WO2000035343A1

WO2000035343A1 - Patient monitoring during childbirth

Info

Publication number: WO2000035343A1
Application number: PCT/GB1999/004218
Authority: WO
Inventors: Melanie Carr; Geraldine Ahern
Original assignee: Melanie Carr; Geraldine Ahern
Priority date: 1998-12-14
Filing date: 1999-12-14
Publication date: 2000-06-22
Also published as: AU1673000A; GB2344893A; GB9906203D0

Abstract

First and second belts (40) of stretch resistant non-woven fibrous material are used to attach a cardiotocograph machine to the abdomen of a patient during ante-natal monitoring or during childbirth. The belts are formed with at least one row of apertures extending along the lengths of the belts for attachment to respective transducers via their buttoms (28). The belts may be made of a non-woven material similar to a disposable washcloth material and hence are disposable.

Description

PATIENT MONITORING DURING CHILDBIRTH

The present invention provides an improved cardiotocograph machine for monitoring uterine contractions and foetal heart rate during childbirth fitted with an improved belt for attachment to the patient. It also provides textile belting for use in attachment of transducers of the machine to the abdomen of a patient. A cardiotocograph machine which enables a practitioner to obtain information concerning the existence and rate of a foetal heartbeat, the length, strength and frequency of uterine contractions , and print such data is shown diagrammatically in Figure 1. The machine comprises a housing 10 provided with processing electronics (not shown) and a chart recorder 12 for a patient's contractions or heart rate record. Attached to the housing 10 is a first lead 14 for a first transducer 16 which may be responsive to heart rate. Also attached to the housing 10 is a second lead 18 for a second transducer 20 which may be responsive to uterine contractions. The form of each of the transducers 16, 20 is shown in Figure 2 and comprises a disc-like transducer body 24 having a face 26 to be contacted with the patient's abdomen and a reverse face provided with a button 28 for attachment to a belt 30 by which the transducer can be fitted to the patient by fastening the belt around the patient's body. Traditionally the belt 30 for each transducer 16,20 is manufactured using strong elasticated material and is about 1.5 m in length and about 5 cm in width. However, existing belts suffer from a number of disadvantages:

(a) discomfort can be caused to the patient if a belt is over-tightened and pressure marks can appear on the skin during periods of prolonged use;

(b) the belts have to be used repeatedly on different patients, sometimes without laundering in between patients, which gives rise to a risk of cross- infection; and (c) in the event of an episode of heavy soiling, the belt will need to be washed, generally by the medical or ancillary staff, but it is not clear how effective this washing is in reducing the risk of cross-infection.

Disposable washcloth material is well-known in hospitals, and such material is available e.g. from Read Schilling of Oxford, UK. Similar washcloth material is known for domestic use, e.g. to make J-cloths (Trade Mark) and the like. There is extensive literature concerning the manufacture of non-woven fabric material of this general kind. For example, US Patent No. 3485706 discloses a textile-like non-woven fabric of fibres locked into place by fibre interaction so as to produce a fabric that is coherent and resistant to stress . The fabric has a regular repeating pattern of regions of higher local fibre density and interconnecting fibres that extend between the regions of higher density, and these regions may be arranged in a regular pattern to provide a fabric having an appearance similar to that of a conventional woven fabric, the pattern being for example a square mesh or a triangular mesh. The fibre interlocking is brought about by subjecting a fibrous web to high-pressure jets of water, and the fibres may be, for example, rayon staple, polyethylene terephthalate filaments, mixtures of acrylic and rayon staple fibres, polypropylene fibres and the like.

A non-woven fabric patterned with a regularly distributed pattern of apertures is disclosed in patent specification No. GB-A-2200927 , and the use of water jets to enable the fibres to be entangled without the use of any binder is described. The base weight of the non- woven fabric may be from 50 to 120 g/m², and the fibre material is not critical, both hydrophobic fibres such as polyester or polypropylene fibres and hydrophillic fibres such as rayon being usable.

Patent Specification No. EP-A-0084963 discloses a wiping cloth material made from a substantially isotropic web of lightly entangled rayon staple fibres containing a small amount of adhesive binder uniformly distributed throughout the web. In the examples, fabrics are produced having a weight of 67.8g/m², and there are produced wiping cloths which can be used to clean kitchens, restaurants, fast food establishments, ice cream counters and other locations where it is desirable to have a wiping cloth which is resistant to staining after repeated use.

An elastic non-woven bandaging material is currently available under the Registered Trade Mark "Cohfast" from Robinson Healthcare Limited of Cheltenham, Gloucestershire, England. This material is non-latex cohesive bandage and is intended to be applied as an outside layer in a "four-layer bandage". The bandage is a non-woven fabric through which a series of parallel elastic strands extend in the longitudinal direction of the bandage. The bandage is impregnated with an adhesive material such that the bandage will stick to itself, but will not adhere to other bandages or to the patient's tissue . The disclosure of these references, which are cited by way of example only, is incorporated herein by reference. Such non-woven materials have not, however, been used for the purpose described below.

The present invention is based on the idea that non- woven material of the general kind which is used in washcloths can be formed into single-ply or multi-ply belting and used to attach the transducers of a cardiotocograph machine to the patient's abdomen for monitoring contractions and heart rate during childbirth. Materials of this kind have an advantageous combination of properties . They are strong enough to provide a secure attachment, they are soft enough to be comfortable in use, and they are sufficiently inexpensive to be disposable. The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 represents a cardiotocograph machine; Figure 2 shows how a transducer of a conventional cardiotocograph machine is attached to a conventional webbing belt;

Figure 3 diagrammatically shows a belt according to the invention; Figure 4 is a section of the belt on the line A-A of

Figure 3; and

Figures 5 and 6 show the belt in use in attaching transducers to the abdomen of a patient during childbirth and/or ante-natal monitoring. Figure 7 is a perspective view of an alternative construction of the belting material.

In Figures 3 and 4 there is shown a belt made of the disposable non-woven washcloth material which is available from Reed Schilling and others . The belting may alternatively be manufactured from "Cohfast" material. The belt material 40 is doubled over as seen in Figure 4 and is fastened together e.g. by overlooking, sewing or by heat bonding at a longitudinal seam 42 to provide a two-ply material . The resulting belting is of width 10 cm and is formed with apertures 42 along its mid-line which may conveniently be about 1.5 cm long with an inter-aperture spacing of 2 cm.

The apertures may be formed by a conventional buttonholing operation, whereby the two layers of non- woven fabric are sewn together around a slit. Alternatively, in non-woven fabrics made from thermoplastic materials, a central region of the belting may be heat-sealed to provide reinforcement and slitted to form the apertures 42. The heat-sealing will reduce the tendency of the fabric to tear from the ends of the slits. Alternatively the slits may be in a 'dumb bell' shape made with rounded ends to resist tearing. This combination of apertures and spaces allows the belts to be anchored on the transducer button 28, with the remainder of the belt being brought around the patient's back and fastened again onto the transducer button 28 as shown in Figures 5 and 6. The belting 40 thereby enables the transducers 16,20 to be held securely in position on the patient, allowing the foetal heart and contractions to be monitored as required. Two or more lengths of belting may be secured to each transducer, if required, to position the transducer in relation to the patient's body. The belting may be provided in the form of a continuous roll of material, which may be cut to length extemporaneously as required. Conveniently, however, it may be provided in lengths of approximately 185 cm, which can provide a standard patient length which can be used for fitting a wide range of patients on the basis that 'one size fits all'.

The use of a non-woven material of weight e.g. 50 - 150g/m² such as washcloth material as set out above enables the belting to be sufficiently inexpensive that it is disposable. The disposable belting significantly reduces the risk of cross-infection, and avoids the labour of washing soiled belting and the consequential risk of cross-infection. The non-woven material may be made wider than the conventional straps and the material itself is less aggressive so that the risk of discomfort and pressure marks is lessened. The belt material is soft and allergy free. The volume of material used in each belt is relatively small, so that disposability and production of large volumes of clinical waste is not a problem. If, as is preferred, the belting is made of a cellulosic material such as rayon, it is biodegradable. The disposability of the present belting provides reassurance for the patient because she will be aware that she has the sole use of this particular item of equipment .

The belting is preferably both wider and longer than conventionally used straps, and provides a more secure anchorage of the transducers on the patient's abdomen. The patient therefore has more freedom of movement. A range of belt widths of 5 cm and above is permissable. However, we have found that a width of approximately 10 cm is very effective, and further increase in belt width has been found to be uncomfortable for the patient and impracticable in use.

The belting may be provided in packs or envelopes containing two individual belts which are pre-cut to length. Provision of two belts per pack is preferred because the machine conventionally monitors both fetal heart rate and uterine contractions.

An alternative form of the belting is shown in Figure 7. In this embodiment, the belting is formed from a single strip of fabric by first making a series of longitudinally extending folds, and then securing the fabric .

The belting is formed from a fabric strip by first folding a first edge region 50 so as to overlie a central area M of the strip. A hem H is folded over on the second edge region 51, and the second edge region is then folded so that hem H overlies the central area M of the strip. The resulting folded structure has no exposed fabric edges , and at its central area M forms a four-ply structure. The absence of exposed edges allows the overlooking step to be dispensed with.

In this four-ply central area, two rows of openings

B, B' are formed in staggered relationship, allowing for finer adjustment of the position of the transducer relative to the belt. In the previous embodiment, a single series of buttonholes or openings is formed along the mid-line of the belting. The transducer is fixable only at points corresponding to the pitch of the series of buttonholes . In the embodiment illustrated in Figure

7, two rows of buttonholes B and B' are symmetrically positioned about the mid-line, and the positioning of the buttonholes of one row coincides with the spacing between buttonholes of the other row. The transducer can thus be attached to the belt at a number of positions spaced longitudinally of the belt by a distance equal to half the pitch of the buttonholes in a row.

In further embodiments, not illustrated, it is foreseen that three or more rows of buttonholes may be formed to extend along the belting. Preferably the rows are positioned in an array of symmetrical about the mid- line of the belting, and the buttonholes in each row are staggered relative to the other rows by 1/n of the buttonhole pitch, where n is the number of rows of buttonholes . Belts having differing number of rows of apertures may be used together to fasten respective transducers to a patient. The belts may be printed with indicia such as user instructions or advertising material, and may be colour coded to distinguish patient length belts of different sizes, or to distinguish belts having apertures of different sizes or spacing pitch, or different numbers of rows of apertures .

Claims

1. A cardiotocograph machine for monitoring uterine contractions and foetal heartbeat during birth, comprising: a housing; first and second transducers connected by wires to the housing, each transducer comprising a plate for contact with the human body and a button facing away from the plate; and first and second belts of non-woven fibrous material formed with apertures at intervals therealong for attachment to respective transducers via their buttons at two spaced positions selected to fit a patient.

2. A machine according to claim 1, wherein the belts are stretch-resistant.

3. A machine according to claim 1 or claim 2, wherein the belts are elastic.

4. A machine according to any preceding claim, wherein the belts are of width about 10 cm.

5. A machine according to any preceding claim, wherein the belts are of length about 180 - 200 cm.

6. A machine according to any preceding claim, wherein the belts are formed along their respective mid-lines with a series of apertures of length about 1.5 cm and of spacing about 2 cm.

7. A machine according to claim 6, wherein at least one of the belts is formed with two rows of apertures.

8. A machine according to claim 7 , wherein the two rows of apertures are symmetrically disposed about the mid- line.

9. A machine according to claim 7 or claim 8, wherein the spacing between adjacent apertures in each of the rows of apertures of the said at least one belt is the same.

10. A machine according to claim 7 or claim 8, wherein the apertures in one of the rows of the said at least one belt are displaced relative to the apertures in the other row.

11. A machine according to claim 6, wherein at least one of the belts is formed with three or more rows of apertures, the rows being arranged symmetrically about the mid-line of the belt.

12. A machine according to any preceding claim, wherein the fibrous material is cellulosic.

13. A machine according to claim 12, wherein the fibrous material is rayon.

14. A machine according to any of claims 1 to 11, wherein the fibrous material is of nylon, polyester, polypropylene or acrylic fibres or of a blend of any of the above with cellulosic fibres.

15. A machine according to any preceding claim, wherein the belt is single-ply.

16. A machine according to any of claims 1 to 14, wherein the belt is of a single sheet folded and fastened together along an edge to give two ply material.

17. A machine according to claim 16, wherein the belt is formed from a single sheet by folding edge regions of the sheet to overlie a central region.

18. For use with a cardiotocograph machine as defined in any preceding claim, belting of non-woven fibrous material formed with apertures therealong at intervals for attachment to transducers of the machine.

19. The belting of claim 18, wherein the belting is stretch-resistant .

20. The belting of claim 18 or claim 19 wherein the belting is elastic.

21. The belting of any of claims 18 to 20, which is a needle-bounded or hydro-entangled textile-like non-woven fabric .

22. The belting of any of claims 18 to 21, in the form of a roll of material to be cut to length.

23. The belting of any of claims 18 to 21 in the form of a patient length of material.

24. A single use pack comprising two patient lengths of the belting of any of claims 18 to 21.

25. A method of monitoring uterine contraction and foetal heartrate during birth which comprises providing a cardiotocograph machine of any of claims 1 to 16 and attaching the transducers to the patient's abdomen by means of the first and second belts.