Abstract: Objective: To explore the effect of enhancing the rate of programmed intermittent epidural bolus(PIEB) on the labor analgesia and the dosage of ropivacaine supplement in the lying-in women,and to provide the basis for studing labor analgesia. Methods: One hundred and twenty-six women with a singleton pregnancy received labor analgesia with PIEB method and were randonly divided into low-rate group (n=60) and high-rate group (n=66). Epidural infusion was given the initial loading dose of 10 mL(0.09% ropivacaine+0.4 mg·L^-1 sufentanil), followed by 100 mL pulse injection pump(0.09% ropivacaine+0.4 mg·L^-1 sufentanil).Every 60 min, intermittent bolus of 10 mL was given; the patient were administered with the rates of 100 mL·L^-1(low-rate group) or 200 mL·L^-1 (high-rate group).The drug administration time of patient-controlled epidural analgesia (PCEA) was set as 5 mL,and the locking time was set as 30 min. The initial pain visual analog scale (VAS) score, duration of labor, delivery mode, supplementary amount and frequency of ropivacaine, first supplementary time of ropivacaine,a mount of PCEA pump, maternal satisfaction score, maximum sensory block level, as well as the incidence of adverse events,such as nausea and vomiting, hypotension, respiratory depression and fever of the lying-in women in the analgesia period were recorded. Results: The initial pain VAS scores, duration of labor, natural delivery rates, assisted vaginal delivery rates and cesarean section rates of the patients in two groups had no significant differences (P>0.05).There were no significant differences in the amount and frequency of supplementary, the first supplement time of ropivacaine,the amount of PCEA pump between two groups(P>0.05).The satisfaction scores of the lying-in women in two groups had no significantly difference(P<0.05).The highest analgesia level in two groups was T7-T8, and no adverse events,such as nausea and vomiting,hypotension, respiratory depression and fever, were observed in all the lying-in women. Conclusion: Compared with low-rate PIEB labor analgesia,the effect of labor analgesia, times of need for supplemental analgesia and the consumption of ropivacaine per hour are not improved by high-rate PIEB.

Key words: labor analgesia, programmed intermittent epidural bolus, epidural analgesia, ropivacaine, patient-controlled epidural analgesia