Central neural blockade in obstetric practice

Abstract

Recent developments in central neural blockade (CNB) in obstetric anaesthetic practice have been predominantly directed towards providing excellent pain relief in labour without concomitant loss of control over body functions such as the ability to walk or to micturate. Low-dose local anaesthetic/opioid mixtures produce less interference with motor and proprioceptive function than is traditionally associated with epidural analgesia for labour. These low-dose mixtures may be given by staff-administered boluses, constant infusion or more innovative techniques such as CSE and PCEA. PCEA uniquely gives the woman the ability to control the intensity of the block in response to her own sensations as labour progresses. Ambulation is possible with any of the modes of administration, provided that motor function and proprioception are intact. These methods are all associated with high rates of maternal satisfaction, even when pain relief is not as complete as with high-dose regimens, emphasizing the psychological complexity of the experience of childbirth. There is little evidence that these techniques increase the spontaneous vaginal-delivery rate. The safety of these techniques and the complication rate of CNB in obstetrics are discussed. Information about the newer agents for CNB, such as ropivacaine, clonidine and neostigmine, all at various stages of development, is presented.