Pain during cesarean delivery (CD) is distressing for a patient, and a leading cause of litigation in obstetric anesthesia.1 It is critical that when providing anesthesia for CD that the parturient is as comfortable as possible.2,3 In parturients who require CD with a labor epidural catheter in situ, surgical anesthesia is frequently initiated by administering a bolus of local anesthetic (LA) via the epidural catheter. The ability to convert a labor epidural to surgical anesthesia for CD is often cited as a benefit of labor epidural analgesia. However, conversion of a labor epidural for surgery is not always successful and may lead to pain and anxiety in the parturient.
Reported epidural conversion failure rates range from 0% to 21%.4-8 The variable incidence may reflect an inconsistent definition. For example, a low reported rate of epidural conversion failure may exclude patients who maintain spontaneous ventilation while receiving significant supplemental intravenous medications (e.g., opioids, propofol, or ketamine). These medications are commonly administered during CD to avoid general endotracheal anesthesia when an epidural anesthetic is inadequate. Realistically then, such practice should be considered as epidural conversion failure. We note that the use of intravenous sedating medications confers drawbacks of aspiration risk, suboptimal pain control, and poor maternal satisfaction.
Multiple factors have been associated with epidural conversion failure (Table 1).9 However, the continued preference of attempted conversion of labor epidural analgesia to anesthesia in parturients requiring CD is somewhat perplexing.10 Stratification of patients more likely to fail epidural conversion with consideration of spinal anesthesia as an alternative may be warranted.
Table 1: Factors Associated with Epidural Conversion Failure
|Breakthrough pain/number of boluses|
|Duration >12 hours since initiation of epidural analgesia|
|Initiation of analgesia using an epidural-only technique as compared to combined spinal epidural|
|Maternal height > 167 cm|
|Urgency of cesarean delivery|
A recent randomized trial compared patients who had epidural anesthesia to those who had an epidural catheter removed and subsequent spinal anesthesia for CD. Maternal comfort during CD was higher in the spinal anesthesia group compared to the epidural anesthesia group.11 The main limitations of this study included recruiting only patients with CD urgency classification of category 3 (needing early delivery but no maternal or fetal compromise) and not reporting the time taken to initiate spinal anesthesia. In two observational studies, patients receiving spinal anesthesia rather than conversion of a labor epidural reported better quality of anesthesia with a side-effect profile similar to patients under spinal anesthesia with no prior epidural catheter.12,13
While spinal anesthesia may provide a superior quality of anesthesia compared to epidural anesthesia,14 the reported increased risk of high or total spinal anesthesia in the setting of pre-existing labor epidural infusion is a potential disadvantage of its use for intrapartum CD.9 However, most reports of high or total spinal anesthesia occurred when a spinal was performed after failed epidural conversion and the patient had received bolus doses of epidural LA.9 In the setting of an urgent or emergent CD, quickly dosing an indwelling epidural catheter may achieve anesthesia faster than providing a new spinal anesthetic. In a study simulating emergency CD, the mean time to spinal anesthesia by expert obstetric anesthesia professionals was just over two minutes compared to one minute 58 seconds for general anesthesia.14 Kinsella and colleagues proposed the concept of a “rapid sequence spinal” in a case series of category 1 (emergent) CD in which the median interquartile range time to prepare and perform a spinal anesthetic was 2 (2–3 [1–7]) min, and time to develop a satisfactory surgical anesthesia was 4 (3–5 [2–7]) min.15
In conclusion, conversion of labor epidural analgesia to epidural surgical anesthesia is associated with a variable and potentially high failure rate. Successful conversion is influenced by multiple factors that may not always be anticipated. Therefore, spinal anesthesia should be considered as a reasonable alternative anesthetic technique for intrapartum CD, even in women with an indwelling labor epidural catheter.
Dr. Ituk is chief of Obstetric Anesthesia in the Department of Anesthesia at Carver College of Medicine, University of Iowa, Iowa City, IA.
The author has no conflicts of interest to disclose.
- McCombe K, Bogod DG. Learning from the law. A review of 21 years of litigation for pain during caesarean section. Anaesthesia. 2018;73:223–230.
- Davies JM, Posner KL, Lee LA, Cheney FW, Domino KB. Liability associated with obstetric anesthesia: a closed claims analysis. Anesthesiology. 2009;110:131–139.
- Szypula K, Ashpole KJ, Bogod D, et al. Litigation related to regional anaesthesia: an analysis of claims against the NHS in England 1995-2007. Anaesthesia. 2010;65:443-452.
- Campbell DC, Tran T. Conversion of epidural labour analgesia to epidural anesthesia for intrapartum Cesarean delivery. Can J Anaesth. 2009;56:19–26.
- Halpern SH, Soliman A, Yee J, Angle P, Ioscovich A. Conversion of epidural labour analgesia to anaesthesia for Caesarean section: a prospective study of the incidence and determinants of failure. Br J Anaesth. 2009;102:240–243.
- Lee S, Lew E, Lim Y, Sia AT. Failure of augmentation of labor epidural analgesia for intrapartum cesarean delivery: a retrospective review. Anesth Analg. 2009;108:252–254.
- Orbach-Zinger S, Friedman L, Avramovich A, et al. Risk factors for failure to extend labor epidural analgesia to epidural anesthesia for Cesarean section. Acta Anaesthesiol Scand. 2006;50:1014–1018.
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- Yoon H-J, Do S-H, Yun YJ. Comparing epidural surgical anesthesia and spinal anesthesia following epidural labor analgesia for intrapartum cesarean section: a prospective randomized controlled trial. Korean J. Anesthesiol. 2017;70:412–419.
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- Visser WA, Dijkstra A, Albayrak M, et al. Spinal anesthesia for intrapartum Cesarean delivery following epidural labor analgesia: a retrospective cohort study. Can J Anaesth. 2009;56:577–583.
- Riley ET, Cohen SE, Macario A, et al. Spinal versus epidural anesthesia for cesarean section: a comparison of time efficiency, costs, charges, and complications. Anesth Analg. 1995;80:709–712.
- Kinsella SM, Girgirah K, Scrutton MJ. Rapid sequence spinal anaesthesia for category-1 urgency caesarean section: a case series. Anaesthesia. 2010;65:664–669.