Appropriate length of epidural catheter in epidural space for labour analgesia with dural puncture epidural combined with programmed intermittent epidural bolus

The dural puncture epidural (DPE) technique combined with programmed intermittent epidural bolus (PIEB) has been widely used in the clinical practice of labour analgesia. Whether varying the length of catheter threaded into the epidural space benefits for DPE combined with PIEB the resultant analgesia remains unclear. 102 women in labour were enrolled, aged 18–45 years, with cervical dilation > 3 cm and a numeric rating scale (NRS) score > 4, were randomly (1:1:1) assigned to three study groups (the epidural catheter threaded 3, 5, or 7 cm into the epidural space) for labour analgesia. The primary outcome was time to reach adequate analgesia, defined as the interval from the administration of the initial bolus (10 mL of 0.1% ropivacaine with 0.3 µg/mL sufentanil) until the NRS score ≤ 3. Secondary outcomes included pain score, anesthetic consumption, duration of labour, adverse events (pruritus, nausea, hypotension, unilateral block, catheter dislodgment, motor blockade) and Apgar scores. Median time to reach adequate analgesia was significant different among three group: 5.2 min vs.7.0 min vs. 8.1 min in 3, 5 and 7 cm insertion, P = 0.001; the incidence of pruritus was 32.4% vs. 20.6% vs. 5.9% in three group, P = 0.001. There were no differences in other severe adverse events among group, the incidence of nausea was 32.4% vs. 17.6% vs. 14.7% in three group, p = 0.272. Hypotension occurred in four patients in the 3 cm group, one in the 5 cm group, and two in the 7 cm group, p = 0.090. Unilateral block was observed in four patients in the 7 cm group, one in the 3 cm group, and two in the 5 cm group, p = 0.119. Pain score, local anaesthetic consumption, labour duration, catheter dislodgment, motor blockade, and Apgar score of the newborns were statistically insignificant. During labour analgesia with DPE combination with PIEB, when the epidural catheter is left 3 cm in the epidural space, the onset of action is faster, but the incidence of pruritus is higher. Therefore, in order to minimize either catheter or drug-related complications and provide satisfactory analgesia, the appropriate length of catheterization for epidural labour analgesia maybe 5 cm, but larger multicenter studies are warranted to confirm generalizability. ClinicalTrials.gov (NCT06602440); retrospectively registered on 17 September, 2024.