Comparative Study of Small-Doses of Intravenous Ketamine Versus Intrathecal Morphine in Cesarean Section Under Spinal Anesthesia

Objectives: The aim of this study was to compare the analgesic and side effects among two doses of intravenous ketamine (0.15mg-kg^-1 and 0.25mg-kg^-1) versus intrathecal morphine in pregnant female undergoing low-risk cesarean section under spinal anesthesia. Study Design: Treatment, Randomized, Double-Blind, Active Control, Parallel Assignment, Safety/Efficacy Study. Settings: Woman Health Hospital, Assiut University, Egypt. Patients and Methods: Sixty pregnant women at term, ASA status 1 or II, aged 18 years or more, undergoing elective or repeated cesarean section were included in the study. The patients were divided into 3 groups (20 in each). Group (A) received intrathecal hyperbaric bupivacaine (12mg) plus 200ug morphine, while group (B) received intrathecal hyperbaric bupivacaine (12mg) only, plus IV intravenous ketamine 0.15mg-kg^-1 over 20 minutes immediately after institution of spinal anesthesia but in group (C) the patients received intrathecal hyperbaric bupivacaine (12mg) only, plus IV Ketamine 0.25mg-kg^-1 over 20 minutes immediately after institution of spinal anesthesia. During the 24-h postoperative period, heart rate, systolic blood pressure, respiratory rate, pruritus scale, nausea and vomiting, Richmond Agitation Sedation Scale (RASS) and visual analogue scale were recorded. Results: In the postoperative period, as regard hemodynamic stability there was no statistically difference in the three groups. Morphine produced more analgesic effect than ketamine groups. The incidences of nausea and vomiting and pruritus were greater in the morphine group than in ketamine groups. Respiratory depression was not recorded in any group. Conclusion: Usage of small dose of IV Ketamine (0.15mg-kg^-1) within 20 minutes after initiation of spinal anesthesia was recommended for cesarean section as it provides a good analgesia and lesser side effects than morphine.