When uterine contractions and cervical dilatation cause discomfort, pain relief with epidural analgesia is a viable option. It can be accomplished by injecting a suitable local anaesthetic agent in to the epidural or peridural space. This space is a potential area that contains areolar tissue, fat, lymphatics and the internal venous plexus, which becomes engorged during pregnancy so that it appreciably reduces the volume of the space. The portal of entry for obstetric analgesia is through either a lumbar intervertebral space for lumbar epidural analgesia (more commonly used), or through the sacral hiatus and sacral canal, for caudal epidural analgesia.
An indwelling plastic catheter is inserted hence more than one injection can be repeated at intervals for pain relief. The lady must be in active labour and cervix must be atleast 3-4cms open.
The procedure of epidural catheterization is done by one of our team of qualified anaesthetists. After an informed consent, patient is hydrated well with Ringer Lactate solution and continuous monitoring of maternal heart rate and blood pressure is required. With the lady in lateral decubitus or sitting position, epidural space is identified with a loss of resistance technique and epidural catheter is threaded 3cms in to the epidural space. A combination of bupivacaine (0.25% to 0.5%) and fentanyl (according to weight of patient) may be used.
The effect of epidural analgesia on labour (on the negative side) may include longer labours and increased incidence of chorioamnionitis, vacuum or caesarean delivery. Most of the times, epidural analgesia is a relatively safe procedure causing significant pain relief to the laboring woman.