The incidence of intrapartum cesarean delivery (CD) varies between 8% and 20% among different hospitals. Anesthesia for intrapartum CD differs from elective CD because:
It is often emergent or urgent.
Usually, the patient has an existing labor epidural rather than a de novo spinal or combined spinal and epidural (CSE).
Failure rates for conversion of labor epidural analgesia to surgical anesthesia for CD can be as high as 20%.1
Postoperative CD analgesia can also be complicated for a patient who has endured both labor pain and CD pain.
Successful conversion of labor epidural analgesia to CD anesthesia is a meaningful measure of quality of care and an important clinical process to reduce the incidence of general anesthesia and ensure maternal comfort during CD.2
The definition of failure of conversion varies greatly in literature resulting in a great difference in the incidence of failure of conversion. Most authors define failed conversion as the need to perform either a repeat neuraxial procedure or general anesthesia.
THE RISKS OF FAILURE OF CONVERSION
The Risks of Failure of Conversion3
Recurrent breakthrough pain requesting multiple epidural boluses (Odds ratio, OR 3.2)
Urgency of CD (OR 40.4)
Long duration of labor epidural
Nonobstetric anesthesia specialized provider (OR 4.6)
STRATEGIES FOR SUCCESSFUL CONVERSION (FIG. 49-1)
Understanding the reasons for failure will help anesthesiologists strategically plan to achieve a successful conversion. Early and active steps to prevent failure are more desirable than late recognition with the potential need for general anesthesia. The following are suggested:
Aggressively treat breakthrough pain (Chapter 42, “Refractory Pain During Labor Epidural Analgesia”).
Replace the epidural catheter early if the sensory level does not improve with repeat boluses.
If breakthrough pain is refractory to treatment during labor, consider replacing a new CSE in the operating room. A reduced dose of bupivacaine (0.8-1.2 mL of 0.75% hyperbaric bupivacaine) for spinal part is recommended.6 Be aware of the risk of high spinal (Chapter 60, “High Spinal”).
A small dose of epidural dexmedetomidine (10-20 µg) may improve pain control (Chapter 6, “Dexmedetomidine”).
Strategies for successful conversion of labor epidural for CD.
R. Failure to extend epidural labor analgesia for cesarean delivery anesthesia. Anesth Analg.
B. Conversion of labour epidural analgesia to surgical anaesthesia for emergency intrapartum caesarean section. BJA Education
et al. Risk factors for failed conversion of labor epidural analgesia to cesarean delivery anesthesia: a systematic review ...