Continuous spinal anesthesia with sufentanil in labor analgesia can induce maternal febrile responses in puerperas

Several studies documented persistent hypothermia in parturients after spinal anesthesia, while others reported that labor analgesia was related to a high incidence of fever. Continuous spinal labor anesthesia with sufentanil (CSLAS) is a new effective technique in labor analgesia but whether it affects maternal temperature has not been clarified. The aim of our study was to explore the relationship between CSLAS and maternal intrapartum temperature during vaginal delivery.

75 healthy term nulliparas of spontaneous labor were randomized to receive CSLAS during delivery in sufentanil group (n=37) or non-pharmacological methods of pain relief in control group (n=38). The maternal tympanic temperature was recorded at each time points we required during labor. IL-6, IL-8 and TNF-α were sampled at baseline (before analgesia) and 5 minutes after delivery. The data on visual analog scale (VAS) in all puerperas, first and second stage durations of labor, vaginal examination, oxytocin augmentation, maternal and neonatal antibiotic therapy, maternal and neonatal infection, need for cesarean section, need for instrumental delivery and Apgar scores were all collected from the patients' medical records.

Baseline characteristics of parturients in the 2 groups were not significant differences. After intrathecal injection of sufentanil, the sensation of pain was attenuated by a wide margin in the sufentanil group compared with the control group. Nine parturients in the sufentanil group (24.32%) and two in the control group (5.26%) had a tympanic temperature above 38°C during the labor (p=0.024). In each group, there was a tendency that maternal temperature elevated gradually with time elapsing and reached the peak value 5 hours after baseline. The changes had significant difference from 3 hours to 7 hours after analgesia compared with baseline. Maternal serum IL-6 and IL-8 levels were increased during the labor, while TNF-α did not vary at any time point in each group. 1 min and 5 min Apgar scores were not significant difference in the two groups and no neonate developed temperature above 38°C in the first 24 hours and with antibiotic therapy.

The technique of continuous sufentanil spinal labor anesthesia is a safe and effective method in labor analgesia; however, it is associated with an increased incidence of maternal fever.