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:

  1. Station of the head
  2. Rotation of the head

Procedure / Criteria
Outlet forceps /
  1. Scalp is visible at the introitus without separating the labia
  2. Fetal skull has reached pelvic floor
  3. Sagittal suture is in anteroposterior diameter, right, or left occiput anterior or posterior position
  4. Fetal head is at or on perineum
  5. Rotation does not exceed 45 degrees

Low forceps / Leading point of fetal skull is at station ≥ +2, and not on the pelvic floor.
  1. Rotation is 45 degrees or less(left or right occiput anterior to occiput anterior, or left or right occiput posterior to occiput posterior)
  2. 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