Previous wet tap does not reduce success rate of labor epidural analgesia

Whether unintentional dural puncture (wet tap) during a previous labor epidural increases the failure rate of epidural analgesia for later deliveries is controversial. In this study, charts of 47 women with a previous wet tap who received epidural analgesia for labor were compared to those of 500 consecutive women receiving epidural analgesia in 1991 and, separately, to 44 women matched for month of delivery, previous epidural without a wet tap, and the same anesthesiologist. In comparison to the 500 consecutive control patients, women with a previous wet tap had a lower incidence of epidural catheter manipulation for inadequate block (9% vs 20%), but a similar incidence of catheter removal for failed block (4% vs 6.7%). In comparison to matched control patients, women with a previous wet tap had a similar incidence of epidural catheter manipulation and removal for inadequate or failed blocks. Epidural analgesia was considered successful in 93% of cases and 89% of matched control subjects by chart review. Two women (4%) with previous wet tap experienced a second wet tap during attempted epidural catheterization, compared to 0% in 500 consecutive patients (P < 0.001). These data suggest that there is no decrease in the success rate of epidural analgesia in women with a previous wet tap, although the chance for a repeated wet tap may be increased.