Vacuum Extraction (Ventouse)

Vacuum Extraction (Ventouse)

It is traction of the foetal head by a created negative pressure through a cup applied to the head.

Description Vacuum extractor is composed of: A specially designed cup with a diameter of

3, 4, 5 or 6 cm. A rubber tube attaching the cup to a glass

bottle with a screw in between to release the negative pressure.

A manometer fitted in the mouth of the glass bottle to declare the negative pressure.

Another rubber tube connecting the bottle to a suction piece which may be manual or electronic creating a negative pressure that should not exceed - 0.8 kg per cm2.

Indications

Alternative its forceps delivery Occipitotransverse or posterior position Delay in descent of the head in case of

the second baby of twins. Delay in late first stage of labour During caesarean section: It may be

used to extract the foetal head through the uterine incision.

Contraindications

* Moderate or severe cephalopelvic disproportion.

* Other presentations than vertex.* Premature infants.* Intact membranes.* Suspected fetal coagulation* Suspected fetal macrosomia

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Conditions to be fulfilled Should not be slightest bony

resistance below the head The head of a singleton baby should

be engaged Cervix should be atleast 6cm dialated

Procedure

* Lithotomy position.*Antiseptic measures for the vagina,

vulva and perineum.* Vaginal examination to check pelvic

capacity, cervical dilatation, presentation, position, station and degree of flexion of the head and that the membranes are ruptured.

Procedure* Application of the cup: The largest cup that can

easily passed is introduced sideways into the vagina by pressing it backwards against the perineum. It is then applied as near as possible to the posterior fontanelle over the mid sagittal line with its edge 3 cm from the anterior fontanelle. This position will promote flexion of the head and brings the smallest diameters of the foetal skull into the maternal passages. Be sure that there is no cervical or vaginal tissues nor the umbilical cord or a limb in complex presentation is included in the cup.

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Procedure* Creating the negative pressure: holding

the cup in place, the negative pressure is gradually increased by 0.2 kg/cm2 every 1 minute until - 0.8 kg/cm2 is attained. This creates an artificial caput within the cup.

* Traction: on the handle is made perpendicular to the cup and intermittently during uterine contractions, the direction of pull is changing as the head descends through the birth canal

Procedure

* Release of the cup: when the head is delivered the vacuum is reduced as slowly as it was created using the screw as this diminishes the risk of scalp damage.

Bird’s safety rules for vacuum extraction:

* The head must be completely or partially delivered with no more than 3 pulls.

* The head is at least begin to move with the first pull.

* The cup must not be applied more than twice.

* Application of the cup must not exceed 20 minutes.

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Complications Maternal:> Vaginal and cervical lacerations.> Annular detachment of the cervix,

cervical incompetence and may be future prolapse if used with incompletely dilated cervix.

Complications

* Foetal:>Cephalohaematoma.>Scalp lacerations. > Rarely, intracranial haemorrhage.

Advantages of Vacuum over Forceps

* Anesthesia is not required so it is preferred in cardiac and

pulmonary patient.

* The ventouse is not occupying a space beside the head

as forceps.

* Less compression force (0.77 kg/cm2) compared to

forceps (1.3 kg/cm2) so injuries to the head is less

common.

* Less genital tract lacerations.

* Can be applied before full cervical dilatation.

* It can be applied on non-engaged head.

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Disadvantage Require maternal effort Equipment more complex and may

fail Take time in fetal distress Cannot be used in preterm More cephal heamatoma