WO2009071700A1

WO2009071700A1 - Medical apparatus and system for monitoring vital signals of a patient

Info

Publication number: WO2009071700A1
Application number: PCT/EP2008/067036
Authority: WO
Inventors: Mikael SAHLSTRÖM
Original assignee: Coolinvest Ltd
Priority date: 2007-12-07
Filing date: 2008-12-08
Publication date: 2009-06-11

Abstract

A vital signal monitoring system suitable for monitoring a patient walking free in urban areas, the system comprising : - a transmitter unit (110) comprising vital signal sensor and being applicable to a person - a personal vital signal monitoring unit (120) devised to receive signals transmitted from the transmitter - a remote unit (130) devised to receive a message from the monitoring unit where the personal vital signal monitoring unit is of a handy format permitting the person to perform normal daily activities.

Description

MEDICAL APPARATUS AND SYSTEM FOR MONITORING VITAL

SIGNALS OF A PATIENT

Field of invention The present invention relates to the field of medical devices. More particularly it relates to the field of medical devices for capturing and analysing vital signals, i.e. ECG signals, of the electrical activity of a patient's organ, i.e. the heart and to the combination of a medical device and a GPS system.

Background

Diseases of the heart are some of the most common causes of death in the industrialised part of the world. Such diseases show a high prevalence, incidence, and mortality. A correct diagnosis is of great value in order to prevent and treat these diseases. Due to their inherent nature, including a very rapid progression in the acute stage, it is often very important to take appropriate action as soon as possible. It may depend on minutes that are absolutely critical to the survival of the patient. Each minute may play a crucial role to the individual patient. This is true for both the survivability in connection with a myocardial infarction, and for the level of quality of life due to permanent effects resulting from such an infarction. The survival rate after ventricular fibrillation is directly and in inverse proportion to the time until adequate treatment is commenced. The most important method for diagnosing heart disease today is electrocardiography (ECG). ECG is also the most important method for monitoring a patient's heart.

Summary of the invention

With the above description in mind, then, an aspect of some embodiments of the present invention is to provide an improved medical device, system and method for monitoring a patient's heart and upon abnormalities alerting or alarming appropriate resources, which seeks to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination.

Accordingly, the present invention provides a system including a personal life guard device to be worn by a person having the need for heart monitoring. The device is devised to pick up ECG signals and to analyze them and recognise common pathological conditions as to heart rhythm, heart rate, and signs of infarction. This is accomplished by continuous interpretation and analysis of ECG signals read by electrodes attached to the person. The analysis is performed by ECG analysis software resident in a device worn by the person.

When something pathological is recognised the personal life guard device issues a first alarm via audiovisual means arranged in connection with the personal life guard device, and simultaneously a second alarm is issued via a cell phone network, for example a GSM network..

The second alarm is sent to an emergency service centre or suitable medical treatment centre, which centre is connected to the system.

In this connection, the phrase "when something pathological is recognised." is in particular meant to include the recognition of the condition bradycardia (low heart rate) and the condition tachycardia (high heart rate). A bradycardia alarm could be of great advantage and use for patients with a non-disclosed cardiologic/medical disease. Therefore the system is also provided with an alarm- limit-broadening- switch, that when activated broadens the interval of heart rate within which interval no alarm is issued.

The system also provides means to communicate with a central service or hospital having specialised physicians for interpreting ECG. The system may further comprise alarm capabilities that issue an alarm when the communication link to the GSM network is broken, and stays broken for more than a predefined number of minutes. The system also alerts when battery capacity is low.

In addition, the system also issues an alert if the connection between an ECG electrode and the skin is broken. The system further comprises means to communicate the ECG curve with or without its own interpretation of the same, preferably via a short message service (SMS) via a GSM network, to be interpreted by specialist physicians who decide upon possible treatments and upon when, and upon which speed to apply them.

The system further comprises a GPS receiver/transmitter in order to make it possible to find the patient wherever he or she may be. This is important no less having the time aspect in mind.

The personal life guard device is designed to be able to attach to the body of the patient. Alternate embodiments includes that the life guard device is integral with a sport bra for women, or is integral with a similar sport holster for men. It may be designed to be able to attach to the body with the aid of a Velcro strap running around the ribcage, and where the apparatus may be built in the strap. The ECG-electrodes/-s may be of a self adhering type and/or may be coated with a contact generating gel on the bottom side to facilitate reading. The patient may in consultation with his physician decide upon which type of device he or she would like to use.

Common to all ways of wearing the personal life guard device described above is that they are easy to use and impossible to use in a wrong way. In particular the first mentioned way is easy because the apparatus can be taken off and put on as desired, for example if a strenuous activity is imminent. The system may also be provided with an alarm limit broadening switch, which in its activated state broadens the range within which the system does not issue an alarm. The switch is preferably used when the patient is going to do something strenuous, and doesn't want the system to issue a false alarm, but simultaneously doesn't want to be without the safety it means to use the personal life guard device. According to a first aspect there is provided an ECG alarm system suitable for monitoring a patient walking free in urban areas, the system comprising:

- a transmitter unit comprising ECG electrodes and being applicable to a persons chest; - a personal ECG monitoring unit devised to receive and analyse signals transmitted from the transmitter unit and to automatically decide when to send an alarm message;

- a remote alarm receiving unit devised to receive the alarm message where the personal ECG monitoring unit is of a handy format permitting the person to perform normal daily activities.

The ECG alarm system where two sets of alarm limits are provided an transferred to the personal ECG monitoring unit, and where the person can manually change between the sets.

The ECG alarm system wherein a GPS unit is arranged to provide a geographical position of the patient.

The ECG alarm system wherein the geographical position is included in the alarm message.

According to a second aspect there is provided a method for monitoring ECG signals of a person wearing a transmitter belt and a personal ECG monitoring unit comprising the following steps:

- receiveing and analysing ECG signals

- extracting ECG parameters

- checking ECG parameters against alarm limits, and;

- based on the check taking alarm action and sending person GPS position to remote unit.

According to a third aspect there is provided a method for monitoring a person's vital signals comprising the steps of

- setting one or more alarm limits outside which the persons vital signal is recognized as abnormal; - comparing the actual vital signal of the person with said alarm limit(s);

- based on the comparision issuing an alarm The method may also comprise the step of

- setting a first alarm limit below which the person's heart rate is recognized as low-heart-rate (bradycardia-alarm) ; - setting a second alarm limit above which the person's heart rate is recognized as high-heart-rate (tachycardia- alarm);

- comparing the actual heart rate of the person with first and second alarm limits; - based on the comparision issuing an alarm including information on the persons position.

The method further comprising the step of replacing the first alarm limit with a third alarm limit different from the first alarm limit, below which limit the person's heart rate is recognized as low-heart-rate (bradycardia-alarm); The method further comprising the step of replacing the second alarm limit with a fourth alarm limit, different from the second alarm limit, above which limit the person's heart rate is recognized as high-heart-rate (tachycardia- alarm);

The method where the alarm includes information on the person's position.

The method wherein the vital signal is a pulse oximetry signal. The method wherein the vital signal is a lung flow signal.

The method wherein the vital signal is a blood pressure signal.

The method wherein the vital signal is a peak expiratory flow signal.

According to a fourth aspect there is provided a monitoring system useable for monitoring a patients vital signal, the system comprising a portable monitoring unit wherein the system comprises means for sensing a vital signal of the patient and transmitting it wirelessly to a remote location.

The monitoring system wherein vital signal and position data are transmitted continously to the remote location.

The monitoring system where the vital signal is transmitted to the remote location together with position data regarding the patients position

The monitoring system wherein the means for sensing a vital signal include one or more ECG electrodes.

The monitoring system wherein the means for sensing a vital signal include a pulsoximeter. The monitoring system wherein the means for sensing a vital signal include a blood pressure gauge.

The monitoring system wherein the means for sensing a vital signal include a lung flow meter.

The monitoring system wherein the portable monitoring unit comprises a GPS receiver for determining the patients position.

The monitoring system wherein the portable monitoring unit comprises a GSM transceiver for determining the patients position.

The monitoring system wherein the portable monitoring unit comprises a radio frequency tracker for determining the patients position. The monitoring system wherein the portable monitoring unit comprises a GPS receiver, and a GSM transceiver and a radio frequency tracker for synergistically determining the patients position.

It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, elements, integers, steps, components or groups thereof.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

Brief description of the drawings

Further objects, features and advantages of the present invention will appear from the following detailed description of the invention, wherein embodiments of the invention will be described in more detail with reference to the accompanying drawings, in which:

Fig. 1 shows a schematic overview over different units of a mobile ECG monitoring system according to an embodiment of the present invention.

Fig. 2 is a more detailed schematic overview over a personal ECG monitoring unit of fig. 1.

Fig. 3 is a flowchart of a method for monitoring ECG signals of a person wearing a transmitter belt and a personal ECG monitoring unit of fig. 1.

Fig. 4 shows a system overview of a monitoring system.

Fig. 5 shows a data flow overview of the system of figure 4.

Description of preferred embodiments

Embodiments of the present invention relate, in general, to the field of medical devices. A preferred embodiment relates to a portable medical device, such as a portable system for monitoring vital signals, such as ECG signals, from a person with communication capabilities, including one or more transmitting devices. However, it should be appreciated that the invention is as such equally applicable to medical devices which do not include any communication capabilities. However, for the sake of clarity and simplicity, most embodiments outlined in this specification are related to ECG monitoring systems. Fig. 1 shows a schematic overview over different units of a mobile ECG monitoring system according to an embodiment of the present invention. A transmitter belt 110 comprises a belt for attachment over a patient's chest with ECG electrodes arranged suitably on the transmitter belt to pick up ECG signals when worn by the patient. The transmitter belt also comprises a short range transmitter unit and a power source. The ECG electrodes are connected to the short range transmitter, which transmitter comprises means for converting the ECG signals picked up from the patient to short range radio frequency transmission signals 140 for communicating the ECG signals to a personal ECG monitoring unit 120, also devised to be worn by the patient. The personal ECG monitoring unit 120 comprises means for receiving the short range radio frequency transmission signals 140 from the transmitter belt, means for analysing the in this way received ECG signals, and means for deciding when to take an alarm action. Such an alarm action includes sending an alarm message 150 to a remote alarm receiving unit 130 arranged to receive such alarm messages. Fig. 2 is a more detailed schematic overview over the personal ECG monitoring unit 120 of fig. 1. The personal ECG monitoring unit 120 comprises a short range radio frequency receiving antenna 260 for receiving the signals transmitted by the transmitter of the transmitter belt. The antenna is connected to a central ECG processing unit 230 where the received ECG signals are processed and analysed and where the decision when to issue an alarm is automatically taken by ECG analysis software. The central ECG processing unit 230 is connected to a remote communications unit 250, in this particular embodiment a GSM unit 250 for sending an alarm message to the remote alarm receiving unit 130. The central ECG processing unit 230 is also connected to a positioning unit 240, in this particular embodiment a Global Positioning System (GPS) unit 240 for providing the central ECG processing unit 230 with position data of the patient to be included in the alarm message sent via GSM. The GPS unit has an antenna 265 for receiving GPS signals. The GSM unit is connected to a SIM card unit 270 that are arranged to hold a SIM card. The central ECG processing unit 230 is further connected to means for providing a local audiovisual alarm. These means may include a speaker 210 and a lamp 220. A local alarm may also comprise a tactile alarm by means of e.g., a vibration unit (not shown). A power supply, preferably a chargeable battery 275 is arranged to supply power. The personal ECG monitoring unit 120 is preferably devised to be of a compact and handy format. It could preferably be wristwatch size or cell phone size. The electronics is preferably contained in a watertight casing. It is equipped with suitable controls to allow for changing of particular setting as described below. The system may also be provided with a blood gas analyser e.g., a pulse oximeter to further add parameters to analyse and improve sensitivity and specificity of alarm decisions.

Trauma sensor

In a further embodiment the personal ECG monitoring unit 120 may be provided with a built in trauma sensor for sensing if a trauma has occurred and alarm accordingly.

Built in diagnostics In still a further embodiment the personal ECG monitoring unit 120 may be provided with a built in continuously operating self diagnostics function that alerts if malfunction is detected. This diagnostics function will detect e.g. low battery level, bad contact, loss of communication or loss of GPS connection or the like.

Fig. 3 is a flowchart of a method for monitoring ECG signals of a person wearing a transmitter belt 110 and a personal ECG monitoring unit 120 of fig. 1.

In an initial procedure the personal ECG monitoring unit 120 is provided 305 with at least a first set of alarm limits. Preferably also provided 310 with a second set of alarm limits, to allow the patient to switch between the sets depending on e.g., if he or she is going to perform a strenuous activity, as explained above.

When in operation the system continuously receives and analyses 315 ECG signals. Parameters are extracted to be compared with current alarm limits. If two sets of alarm limits are provided the system checks which one of them that are to be applied and applies that set 320.

The system subsequently checks 325 if the ECG parameters is within the chosen alarm limits. If it is so it continues and repeats steps 315, 320, 325.

If it is not so, that s, parameters are outside alarm limits the system takes alarm action 330, sends 335 an alarm message including GSM position to remote unit, and receives 340 and forwards 345 continuously ECG signal and GSM position to remote unit.

The mobile ECG monitoring system according to an embodiment of the present invention may further comprise a garment having the chest electrodes and the personal ECG monitoring sewn into or otherwise integrated into said garment to provide an easy way of put on the mentioned units of the system. Such garment may make use of conducting textiles to provide communication between chest electrodes and the personal ECG monitoring unit 120, eliminating the need for wires and radio frequency equipment.

Memory function

The personal ECG monitoring unit is equipped with a memory for storing information representing 24 hours of ECG signals. This information may, dependant on operator settings, be transferred to the remote alarm receiving unit for statistic analysis, or may be overwritten. Individual alarm limit setting

The alarm limits defining at least a first normal range are preferably individually determined using a procedure involving that the patient spends one night in a hospital for continuous ECG monitoring and also involving a maximum heart rate test or similar. The limit values are subsequently transferred to the personal ECG monitoring unit by radio communication or by manual input.

In a second embodiment there is provided a portable ECG monitoring system to be worn by a person in need thereof, for sensing and monitoring of the wearers ECG signal and for sending an alert message to an alert receiving facility, should the ECG monitoring system interpret the ECG signal as representing a condition that should be alerted to said facility. The portable ECG monitoring system comprises an ECG signal pickup device for sensing ECG signals, the device having one or more electrodes arranged to make contact to the wearer's chest at suitable locations.. The portable ECG monitoring system further comprises an interpretation unit, also devised to be worn by the wearer, for receiving ECG signals from the ECG signal pickup device. These signals are preferably sent from the ECG signal pickup device to the interpretation unit wirelessly.

The interpretation unit is small and compact and is preferably arranged to be worn in the wearer belt or around the wearer's wrist similar to a wristwatch. The interpretation unit comprises a signal processing unit for signal processing of the ECG signals. The signal processing unit is arranged to extract key features of the ECG signal, a first key feature is heart rate, and a second key feature is rhythm index. The rhythm index indicates one of the following: normal sinus rhythm, atrial flutter, or ventricular flutter. The interpretation unit further comprises a classification unit for classification of the ECG signals based on the key features. In particular, the classification unit is arranged to classify ECG signals into three groups;

Group I, normal or near normal, not needing attention; Group II, suspected ECG. ECG signal is sent to alert receiving facility for human interpretation;

Group III, alarming ECG. ECG signal and wearers position is continuously sent to alert the receiving facility.

The interpretation unit further comprises a communications unit which is connected to the classification unit, which communications unit is arranged to act according to what is stated for each group I- III above.

In particular, when the ECG signal is classified as a Group II signal, the communications unit opens a connection, preferably via a GSM-unit, also encompassed within the interpretation unit, to the receiving facility, and starts transmitting suspected ECG signal.

When the ECG signal is classified as a Group III signal, the communications unit opens a connection, if it is not already open, via the GSM-unit, to the receiving facility, and starts transmitting alarming ECG signal. The position of the wearer is determined via a GPS receiver also encompassed within the interpretation unit

A further feature of the system is that the wearer himself can influence the criteria of when the ECG signal is to be classified as a group I, II or III. For example, the interpretation unit comprises an input organ where a first high heart rate limit, above which the ECG is classified as group II, can be changed by the wearer. This is advantageous to get down the rate of false alerts and false alarms.

Overall, there are great advantages connected with using a portable ECG monitoring system of above. The wearer can be confident that if his heart shows signs of malfunctioning, somebody will be alerted and help can be sent immediately to the right location. Figure 4 shows a system overview of a personal ECG monitoring system

401. A portable personal ECG monitoring unit 405 is provided with means for receiving sensor data from one or more ECG electrodes. The ECG electrodes are preferably one to three torso electrodes, suitable to attach to a patients torso for collecting ECG signals. The monitoring unit is preferably also provided with means for receiving a pulse oximetry signal from a pulse oximetry sensor. Means may also be provided for receiving peak expiratory flow and/or blood pressure signals. In the following the expression "vital signals" is meant to include ECG signal and none or more of pulse oximetry signal, peak expiratory flow signal, lung flow signal, and blood pressure signal. For providing these signals corresponding meters may be provided, i.e., pulse oximeter, PEF-meter, lung flow meter, and blood pressure meter.

The portable personal ECG monitoring system 401 is provided with a position determining unit 407 comprising a GPS receiver, a GSM transceiver, and a radio frequency tracker. The position determining unit 407 is arranged to accurately provide position for the patient wearing the portable personal ECG monitoring unit 405, if possible, wherever in the world and in whatever building the patient may be. The tracker is arranged to be able to provide an indication on what floor of the building the patient is. The three positioning devices, i.e., the GPS, the GSM and the tracker are arranged for synergistically determining the patient's position. The term "position" in this context is meant to include information such that a rescue team easitly can find the patient, and if available this include, except for geographical position data also building and floor data, depending on accuracy of radio frequency tracker.

The portable personal ECG monitoring system 401 is provided with a remote alarm unit for receiving alarm signals from the ECG monitoring unit.

The portable personal ECG monitoring system 401 is further provided with connection to a remote hosting centre 502, as shown I fig 5, via the GSM transceiver 407 and internet. The portable personal ECG monitoring unit 405 is provided with circuitry for arranging such that the vital signals is continuously transmitted from the sensors to the hosting centre 502 via the GSM transceiver. In the hosting centre 502 the vital signal(s) is/are monitored and interpreted and recorded.

Figure 5 shows a data flow overview and method steps for a system according to figure 4.

Claims

1. An ECG alarm system suitable for monitoring a patient walking free in urban areas, the system comprising:

- a transmitter unit comprising ECG electrodes and being applicable to a persons chest;

- a personal ECG monitoring unit devised to receive and analyse signals transmitted from the transmitter unit and to automatically decide when to send an alarm message;

2. The ECG alarm system as recited in claim 1 where two sets of alarm limits are provided an transferred to the personal ECG monitoring unit, and where the person can manually change between the sets.

3. The ECG alarm system as recited in claim 1 wherein a GPS unit is arranged to provide a geographical position of the patient.

4. The ECG alarm system as recited in claim 3 wherein the geographical position is included in the alarm message.

5. A method for monitoring ECG signals of a person wearing a transmitter belt and a personal ECG monitoring unit comprising the following steps:

- receiving and analysing ECG signals

- extracting ECG parameters

- checking ECG parameters against alarm limits, and; - based on the check taking alarm action and sending person GPS position to remote unit.

6. A method for monitoring a person's vital signals comprising the steps of

- setting one or more alarm limits outside which the persons vital signal is recognized as abnormal;

- comparing the actual vital signal of the person with said alarm limit(s);

- based on the comparison issuing an alarm.

7. The method of claim 6 comprising the step of - setting a first alarm limit below which the person's heart rate is recognized as low-heart-rate (bradycardia- alarm) ;

- setting a second alarm limit above which the person's heart rate is recognized as high-heart-rate (tachycardia- alarm); - comparing the actual heart rate of the person with first and second alarm limits;

- based on the comparison issuing an alarm including information on the persons position.

8. The method of claim 7 further comprising the step of replacing the first alarm limit with a third alarm limit different from the first alarm limit, below which limit the person's heart rate is recognized as low-heart-rate (bradycardia-alarm).

9. The method of claim 6, 7 or 8 further comprising the step of replacing the second alarm limit with a fourth alarm limit, different from the second alarm limit, above which limit the person's heart rate is recognized as high-heart-rate (tachycardia- alarm).

10. The method of any of the claims 6 to 9 where the alarm includes information on the person's position.

11. The method of claim 6 wherein the vital signal is a pulse oximetry signal.

12. The method of claim 6 wherein the vital signal is a lung flow signal.

13. The method of claim 6 wherein the vital signal is a blood pressure signal.

14 The method of claim 6 wherein the vital signal is a peak expiratory flow signal.

15. A monitoring system useable for monitoring a patients vital signal, the system comprising a portable monitoring unit wherein the system comprises means for sensing a vital signal of the patient and transmitting it wirelessly to a remote location.

16. The monitoring system of claim 15 wherein vital signal and position data are transmitted continuously to the remote location.

17. The monitoring system of claim 15 or 16 where the vital signal is transmitted to the remote location together with position data regarding the patients position

18. The monitoring system of claim 15, wherein the means for sensing a vital signal include one or more ECG electrodes.

19. The monitoring system of claim 15, wherein the means for sensing a vital signal include a pulsoximeter.

20. The monitoring system of claim 15, wherein the means for sensing a vital signal include a blood pressure gauge.

21. The monitoring system of claim 15, wherein the means for sensing a vital signal include a lung flow meter.

22. The monitoring system of claim 15, wherein the portable monitoring unit comprises a GPS receiver for determining the patients position.

23. The monitoring system of claim 15, wherein the portable monitoring unit comprises a GSM transceiver for determining the patients position.

24. The monitoring system of claim 15, wherein the portable monitoring unit comprises a radio frequency tracker for determining the patients position.

25. The monitoring system of claim 15, wherein the portable monitoring unit comprises a GPS receiver, and a GSM transceiver and a radio frequency tracker for synergistically determining the patients position.