WO2003088837A1

WO2003088837A1 - A device and a method for monitoring a foetus

Info

Publication number: WO2003088837A1
Application number: PCT/SE2002/001666
Authority: WO
Inventors: Roger E. Hansson; Berndt Lorenzen
Original assignee: Medexa Diagnostisk Service Ab
Priority date: 2002-03-04
Filing date: 2002-09-17
Publication date: 2003-10-30
Also published as: SE0200676D0; SE0200676L; AU2002338056A1

Abstract

Device for foetal temperature measuring, wherein a temperature sensing micro sensor (13) is combined with a scalp electrode (10). The temperature measuring and a recording of CTG are performed simultaneously with a common device (10; 13).

Description

A device and a method for monitoring a. foetus

BACKGROUND

In connection with maternity care there is a need for measuring the foetal temperature during delivery. In this connection there has been a discussion whether different factors, such as the CTG pattern, PH value, lactate and medication of the mother, different states of ill-health etc., possibly can be correlated to the foetal tem- perature, and also to a possible temperature difference between mother and foetus.

PRIOR ART Many attempts already made for measuring foetal temperatures have failed, mainly because the measured quantity rather being the temperature of the mother. There have also been suggested detailed and not exactly methods that have not given the desired results. An object of the present invention is to provide a device that can be used to obtain in a secure and simple way the foetal temperature.

SUMMARY OF THE INVENTION

In accordance with the invention existing techniques from two different areas have been combined, and as a result a secure and compact measuring apparatus is presented. One basic element included is a so called scalp electrode which has been available and in use for at least 20 years. Normally, a scalp electrode is used for measuring purposes in connection with a CTG device (cardiotocograph) indicating among other things the foetal heart rate and together with a tocodynamometer also uterine contractions. In accordance with the invention the scalp electrode is used also for positioning a temperature transducer. A specifically designed micro sensor, also included in the temperature transducer, forms a second basic element. Said micro sensor preferably is insulated and designed for measuring the temperature in real time with high accuracy. By combining the scalp electrode and the temperature transducer the invention can be used in practice in line with previously known methods of working by the personnel also henceforth. Thus, no further education of the personnel is required in this respect. Also, the use will be cost-efficient because no further education is required and because the sensor can be produced together with other components of the scalp electrode.

The device in accordance with the invention readily can be implemented to- gether with existing monitoring equipment. It will also produce needed foetal information in a way corresponding to information from other categories of patients. The combined device including a scalp electrode and a micro sensor will be very stable mechanically and thus improve the reliability. In use existing personnel can continue to use existing techniques for the placement of the combined device. The scalp elec- trade can be provided with an electrode tip that in use is inserted under the foetal skin.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be further described below by means of embodiments with reference to the accompanying drawings in which

Fig. 1 is a schematic side elevational view of a device in accordance with one embodiment of the invention, Fig. 2 is a schematic perspective view of the device in Fig. 1 ,

Fig. 3 is a schematic perspective view, partly in a longitudinal section, of the device in Fig. 1 somewhat enlarged, and

Fig. 4 is a schematic perspective view of an alternative embodiment of an electrode tip of the scalp electrode.

DETAILED DESCRIPTION

Fig. 1 and Fig. 2 show a practical embodiment of a device in accordance with the invention. In the embodiment shown a standard type scalp electrode 10 is used. The scalp electrode is designed as a circularly cylindrical solid body and is in a first end provided with a helix electrode tip 11. The helix electrode tip 11 extends from an embedded circular section 12 in said first end.

In a central position of the embedded section 12 there is provided a micro sensor 13 for measuring the temperature. The micro sensor is connected to a tem- perature measuring device 14 over a measuring wire 15. The micro sensor 13 is de- signed for real time measuring. One end of the sensor is pointed and extends approximately only 1 mm, thus not being able to harm the foetus. As shown in Fig. 1 the pointed end is located below an upper section of the electrode tip and can be formed as a conventional needle point or a specifically formed needle point, cf. also Fig. 3. A temperature transducer is arranged in the needle point. Preferably the temperature transducer comprises a thermocouple. Data measured by the temperature measuring device 14 can be stored in databases in the temperature measuring device or in another storing unit connected thereto, such as a computer 24. It is possible also to transfer measured data continuously or gradually to another device for analysis.

In a conventional manner the scalp electrode 10 can be provided with an earth terminal 16. A twisted pair wire 17 connects in a conventional manner the electrode tip and the earth terminal, respectively, to a measuring apparatus, which can be integrated with the temperature measuring device 14. As an alternative said earth termi- nal 16 can be connected to an outer lead in the measuring wire 15.

The perspective view in Fig. 2 shows in more detail the helix electrode tip 11 and the micro sensor 13 located in a central position inside the electrode tip. Also the circularly cylindrical shape of the scalp electrode 10 is shown. The micro sensor 13 can be arranged correspondingly with other types of scalp electrodes. In the shown embodiment the earth terminal 16 is formed as a flat plate extending to some extent outside the scalp electrode and centrally through the major part thereof.

Fig. 3 shows in more detail one embodiment of the micro sensor 13 situated in the scalp electrode 10. The micro sensor 13 comprises in this embodiment a tipped end shaped as a conventional needle point 18, which is located centrally in the em- bedded circular section 12. The helix electrode tip 11 forms a circular protection around and above the micro sensor 13.

Inside the needle point 18 there is provided a temperature transducer 19. Preferably a soldered seam 20 made by silver or a similar material connects the temperature transducer 19 to the needle point 18. The measuring wire 15 extends from the temperature transducer 19 and in the shown embodiment the measuring wire 15 is formed by a shielded cable having an inner conductor 21 and a grounded outer conductor 22. An embodiment with a shielded and grounded measuring wire will ensure that the temperature measuring process and the CTG measuring process will not interfere.

The measuring wire 15 runs through an opening 23 extending from a bottom of the scalp electrode 10 opposite the embedded section 12 to a lower section of the needle point 18. The orientation and length of the opening 23 may vary in dependence of the design of the scalp electrode 10 and the earth terminal 16.

Fig. 4 shows schematically a modified electrode tip 24. In this embodiment a modified temperature transducer 25 is integrated in the modified helix electrode tip 24. Thus, no separate needle point for the temperature measuring has to be pro- vided. In other aspects this embodiment corresponds to what was mentioned above. When applying the scalp electrode the temperature transducer 19 will penetrate, in a preferred embodiment, the foetal skin and also will press with some pressure on the foetal skull. As a result of penetrating the skin it is prevented that amni- otic fluid or a part of the body of the mother has an influence on the recording of temperature data. The fixed positioning normally provided by the scalp electrode will ensure that also the temperature transducer is positioned. In other embodiments the micro sensor can be bevelled and be forced to engage at some pressure the foetal scalp in connection with the scalp electrode being screwed under the foetal scalp skin. A further improvement of the monitoring possibilities can be achieved by connecting at least one further temperature transducer to the temperature measuring device 14. The further temperature transducer should be thermally connected to the mother, who can be monitored continuously. Temperature data from the foetus also can be combined with temperature data from the mother and as a result it will be possible to discover relations between different courses of events and types of diseases on one hand and the temperature data on the other hand. Similar advantages can be obtained by combining the device and the method in accordance with the invention with a device and a measuring method for measuring the foetal oxygen level (pulse oximetry).

Claims

1. Device for foetal temperature measuring, c h a ra c t e ri s e d in that a temperature sensing micro sensor (13) is combined with a scalp electrode (10).

2. Device in accordance with claim 1, wherein said scalp electrode (10) comprises a projecting helix electrode tip (11) and wherein said micro sensor (13) is pro- vided in a central position inside said projecting helix electrode tip.

3. Device in accordance with claim 1, wherein said scalp electrode (10) comprises a projecting helix electrode tip (11) and wherein said micro sensor (13) is integrated with said projecting helix electrode tip.

4. Device in accordance with claim 1, wherein said micro sensor (13) is opera- tively connected to a temperature measuring device (14) for measuring temperatures in real time.

5. Device in accordance with claim 4, wherein said temperature measuring device (14) is connected to a storing device for storing measured data in a database.

6. Device in accordance with claim 1, wherein said micro sensor (13) comprises a pointed end (18) projecting from the scalp electrode (10).

7. Device in accordance with claim 1, wherein said micro sensor (13) comprises a temperature transducer (19) arranged thermally in contact with said pointed end (18).

8. Device in accordance with claim 7, wherein said temperature transducer

(19) is soldered to a needle point forming said pointed end (18).

9. Device in accordance with claim 1 , wherein said temperature transducer (19) is a thermocouple.

10. Device in accordance with claim 4, wherein a shielded measuring wire (15) connects said micro sensor (13) to said temperature measuring device (14).

11. Method for foetal temperature measuring, c h a r a c t e ri s e d by performing the temperature measuring and a recording of CTG simultaneously with a common device (10; 13).

12. Method in accordance with claim 11 , further including the step of placing a scalp electrode in contact with the foetal scalp while simultaneously inserting a temperature sensing micro sensor (13) partially under the skin of the foetal scalp.