Spinal anaesthesia for obstetrics.

For a long time, epidural anaesthesia has been considered the method of choice for Caesarean delivery. The increased incidence of hypotension by the rapid onset of sympathetic blockade under spinal anaesthesia has been associated with a decline in uteroplacental blood flow and significant fetal acidosis, which may compromise neonatal well-being. Nevertheless, a decrease in fetal pH has not been shown to reduce neonatal Apgar or neurobehavioural assessment scores. Maternal blood pressure can be preserved with little side effects with low doses of vasopressors. On the other hand, spinal anaesthesia conveys significant advantages over epidural anaesthesia such as the simplicity of its use and the speed of onset, which allows neuraxial anaesthesia in urgent Caesarean sections and thus reduces the necessity for general anaesthesia. The small doses of local anaesthetics required to perform spinal anaesthesia reduce the risks of systemic toxicity to zero. Spinal anaesthesia is now considered the method of choice for urgent Caesarean section. The use of intrathecal opioids has profoundly changed the quality of spinal anaesthesia, with improved analgesia, a reduction in local anaesthetic requirements and shorter duration of motor blockade. Preliminary studies indicate that spinal anaesthesia may be safely performed in patients with severe pre-eclampsia, in whom spinal anaesthesia was previously considered contraindicated.