INSTRUMENTAL DELIVERY
FORCEPS
Parts of forceps
Handles – to grip the forceps
Lock – holds the two blades together
–English lock /French lock /Sliding lock
Shank – connects handle and blade
Blades – toe and heel
Shape – solid, semifenestrated and fenestrated
Diameter – widest distance between the two blades 7.5cms
Two curves – cephalic (fits the shape of fetal head) and pelvic ( follows direction of birth canal
Indications:
Maternal exhaustion
Prolonged second stage of labor
–>3hr with and> than 2hr without regional analgesia in primi
–>2hr with and >1hr without regional analgesia in multi
Fetal distress
Prophylactic indication
Contraindications:
Infectious disease
Fetal bleeding disorders
Classification(American College of Obstetrics and Gynaecology)
Two important factors are taken into consideration:
- Station of the head
- Rotation of the head
Procedure / Criteria
Outlet forceps /
- Scalp is visible at the introitus without separating the labia
- Fetal skull has reached pelvic floor
- Sagittal suture is in anteroposterior diameter, right, or left occiput anterior or posterior position
- Fetal head is at or on perineum
- Rotation does not exceed 45 degrees
Low forceps / Leading point of fetal skull is at station ≥ +2, and not on the pelvic floor.
- Rotation is 45 degrees or less(left or right occiput anterior to occiput anterior, or left or right occiput posterior to occiput posterior)
- Rotation is greater than 45 degrees.*
Midforceps
High / Station above +2but*head is engaged.
Not included in classification.
*To be decided and done only by consultant
Prerequisites
Adequate pelvis
Good uterine contractions
Station of head +2 or more
Presentation must be suitable Vertex, face(chin anterior), after coming head
Cervix completely dilated
Sagittal suture in anteroposterior diameter
Membranes should be absent
Suitably anaesthetised
Bladder/ bowel empty
Application of forceps
Outlet forceps application
Cephalic application (always)
Axis of traction isBiparietal-Bimalar
Technique
Identification of blades –
“Ghosting” or “Phantom” application
The instrument should be placed in front of the pelvis with the tip
pointing upwards and pelviccurve forwards
First the left blade should be applied guided by the right hand & then the right blade with the left hand
Application of left blade –
Hold the handle of left blade by pen grip vertically near right groin of the mother
Pelvic curve is directed downward and cephalic curve inward toward the vulva with plane of shank perpendicular to the floor
Fingers of right hand are placed in the vagina between fetal head and left vaginal wall
Left blade is inserted at 5 o’clock positon between head and fingers. The handle is lowered slowly to the horizontal and moved up by the vaginal finger giving an occipitomental position
When right blade is in place, handles are locked
After handles are locked satisfactorily the application is checked
When forceps are applied correctly locking is easy.
Preextraction examination:
FHS auscultation
Vaginal examination to rule out cord, membrane or cervical entrapment
Episiotomy must be given when perineum is overstretched (in low forceps)
Check the application
Check points
Posterior fontanellae should be located midway between the sides of blades & one finger breadth above the plane of shanks
The Sagittal suture should be perpendicular to the plane of shanks through out its length
Fenestrations of blade felt should be equal and not more than finger tip on either side
Traction
Extraction of fetal head:
Operator should sit on a stool and grasp forceps with one hand on the handle and other on the shank
Traction must be intermittent, every 1-2 minutes for 30-40 seconds during uterine contractions
Forceps need not be unlocked in between contractions
Use flexors of the arm (at the level of wrist joint)
Direction of traction must follow birth canal. First outwards and posteriorly until the occiput comes under the symphysis pubis and neck pivots in the subpubic angle, then the direction is changed to outward and anteriorly to promote extension of the head.
Not more than 3 attempts provided there is descent with first attempt
Birth of the head:
Traction is continued with extension of the head, forehead, face and chin are born
Removal of forceps:
After the birth of head forceps is removed in reverse process as application
Examination of vagina, cervix and uterus for lacerations and repaired
Face to pubis
Blades should be equidistant from sinciputocciput
Traction - Horizontal till the root of the nose is under the pubic symphysis, then upward till the occiput emerges over the perineum & finally downwards
Documentation:
Discussion with parents, relatives-informed consent
Indications for the forceps operation
Position & station of the vertex at the time of application of forceps
Pre & postdelivery status, procedure,degree of difficulty in detail
VECTIS
A single blade to extract baby during caesarean section
It is used as a lever or a tractor or an artificial right hand.
Also called the lever or extractor
VENTOUSE
Types
Metal cups : Stainless steel -Malmstrom’s
Bird’s cup- Ant. & posterior
Soft cups : Silastic& Plastic –Kobayashi,Mityvac
Kiwi-Omni – for LSCS
Parts
Vaccum cup
Rigid cups – stainless steel
Flexible cups – polyethylene silastic
Cup sizes – 30, 40, 50, 60 mm
Traction tubings
Vaccum generator
Prerequisites
Similar to that of forceps except that
it can be used even when the head is 45 degrees short of rotation
when head is at or below ‘0’ station
when cervix is not fully dilated in case of cord prolapsed
Application
Insertion -cup is lubricated, collapsed and introduced
Largest cup to be placed on the fetal head with knob pointing towards the occiput and the centre of the cup at the flexion point which is 1-2cms anterior to posterior fontanelle,it is a point through which mentovertical diameter passes (clinically it should be applied more posteriorly)
Application distance means distance between anterior margin of cup &ant.fontanelle.It should be 3 cm or more
Paramedian Centre of the cup is1cm away from sagittal suture
How will you create the vacuum ?
Pressure is slowly raised from 0.2 to 0.8kg/cm2(600mmhg)for metal cup but rapidly in case of silastic cup
Check for proper application & see that no maternal tissues included
Rapid ventouse (LSCS)
Principles of traction
Two handed technique – three finger grip
Should be synchronous with uterine contraction & maternal bearing down efforts
Should be in the direction of pelvic axis & perpendicular to cup
Traction force-Average 8 to15 kgs
Episiotomy when the head is bulging theperineum
Asthe development of vacuum progresses, artificial caput succedaneum called chignon develops (metal cup)
Once the head is delivered ,the suction pressure is released & vacuum cup removed
When should the operative vaginal deliveries be abandoned?
No evidence of progressive descent with each pull
When delivery is not imminent following 3 pulls
3 Cup detachments (pop-off)
Time limit of 30 min
Application of vacuum cup during Caesarean section
Deep fetal head-elevated from below-then apply ventouse
High floating head-fundal pressure-fetal head comes to incision site-apply ventouse
Soft cups are best suited for this application
Documentation
Same as that of forceps delivery
FORCEPS
VACUUM DELIVERY