By Dr. Dwight Walcott, ContributorVACUUM EXTRACTION is a popular method of assisted delivery now used in about six per cent of births in the United States. The modern vacuum extractor is a relatively compact instrument with a soft silastic cup far removed from the original bulky instrument of metal and chains invented by Malstrom in 1954.
Despite the simplicity of the device, relative ease of operation and the minimal maternal risk, foetal injuries are possible and the instrument should only be used by appropriately-trained surgeons in the appropriate clinical setting. In general, vacuum extraction has the same indications for use as forceps delivery.
PREREQUISITES FOR USE
Informed consent The risks and benefits of the procedure should be explained to the patient and her consent obtained. Obtaining bedside consent from a labouring patient may be difficult, so ideally possible obstetric interventions should be discussed with the families earlier in the antenatal period so that if required in labour these procedures are not entirely new or unanticipated.
Additionally the cervix should be fully dilated, the head engaged and the membranes ruptured. Use of vacuum extraction is best avoided for foetuses of less than 34 weeks gestational age. An empty bladder is also essential.
In addition to a prepared patient, the surgeon should also be prepared for the procedure. He should have sound knowledge of the instrument and the technique. The passage should be adequate to permit delivery and the surgeon should also be prepared to abandon the procedure if it proves difficult.
INDICATIONS FOR USE
The vacuum extractor is often used when the second stage of labour is prolonged. This is sometimes due to poor maternal effort or ineffective uterine contractions. Shortening the second stage of labour is appropriate in some patients with cardiac, cerebrovascular or neuromuscular disease where voluntary expulsive efforts may be impossible or contraindicated.
Expeditious vacuum delivery may be necessary in some situations where assisted vaginal delivery is appropriate. Presumed foetal distress often requires urgent delivery and the vacuum extractor may be used to expedite the second stage of labour.
Overall, the vacuum extractor is a useful tool in the armamentarium of the obstetrician. Like any other procedure, there are associated risks. By carefully following recommended guidelines, successful outcomes can be anticipated.
Dr. Dwight Walcott is a Consultant Obstetrician and Gynaecologist and President, Grabham Society.
