Definition
It is an instrumental device
designed to assist delivery by
creating a vacuum between it and
the fetal scalp
INDICATIONS
 CONVENTIONAL
 NON CONVENTIONAL
 NON OBSTETRICS
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
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.
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)
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
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
Either a rigid(metal)
Or a flexible ( soft)
Design of vacuum extractor
 METAL CUPS
SILICONE RUBBER CUPS
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)
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.
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
Silastic cups
Cups made of
silastic instead of
metal are pliable,
softer, less
traumatic and
safer. They are
used more
commonly in
obstetrics
Plastic cup (mity vac)
It consists of a
disposable
plastic cup and
handle, suction
tube and a
hand pump
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 1- 2
minutes) and is very handy and
transportable and can be used even in the
absence of electricity.
Manipulator cup
It is a
reusable
Plastic
vacuum
Extraction
set
Types of cup applications
There are four types
a. 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

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
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
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
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
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)
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)
Cont…
Ghosting : A ghost or phantom application is
performed prior to the attempt at cup insertion.
Assemble the article and check for possible leak
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.
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
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
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
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 10-30 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.
Cont..
 Chignon is a edematous artificial caput,
formed beneath the vacuum cup.( artificial
caput succedaneum)
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
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.
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.
Ventouse exert 4 types of
forces on the fetal scalp:

self.
Negative suction from the vacuum it
 Downward traction from pulling.
 Circular force, if rotation occurs.
 Shearing force if the direction
 of traction is not perpendicular
to the scalp surface.
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.
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
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
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
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
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