It receives the medical data of all ECG monitor modules in range 1. In addition, the parameters required for the location (received signal strength, bit error rate) are logged by the communication adapters. On the basis of these data, the actual symbolic location takes place later in the control station 19. The accuracy of the location depends significantly on the number of installed stationary communication adapter 13. The higher the density of stationary communication adapter 13, the more data is available to the central computer or the control station 19 for the location. On the one hand, this method makes it possible to consciously reduce the radio illumination of critical building areas (eg operating room) and thus possible interference with medical devices. On the other hand, in the reverse case, the accuracy in less critical areas (eg bed house) can be increased.

For the communication of the stationary communication adapter 13 with the central computer or the control station 19, the module has two interfaces 25, 27 to the intranet 15. Since in principle must be assumed that the occupancy of the network ports 29 in the premises of the medical device, could only a technical device 21 (shown in the figures as a PC) are connected. By implementing two network connections 25, 27 in the communication adapter 13, both the computer and the stationary communication adapter 13 can be operated at a network connection 29 in a room of the medical facility (see FIG. In this case, the stationary communication adapter 13 additionally assumes the function of a network switch 31. The data traffic of the computer 21 in the intranet / Internet 15 is neither logged nor analyzed or suppressed, so that there is no impairment in the data flow. Only the traffic intended for the communication adapter 13 is redirected to the central processing unit 33 of the stationary communication adapter 13. For a unique addressing of the adapter in the intranet 15, therefore, all stationary communication adapter 13 in addition to a separate MAC address also need their own IP address, which must be provided from the range of available IP addresses of the subnet.

As a central processing unit 33, the communication adapter 13 has a microcontroller. It controls the communication process both on the radio side and on the network side. This is the implementation of the respectively used protocols required (eg TCP / IP stack). In addition, the block encrypts the raw data to be transmitted, making unauthorized data access more difficult.

The power required to operate the stationary adapters is provided by an external power supply 35 (e.g., AC adapter).

3rd control station

The application software runs on a standard PC (primarily in the control station 19) and takes over all administrative tasks. The computer periodically polls all connected stationary communication adapters 13. These buffer the data of the ECG monitor modules 1 as well as their received signal strength and bit error rate. The current position of the transmitting ECG monitor module 1 is symbolically determined from the determined data by statistical methods. In addition to triangulation algorithms for position estimation, these include tracking algorithms that check the plausibility of the position. For example, position jumps of several 100 meters within one second are to be recognized as unrealistic and thus as a mistake. For the location, therefore, preferably a detailed floor plan and a site plan should be deposited. In addition, the software should be aware of the location of all in-system stationary communication adapters 13.

When setting up the entire system, the field distributions are not yet known. Here, a building-specific and static signal distribution card to be created can be stored. However, the setup cost of this method would be relatively high and inflexible, since it would have to be redone for major structural change. Alternatively, the possibilities of an adaptive, self-learning algorithm for symbolic location are currently being investigated. The continued operation of the system alone would successively bring the accuracy of the symbolic location closer to an optimum.

A possible alerting of the hospital staff in the case of a patient emergency beyond the provided standard Information channels performed. For example, messages can be sent to computer 21 located in network 15, or the service personnel can be informed by the sister on duty. Finally, the current location of the patient and his current medical condition are graphically displayed on the software to be developed. The results could look as shown schematically in FIG.

4. Radio network

The radio network represents the connection between the ECG monitor modules 1 and the stationary communication adapters 13 and enables telemetry with localization. The choice of the radio standard used is the required boundary conditions, as shown below, adapt.

high range,

low transmission power,

Transmission / output of additional parameters (received signal strength indicator, bit error rate),

Low energy consumption,

high immunity to interference,

- low geometric dimensions and

low data rate

Although many systems (e.g., WLAN, BLUETOOTH) are available on the market, the wireless standard of nanoTRON appears to be the most appropriate. The used radio frequency of 2.4 GHz is just like WLAN and BLUETOOTH in a license-free ISM band.

The standard combines many of the above points and allows with a max. Transmission power of 8 dBm (corresponds to 6.3 mW) omnidirectional ranges of 60 m for the "indoor" area and 900 m for the "outdoor" area Area. This eliminates the need for an additional location system for outdoor use (eg GSM with coupled GPS).

The presented invention leads to a reliable radio-based location system for the localization of patients, which allows the use of existing line-guided communication channels for transmitting information and to a suitable mobile ECG monitoring module. Its focus is on reducing its size and cost. In addition, the use of a radio standard for both the "indoor" and the "outdoor" area causes a significant simplification of the system.

Claims

claims

1. ECG monitoring module (1) with a number of electrodes (3) which are suitable for being attached to the body of a patient for the purpose of accepting electrical biosignals, an evaluation unit (7) connected to the electrodes (3) and configured in this way in that on the basis of the removed electrical biosignals they state statements about the frequency, the amplitude and the

Meeting rhythmic activity of the heart and the statements representing output signals can create, and a transmitting unit (9), which is connected to receive an output signal to the evaluation unit (7) and configured such that they forward the received output signal wirelessly to a receiver (13) can.

2. ECG monitoring module (1) according to claim 1, in which the evaluation unit (1) is designed such that it can distinguish on the basis of the removed electrical biosignals between the following cardiac conditions: a) normal heart rate, b) too high / too low heart rate, c) asystole, d) ventricular fibrillation and that they can produce different output signals representing the respective cardiac condition.

3. ECG monitoring system with - an ECG monitoring module (1) according to claim 1 or 2, a number of spatially distributed receiver (13), which are configured such that they receive from the transmitting unit (9) wirelessly forwarded output signals and to a Control station (19), and a control station (19) connected to the receivers (13), which comprises a position determination module which is designed such that it determines the position of the transmitting ECG from the data transmitted by the receivers (13). Monitor module (1) can determine.

4. ECG monitoring system according to claim 3, which further comprises a tracking module which is configured to monitor temporally successive positions of the transmitting ECG monitoring module (1) and to detect unrealistic position changes.

5. ECG monitoring system according to claim 3 or claim 4, in which the receivers (13) are also designed as network switches (31) with two cable network connections (25, 27).

A method for monitoring cardiac patients using an ECG monitoring module (1) generating diagnostic data in which only the diagnostic data from the ECG monitoring module (1) is wirelessly sent to at least one of a plurality of isolated receivers (13) receiving data from the receiving ECG Receiver or the receiving receivers (13) are forwarded to a control station (19) and determined in the control station, the position of the transmitting ECG monitoring module (1) from the location or the locations of the receiving receiver or the receiving receiver (13) becomes.

7. The method of claim 6, in which the position of the transmitting ECG monitoring module (1) is monitored continuously and unrealistic position changes are eliminated using a tracking algorithm.

8. The method according to claim 6 or claim 7, in which the position of the ECG monitoring module (1) together with the diagnostic data sent by him in the control station (19) is displayed visually and / or acoustically.