Attempts have been made to use this form of analgesia in obstetrics since the beginning of this century, but continuous epidural anaesthesia was only introduced by Curbello in 1949.
While the commonest indication for epidural block is the relief of labour pain, there are many other reasons for placing 'an epidural'.
These indications include:
1. Maternal distress caused by painful uterine contractions not adequately relieved by simpler forms of analgesia (pethidine (demerol), nitrous oxide);
2. Caesarean section. In many centres, the majority of Caesarean sections are performed under epidural or combined spinal-epidural (CSE) anaesthesia (Figure 73.1);
3. Provision of anaesthesia for instrumental delivery;
4. Treatment of pregnancy-induced and -associated hypertension (PIH). Epidural anaesthesia not only reduces the amount of sedation required but also lowers the arterial blood pressure. Once the blood pressure is controlled, the likelihood of eclampsia becomes more remote;
5. Provision of analgesia for repairs to birth canal tears, eg. episiotomy;
6. Breech delivery where the presence of an epidural in situ gives the obstetrician increased flexibility to intervene expeditiously should the need suddenly arise, eg. to apply forceps to the difficult-to-deliver aftercoming head (Figure 14.1);
7. Multiple delivery where anaesthesia (or, at least, superior analgesia) may be required urgently to deliver the second (and subsequent) infants, eg. for version of the second twin;
8. Cardiac disease or pulmonary hypertension where the epidural will attenuate the increase in cardiac output, mean arterial pressure and cardiac work which occurs during labour.
9. Restoration of coordinate uterine activity when the endocrine response to stress and pain has induced abnormal uterine activity.