Evaluation of the analgesic effects of ketamine and fentanyl as an Additive to Intrathecal bupivacaine in patients undergoing cesarean section

Objective :To compare the analgesic effect of intratechal fentanyl and ketamine 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 ketamine group (groupK) received bupivacaine 10mg combined with 0.1 mg/kg ketamine preservative free ,the fentanyl group (groupF) received bupivacaine 10mg combined with 25 microgram 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.