WO2007057625A1

WO2007057625A1 - Amnioscope

Info

Publication number: WO2007057625A1
Application number: PCT/GB2005/004463
Authority: WO
Inventors: Phillip M. Barclay; Salli Ann Merola
Original assignee: Barclay Phillip M; Salli Ann Merola
Priority date: 2005-11-18
Filing date: 2005-11-18
Publication date: 2007-05-24
Also published as: EP1948001A1

Abstract

A disposable amnioscope (1) comprising an elongate tubular member (9) having a light source (10) fixed therein and power source (15) for the light source (10) fixed thereto. The light source (10) is arranged to be illuminated automatically when an obturator (2) is withdrawn from the amnioscope (1). The amnioscope (1) is supplied sealed within the sterile package (20).

Description

Amnioscope

The present invention relates to an amnioscope for use in fetal blood sampling.

Fetal blood sampling (FBS) is a useful tool for the diagnosis of fetal distress, where delivery is contemplated because of an abnormal heart rate, and in the case of suspected fetal acidosis.

Recent observations would suggest that about 30% of all equivocal fetal heart rate (FHR) patterns should be sampled for FBS pH values or lactate. In order to provide a trend of pH or lactate value, 20 minute sample intervals are recommended. Further investigation of reported figures suggests that currently only approximately 3-5% of equivocal FHR patterns are sampled for pH values, far below the recommended incidents. This may result in increased levels of caesarean section rates.

In known techniques for fetal blood sampling an amnioscope made of, for example, stainless steel or other materials is used to provide access to the fetal scalp. The amnioscope is provided with a removable obturator to assist with the positioning of the amnioscope against the fetal scalp to avoid entrapment of internal tissues. The obturator also serves to ameliorate insertion of the amnioscope into the birth canal .

When the amnioscope is in the correct position the obturator is removed. An external light source is then used to illuminate the fetal scalp. An area of the scalp is then cleaned and incised to allow a blood sample to be taken.

Commonly, fetal blood sampling techniques require the use of a fibre optic light source to illuminate the fetal scalp. However, because existing fibre optic systems are cumbersome and often require complex components to be assembled prior to use, in practice, obtaining fetal blood samples can be a complicated and time consuming process requiring considerable manpower. In addition, since there is often no easy access to fibre optic equipment in Obstetrics, it is often not possible to illuminate the fetal scalp in this way. As a result fetal blood sampling is not carried out as regularly as it could be.

An alternate technique which has been adopted is to use an amnioscope and illuminate the fetal scalp with a hand held torch. This is often problematic as the torch obstructs access to the amnioscope thereby making incision of the scalp and collection of the blood sample difficult. This is aggravated by the fact that it is generally necessary for the torch to be held by a second person. The need for an additional person therefore complicates the procedure and increases the manpower required.

United States patent number US 6,423,011 discloses a method of illuminating the fetal scalp by attaching a light source and a power source to the interior of an amnioscope with a clip. The light source, power source and clip are removable to allow sterilisation and re-use of the amnioscope. Therefore, before the fetal scalp can be illuminated with the apparatus disclosed in US 6,423,011, the separate components must be located and assembled. In addition, it must also be established that each of the components is working following any previous uses.

According to the present invention there is provided a disposable amnioscope comprising an elongate tubular member having a light source fixed therein and a power source for the light source fixed thereto.

The amnioscope of the present invention provides the benefit that it is ready for immediate use without the need to provide an external light/power source or assemble separate components prior to use. The fixed nature of the light source ensures that the light is properly directed and, since the amnioscope is a disposable device, the power source will not have been run down by previous uses.

In a preferred example the amnioscope comprises an elongate obturator member removably located within the amnioscope. As mentioned above, the obturator assists with the positioning of the amnioscope against the fetal scalp, to avoid entrapment of internal tissues, and ameliorates insertion of the amnioscope into the birth canal .

Preferably the light source is arranged to be illuminated automatically when the amnioscope is prepared for use, for example on removal of the Obturator.

This arrangement is advantageous as it simplifies use of the amnioscope for medical staff by removing the need to perform a separate step in order to illuminate the light source . To achieve this, the amnioscope may be provided for example with a motion sensitive switch or light sensitive switch.

In a preferred example the light source is a light emitting diode (LED) . LEDs are cheap, compact, readily- available light sources which can operate from similarly cheap, compact batteries. LEDs are therefore ideally suited for use in a disposable apparatus such as the amnioscope of the present invention. In an alternative example the light source and power source comprise a chemical light.

Preferably the light source is a non-replaceable single use light source and the power source is a non-replaceable single use power source. The use of non-replaceable single use components allows the design and construction of the amnioscope to be simplified, thereby reducing manufacturing costs and increasing its suitability for disposal after use.

In a preferred example the amnioscope is sealed in a sterile package. This has the advantage that the amnioscope is supplied in a sterile condition and is available for immediate use .

Examples of an amnioscope in accordance with the present invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a sectional view of the disposable amnioscope sealed within a sterile package; Figure 2 is an isometric view of the disposable amnioscope of Figure 1 and

Figure 3 is an exploded isometric view of the amnioscope of Figure 1.

Figure 1 shows a disposable amnioscope 1 comprising an elongate tubular member 9. The amnioscope 1 is generally frustoconical in shape and approximately 14cm in length. The proximal end 13 of the amnioscope 1 typically has a diameter of approximately 5.2cm and the distal end 12 typically has a. diameter of approximately 3.3cm. The amnioscope 1 will generally be fabricated from a plastics material such as, for example, ABS (Acrylonitrile butadiene styrene) or other similar materials. However, the amnioscope 1 may be fabricated from any other suitable material such as stainless steel .

The amnioscope 1 further comprises a light emitting diode (LED) 10, a magnetically operated reed switch 7 and battery 15 located within an adapter 14 which is fixed to the interior proximal end of the elongate tubular member 9.

An elongate obturator 2 is removably disposed within the amnioscope 1. As shown in Figure 3, the obturator 2 comprises a domed distal end 4, a proximal end 11 comprising a D-shaped handle 3 and a connecting stem 5. The domed distal end 4 of the obturator 2 is arranged to fit within the distal end 12 of the amnioscope 1, and the proximal end 11 is arranged to fit within the proximal end 13 of the amnioscope 1. The obturator 2 further comprises a magnet 6 located within the proximal end 11. Prior to use the obturator 2 is positioned within the amnioscope 1. In this configuration the magnet 6 is positioned adjacent to the magnetically operated reed switch 7, thus causing the magnetically operated reed switch 7 to be held in the open position. Therefore, when the obturator 2 is in place within the amnioscope 1, the LED 10 is disconnected from the battery 15.

Figure 1 shows the disposable amnioscope 1 sealed within a sterile package 20. The amnioscope 1 will ideally remain sealed within the sterile package 20 until it is required for use. When required, the amnioscope 1 is removed from the sterile package 20.

In use, the amnioscope 1 is inserted into the birth canal. When the distal end 12 of the amnioscope 1 is in the correct position against the fetal scalp the obturator 2 is withdrawn. Withdrawal of the obturator 2 causes the magnet 6 to be separated from the magnetically operated reed switch 7. The magnetically operated reed switch 7 is therefore able to close and connect the battery 15 to the LED 10 causing the light emitting diode to illuminate. The fetal blood sample may then be taken.

The disposable amnioscope 1 may be reused with the same patient as many times as necessary during delivery of the fetus. The life of the battery is typically four hours thus generally providing sufficient time for multiple uses _swith the same patient during delivery of the fetus . Should the battery life prove to be insufficient, the amnioscope 1 may simply be disposed of and a new amnioscope 1 used in its place. The disposable nature and ease of use of the amnioscope 1 therefore facilitates the collection of as many fetal blood samples as is deemed necessary.

The connection of the battery 15 to the LED 10 may be accomplished by the use of any suitable motion sensitive switch in place of the magnetically operated reed switch 7 described above .

In a second example, the amnioscope 1 may comprise a light sensitive switch (not shown) as an alternative to the magnetically operated reed switch or motion sensitive switch described above. The light sensitive switch may be located within the amnioscope 1 in order to illuminate the LED upon withdrawal of the obturator 2. Alternatively, the light sensitive switch may be located on the exterior of the amnioscope 1 in order to illuminate the LED when the sterile package 20 is opened.

In a further alternative example, the light source and power source of the amnioscope 1 may comprise a chemical light (not shown) . As is well known in the art, chemical lights are illuminated when a frangible member within the chemical light is broken thus causing two chemical substances within the chemical light to mix and thereafter fluoresce. In this alternative example the chemical light may be arranged to illuminate upon withdrawal of the obturator 2 from the amnioscope 1, or upon opening of the sterile package 20.

Because of its basic shape, the amnioscope 1 may, if necessary, be used as a conventional amnioscope, i.e. with a re-usable detachable fibre optic light source and light adapter.

Claims

Claims :

1. A disposable amnioscope comprising an elongate tubular member having a light source fixed therein and power source for the light source fixed thereto.

2. An amnioscope according to claim 1 further comprising an elongate obturator member removably located within the amnioscope .

3. An amnioscope according to either of claims 1 or 2 wherein the light source is arranged to be illuminated automatically when the amnioscope is prepared for use.

4. An amnioscope according to claims 2 and 3 wherein the light source is arranged to be illuminated automatically when the obturator is withdrawn from the amnioscope.

5. An amnioscope according to either of claims 3 or 4 further comprising a motion sensitive switch to automatically illuminate the light source when the amnioscope is prepared for use.

6. An amnioscope according to either of claims 3 or 4 further comprising a light sensitive switch to automatically illuminate the light source when the amnioscope is prepared for use .

7. An amnioscope according to any preceding claim wherein the light source is a light emitting diode.

8. An amriioscope according to any one of claims 1, 2, 3 or 4 wherein the light source and power source comprise a chemical light.

9. An amnioscope according to any preceding claim wherein the light source is a non-replaceable single use light source .

10. An amnioscope according to any preceding claim wherein the power source is a non-replaceable single use power source .

11. A combination of the amnioscope of any preceding claim and a sterile package, wherein the amnioscope is sealed within the sterile package.

12. A combination according to claims 3 and 10 wherein the light source is arranged to be illuminated automatically when the sterile package is opened.