LAUSR

BACKGROUND The failure rate of neuraxial labor analgesia has not been investigated in super-obese women (body mass index ≥50 kg/m2). METHODS We performed a retrospective study of neuraxial labor analgesia in super-obese women (January 2012 to August 2019). The primary outcome was the failure rate of the first neuraxial catheter. Secondary outcomes were failure rates by neuraxial technique, at cesarean delivery, and rate of catheter replacement. RESULTS Neuraxial labor analgesia was used by 233 super-obese women: 153 epidural catheters placed using a combined spinal-epidural (CSE) or dural puncture epidural techniques with visualization of cerebrospinal fluid; 63 placed without dural puncture (including procedures without attempted dural puncture or attempted CSE or dural puncture epidural); and 17 intrathecal catheters (seven intentional). Thirty-two of 233 neuraxial catheters failed (13.7%, 95% Confidence Interval [CI] 9.9 to 18.7%). Epidural catheters placed using CSE or dural puncture epidural had a lower failure rate than those placed without dural puncture (9.2% [95% CI 5.5% to 14.7%] vs 28.6% [95% CI 18.9 to 40.7%]; P<0.001). Catheter migration was documented for 29.4% (95% CI 16.8 to 46.2%) of catheters that failed. CONCLUSIONS Epidural catheters placed using CSE or dural puncture epidural techniques were more reliable than those placed without dural puncture in super-obese parturients. It is unclear whether the result was driven by grouping procedures without attempted dural puncture with those in which dural puncture was attempted but cerebrospinal fluid was not obtained. Catheter migration was a major source of failure.