Patent Application
20100081950
The invention relates to the field of diagnostic apparatus which detect bioelectric potentials. The invention specifically relates to an ECG system and to a corresponding method.
Specifically, the invention relates to the field of ECG systems according to the preamble of patent claim 1 and to a method according to the preamble of patent claim 8.
In medical science various measuring techniques are known to determine parameters of a patient's body. For the present application, above all the picking off of electric potentials from the upper part of the human body in order to obtain electrocardiograms (ECGs) is relevant.
In order to obtain an electrocardiogram (ECG) the bioelectric potentials or potential differences which occur during the depolarization and repolarization of the heart are recorded. The measurement of the potentials may be performed bipolar or unipolar by means of electrodes on the body surface.
Apparatus for acquiring ECGs fall under the generic term diagnostic apparatus. However, for example, a defibrillator likewise measures an ECG. Therefore, for the purposes of the present application, therapeutic apparatus which measure bioelectric potentials, that is, which also comprise a diagnostic unit, shall be equally covered by the generic term diagnostic apparatus.
A problem with an ECG apparatus is that, despite the internationally standardized color coding and terms used for the electrodes and/or the electrode cables, the electrodes are confused (compare A. Rudiger, L. Schöb ECG of a young patient with influenzal complaints, who is suspected of having ischaemia, Switzerland Med Forum No. 28, 11.7.2001, Page 741 et seq.). At least in simple cases, current signal evaluation methods are able to detect in the potential curves over time if electrodes were confused (Kors J. A., van Herpen G.: Accurate automatic detection of electrode interchange in the electrocardiogram, Am J. Cardiol, 15.8.2001; 88(4):396-9).
If the potential curves are abnormally changed or noisy, these methods quickly reach their limits. Especially when chest leads (V1-V6) are made, the physical distance between the electrodes is so small that a safe detection of confused electrodes is very difficult.
U.S. Pat. No. 5,042,498 as well as the other patent family members EP 0 450 350 A1, DE 69119133 T2 and JP 4227229 A disclose an intelligent ECG system. The electrodes used comprise a pad with a post and a snap connector which clamps the post and includes an LED anchored in the top central portion of the snap connector. A lead with three wires connects the snap connector to the ECG apparatus. One wire contacts the snap connector itself. The other two wires contact the LED. A detector circuit in the ECG apparatus supplies via a wire in the lead a constant current to the post. If the voltage drop between the post and the body of a patient is too great, a poor contact is assumed and the LED is switched on. The wire that connects the LED to a ground connection in the ECG apparatus may be used as a shielding for the wire providing the ECG signal.
DE 100 29 205 A1 discloses an apparatus for measuring physiological parameters. ECG measuring electrodes are movably positioned in a belt system. The belt system further comprises an electronic measurement system, a device for the wireless transmission of the digitalized measured signals, a power supply unit and an antenna. The electrodes are arranged movably and include an LED display. The receiving station detects by means of a program whether the individual electrodes are possibly not connected or wrongly positioned, which is signalized, for example, by a red LED display on the respective electrode.
It is the object of the invention to provide a user-friendly ECG system and a corresponding method.
This method is achieved with the teaching of the independent claims.
Preferred embodiments of the invention are defined in the dependent claims.
A running light on the ECG electrodes has the advantage that the running light is easy to implement in an ECG apparatus. The “evaluation” is more or less made by the user, so that no complicated algorithms are necessary. The type and quality of the recorded ECG signals has no influence on the accuracy of the evaluation.
The evaluation may also be made by an image recorder (e.g. simple digital camera or web cam) and an evaluation software.
A preferred embodiment of the invention will be explained in more detail below, with reference to the accompanying drawing. In the drawing:
This invention helps a user to check proper placement of the electrodes quickly and comfortably after having fixed the electrodes on the patient 1. The reader will appreciate that it is sometimes necessary to measure ECGs in error-prone situations, e. g. in accidents at nighttime, when the user is tired. It is important that the user notices a possible confusion of the electrodes as quickly as possible after placement. To this end a so-called running light mode is provided in which the electrodes are switched on and off again like a running light. This means that the light sources assigned to the electrodes are switched on in a predetermined sequence and are switched off again in this sequence, whereby a different number of light sources can light up simultaneously.
If a succeeding light source is switched on as the light source directly preceding the succeeding light source is switched off, and the last light source is followed by the first light source, always one single light source is switched on.
If the xth light source in the sequence is switched on as the (x-2)th light source is switched off, two light sources light up simultaneously. This embodiment is illustrated in
In another embodiment the overlap between two light sources may be smaller, e. g. 5% to 40%, in particular 20% of the time between switching on the x-th and the (x+1)th light source. This may be referred to as a slight overlap. The x-th and the (x+1)th light source may be designated neighboring light sources.
In the extreme case all light sources may be switched on before the first light source is switched off again, so that there is a time when all light sources light up. Also, the light sources may be switched on successively and switched off simultaneously, or switched on simultaneously and switched off successively.
The running light mode may be described as a sequence of states, wherein no, one, several or all light sources may be switched on in each state. Each switching on and off of a light source is then a state change.
It should be expedient to switch the light sources on at an interval of approximately 0.5 to 2 seconds, for example one second and to chose this time interval also for switching them off. Thus, with ten electrodes and light sources and without an interval between the last and the first light source, a period of 5 to 20 seconds, for example 10 seconds is obtained, corresponding to a frequency of 0.2 to 0.05 Hz, for example 0.1 Hz. Especially in embodiments in which many or all light sources light up simultaneously, there should be a pause between the last and the first light source, that is, before the sequence of switching the light sources on and off is repeated.
The keys may allow a user to adjust the interval between switching on neighboring light sources for example from 0.3 to 3 seconds. Also the overlap may be adjusted by the keys from 0% to 900% of the interval between switching on neighboring light sources. 0% overlap means that the (x+1)-th light source is switched on when the x-th light source is switched off. Skilled persons will appreciate that the ECG apparatus is micro processor controlled and that the micro processor is a suitable means for controlling the switching on and off of the light sources. The micro processor or a memory within the ECG apparatus may store different settings for the interval and the overlap.
As can be seen in
If the ECG apparatus 2 is switched on, for example, by means of the starter button 5 the ECG apparatus 2 can automatically switch into the running light mode. Subsequently, a user can secure the ten electrodes or a part thereof on the patient 1, while the running light helps to avoid a confusion of the electrodes. Next, the user can exit the running light mode by pressing the stop button 6. By means of the test key 4 the running light mode may be activated again.
In another embodiment, the ECG apparatus 2 may automatically switch to the running light mode, after the electrodes have been secured on the patient 1 and successful electrode contact quality check was performed by the ECG apparatus 2. After the ECG apparatus 2 has been switched on, it starts to check electrode contact quality, up until all or a predefined subset of electrodes is secured with sufficient contact quality to the patient 1. During this period the LEDs may indicate poor-contact electrodes. After switching to the running light mode, the user can quickly and reliably check the proper sequence of the electrodes.
There are many ways known in the art to perform an electrode contact quality check, cf e. g. U.S. Pat. No. 5,042,498. In a further embodiment, the user may select as to whether the ECG apparatus 2 switches directly into the running light mode or does the electrode contact quality check first after it has been switched on. The user may also cancel a unsuccessful contact quality check and switch to the running light mode.
The invention was explained in more detail by means of preferred embodiments above. A person skilled in the art will appreciate, however, that various alterations and modifications may be made without departing from the spirit of the invention. Therefore, the scope of protection will be defined by the accompanying claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2008 049 287.6 | Sep 2008 | DE | national |
