To compare the effect of remifentanil parturient-controlled intravenous analgesia and sufentanil combined ropivacaine parturient-controlled epidural analgesia in labor, in order to assess the safety and feasibility of remifentanil patient-controlled intravenous analgesia in labor.

From June to December 2014, a total of 427 cases of pregnant women who delivered in Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine and demanded for analgesia voluntarily were enrolled as research subjects. According to the analgesia method pregnant women chose for, they were divided into study group (n=159) who received remifentanil parturient-controlled intravenous analgesia and control group (n=268) who received sufentanil combined ropivacaine parturient-controlled epidural analgesia. All the 427 cases of pregnant women were grade Ⅰ-Ⅱ in American Society of Anesthesiologists (ASA), single birth, full term, received analgesia voluntarily and with vaginal trial delivery. The analgesia method in study group was with remifentanil 20 μg/mL, first dose of remifentanil: 0.4 μg/kg, background dose: 0.04 μg/(kg·min), patient controlled analgesia (PCA) dose: 0.4 μg/kg and lockout time: 3 minutes. While the analgesia method in control group was with sufentanil 0.3 μg/mL + 0.068% ropivacaine, background dose: 6~8 mL, PCA dose: 5 mL, and lockout time: 20 minutes. At the time fetus delivered out, 1 mL umbilical artery (UA) blood was exsanguinated immediately and did blood gas analysis. Blood pressure, heart rate, respiratory rate, hemoglobin oxygen saturation by pulse oximetry (SpO₂), visual analogue scale (VAS) score and Ramsay sedation score before analgesia, at the onset of analgesia, 1 hour, 2 hours and 3 hours after analgesia of two groups were recorded. The period of effective analgesia, the period of first, second, and third stage of labor, the use of oxytocin, forceps delivery rate, cesarean section rate, Apgar scores, UA blood gas analysis, adverse reactions, and the satisfaction of pregnant women and their families of two groups were also recorded. Statistical methods were analyzed between two groups among those indexes mentioned above. The study protocol was approved by the Ethical Review Board of Investigation in West China Second University Hospital, Sichuan University. Informed consent was obtained from each participant.

①There were no statistically significant differences between two groups among the age, body weight, body height, body mass index and gestational age and so on (P>0.05). ②There were no statistically significant differences between two groups among mean arterial pressure, heart rate, breathing rate and SpO₂ before analgesia, the onset of analgesia, 1 hour, 2 hours and 3 hours after analgesia (P>0.05). ③The analgesia onset time in study group was (1.0±0.1) minutes which was significantly shorter than that of (15.7±1.9) minutes in control group, and the difference was statistically different (t=126.408, P=0.000). The Ramsay sedation scores in study group at the onset of analgesia and 1 hour after analgesia were (2.4±0.6) score, (2.3±0.4) score which were significantly higher than those of (1.9±0.4) score, (1.9±0.4) score, respectively in control group, and both the differences were statistically significant (t=10.599, 10.722; P=0.000). While there were no statistical differences of Ramsay sedation scores before analgesia, 2 hours and 3 hours after analgesia between two groups (P>0.05). The VAS scores at the onset of analgesia and 1 hour, 2 hours and 3 hours after analgesia in study group were all higher than those in control group, and all the differences were statistically different (P<0.05). And the VAS score in study group was in an increasing trend 1 hour after analgesia, while the trend in control group was relatively stable. ④There were no statistical differences among the mode of delivery, labor process, forceps delivery rate, cesarean section rate and the rate of using of oxytocin between groups (P>0.05). There were no statistical differences between two groups in the incidences of vomiting and pruritus (P>0.05). 22.0% (31/141) patients in study group encountered dizziness, which was far higher than that in control group 1.8% (4/228) and the difference was statistically different (χ²=41.535, P=0.000). But the incidence of lower limb numbness in study group (0.7%, 1/141) was lower than that in control group (6.6%, 15/228), and the difference was also statistically significant (χ²=7.236, P=0.007). ⑤The Apgar score, the pH value and base excess level of UA blood gas analysis of the newborn infants between two groups were not statistically significant (P>0.05). ⑥Both two groups obtained high degree of satisfaction from pregnant women and their family, and both the differences between two groups were not statistically significant [pregnant women: 94.3% (150/159) vs 95.1% (255/268), χ²=0.13, P=0.714; their family: 95.0% (151/159) vs 96.3% (258/268), χ²=0.42, P=0.518].

Compared to traditional sufentanil combined ropivacaine parturient-controlled epidural analgesia in labor, remifentanil parturient-controlled intravenous analgesia is confirmed secure, effective and convenient. As an alternative mode of labor analgesia, remifentanil patient-controlled intravenous analgesia with background dose 0.04 μg/(kg·min) and PCA dose 0.4 μg/kg can be used under the precondition of ensuring one-to-one beside care, continuous monitoring, oxygen supply and preparation for neonatal resuscitation.