Abstract:

Objective To evaluate the inhibitory effect of regular intermittent epidural injection(RIEI)at different vertebra interspace during labor analgesia on breakthrough pain. Methods Ninety primiparas who requested labor analgesia were randomized into three groups: group of L_2-3(group A), group of L_3-4(group B)and group of L_4-5(group C). Epidural puncture procedure was performed at L_2-3, L_3-4, L_4-5, respectively for the 3 groups. After the catheter was inserted into epidural space, a test dose of 5 mL and loading dose of 10 mL was injected subsequently. All subjects were given pumps and received same parameter setting: manual bolus dose 8 mL+ lockout time 15 min+background continuous infusion dose 0+bolus dose 8 mL/h. RIEI started 60 min after test dose was injected. The blood pressure(BP), heart rate(HR), respiratory rate(RR), SpO₂, fetal heart rate(FHR), visual analog scale(VAS), modified Bromage score, the consumption of anesthetic, maximum blocked segment, breakthrough pain, stage of labor, delivery mode, amount of oxytocin, postpartum hemorrhage, the side-effects and Apgar score of neonates were recorded. Results The VAS obviously decreased in three groups since receiving labor analgesia(P <0.05), but no significant difference in VAS was found among the three groups(P>0.05). Compared with group A and group B,the maximum blocked segment in group C was significantly lower during labor analgesia(P <0.05), but the incidence of breakthrough pain was similar among the three groups(P>0.05). There was no significant difference in the other indexes among the three groups(P>0.05). Conclusion Similar clinical analgesic effect and incidence of breakthrough pain were acquired with regular intermittent epidural injection technique at L_2-3, L_3-4 or L_4-5, respectively. Therefore, the ideal choice of vertebral interspace should meet two standards: clear anatomic structure location and easy to perform the puncture.

Key words: epidural space, regular, intermittent, labor analgesia