WO2019109136A1

WO2019109136A1 - Obstetrical vacuum apparatus

Info

Publication number: WO2019109136A1
Application number: PCT/AU2018/051293
Authority: WO
Inventors: Pek Joo TEOH
Original assignee: JCT Solutions Pty Ltd
Priority date: 2017-12-07
Filing date: 2018-12-04
Publication date: 2019-06-13

Abstract

An obstetrical vacuum apparatus (10) for operatively applying traction to a fetal head (18), comprising a fetal vacuum cup (12) defining at least one chamber (14) in which a negative pressure or vacuum enables operative attachment of the cup (12) to a fetal head (18), and a housing (20) comprising a body portion (20.1) and a handle portion (20.2). The housing (20) includes a negative pressure generator (22), a controller (26), and a mass arrangement (54) configured to determine a centre of mass (42) of said housing (20). Apparatus (10) also includes a flexible tube (28) in fluid communication with the negative pressure generator (22) to operatively define an axis of (traction 40) along the tube and passing through said handle portion (20.2) with the centre of mass (42) on or below the axis of traction (40) when in use to allow ergonomic manipulation of said obstetrical vacuum apparatus (10).

Description

OBSTETRICAL VACUUM APPARATUS

TECHNICAL FIELD

[0001] This invention relates to an obstetrical vacuum apparatus for operative releasable attachment to a fetal head, and an associated obstetrical method for applying traction to a fetal head.

BACKGROUND ART

[0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

[0003] The present invention lies in the field of obstetrics, in general. Currently, there are two major methods for delivering a fetus, namely the Caesarean section delivery and the vaginal delivery .

[0004] In Caesarean section deliveries, the fetus is delivered through an incision made in the uterus and a corresponding incision made in the abdomen. An upward pulling force is required in order to pull the fetus through the incisions and out of the mother. Often the force is provided by the doctor's hands directly pulling the fetus through the abdominal incision.

[0005] In vaginal deliveries, the fetus is delivered through the vaginal passage after the cervix has fully dilated and effaced. [0006] Passing the fetus through the vaginal passage requires that the vaginal muscles be forced to stretch as the fetal head is generally much larger than the vaginal passage under normal circumstances. Some stretching force is applied to the vaginal tissues by the mother herself. The involuntary contractions of the uterus during labour push the fetus (typically the fetal head) into the vaginal passage to stretch the vaginal tissues. The stretching force of these involuntary uterine contractions is combined with the stretching force caused by voluntary contractions of the mother' s abdominal muscles as the mother tries to push the fetus out of the uterus.

[0007] Often the forces described above are not strong enough or are not medically advisable to use in extracting the fetus. Supplementary force may be applied with a fetal vacuum extractor, for example, in conditions of dystocia (i.e., slow or difficult labour or delivery) , uterine inertia, maternal exhaustion, maternal distress, or fetal distress.

[0008] In a conventional fetal vacuum extractor, a vacuum cup is sealed over a portion of the fetal head (e.g., the occiput) . A flexible tube connects the vacuum cup to a vacuum pump operated by a secondary operator such as a nurse. The vacuum pump allows the nurse to provide a vacuum within the vacuum cup thereby creating suction between the fetal head and the vacuum cup. As long as a sufficient vacuum is maintained, the primary operator, such as a doctor, may pull on the vacuum cup handle thereby applying traction (i.e., a pulling force, a delivering force, a traction force, etc.) to the fetal head.

[0009] The degree of vacuum determines the traction forces. Effective traction usually requires a pressure of at least -0.6 kg per cm² (440 mm Hg) . Although more negative pressure reduces the risk of vacuum cup detachment, lowering the pressure beyond -0.8 kg per cm² (588 mm Hg) increases the risk of fetal scalp and cerebrocranial trauma.

[ 0010 ] Bodily fluids on the fetal head generally assist in making a seal between the fetal head and the vacuum cup to define a vacuum chamber. However, a vacuum so established is sometimes compromised by an imperfect seal between the fetal head and the vacuum cup. In order to minimise the chances of fetal injury, the vacuum can be intentionally lowered between contractions or when the vacuum is determined to be too strong. Therefore, the vacuum is generally constantly monitored and adjusted, and must have a feature to release or lower the vacuum when necessary.

[ 0011 ] U.S. Pat. No. 6,074,399 describes an obstetric vacuum extractor comprising a suction cup, handle and a manually manoeuvred vacuum pump, which parts are delivered as one unit. This prior art vacuum extractor requires a specially configured hand pump, which leads to complicating the manufacturing process. The manufacture is further expensive, in particular when the suction device is made as a disposable item, leading to an expensive product when bought. In addition, if the seal is broken, the operator has to manually pump the device to return to the desired vacuum pressure; the pumping procedure often consumes the precious few seconds the operator has to apply traction to deliver the baby before the contraction subsides. Due to this shortcoming, a number of obstetricians opined this invention as not the most effective instrument for vacuum delivery.

[ 0012 ] A further shortcoming in the art is a need to mitigate complications that may arise from an imperfect seal with a fetal head. As such, the Applicant has identified a shortcoming in the art for an improved obstetrical vacuum apparatus that is ergonomic and simple to use, safe, and provides improved mobility and handling whilst being able to provide the negative pressure needed .

[0013] A yet further shortcoming in the art of conventional obstetrical vacuum apparatus is the general need for an operator, such as a delivering physician, to apply a "resting" manual downward traction on the fetal head in-between uterine contractions to prevent the fetal head from retracting back into the womb .

[0014] As a result, there exists a need in the art for an obstetrical vacuum apparatus which is fully operable by a single user, such as the delivering physician, without any assistance and in a limited timeframe, whilst addressing issues concerning fetal head retraction due to uterine contractions and providing ergonomic and efficient fetal delivery.

[0015] The current invention was conceived with these shortcomings in mind.

SUMMARY OF THE INVENTION

[0016] According to an aspect of the invention there is provided an obstetrical vacuum apparatus for operatively applying traction to a fetal head, said apparatus comprising:

a fetal vacuum cup defining at least one chamber in which a negative pressure or vacuum enables operative attachment of the cup to a fetal head;

a housing comprising a body portion and a handle portion and having :

i) a negative pressure generator configured to operatively generate such negative pressure or vacuum within the chamber; ii) a controller configured to control the generator to automatically maintain a desired negative pressure value within said chamber; and

iii) a mass arrangement configured to determine a centre of mass of said housing; and

a flexible tube arranging said chamber in fluid communication with the negative pressure generator;

wherein the flexible tube is fast with the body portion to operatively define an axis of traction along the tube and passing through said handle portion with the centre of mass on or below the axis of traction when in use to allow ergonomic manipulation of said obstetrical vacuum apparatus.

[0017] Typically, the mass arrangement is user-configurable to allow adjustability of said centre of mass.

[0018] In one embodiment, the mass arrangement comprises the negative pressure generator and/or the controller.

[0019] In an embodiment, the mass arrangement comprises a mass receptacle defined by the housing, and at least one removable mass for operative placement within said mass receptacle.

[0020] Typically, the mass arrangement is selected to fall in the range of 50g to 500g, preferably lOOg to 300g, and most preferably 150g to 250g.

[0021] The skilled addressee is to appreciate that the mass arrangement typically facilitates in the prevention of fetal head retraction due to uterine contractions, i.e. obviates the manual application of a "resting" downward traction on the fetal head, as is conventionally required. [0022] Typically, the handle portion is arranged transverse to the body portion so that when said handle is grasped by a user, the axis of traction lies substantially parallel or coaxial with a forearm of said user.

[0023] Typically, the housing includes a user input configured to allow selection of the desired negative pressure value.

[0024] Typically, the user input is located on the handle such that the user is able to manipulate said input ergonomically with a thumb whilst grasping the handle.

[0025] It is to be appreciated that the housing is typically sized, shaped and dimensioned for one-handed operation.

[0026] In one example, the flexible tube comprises a pulling member .

[0027] Typically, the pulling member comprises a cable threaded through the tube for providing mechanical strength whilst allowing tube flexibility.

[0028] Alternatively, the pulling member comprises walls of the flexible tube having a wire or nylon braided weave for providing mechanical strength whilst allowing tube flexibility.

[0029] Typically, the apparatus comprise a traction force indicator configured to indicate a value of traction applied to the pulling member.

[0030] In one example, the traction force indicator includes a strain gauge. [0031] In one example, the apparatus includes a negative pressure or vacuum release valve configured to release or minimise a vacuum or negative pressure within the vacuum cup chamber.

[0032] Typically, the negative pressure or vacuum release valve is controlled by the controller.

[0033] In one example, the negative pressure generator comprises an electromechanical pump configured to extract fluid from the chamber in the vacuum cup.

[0034] In one example, the controller is configured to control the generator to automatically maintain the selected negative pressure value within said chamber by increasing a negative pressure generation capability of the generator to accommodate an unwanted negative pressure decrease within the chamber.

[0035] Similarly, in one example, the controller is configured to control the generator to automatically maintain the selected negative pressure value within said chamber by decreasing a negative pressure generation capability of the generator to accommodate an unwanted negative pressure increase within the chamber .

[0036] In one example, the controller is configured to activate the release valve to accommodate an unwanted negative pressure increase within the chamber.

[0037] In an embodiment, the controller includes a traction sensor configured to sense a traction force applied along the flexible tube, the negative pressure generator configured to automatically vary the negative pressure value according to the traction force sensed by the traction sensor. [0038] In an embodiment, controller is configured to automatically control the generator to vary the negative pressure value between a higher, attachment value (where the negative pressure value is just sufficient to maintain attachment of the cup to the fetal head) and a lower, traction value (where the negative pressure value allows traction applied to the fetal head) . For such negative pressure values, it is to be appreciated that 'lower' refers to further away from zero, and 'higher' refers to closer to zero, where zero equals no negative pressure.

[0039] In an embodiment, the attachment value of the negative pressure value is more than or equal to -0.6 kg per cm² (440 mm Hg) .

[0040] In an embodiment, the traction value of the negative pressure value is less than the attachment value and less than or equal to -0.8 kg per cm² (588 mm Hg) .

[0041] In an embodiment, the traction value of the negative pressure value is less than -0.8 kg per cm² (588 mm Hg) .

[0042] In an embodiment, the fetal vacuum cup includes an orientation indicator configured to provide operative indication of rotation of the fetal head during delivery.

[0043] In an embodiment, the orientation indicator comprises at least one light emitting diode (LED) arranged on the fetal vacuum cup .

[0044] In one embodiment, the flexible tube includes an adjustor configured to adjust a length of the tube between the vacuum cup and the housing to facilitate operative distance adjustability between the vacuum cup and the handle portion. [0045] In an embodiment, the adjustor includes a spool-type adjustor whereby the tube can be spooled or unspooled to adjust the length thereof.

[0046] In an embodiment, the adjustor is configured to allow automatic and/or manual adjustment of the tube length.

[0047] In an embodiment, the adjustor includes an orientation sensor configured to sense an orientation of the housing, wherein the adjustor is configured to automatically adjust the tube length according to the sensed orientation.

[0048] Typically, the controller is configured to provide an indication when the vacuum cup has been attached to the fetal head for a predetermined amount of time.

[0049] According to a second aspect of the invention there is provided an obstetrical method for applying traction to a fetal head, said method comprising the steps of:

providing apparatus in accordance with the first aspect of the invention;

attaching a vacuum cup of said apparatus to the fetal head; and

applying traction to the fetal head via said apparatus to facilitate in fetal delivery.

BRIEF DESCRIPTION OF THE DRAWINGS

The description will be made with reference to the accompanying drawings in which: Figure 1 is a perspective-view diagrammatic representation of one example of an obstetrical vacuum apparatus in accordance with an aspect of the invention;

Figure 2 is a perspective-view diagrammatic representation of the obstetrical vacuum apparatus of Figure 1;

Figure 3 is side-view diagrammatic representation of the obstetrical vacuum apparatus of Figures 1 and 2;

Figure 4 is a further side-view diagrammatic representation of the obstetrical vacuum apparatus of Figures 1 and 2;

Figure 5 is a front-view diagrammatic representation of the obstetrical vacuum apparatus of Figures 1 and 2;

Figure 6 is a perspective-view diagrammatic representation of a yet further example of an obstetrical vacuum apparatus in accordance with an aspect of the invention;

Figure 7 is a perspective-view diagrammatic representation of another example of an obstetrical vacuum apparatus in accordance with an aspect of the invention; and

Figure 8 is a side-view diagrammatic representation of a general example of an obstetrical vacuum apparatus in accordance with aspects of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0050] Further features of the present invention are more fully described in the following description of several non limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention to the skilled addressee. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. In the figures, incorporated to illustrate features of the example embodiment or embodiments, like reference numerals are used to identify like parts throughout.

[0051] With reference firstly to Figure 8 of the accompanying figures, there is shown a broad and general example of an obstetrical vacuum apparatus 10. As discussed in the background above, the apparatus 10 is typically used in the delivery of a fetus, as is well-known in the art. In the embodiment exemplified, a portion of a fetal head is generally indicated by reference numeral 18.

[0052] Accordingly, the apparatus 10 generally includes a fetal vacuum cup 12 that defines at least one chamber 14, as shown. The vacuum cup 12 also typically includes a seal 16 for assisting in establishing a fluid-tight seal between the chamber 14 of the cup 12 and the fetal head 18. Such a seal 16 is typically of a soft material, such as silicone, rubber, a polymer material, or the like. It is to be appreciated that a negative pressure or vacuum created, made or established within the chamber 14 generally enables operative attachment of the cup 12 to the fetal head 18, i.e. sucks the cup 12 onto the fetal head 18.

[0053] The apparatus 10 also includes a housing 20 which, in a preferred embodiment, generally has a negative pressure generator 22, a user input 24, a controller 26, a traction force indicator 34, energising means 36, and a release valve 38, as shown. As shown in more detail later on in this description, the housing 20 typically comprises a body portion 20.1 and a handle portion 20.2. a [0054] The apparatus 10 further comprises a flexible tube 28 which connects, links or arranges the vacuum cup's chamber 14 in fluid communication with the negative pressure generator 22. In various embodiment, the apparatus 10 may also comprise a traction sensor 44, an orientation indicator 46, and a tube adjustor 48 as will be described in more detail below.

[0055] As such, the negative pressure generator 22 is configured to operatively generate a negative pressure or vacuum within the chamber 14 of the cup 12. The negative pressure generator 22 typically generates a vacuum by extracting fluid, such as air, from the chamber 14 in the vacuum cup 12. Such a generator 22 may include an electro-mechanical motor or pump, as is generally known in the art. It is, however, to be appreciated that the generator 22 is preferably a small, high-powered device, as the apparatus 10 is ideally configured for mobile, hand-held, one-handed operation.

[0056] In one embodiment, the user input 24 enables a user to select a specific or desired negative pressure value and also typically enables activation or deactivation of the apparatus 10, i.e. an on/off switch. For example, depending on obstetrical requirements, one particular negative pressure value may be appropriate under certain circumstances, with another value more appropriate under different circumstances.

[0057] A size or position of the fetal head 18 may, for example, require a specific negative pressure value, e.g. a smaller fetal head may benefit from a smaller negative pressure value, whereas a larger fetal head may require a larger negative pressure value. Similarly, a required traction force exertable via the apparatus is typically directly proportional to the selected negative pressure value. Such obstetrical practices are generally known in the art and will not be described in any particular detail herein. [0058] In one example, the user input 24 may comprise a plurality of buttons or similar selection means, e.g. fine-tuning buttons and buttons denoting set pressure values commonly used in practice. For example, such set pressure values (with associated buttons) may include one button at -0.2kg/cm² and one at -0.8kg/cm². The user input 24 may also include a pressure release button, activation of which deactivates the generator 22, and/or activates a vacuum release valve 38 (described in more detail below) . The skilled addressee will appreciate that other configurations for the user input 24 may be possible, i.e. a dial, a knob, buttons, wireless selection, touchscreen input, audio input, etc. As shown in Figure 2, the user input 24 is preferably located on the handle 20.2 such that the user is able to manipulate said input 24 ergonomically with a thumb whilst grasping the handle.

[0059] In one embodiment, the controller 26 is generally configured to receive such user input and to subsequently control the generator 22 in order to automatically maintain the selected negative pressure value within the chamber 14 of the cup 12. In such a manner, the controller 26 is able to automatically accommodate any operating pressure variations within the chamber 14, whereby the apparatus 10 enables a user to apply a traction force to the fetal head 18 without having to constantly monitor and control the generated negative pressure.

[0060] It is to be appreciated that any such operating pressure variations may result from a variety of external aspects, such as an imperfect seal between the vacuum cup 12 and the fetal head 18, fluid leaks developing as a result of movement of the fetal head 18, and/or the like. It is not uncommon for the cup 12 to have an adequate seal on the fetal head 18 at one point or stage of the delivery process, only to later develop an imperfect seal during the process of delivery as traction is applied via the cup 12 to the fetal head 18.

[0061] In a preferred embodiment, the housing 20 is typically sized, shaped and dimensioned for handheld or mobile, hand- portable operation. As a result, the housing 20 is configured to fit into a user' s hand in an ergonomic manner, whereby the user can control the apparatus's operation, i.e. use the user input 24, as well as apply traction to the fetal head 18, all with a single hand.

[0062] In one embodiment, the housing 20 generally defines a separate handle portion 20.2 which is ergonomically sized, shaped and dimensioned to facilitate hand-held operation of the apparatus 10. Typically, the handle portion 20.2 is arranged transverse to the body portion 20.1 so that when said handle 20.2 is grasped by a user, the axis of traction 40 lies substantially parallel or coaxial with a forearm of said user. As shown in the figures, different housing 20, body portion 20.1 and handle portions 20.2 configurations are merely design dependent to provide different options and variations can exist within the scope of the present invention.

[0063] Importantly, the housing 20 further includes a mass arrangement 54 which is generally configured to determine a centre of mass 42 of the housing 20. This mass arrangement 54 is typically user-configurable to allow adjustability of said centre of mass 42, i.e. the user can determine where such centre of mass 42 lies within housing 20 by moving or shifting a location of the mass arrangement 54 within (or even outside) the housing 20.

[0064] In one embodiment, the mass arrangement 54 comprises the negative pressure generator 22 and/or the controller 26 (or energising means 36, described below) . In another embodiment, the mass arrangement 54 comprises a mass receptacle 50 which is defined by the housing 20, and at least one removable mass 52 for operative placement within the mass receptacle 50. In such a manner, a variety of masses 52 can be used and interchanged in order to customise a 'feel', i.e. manoeuvrability determined by placement of the centre of mass 42, of the apparatus 10 according to user requirements.

[0065] Typically, the mass arrangement 54 is selected to fall in the range of 50g to 500g, preferably lOOg to 300g, and most preferably 150g to 250g. The skilled addressee is to appreciate that the mass arrangement typically facilitates in the prevention of fetal head retraction due to uterine contractions, i.e. obviates the manual application of a "resting" downward traction on the fetal head, as is conventionally required. The mass arrangement 54 may be configurable to provide a weight which is subjectively not too heavy for manoeuvrability, yet enough to assist the user by contributing to the residual traction between contractions to prevent the retraction of the fetal head back into the womb.

[0066] The housing 20 also typically includes energising means 36 for providing the negative pressure generator 22 with operating energy. In one example, the energising means 36 may comprise a plurality of electrochemical cells for supplying electrical energy, i.e. a battery. Preferably, these electrochemical cells may be configured to be rechargeable; however, this is not a limiting requirement. In an alternative embodiment, the energising means 36 may also comprise a mains-power inlet with a step-down transformer, or the like. It is to be appreciated that numerous variations of the energising means 36 are possible and will be understood by the skilled addressee. [0067] In a preferred example, the apparatus 10 generally includes a negative pressure or vacuum release valve 38 which is configured to release, minimise or reduce a vacuum or negative pressure within the vacuum cup's chamber 14. Accordingly, such a negative pressure or vacuum release valve 38 is typically controlled by the controller 26 and/or the user. As such, the user input 24 may also be configured to control the vacuum release valve 38, e.g. so that when the apparatus is deactivated, the valve 38 is activated to release the cup 12 from the fetal head 18.

[0068] Generally, when in use, the controller 26 is configured to control the generator 22 to automatically maintain the selected negative pressure value within the chamber 14 by increasing a negative pressure generation capability of the generator 22 in order to accommodate an unwanted negative pressure decrease within the chamber 14.

[0069] Similarly, the controller 26 is typically configured to control the generator 22 to automatically maintain the selected negative pressure value within the chamber 14 by decreasing a negative pressure generation capability of the generator 22 to accommodate an unwanted negative pressure increase within the chamber 14. Alternatively, or in addition, the controller 26 may also be configured to activate the release valve 38 to accommodate an unwanted negative pressure increase within the chamber 14.

[0070] The controller 26 is also typically configured to provide an indication when the vacuum cup 12 has been attached to the fetal head 18 for a predetermined amount of time, e.g. the user input 24 may include some manner of alarm indicator which alerts a user that the vacuum cup 12 has been attached to the fetal head 18 for 10 minutes, 5 minutes, 15 minutes, etc. Such alarm indication generally serves to prevent any harm to the fetal head from having the vacuum cup 12 attached for too long.

[0071] As mentioned above, the flexible tube 28 links the housing to the cup 12. This is generally in order to arrange the generator 22 in fluid combination with the chamber 14, as well as to provide a means whereby a traction force can be applied to the cup 12 by the handle 30. However, other embodiments are possible, as will be described below.

[0072] Typically, the tube 28 has a small average outside diameter compared with conventional fetal vacuum tubes. For example, the flexible tube 28 may have an outside diameter in the range of 5mm to 200mm. Preferably the flexible tube 28 has an outside diameter in the range of 10mm to 30mm, although these ranges are to be considered non-limiting.

[0073] In one example, traction is applied to the fetal head 18 by pulling on the housing 20 which comprises a handle 30, or on a handle 30 defined on the housing 20 (Figure 2) . In a further embodiment, as shown in Figure 3, the apparatus 10 may have a separate pulling member 32 fast at one end to the vacuum cup 12 and a handle 30 defined at the other end of said pulling member 32 for operatively applying traction to the vacuum cup 12.

[0074] It is to be appreciated that the flexible tube 28 does not have to enter the cup 12 at the centre thereof, as shown. The tube 28 may enter the cup 12 anywhere practicable, dependent on design requirements. However, the pulling member 32 generally attaches to the cup 12 so that an even traction force can be applied to said cup 12, when in use, i.e. typically at the centre thereof, or the like.

[0075] In one example, the flexible tube 28 may comprise the pulling member 32. Typically, the pulling member 32 is a cable threaded through the tube 28 for providing mechanical strength whilst allowing tube flexibility. Alternatively, the pulling member 32 may comprise walls of the flexible tube 28 having a wire or nylon braided weave (not shown) for providing mechanical strength whilst allowing tube flexibility. As such, in one embodiment, a traction force may be primarily applied through the pulling member 32 (e.g., a cable) threaded through the tube 28 for preventing irreversible strain of the tube.

[0076] Typically, the apparatus 10 further comprises a traction force indicator 34 which is configured to indicate a value of a traction force applied to the pulling member 32. In one example, the traction force indicator may include a strain gauge, or the like. Such a traction force indicator 34 is helpful to a user of the device to determine how much traction force is applied to the fetal head 18. In one example, the controller 26 is configured to deactivate the generator 22 and/or activate the release valve 38 when a predetermined traction force is reached, i.e. to avoid harm to the fetus, or the like.

[0077] Referring now more specifically to Figures 2 to 7 of the accompanying figures, there are shown various further embodiments of apparatus 10. In such different embodiments, the flexible tube 28 is typically fast with the body portion 20.1 to define the 40 axis of traction 40 along the tube 28 and passing through the handle portion 20.2. Importantly, for reasons of ergonomics and ease-of-operation, the housing 20 is generally configured so that the centre of mass 42 (diagrammatically represented by point 42) of the housing 20 lies on or below this axis of traction 40 when in use.

[0078] It is to be appreciated that apparatus 10 is generally used with the handle portion 20.2 pointing in an upward direction to facilitate gripping thereof by a delivering physician. Accordingly, reference to the centre of mass 42 of apparatus 10 being on or below the axis of traction 40 refers to the centre of mass 42 lying below axis 40 when the handle portion 20.2 point substantially upwards when used.

[0079] In the embodiment of Figures 1 and 7, the body portion 20.1 and handle portion 20.1 are arranged as a dogleg, i.e. angled with respect to each other, arranged in an L-shape, or the like. When traction is applied to the handle portion 20.2 when the apparatus 10 is used, the axis of traction typically passes through the handle portion 20.2.

[0080] In general, the housing 20 is configured so that the centre of mass 42 of the housing 20 lies on or below the axis of traction 40 by the use of the mass arrangement 54 and/or the negative pressure generator 22, controller 26 and energising means 36 being suitably arranged in the body 20.1 and handle 20.2 portions, e.g. heavier components arranged lower in the housing 20, or the like.

[0081] In another embodiment, the controller 26 includes a traction sensor 44 which is configured to sense a traction force applied along the flexible tube 28 or pulling member 32. In such an example, the negative pressure generator 22 can be configured to automatically vary the negative pressure value according to the traction force sensed by the traction sensor 44.

[0082] For example, the negative pressure generator 22 is configured to automatically vary the negative pressure value between a higher (closer to zero, but still negative) , attachment value (where the negative pressure value is just sufficient to maintain attachment of the cup 12 to the fetal head 18) and a lower (negative value further from zero) , traction value (where the negative pressure value allows traction to be applied to the fetal head 18) . In an embodiment, the attachment value of the negative pressure value is more than or equal to -0.6 kg per cm² (440 mm Hg) , e.g. -0.4 kg per cm². In an embodiment, the traction value of the negative pressure value is less than the attachment value and more than or equal to -0.8 kg per cm² (588 mm Hg) , e.g. -0.7 kg per cm². In an embodiment, the traction value of the negative pressure value is less than -0.8 kg per cm² (588 mm Hg) , e.g. -1 kg per cm².

[0083] For example, the apparatus 10 can simply keep the cup 12 attached to the fetal head 18 when no traction force is applied to minimise risk of fetal scalp and cerebrocranial trauma, i.e. at the attachment negative pressure value. As soon as any traction force is applied, the controller 26 is able to detect such force via the traction sensor 44 and to immediately and automatically decrease the negative pressure to the traction value which allows more force to be applied via apparatus 10. In addition, controller 26 may also be configured to provide the indication when the vacuum cup 12 has been attached to the fetal head 18 for a predetermined amount of time relative to the negative pressure value and the time which such value has been maintained.

[0084] For example, the controller 26 may be configured to alert the user after only 3 minutes if the negative pressure value has been maintained at -0.8 kg per cm² (588 mm Hg) , but only after 10 minutes if the negative pressure value has been maintained at -0.6 kg per cm² (440 mm Hg) , or the like.

[0085] It is also to be appreciated that the negative pressure value can be scaled and adjusted in some relation to the traction force applied to the fetal head 18, i.e. a high traction force leads to a lower negative pressure value, or a low traction force leads to a higher negative pressure value, i.e. closer to zero value . [0086] In another embodiment, the fetal vacuum cup 12 includes an orientation indicator 46 which is configured to provide operative indication of rotation of the fetal head 18 during delivery. For example, the orientation indicator 46 comprises at least one light emitting diode (LED) arranged on the fetal vacuum cup 12. In use, the cup is attached so that the LED indicator 46 points in a certain direction, e.g. upwards. Should the fetal head 18 rotate within the birth canal, the LED indicator 46 will point in another direction, e.g. a 3-o'clock direction, or the like. In this manner, a delivering physician can monitor any rotation of the fetal head 18.

[0087] In a yet further embodiment, the flexible tube 28 includes an adjustor 48 which is configured to adjust a length of the tube 28 between the vacuum cup 12 and the housing 20 to facilitate operative distance adjustability between the vacuum cup 12 and the handle portion 20.2. Such adjustor 48 may include a spool-type adjustor whereby the tube 28 can be spooled or unspooled to adjust the length thereof. The adjustor 48 can also be configured to allow automatic and/or manual adjustment of the tube length, e.g. a large traction force applied along the axis of traction 40 may lead to an automatic reduction of tube length to facilitate control by the delivering physician, or the like.

[0088] In another embodiment, the adjustor 48 includes an orientation sensor configured to sense an orientation of the housing 20, wherein the adjustor 48 is configured to automatically adjust the length of tube 28 according to the sensed orientation, e.g. the adjustor 48 may be configured to automatically shorten the tube length if the handle portion 20.2 is raised above or tilted relative to the body portion 20.1, or the like. It is to be appreciated that the adjustor 48 may be adjusted for such orientation adjustment according to requirements, preference, etc .

[0089] It is to be appreciated that the layout and configuration of the housing 20, which is generally sized, shaped and dimensioned to be easily man-portable and to be easily handled, held and operated with one hand, is important. Such ergonomics are particularly useful during a delivery, as the delivering physician only requires one hand to control and operate the apparatus, as well as to apply traction to the fetal head when necessary.

[0090] Such an example has the housing 20 including the negative pressure generator 22 configured to operatively generate the negative pressure or vacuum within the chamber 14, as well as user input 24 via which a user is able to select a negative pressure value. Housing 20 also includes the controller 26 which is configured to control the generator 22 to automatically maintain the selected negative pressure value within said chamber 14.

[0091] It is to be appreciated that the present invention also provides for an associated obstetrical method for applying traction to a fetal head. Such as method broadly comprises the steps of providing any versions of the apparatus 10 described above, attaching the vacuum cup 12 of apparatus 10 to the fetal head 18, and applying traction to the fetal head 18 via said apparatus 10, typically by means of handle 30 with pulling member 32.

[0092] The Applicant believes it advantageous that the apparatus 10 provides for a fully portable and easily operable obstetrics vacuum that is less likely to 'pop off' during traction due to inadequate seal. The design of apparatus 10 also allows it to be used for fetuses facing in any direction; minor variations may be designed for the apparatus 10 to be used in possible more difficult cases. In the absence of the known conventional vacuum pumps, the improved effectiveness in the delivery of babies by using this portable apparatus 10 can potentially reduce any long term adverse health outcomes, or even save the lives of mothers and babies.

[0093] In addition, Applicant believes it additionally advantageous that the apparatus is able to enhance the effectiveness of a safe and successful delivery which is otherwise difficult, e.g. difficulty with a mal-presenting fetus when there is no electrical source or space for a conventional vacuum pump apparatus .

[0094] Applicant also believes it particularly advantageous that the present invention provides for an obstetric vacuum apparatus which is able to automatically control applied vacuum according to a traction force applied thereto. In addition, the housing 20 allows for comfortable and ergonomic operation due to a centre of mass 42 of the housing lying on or below the axis of traction .

[0095] Applicant further believes it particularly advantageous that the present invention provides for an apparatus able to automatically decrease the negative pressure value between the application of traction to reduce any unnecessary force to the fetus, as well as monitoring a time period for which the vacuum cup 12 has been attached to the fetal head 18, and being able to automatically changing the length of the tube.

[0096] A yet further advantage is believed to reside in the mass arrangement typically facilitating the prevention of fetal head retraction due to uterine contractions, i.e. obviates the manual application of a "resting" downward traction on the fetal head, as is conventionally required

[0097] Optional embodiments of the present invention may also be said to broadly consist in the parts, elements and features referred to or indicated herein, individually or collectively, in any or all combinations of two or more of the parts, elements or features, and wherein specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. In the example embodiments, well-known processes, well-known device structures, and well- known technologies are not described in detail, as such will be readily understood by the skilled addressee.

[0098] The use of the terms "a", "an", "said", "the", and/or similar referents in the context of describing various embodiments (especially in the context of the claimed subject matter) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. No language in the specification should be construed as indicating any non-claimed subject matter as essential to the practice of the claimed subject matter.

[0099] It is to be appreciated that reference to "one example" or "an example" of the invention, or similar exemplary language (e.g., "such as") herein, is not made in an exclusive sense. Various substantially and specifically practical and useful exemplary embodiments of the claimed subject matter are described herein, textually and/or graphically, for carrying out the claimed subject matter.

[ 00100 ] Accordingly, one example may exemplify certain aspects of the invention, whilst other aspects are exemplified in a different example. These examples are intended to assist the skilled person in performing the invention and are not intended to limit the overall scope of the invention in any way unless the context clearly indicates otherwise. Variations (e.g. modifications and/or enhancements) of one or more embodiments described herein might become apparent to those of ordinary skill in the art upon reading this application. The inventor (s) expects skilled artisans to employ such variations as appropriate, and the inventor (s) intends for the claimed subject matter to be practiced other than as specifically described herein.

[ 00101 ] Any method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

Claims

1. An obstetrical vacuum apparatus for operatively applying traction to a fetal head, said apparatus comprising: a fetal vacuum cup defining at least one chamber in which a negative pressure or vacuum enables operative attachment of the cup to a fetal head;

a housing comprising a body portion and a handle portion and having:

i) a negative pressure generator configured to operatively generate such negative pressure or vacuum within the chamber;

ii) a controller configured to control the generator to automatically maintain a desired negative pressure value within said chamber; and

iii) a mass arrangement configured to determine a centre of mass of said housing; and a flexible tube arranging said chamber in fluid communication with the negative pressure generator;

2. The obstetrical vacuum apparatus of claim 1, wherein the mass arrangement is user-configurable to allow adjustability of the centre of mass.

3. The obstetrical vacuum apparatus of either of claims 1 or 2, wherein the mass arrangement comprises the negative pressure generator and/or the controller.

4. The obstetrical vacuum apparatus of any of claims 1 to 3, wherein the mass arrangement comprises a mass receptacle defined by the housing, and at least one removable mass for operative placement within said mass receptacle.

5. The obstetrical vacuum apparatus of any of claims 1 to 4, wherein the handle portion is arranged transverse to the body portion so that when said handle is grasped by a user, the axis of traction lies substantially parallel or coaxial with a forearm of said user.

6. The obstetrical vacuum apparatus of any of claims 1 to 5, wherein the housing includes a user input configured to allow selection of the desired negative pressure value.

7. The obstetrical vacuum apparatus of claim 6, wherein the user input is located on the handle such that the user is able to manipulate said input ergonomically with a thumb whilst grasping the handle.

8. The obstetrical vacuum apparatus of any of claims 1 to 7, wherein the flexible tube comprises a pulling member.

9. The obstetrical vacuum apparatus of claim 8, wherein the pulling member comprises a cable threaded through the tube for providing mechanical strength whilst allowing tube flexibility .

10. The obstetrical vacuum apparatus of either of claims 8 or 9, wherein the pulling member comprises walls of the flexible tube having a wire or nylon braided weave for providing mechanical strength whilst allowing tube flexibility.

11. The obstetrical vacuum apparatus of any of claims 8 to 10, which comprises a traction force indicator configured to indicate a value of traction applied to the pulling member.

12. The obstetrical vacuum apparatus of claim 11, wherein the traction force indicator includes an electronic and/or mechanical strain gauge.

13. The obstetrical vacuum apparatus of any of claims 1 to 12, which includes a negative pressure or vacuum release valve configured to release or minimise a vacuum or negative pressure within the vacuum cup chamber.

14. The obstetrical vacuum apparatus of claim 13, wherein the negative pressure or vacuum release valve is controlled by the controller.

15. The obstetrical vacuum apparatus of any of claims 1 to 14, wherein the negative pressure generator comprises an electromechanical pump configured to extract fluid from the chamber in the vacuum cup.

16. The obstetrical vacuum apparatus of any of claims 1 to 15, wherein the controller is configured to control the generator to automatically maintain the selected negative pressure value within said chamber by increasing a negative pressure generation capability of the generator to accommodate an unwanted negative pressure decrease within the chamber.

17. The obstetrical vacuum apparatus of any of claims 1 to 16, wherein the controller is configured to control the generator to automatically maintain the selected negative pressure value within said chamber by decreasing a negative pressure generation capability of the generator to accommodate an unwanted negative pressure increase within the chamber.

18. The obstetrical vacuum apparatus of claims 14 or 17, wherein the controller is configured to activate the release valve to accommodate an unwanted negative pressure increase within the chamber.

19. The obstetrical vacuum apparatus of any of claims 1 to 18, wherein the controller includes a traction sensor configured to sense a traction force applied along the flexible tube, the negative pressure generator configured to automatically vary the negative pressure value according to the traction force sensed by the traction sensor.

20. The obstetrical vacuum apparatus of any of claims 1 to 19, wherein the controller is configured to automatically control the generator to vary the negative pressure value between a higher, attachment value (where the negative pressure value is just sufficient to maintain attachment of the cup to the fetal head) and a lower, traction value (where the negative pressure value allows traction applied to the fetal head) .

21. The obstetrical vacuum apparatus of claim 20, wherein the attachment value of the negative pressure value is more than or equal to -0.6 kg per cm² (440 mm Hg) .

22. The obstetrical vacuum apparatus of either of claims 20 or 21, wherein the traction value of the negative pressure value is less than the attachment value and less than or equal to -0.8 kg per cm² (588 mm Hg) .

23. The obstetrical vacuum apparatus of any of claims 20 to 22, wherein the traction value of the negative pressure value is less than -0.8 kg per cm² (588 mm Hg) .

24. The obstetrical vacuum apparatus of any of claims 1 to 23, wherein the fetal vacuum cup includes an orientation indicator configured to provide operative indication of rotation of the fetal head during delivery.

25. The obstetrical vacuum apparatus of claim 24, wherein the orientation indicator comprises at least one light emitting diode (LED) arranged on the fetal vacuum cup.

26. The obstetrical vacuum apparatus of any of claims 1 to 25, wherein the flexible tube includes an adjustor configured to adjust a length of the tube between the vacuum cup and the housing to facilitate operative distance adjustability between the vacuum cup and the handle portion.

27. The obstetrical vacuum apparatus of claim 26, wherein the adjustor includes a spool-type adjustor whereby the tube can be spooled or unspooled to adjust the length thereof .

28. The obstetrical vacuum apparatus of either of claims 26 or 27, wherein the adjustor is configured to allow automatic and/or manual adjustment of the tube length.

29. The obstetrical vacuum apparatus of any of claims 26 to 28, wherein the adjustor includes an orientation sensor configured to sense an orientation of the housing, wherein the adjustor is configured to automatically adjust the tube length according to the sensed orientation.

30. The obstetrical vacuum apparatus of any of claims 1 to 29, wherein the controller is configured to provide an indication when the vacuum cup has been attached to the fetal head for a predetermined amount of time.

31. The obstetrical vacuum apparatus of any of claims 1 to 30, wherein the mass arrangement is selected to fall in the range of 50g to 500g, preferably lOOg to 300g, and most preferably 150g to 250g.

32. An obstetrical method for applying traction to a fetal head, said method comprising the steps of:

providing apparatus in accordance with any of claims 1 to 31;

attaching a vacuum cup of said apparatus to the fetal head; and