1. Vacuum Extraction
(The Ventouse)

3. Definition
It is an instrumental device designed to assist delivery by creating a vacuum between it and the fetal scalp

4. INDICATIONS
CONVENTIONAL
NON CONVENTIONAL
NON OBSTETRICS

5. Conventional uses
Shortening second stage (Conditions in which voluntary expulsive efforts are contra indicated)
Prolonged second stage
Maternal exhaustion
Presumed fetal jeopardy / fetal distress in late labour
Occipito posterior position (persistent occipito posterior or deep transverse arrest)
To end trial of labor successfully in borderline CPD
To deliver second twin if head is presenting

6. Non - conventional To deliver fetal head at CS To deliver frank breech
Compound presentation
To arrest brisk hemorrhage in minor degree placenta previa with vertex presentation
To manipulate and deliver large ovarian cysts without enlarging abdominal incision.

7. Contra indications Inexperience
Inability to achieve a proper application
Uncertainty concerning fetal position / station
Suspicion of moderate to severe feto - pelvic disproportion
High fetal head ( station above 0)

8. Contd…. Malposition ( breech, face, brow) After coming head of breech
Known or suspected fetal coagulation defect
Prematurity
Intra uterine fetal death : chignon cannot form
Congenital anomalies of fetus: macrosomia
Prior scalp sampling

9. Pre requisites When pelvic adequacy is good
Parturient is willing and able to assist
An experienced surgeon is present
Essential pre requisites are:
Informed consent
An engaged fetal head
Legitimate indication
No suspicion of feto- pelvic disproportion
Cervical dilatation of at least 7 cm

10. Either a rigid(metal)
Or a flexible ( soft)

11. Design of vacuum extractor
METAL CUPS
SILICONE RUBBER CUPS

12. Parts of Ventouse
Stainless steel cups in 4 sizes, 30, 40, 50, 60 mm in diameter, Silastic cups are lighter.
The depth of cup is 20 mm.
The greatest diameter of cup is 8 mm below the point of application
The metal plate
The traction chain attached to the plate
Traction handle with metal pin
Pressure rubber tube which encloses the traction chains
Vacuum bottle with pressure gauge
Vacuum pump ( manual or electric)

14. Bird’s modification of Ventouse
In this modification vacuum tube is attached to the opening near to the periphery of the cup and the traction chain to the hook in the centre of the cup.

15. Cont… There are two types of cups
Anterior cup: used for occipito anterior position
Posterior cup: used for persistent occipito - posterior and occipito transverse positions
Advantages
Easy assembly and easy application
Fewer tendencies to slip with oblique traction

16. Silastic cups
Cups made of silastic instead of metal are pliable, softer, less traumatic and safer. They are used more commonly in obstetrics

17. Plastic cup (mity vac)
It consists of a disposable plastic cup and handle, suction tube and a hand pump

18. Cont…
The mity vac hand pump set consists of a tube attached to the cup, a handle that can be pressed to be the vacuum, a pressure release valve, and a pressure gauge.
It builds pressure quickly ( within minutes) and is very handy and transportable and can be used even in the absence of electricity.

19. Manipulator cup
It is a reusable Plastic vacuum Extraction set

21. Types of cup applications
There are four types
Flexing median:( correct or ideal application was first defined by Bird in 1976 )
The centre of the cup should be over the vertical point i.e. 3 cm anterior to the posterior fontanel called the “flexion or pivot point”
The distance between leading anterior edge of the cup and the anterior fontanel should be 3 cm( 2 finger breadths); this is called the application distance

22. b.Flexing Para median When the centre of the Cup is situated more than
1 cm to either side of the
Saggital suture,but application
Distance is 3 cm

23. c. Deflexing median: when the centre of the cup is situated over the saggital suture, but application distance is less than 3 cm
d.Deflexing paramedian :
When the centre of the is situated more than 1 cm to either side of the saggital suture , but application distance is less than 3 cm

24. PROCEDURE PRELIMINARIES Pudendal block or perineal infiltration
Assemble the equipment
Test the vaccum
APPLICATION OF THE CUP
Retract the perineum with two fingers of other hand
Cup placed against fetal head near occiput
Knob of the cup should be pointing towards occiput
TRACTION
Traction must be at right angle to the cup
Traction synchronus with uterine contraction
Traction along the axis of birth canal
Traction should not exceed 30 mins
No more than 4 successive contraction

25. Technique of vacuum extraction
A proper vacuum extraction depends on:
The accuracy of cup application
The traction technique
The fetal cranial position and station at the time of application
The cup design
The feto - pelvic relationship

26. Cont…
Positioning : lithotomy position, bladder is emptied, parts painted and draped.
Assess : the pre requisites for vacuum extraction by per vaginal examination.(position, station, and attitude of head)

27. Cont… Anesthesia : perineal infiltration
In multiparas and low stations no anesthesia
For high station of head bilateral pudendal block is necessary
General anesthesia is contraindicated (mothers active participation is required)

28. Cont…
Ghosting : A ghost or phantom application is performed prior to the attempt at cup insertion. Assemble the article and check for possible leak

29. INSERTION OF CUP Aplication of the cup:
The largest possible cup according to the dilatation of the cervix is to be selected.
The cup is introduced after retraction of the perineum with two fingers of the other hand. If soft cup is employed, it is partially collapsed by the hand of the operator and then introduced through labia.
Rigid cups are turned side ways, the labia are gently spread, and the device is slipped into the vagina.

30. Cont..
The cup is applied directly to fetal scalp as near the posterior fontanel as possible and over the saggital suture
The knob on the cup should be in the direction of the occiput.
A careful check of cup placement follows (mid saggittal, over pivot point). A finger is swept around the cup to ensure that no maternal tissue is interposed between cup and head

31. Cont…
A vacuum of 0.2 kg/cm2 ( 100 mmHg ) is introduced by the pump slowly taking at least 2 minutes sufficient to fix the cup to the fetal head.
With the onset of contraction, suction pressure is raised to a range of 380 to 580 mmHg.(negative pressure should not exceed 600 mmHg or 8kg/cm2
Bird advised highest possible vacuum level; an electrical pump or vacuum hand pump can be used for this purpose

32. Cont..
During traction and in between contractions, the pressure is applied with two fingers.(thumb against the dome of the cup and index finger on the scalp in front of the cup) of the non-dominant hand over the cup so as to maintain it in firm contact with the head and prevent cup detachment

33. Cont..
Traction is applied with the uterine contraction( the mother bearing down) in a direction always perpendicular to the plane of the cup.
Oblique traction ( angle of degrees) reduces effective traction force by 25 to 50%
Traction is discontinued between contractions ( intermittent vacuum technique) or if an audible hiss is heard signaling loss of vacuum.

34. Cont..
Chignon is a edematous artificial caput, formed beneath the vacuum cup.( artificial caput succedaneum)

35. Traction principles:
Traction must be at right angle to the cup.
Traction should be synchronous with the uterine contractions.
Traction should be made using one hand along the axis of the birth canal. The fingers of the other hand are to be placed against the cup to note the correct angle of traction, rotation and advancement of head.
The vacuum pump is actuated until the appropriate degree of vacuum is present

36. Cont…
Tension on the extractor handle is allowed to build gradually, paralleling the uterine contractions.
As the contraction wanes, the tension on the extractor progressively is relaxed.
At the discretion of surgeon, the vacuum can either be maintained or reduced to less than 200 mmHg between contractions.
Should the cup be dislodged, the fetal scalp is to be checked before the cup is reapplied
When the contraction subsides, the suction pressure is reduced to 100mmHg
The sequence is repeated with each contraction
More than three good attempts are not recommended unless progress is being made.

37. Cont…
If there is no advancement during four successive tractions, it is to be abandoned. On no account, traction should exceed 30 minutes.
As soon as the head is delivered, the vacuum is reduced by opening the screw-release valve and the cup is then detached. The delivery is completed in the normal way.

38. Ventouse exert 4 types of forces on the fetal scalp:
Negative suction from the vacuum it self.
Downward traction from pulling.
Circular force, if rotation occurs.
Shearing force if the direction
of traction is not perpendicular
to the scalp surface.

39. Cont..
Failure rate:
The mean failure rate for metal vacuum cup is 4.5% and for the soft cups is 14%
Detachment of the cup( pop – offs) could be because of leak of the vacuum apparatus(mechanical failure) or because of paramedian application combined with oblique traction.

40. Complications of Vacuum delivery
Maternal complications
Vaginal lacerations & hemorrhage.
Cervical lacerations( if cervix is not fully dilated)
Annular detachment of cervix, cervical incompetence.
V.V.F. is also reported
rupture of pubic symphysis

41. Fetal complications Mechanical trauma Jaundice
Intracranial damage (<0.5%)
Scalp abrasions and lacerations
Scalp ecchymosis
Cephalic hematoma(accumulation of blood under the periosteum)
Skull fracture

42. Advantages of ventouse over forceps
It can be used in un rotated and malrotated occipito - posterior position of the head
It can be applied even through incompletely dialated cervix( minimum 7 cm dilatation)
Lesser traction force is needed(10 kg)
Safe even when the head is high in second baby of twins
It is comfortable and injuries to the mother are less
Fetal complications are less
Requires less technical skill(suitable for trained midwives

43. Cont… Compression force is less ( 1/20 th of forceps)
Does not require additional space between tight fitting head and pelvis
Maternal morbidity is less than that with forceps deliveries

44. Advantages of forceps over vacuum
Can be applied to after coming head of breech or anterior face
Can be applied to face presentation
Can be applied to dead fetus
A vacuum extraction operation has a higher failure rate than a forceps operation
Fetal soft tissue trauma ( especially cephal hematoma and retinal hemorrhages) is less