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Introduction Emergency caesarean section is a decision taken by obstetricians when there is concern about the health of the mother or the foetus, or when a vaginal delivery is not deemed a suitable option. In this situation, anaesthesiologists need to provide anaesthesia in a timely manner, for the duration of the surgical procedure. In modern obstetric anaesthesia practice, neuraxial techniques are preferred over general anaesthesia in most scenarios, for improved maternal and foetal outcomes. When epidural analgesia is already established for labour pain, the possibility of converting this epidural analgesic to an epidural anaesthetic provides significant benefits over taking it out and using a single shot spinal. These include providing a safe, fast, and reliable anaesthetic; reducing the need for further neuraxial procedures and their potential complications; as well as additional considerations including financial implications, environmental impact, anaesthesiologist workload, and patient perspectives.Providing Safe, Fast, and Reliable Epidural AnaesthesiaLumbar epidurals are regarded as the gold standard for labour analgesia.1 Unless specifically contraindicated in individual parturients, labour epidural analgesia is suggested or recommended for high-risk obstetric patients, such as those living with modified WHO 3 and WHO 4 heart disease,2 with maternal obesity,3 in the presence of some ophthalmic pathologies,4 and in laboring women with pre-eclampsia.5 In these women, the recommendation for labour epidural analgesia is aims to achieve patient comfort; prevent deterioration of maternal medical conditions; reduce severe maternal morbidity,6 and avoidance of further anaesthetic interventions including general anaesthesia, should an intra-partum surgical procedure be required.The Obstetric Anaesthetists’ Association (OAA) in the United Kingdom states that only 5% of labour epidurals will not work well enough for a Caesarean section.7 In an Irish study, the rate of labour epidurals converted to spinal or general anaesthesia for Caesarean section was 9%,8 the rate from an Indian study was approximately 4%,9 a Maltese study identified a rate of epidural conversion to spinal or general anaesthesia for Caesarean section as 0.85% and 1.5% respectively,10 a Chinese publication showed a conversion rate to general anaesthesia of 3%,11 while a systematic review in 2022 by authors from the United Kingdom and the United States of America including over 3000 patients showed an overall prevalence of inadequate epidural anaesthesia of around 30%.12 It is however worth noting that this systematic review relates to elective caesarean section, and not emergencies, with the possibility that epidural analgesia was not established for a sufficient period of time, prior to the procedure.Most recently, the ESAIC focused guidelines for the management of the failing epidural during labour epidural analgesia published in 202513 quote a rate of failure to convert epidural analgesia to anaesthesia for intrapartum caesarean section requiring general anaesthesia between 3.5 – 38%. These rates were obtained from four publications, including two observational studies, one randomized controlled trial, and one systematic review. Despite this, the authors issued a clinical practice statement stating: ‘We recommend pro-active early management of a failing epidural as the preferred technique to facilitate successful conversion to anaesthesia for intrapartum caesarean delivery’ implying that conversion to epidural anaesthesia for emergency caesarean section would still be their preferred approach compared to alternatives.Therefore, it is essential to ensure that the labour epidural analgesia is working well to increase chances of success of epidural anaesthesia for emergency Caesarean section.13 14 Several risk factors have been identified as being associated with a failure of conversion from epidural analgesia to anaesthesia including a greater number of unplanned epidural top ups needed to maintain effective analgesia in labour,15–17 increased maternal reported pain in the two hours before caesarean section,15 management by a non-obstetric anaesthetist,15 18 19 and urgency of the caesarean section.15 In relation to speed of onset, the time required for an epidural top up to a level adequate for surgical anaesthesia compares favourably with that required for a spinal, and in some cases, even with that required for a general anaesthetic. A 2018 retrospective cohort study showed that unadjusted median operating room-to-incision intervals were 6 minutes for general anaesthesia, 11 minutes for epidural top-up, and 13 minutes for spinal anaesthesia.20 It is important to point out that when relating to clinical significance, general anaesthesia was associated with worse short term neonatal outcomes in this study, and that longer time intervals to establishment of surgical anaesthesia for epidural were not associated with worse neonatal outcomes.20 A 2007 retrospective audit from Australia showed mean decision-to-delivery times of 17 (±6) minutes for general anaesthesia, 19 (±9) minutes for epidural, and 26 (±9) minutes for spinal.21 It has also been reported that established epidural analgesia may mitigate the increased anaesthesia and surgery time required in obese obstetric patients undergoing caesarean section.22 Finally, epidural anaesthesia for emergency caesarean section has the benefit of being topped up as often as required to prolong the duration of the anaesthetic block. It allows for manipulation of the time of onset of the anaesthetic, speeding it up by using lignocaine together with adjuvants such as opiates, bicarbonate, or adrenaline; or even providing a gentle onset of neuraxial anaesthetic blockade when required, for example, in patients with severe heart disease. Single shot spinal anaesthesia does not confer these benefits.Therefore, it can be said that in over 60–90% of cases where functioning labour epidural analgesia is present, this can be satisfactorily used for emergency Caesarean section anaesthesia in a timely manner. This encourages the anaesthesiologist to utilize the labour epidural, instead of removing it and attempting an alternative technique. This position is supported by Guasch et al.23 in their 2020 experts’ consensus publication regarding European minimum standards for obstetric analgesia and anaesthesia departments where they ‘advise administration of an epidural top-up’ in case of emergency caesarean section, especially if category 1.Reducing the Need for Further Neuraxial Procedures and Their Potential ComplicationsThe decision to remove a labour epidural for an emergency caesarean section and opt for a spinal anaesthetic has disadvantages. Firstly, as described above, the anaesthesiologist is losing an anaesthetic option which has a high chance of success. Secondly, the patient is being exposed to the potential complications associated with a second procedure, which may not have been justifiably necessary. In this case, there is always the possibility that a spinal anaesthetic is not possible to site due to patient anatomy, difficulty with appropriate positioning in an emergency, and psychological stress due to the urgency felt by the multidisciplinary team, among others. This may result in the anaesthesiologist having to resort to general anaesthesia, which may further expose the patient to complications such as awareness, aspiration, and difficulty with airway manoeuvres.Additionally, there is controversy in the literature regarding the safety of spinal anaesthesia following pre-established labour epidural analgesia in obstetric patients. Several authors express concerns regarding the risk of high spinal or total spinal with the injection of local anaesthetic and adjuvants into the cerebrospinal fluid once this is already compressed by the contents of the epidural space.15 24 This seems to be more of an issue if a recent epidural bolus would have just been administered, as compared to an epidural infusion only.24 25 Case reports of these complications have been published, even as early as 1994,26 27 and the 2025 ESAIC guidelines13 also comment about the possibility of high spinal block in these instances.Additional Considerations When considering the choice between topping up a labour epidural or removing it and using a spinal for emergency caesarean section, one should also factor in financial issues, environmental impact, anaesthesiologist workload, and patient perspectives.It can be argued that removing a labour epidural and performing spinal anaesthesia is more costly than topping up the already-present epidural. New sterile attire is used by the anaesthesiologist, together with the opening of a new sterile pack for spinal anaesthesia. This will include consumables, such as the spinal needle, the cleaning solution and swabs; as well as the cost of cleaning, decontamination, and sterilization of any reusable items, which involves the cost of additional staff. The repeated use of personal protective equipment, utilization of consumables, and processes associated with cleaning, decontamination, and sterilization also carries an environmental impact. In a world where cost-efficiency is key, and minimization of environmental impact is important, these considerations cannot be ignored.Choosing to remove a labour epidural and use a spinal anaesthetic for an emergency caesarean section may also affect the anaesthesiologist in terms of stress and workload. Deciding to remove a satisfactory epidural analgesia catheter before even giving it a chance to work is eliminating a realistic anaesthetic option for an emergency procedure. This limits the tools available to the anaesthesiologist as it is not usually feasible for an epidural catheter to be re-inserted in an emergency. It also requires the anaesthesiologist to explain this additional procedure to the patient and gain informed consent in a challenging situation. This extra workload, i.e., explaining, gaining informed consent, and inserting a spinal anaesthetic, may be stressful for the anaesthesiologist. Also, the individual is now required to perform a procedure in a time-pressured and high-stakes environment. Performance anxiety may play a part if the anaesthesiologist is very keen to avoid a general anaesthetic, for example, if they feel the patient’s airway looks particularly difficult or the patient has pre-eclampsia and would therefore be at a higher risk of complications.Patient perspectives should also be considered. The author has found no published literature specifically relating to patient preference regarding epidural or spinal anaesthesia for emergency Caesarean section. However, it is reasonable to think that a patient who has a working labour epidural already has confidence in the technique and as a result, may feel more reassured with epidural anaesthesia for emergency caesarean section as compared to alternatives.Conclusion In summary, labour epidurals providing satisfactory analgesia should be topped up to provide epidural anaesthesia for emergency caesarean sections. In fact, this is one of the main benefits of siting labour epidurals in patients who are at a higher risk for caesarean section. In addition, there are disadvantages to the alternative of removing the labour epidural and using a single shot spinal. Finally, there are financial, environmental, anaesthesiologist, and patient considerations that may further support the choice of epidural anaesthesia over single shot spinal.References Kumar, Nishant DA, DNB, MNAMS. Epidural technique in obstetric anesthesia. Anesthesia & Analgesia March 2021;132( 3):e40. doi: 10.1213/ANE.0000000000005359National Institute for Health and Care Excellence (Great Britain). Intrapartum care for women with existing medical conditions or obstetric complications and their babies. National Institute for Health and Care Excellence (NICE); 2019.Denison FC, Aedla NR, Keag O, Hor K, Reynolds RM, Milne A, Diamond A, on behalf of the Royal College of Obstetricians and Gynaecologists. 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