Addition of dexmedetomidine to epidural morphine to improve anesthesia and analgesia for cesarean section

Abstract

The aim of the present study was to evaluate the effectiveness and safety of the combination of epidural dexmedetomidine and morphine in providing anesthesia during cesarean surgery and analgesia for post-cesarean pain relief when added to epidural ropivacaine. A total of 80 females at term scheduled for elective cesarean delivery were randomly assigned to two groups (n=40/group): In the morphine group (group M), patients received an epidural injection of 0.75% ropivacaine (12 ml) and morphine (2 mg) for surgical anesthesia, and epidural infusion of morphine (2 mg) in 100 ml 0.2% ropivacaine at 2 ml/h for 48-h post-operative analgesia; and in the morphine combined with dexmedetomidine group (group DM), patients received an epidural injection of 0.75% ropivacaine (12 ml) and morphine (2 mg) combined with dexmedetomidine (0.5 µg/kg) for surgical anesthesia, and epidural infusion of morphine (2 mg) and dexmedetomidine (200 µg) in 100 ml 0.2% ropivacaine at 2 ml/h for 48-h post-operative analgesia. The primary outcomes included blockade and analgesic effects, sedation and adverse reactions associated with the drugs. Neonatal outcome was also assessed by determining the Apgar score and umbilical cord blood analysis. There was no significant difference between the groups in the cephalad levels of sensory blockade at 20 min post-injection, or in muscle relaxation scores or pain intensity scores at rest or upon movement at 4, 12, 24 or 48 h post-injection (P>0.05). The maternal patients in the DM group experienced more complete motor blockade at 20 min post-injection, better sedation during surgery and following delivery, and less visceral pain caused by peritoneal traction during surgery and by uterine contraction after delivery, compared with those in group M (P<0.05). The patients in group M had a lower incidence and severity score of post-operative nausea than those in the DM group (P<0.05). There was no significant difference between the groups in terms of Apgar score or umbilical cord blood gas values (P>0.05). In conclusion, epidural dexmedetomidine reduces intra-operative and post-operative visceral pain and produces better sedation during surgery and following delivery, without any significant influence on morphine-associated side effects and post-operative analgesia, in females undergoing elective cesarean section under epidural anesthesia with morphine and ropivacaine (registration number ChiCTR1900027942; retrospectively registered with the Chinese Clinical Registry Center on December 6, 2019).

Keywords: adverse reactions; cesarean section; dexmedetomidine; epidural anesthesia; morphine.