Fetal responses to epidural analgesia as evidenced by Doppler indices.

Background: This study was designed to evaluate the maternal effects ofepidural analgesia by different local anesthetics and their impact on placental and fetal blood flow.

Methods: Depending on the type of local anesthetics used, sixty full-term parturients were randomly allocated into 3 equal groups in a randomized blind study; Group (1) received Bupivacaine (0.125%), Group (2) received Ropivacaine (0.2%) and, Group (3) received Levobupivacaine (0.125%). Epidural fentanyl (100 microg) was added to all groups. Safety was assessed by recording the mothers' characters and vital signs as well as the fetal Doppler indices while efficacy was assessed by measuring severity of pain, onset and duration of analgesia, and the motor blockade. Doppler velocimetry studies for fetus included monitoring of Umbilical Artery Pulsitility Indices (UAPI) and Middle Cerebral Artery Pulsitility Indices (MCAPI).

Results: Parturient in all groups were comparable. Pulse rate and arterial blood pressure were significantly decreased in all groups after analgesia, but remained within normal ranges. The pain score, had significant reduction in all groups with best results observed in Group 3. The onset of analgesia was relatively rapid in Group 2 followed by Group 3 then Group 1. The duration of analgesia was prolonged in Group 1 followed by Group 3 and then Group 2. There was no incidence of motor block except in 5 parturient (20%) in Group 1. UAPI was significantly decreased in the three studied groups after epidural analgesia. But, during uterine contraction, there was slight elevation in the UAPI in all groups. The best improvement in placental perfusion was observed in Group 3, then Group 1, and the least was Group 2. On the other hand, MCAPI was significantly increased in al groups after epidural analgesia. But, during uterine contraction, there was slight decrease in the MCAPI in the three groups. The best improvement in MCAPI was observed in Group 3, then Group 1, and the least was Group 2.

Conclusion: All local anesthetics produced excellent analgesia during labor. The Doppler indices were improved in the three groups with the best results in levobupivacaine group.