The dose response of sufentanil as an adjuvant to ropivacaine in cesarean section for relief from somato-visceral pain under epidural anesthesia in parturients with scarred uterus

Abstract

Visceral pain is common during epidural anesthesia with mini dose local anesthetics in parturients during cesarean section. To reduce or avoid this complication caused by traction on the abdominal viscera, this study aimed to determine the 50% effective dose (ED50) and 95% effective dose (ED95) of epidural sufentanil as an adjuvant combination with local anesthetics for relief visceral pain in parturients with scarred uterus undergoing elective cesarean section.One hundred parturients with scarred uterus undergoing elective cesarean section under epidural anesthesia were enrolled in this randomized, double-blinded, dose-ranging study. Parturients received 5, 10, 15, 20, and 25 μg epidural sufentanil as an adjuvant with 10 mL of 0.65% ropivacaine. Successful epidural anesthesia was defined as a sixth thoracic vertebra (T6) sensory level achieved within 20 minutes after epidural drugs administration and/or no visceral pain by traction on the abdominal viscera during the cesarean section. The ED50 and ED95 were calculated with a logistic regression model.ED50 and ED95 of epidural sufentanil for successful of the pain-free from visceral pain were 10.7 μg [95% confidence interval (CI): 2.4-14.4 μg) and 28.1 μg (95% CI: 19.4-44.0 μg), respectively. The onset time to sensory block, maximum Bromage scale and duration of motor block were significant different with dose of sufentanil >20 μg (P < .05, compared with the other dose groups). With the dose of epidural sufentanil >20 μg could result in an increase of incidence of maternals' adverse effects. Compared with a different dose of sufentanil, epidural administed sufentanil between 15 μg and 20 μg can maximize parturients' satisfaction.Our study showed that sufentanil could be used in combination with ropivacaine for relief from somato-visceral pain in patients with scarred uterus during elective cesarean section during epidural anesthesia, and that maximized parturients' satisfaction could be achieved when the use of sufentanil with the dose between 15 μg and 20 μg for epidural anesthesia.

Figure 1

The percentages of success free pain at different doses of epidural sufentanil for the intraoperative visceral pain.

Figure 2

Logistic regression plot of the probability of successful epidural anesthesia versus epidural sufentanil dose. The probability of 0.5 and 0.95 was used for deriving the 50% effective dose and 95% effective dose of epidural sufentanil to achieve successful epidural anesthesia for cesarean section.

Figure 3

Parturients’ overall postoperative satisfaction rating at different doses of epidural sufentanil for the cesarean section. The satisfaction score was assessed using a 4-point scale (not satisfied, moderately satisfied, satisfied, and very satisfied). The 5 categories (n = 100, Mean Rank were 38.2, 44.0, 60.6, 66.3, and 43.6, respectively, x² = 13.7, df = 4, P = .008).