Background:
Dural puncture epidural anesthesia (DPEA) has become effective during normal labor. There were insufficient data about DPEA during cesarean section (CS).

Methods:
A total of 110 ASA I and II parturients aged 20–35 years old underwent scheduled CS using DPEA with either 25G or 27G Whitacre needles. A T10 sensory block was achieved and maintained using a low concentration of bupivacaine with fentanyl through the epidural catheter until the end of surgery. Epidural extension anesthesia was initiated inside the operating room. The primary outcome was time taken from the start of epidural extension until achievement of bilateral T6 sensory block. The secondary outcome was quality of DPEA (composite).

Results:
The primary outcome, median (IQR) time to surgical anesthesia, was 9.12 (8.71–18.54) minutes in the 25G-DPEA group and 14.18 (12.43–23.56) minutes in the 27G-DPEA group. The difference in the onset time of sensory block between the 2 groups was 5.06 (3.72–5.02) min, which was statistically significant (HR: 2.3; 95% CI: 1.79–3.14%; P < 0.0001). Failure of DPEA was observed in 9 of 55 parturients (16.4%) in the 25-DPEA group compared with 37 of 55 parturients (67.3%) in the 27-DPEA group (OR = 0.095; 95% CI: 0.04–0.24 %; P < 0.0001). Adverse effects and neonatal outcomes were comparable between the two groups.

Conclusions:
25G-DPEA resulted in faster onset and improved block quality during epidural extension compared with 27G-DPEA. Further studies are needed to confirm these findings in the setting of intra-partum CS.