Ultra-low local anesthetic for labor epidural analgesia improves outcomes without compromising analgesia
UK: Findings from a meta-analysis revealed that ultra-low concentration local anesthetic for labor epidural attains similar or better maternal and neonatal outcomes compared to low and high concentrations of local anesthetic albeit with reduced consumption of local anesthetic.
The findings of the study, published in the journal Anaesthesia, may be useful for aiding decision-making towards further optimization of epidural local anesthetic regimes in labor.
For labor analgesia, the lumbar epidural is the gold standard. Low concentrations of local anesthetic are recommended. Network meta-analysis by L. Halliday, School of Medicine, Dentistry and Nursing, University of Glasgow, UK, and colleagues examined whether further reducing the concentration of local anesthetic can improve maternal and neonatal outcomes without compromising analgesia.
For this purpose, a systematic search of relevant databases for randomized controlled trials comparing high (>0.1%), low (>0.08% to ≤0.1%), or ultra-low (≤0.08%) concentration local anesthetic (bupivacaine or equivalent) for labor epidural.
Outcomes included duration of labor, mode of delivery, and maternal/neonatal outcomes. Odds ratios or weighted mean differences were calculated using Bayesian network meta-analysis with random-effects modeling. A total of 32 studies consisting of 3665 women met inclusion criteria.
The study led to the following findings:
- The total dose of local anesthetic received increased as the concentration increased; ultra-low compared with low (weighted mean difference −14.96 mg) and low compared with high groups (weighted mean difference −14.99), though there was no difference in the number of rescue top-ups administered between the groups.
- Compared with high concentration, ultra-low concentration local anesthetic was associated with an increased likelihood of spontaneous vaginal delivery (OR 1.46), reduced motor block (Bromage score >0; OR 0.32), and reduced duration of the second stage of labor (weighted mean difference −13.02 min).
- Compared with low, ultra-low concentration local anesthetic had similar estimates for the duration of the second stage of labor (weighted mean difference −1.92 min); spontaneous vaginal delivery (OR 1.07; assisted vaginal delivery (OR 1.35); cesarean section (OR 0.76); pain (scale 1–100, weighted mean difference −5.44); and maternal satisfaction.
- Although a lower risk of an Apgar score < 7 at 1 min (OR 0.43) was reported for ultra-low compared with low concentration, this was not sustained at 5 min (OR 0.12).
"Ultra-low concentration local anesthetic for labor epidural achieves similar or better maternal and neonatal outcomes as low and high concentration, but with reduced local anesthetic consumption," wrote the authors.
"A randomized controlled trial comparing low and ultra-low concentration local anesthetic for labor epidural is warranted."
Reference:
The study titled, "Comparison of ultra-low, low and high concentration local anaesthetic for labour epidural analgesia: a systematic review and network meta-analysis," was published in the journal Anaesthesia.
