Instrumental and operative delivery Flashcards
What is the ventouse?
It is also known as the vacuum - it has a plastic, rubber or metal cap which is fixed near the occiput by suction. Traction during suction will deliver as occipito-anterior positioned head, but also often allows the shape of the pelvis to simultaneously rotate a malpositioned head to the OA position.
What types of obstetric forceps are there?
Non-rotational (Simpson’s, Neville-Barnes) grip the head in whatever position it is and allow traction. They are only suitable when the occiput is anterior. They have a pelvic curve (for maternal sacrum) and a cephalic curve (for the foetal head).
Rotational forceps (e.g. Kielland’s) have no pelvic curve and enable a malpositioned head to be rotated to the OA position, before traction is applied.
What foetal complications are there for a ventouse delivery?
An unsightly chignon (a swelling in the area of the scalp that was drawn into the cup by suction) is usual. It diminishes over a period of hours, but a mark might be visible for days.
Scalp lacerations, cephalhaematoma and neonatal jaundice are more common with the ventouse.
Prolonged traction is dangerous.
What foetal complications are there for forceps delivery?
Facial bruising, facial nerve damage and even skull fractures can occasionally occur with injudicious use of forceps and prolonged traction is dangerous.
What are the indications for instrumental delivery?
Prolonged second stage: if 1-2 hours of pushing (active second stage) has failed to deliver the baby.
Maternal exhaustion
Foetal distress
Prophylactic use: indicated to prevent some women pushing with medical problems such as cardiac disease and hypertension.
In a breech delivery.
Which type of analgesia increases the chances of instrumental delivery?
Epidural analgesia.
What should be changed in labour if epidural anaesthesia is used?
The mother should not begin pushing until an hour after the diagnosis of the active phase of second stage of labour being reached (unless the head is low or the mother has the urge to push).
Oxytocin should be considered in nulliparous women if descent of the head is poor.
What happens if moderate traction of any instrument does not produce immediate and progressive decent?
Caesarian section is indicated.
What is the definition of a low-cavity delivery and which instruments can be used to assist?
Low cavity delivery is when the head is well below the level of the ischial spines and is usually occipito-anterior (OA).
Forceps of ventouse is appropriate.
What nerve block is used for a low-cavity instrumental delivery?
Pedendal block.
What is a mid-cavity delivery?
When the head is engaged, but is at or just below the level os the ischial spines.
What type of analgesia is used in a mid-cavity instrumental delivery?
Epidural or spinal analgesia.
If there is any doubt about a mid-cavity delivery with instruments being successful, where should it be performed?
In theater.
What instruments can be used in the different mid-cavity delivery presentations?
Occipito-anterior position: forceps or ventouse.
Occipito-transverse position: this usually results from insufficient descent of the head to make it rotate. Therefore, descent is achieved with a ventouse, with rotation resulting.
Non-rotational are contra-indicated.
Rotation in situ followed by descent can be achieved by rotational forceps or manual rotation.
Occipito-posterior position: 180* rotation is most successfully achieved with Keilland’s rotational forceps. However, it may be achieved with ventouse or manual rotation.
What are the prerequisites for instrumental vaginal delivery?
Head must not be palpable abdominally (and therefore deeply engaged).
Head must be at or below the level of the ischial spines on vaginal examination.
The cervix must be fully dilated (i.e. the second stage must have been reached).
The position of the head must be known.
Adequate analgesia.
Delivering for a valid reason.
Bladder empty.
