Comparative Evaluation of Intrathecal Dexmedetomidine and Fentanyl as an Adjuvant for Combined Spinal-Epidural Analgesia for Labor.

Background: Combined spinal-epidural technique is a widely accepted and popular modality for labor analgesia. Opioids are being used as adjuvants since long time. Dexmedetomidine is a new drug that is being used as an intrathecal adjuvant.

Aim: The study aims to compare the safety and efficacy of fentanyl and dexmedetomidine as intrathecal adjuvants in labor analgesia.

Settings and design: This was a continuous, prospective, randomized controlled trial with 120 parturients.

Materials and methods: After ethical approval and written consent, participants were divided randomly into two groups: Group A - bupivacaine 2.5 mg (0.5 mL diluted to 2 mL) + 20 μg of dexmedetomidine in 1 mL saline intrathecally (total volume: 3 mL) and Group B - bupivacaine 2.5 mg (0.5 mL diluted to 2 mL) + 15 μg of fentanyl in 1 mL saline intrathecally (total volume: 3 mL). Primary outcomes were satisfactory analgesia, mode of delivery, and neonatal outcome. Participants were monitored for the onset and duration of analgesia, degree of motor block, and maternal and fetal side effects.

Results: A total of 108 parturients reported sufficient analgesia (Group A: 57; Group B: 51), and 74 patients delivered vaginally (Group A: 41; Group B: 44). The rates of normal vaginal delivery were higher in Group B. Group A reported earlier onset of analgesia (61.26 ± 18.23 s) that lasted for longer duration (124.16 ± 26.23 min) than in Group B. There were no serious side effects in any of the groups. Fetal ultrasound revealed attenuation of fetal heart rate variability. The heart rate of newborns was also found to be low in Group A.

Conclusion: Chances of vaginal delivery are higher with intrathecal fentanyl as an adjuvant. Intensity and duration of analgesia are better with intrathecal dexmedetomidine.