Your next patient will receive a dural puncture epidural for labor. According to a recent study, which of the following is MOST likely to be lower in this patient, compared with a similar patient receiving lumbar epidural anesthesia without dural puncture?

  • □ (A) Risk of postdural puncture headache
  • □ (B) Need for an epidural blood patch
  • □ (C) Need for catheter replacement
There have been many studies comparing lumbar epidural anesthesia, combined spinal-epidural anesthesia, and dural puncture epidural. Dural puncture epidural differs from combined spinal-epidural anesthesia in that no intrathecal medication is injected after the dural puncture is performed, but an epidural catheter is left in place. The benefits of combined spinal-epidural anesthesia over epidural analgesia have mainly been faster onset time and a reduced need for catheter replacement. The authors of a recent study postulated that, as dural puncture epidural involves dural puncture, similar to combined spinal-epidural anesthesia, dural puncture epidural also may have a lower catheter replacement rate compared with lumbar epidural analgesia.

In this single-center, retrospective study, investigators reviewed records from a five-year period (June 1, 2016-May 31, 2021) at a U.S. academic institution. Anesthesia records were cross-referenced with obstetric delivery records, electronic health records, and in-house obstetric logs. Investigators included all laboring women who received neuraxial anesthesia and had vaginal or cesarean delivery. Neuraxial analgesia placement was completed using a 17-gauge Tuohy needle and a 27-gauge pencil-point spinal needle with 24- and 25-gauge needles available as needed. A flexible wire-reinforced catheter was threaded to a depth of 4-5 cm after loss of resistance was achieved, and an epinephrine test dose was used to confirm nonvascular placement. The dosing regimen for both epidural analgesia and dural puncture epidural analgesia was a continuous dose of 15 mL/h of 0.04% bupivacaine with 1.67 μg/mL of epinephrine and 1.67 μg/mL of fentanyl after an initial 15-mL bolus. Epidural analgesia was maintained via patient-controlled analgesia with a bolus dose of 10 mL and a lockout period of 20 minutes.

Patients were assessed for pain each hour by the obstetric nurse and every four hours by the anesthesia team. A standardized protocol was followed for postoperative pain assessment. If the catheter was in the correct location, a clinician administered a bolus of 8 mL of 0.125% bupivacaine with or without 100 μg of fentanyl. Twenty minutes later, the patient was reassessed. If breakthrough pain continued, a second bolus was administered. If there was no improvement after two boluses, the epidural was replaced. These protocols did not change during the study period. The study groups were matched for comparisons, with the primary outcome being the rate of catheter replacement, including catheter failure rate. Other analyzed outcomes included conversion to general anesthesia, the rate of dural puncture headache, the need for blood patch, the need for supplemental epidural bolus, the timing of supplemental epidural bolus, and the time to rescue bolus.

Investigators included 26,613 delivery records from 20,651 patients. After excluding combined spinal-epidural anesthesia, 3,477 anesthetics were included in the analysis: 2,667 patients received lumbar epidural analgesia and 810 received dural puncture epidural. The study found that the catheter replacement rate was 5.9% in the dural puncture group versus 9.0% for lumbar epidural analgesia, while the catheter failure rate was 6.5% in the dural puncture group versus 9.8% in the lumbar epidural group. The dural puncture catheters were also noted to function for a longer period of time than the lumbar epidural-only catheters (44.7 vs. 35.4 hours).

Investigators found that body mass index (BMI), parity, gravidity, gestational age, catheter dwell time, and time to first physician-given epidural bolus were associated with catheter failure. There was a 3.0% absolute risk reduction for catheter replacement (95% CI, 0.4%-5.7%) with dural puncture epidural, including 3.3% fewer catheter failures (95% CI, 0.6%-6.0%). In a Cox multivariate analysis, dural puncture epidural was associated with fewer catheter failures (hazard ratio, 0.61; 95% CI, 0.44-0.86). The time to first epidural bolus was significantly longer with dural puncture epidural (450 vs. 367 minutes in the lumbar epidural group; difference, 83 minutes; 95% CI, 36-131 minutes). No differences were noted in the rate of conversion to general anesthesia, the need for supplemental bolus, the rate of postdural puncture headache, or the need for an epidural blood patch.

This retrospective study demonstrated some potential benefits of dural puncture epidural versus nondural puncture lumbar epidural analgesia for laboring women; namely, a reduced risk of catheter failure and a reduced need for catheter replacement. Most of the other outcomes were similar between groups; however, time to first epidural bolus was longer in the dural puncture group, potentially indicating better pain control. Lastly, the study identified several patient-related risk factors that may also affect catheter failure, such as higher BMI and lower parity.

Answer C