The primary goals in choosing anaesthesia for Caesarean section (CS) are ensuring the safety of the mother, the safety of the baby, and providing adequate conditions for surgery. Anaesthesia for Caesarean section can be broadly classified into two categories: General Anaesthesia and Regional Anaesthesia. Regional anaesthesia includes both spinal and epidural techniques.
Obstetric anaesthesia has evolved considerably over the last two decades, with regional anaesthetic techniques becoming increasingly popular for Caesarean delivery. Regional anaesthesia, particularly spinal and epidural anaesthesia, is often preferred for elective Caesarean sections because it provides an optimal balance of benefits and risks for both the mother and the fetus.
Spinal anaesthesia is considered a reliable and relatively simple technique to perform because it involves a clearly identifiable endpoint, namely the cerebrospinal fluid (CSF). In 1946, Ullery noted that spinal anaesthesia could be performed easily even by occasional operators because the technique essentially consists of creating and maintaining a spinal puncture. In spinal anaesthesia, the anaesthetic agent is injected directly into the cerebrospinal fluid within the subarachnoid space. This results in rapid onset of sensory and motor blockade, producing numbness of the lower half of the body. Compared with epidural anaesthesia, spinal blocks act more quickly and require a smaller dose of anaesthetic medication.
In contrast, epidural anaesthesia involves injection of the anaesthetic agent into the epidural space surrounding the spinal cord in the thoracic or lumbar region. This technique blocks only the nerves supplying the specific region affected by the injection. Pain relief from epidural anaesthesia generally begins within 10 to 20 minutes after administration.
Many anaesthesiologists prefer maintaining an epidural catheter in situ for emergency Caesarean sections in women who initially receive epidural labour analgesia but subsequently require operative delivery. However, some clinicians continue to prefer spinal anaesthesia because of its rapid onset, reliable motor blockade, and the relatively higher failure rate associated with epidural anaesthesia during scheduled Caesarean sections.
Administration of spinal anaesthesia following epidural anaesthesia may occasionally result in unexpectedly high sensory blockade or even total spinal anaesthesia, although studies have shown no statistically significant difference compared with spinal anaesthesia alone. Despite its advantages, regional anaesthesia may be contraindicated in patients with hypovolemia, coagulopathy, infection at the injection site, or when the patient refuses the procedure.
Regional anaesthesia offers several benefits over general anaesthesia, including preservation of maternal consciousness, avoidance of neonatal respiratory depression, and elimination of airway manipulation. Nevertheless, complications may occur, including hypotension, post-dural puncture headache, local anaesthetic toxicity involving the central nervous and cardiovascular systems, high spinal block, total spinal anaesthesia, bradycardia, and failed block.
Women receiving either spinal or epidural anaesthesia may experience a sudden drop in blood pressure. One important advantage of epidural anaesthesia is the ability to provide continuous anaesthesia through an indwelling epidural catheter, making it particularly suitable for prolonged procedures such as labour and delivery. Additionally, epidural anaesthesia reduces the risk of introducing infection into the cerebrospinal fluid, a complication more commonly associated with spinal anaesthesia.
Despite these advantages, many anaesthesiologists continue to use spinal anaesthesia because of its rapid onset and effective motor blockade. Therefore, the present study was undertaken to compare the haemodynamic changes occurring in patients undergoing Caesarean section under different regional anaesthetic techniques.