Comparison of Postoperative Analgesic Effect of Intrathecal Clonidine and Fentanyl Added to Bupivacaine in Patients Undergoing Cesarean Section

Objective :To compare the analgesic effect of intrathecal clonidine and fentanyl as an additive to bupivacaine in patients undergoing cesarean section .

Methods:Following Ethics Committee approval and informed patients consent, Ninety patients 18-45 yr old ASA physical status I or II, scheduled for cesarean section under spinal anesthesia, were studied in a prospective, double-blinded, randomized way. The patients were randomly allocated to one of three groups of 30 each. The clonidine group (groupC) received bupivacaine 10mg combined with 75microgram clonidine preservative free ,the fentanyl group (group F) received bupivacaine 10mg combined with25microgram fentanyl and the placebo group (group P) received bupivacaine 10mg combined with 0.5ml distilled water intrathecally . Time to first requirement of analgesic supplement, Sensory block onset time, maximum sensory level , onset of motor block, duration of blockade, hemodynamics variables, the incidence of hypotension, ephedrine requirements, bradycardia ,hypoxemia [Saturation of peripheral oxygen (SpO2)<90], postoperative analgesic requirements and Adverse events, such as sedation, dizziness , Pruritus and postoperative nausea and vomiting were recorded. Patients were instructed preoperatively in the use of the verbal rating scale (VRS) from 0 to 10 (0no pain, 10maximum imaginable pain) for pain assessment. If the VRS exceeded four and the patient requested a supplement analgesic, diclofenac Na supp 100 mg was to be given for post-operative pain relief as needed . For breakthrough pain(VRS >4) if time of administration of diclofenac Na less than 8h,Pethidine 25 mg IV was given.