Comparison Between Analgesic Effect of Dexamethasone and Dexmedetomidine as an Adjuvant to Bupivacaine for Spinal Anaesthesia for Elective Caesarean Sections

Abstract

Background Caesarean sections are usually performed under spinal anaesthesia. It provides effective postoperative pain control over a limited period of time. As a result, various intrathecal additives have been used. Recently, dexamethasone and dexmedetomidine have been used as adjuncts for different types of regional anaesthesia without increasing the risk of neurological complications. Objectives: We compared the analgesic effects of intrathecal dexamethasone and dexmedetomidine in elective caesarean sections. Design: A single-blind randomized trial. Setting: Benha University Hospital, between February 2021 and July 2021. Patients: We randomly enrolled 633 pregnant women in this study. Only 580 patients met all the inclusion and exclusion criteria. The inclusion criteria were age of 18 to 40 years old, an ASA class ІІ - III, gestational age > 37 weeks, BMI less than 30 kg/m2 who were electively scheduled for. The exclusion criteria included patient refusal, age < 18 or > 40 years, known allergy to medications used in the study, BMI more than 30 kg/m2, coagulopathies or anticoagulant use, cerebrovascular insufficiency, neuromuscular diseases and diabetic neuropathy. Intervention: The dexmedetomidine group (A) received 10 μg of dexmedetomidine with 12.5 mg hyperbaric bupivacaine 0.5%intrathecally(n=290). The dexamethasone group (B) received 4 mg of dexamethasone with 12.5 mg hyperbaric bupivacaine 0.5%intrathecally(n=290). Main outcome: The time to initial analgesic rescue (pethidine 0.5 mg/kg) and the duration of motor blockage were assessed. Results: The time to the first rescue analgesia and motor blockade were significantly higher in the dexmedetomidine group. (418 min vs 190 min), P<0.001, (324 min vs 144 min), P <0.001 respectively. Conclusion: According to this study, both drugs could be safely added to bupivacaine intrathecally. Dexmedetomidine provides significantly longer postoperative analgesia and motor blockade times than dexamethasone. Further dose-response studies are needed to determine the optimum dosage of dexamethasone and dexmedetomidine and the safety of the intrathecal route.