A comparison of pain relief from three different drug regimes for women undergoing cesarean section

INTERVENTION: Ninety patients 18‐45 yr old American Society of Anesthesiologists ( 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 10 mg combined with 0.1mg/kg ketamine preservative free solution ,The midazolam group (groupM) received bupivacaine 10mg combined with0.02 mg/kg midazolam and The placebo group (group P) received bupivacaine 10mg combined with 0.5ml distilled water(intrathecally) for each three groups 5 minutes prior to surgery) CONDITION: post‐operative pain in Patients undergoing cesarean section PRIMARY OUTCOME: Time to first requirement of analgesic supplement(analgesic administration was initiated by patient request(verbal rating scale[ VRS]>4) SECONDARY OUTCOME: Duration of motor block (the time from intrathecal injection to Bromage score 0) will be assessed by the modified Bromage score (0, no motor loss; 1, inability to flex the hip; 2, inability to flex the knee; and 3, inability to flex the ankle) Duration of sensory block will be assessed by a pinprick test Heart rate is assessed by echocardiogram monitoring Mean arterial blood pressure is assessed by nonivasive automatic blood pressure measurement Sensory block onset time will be assessed by a pinprick test The onset of motor block will be assessed by the modified Bromage score (0, no motor loss; 1, inability to flex the hip; 2, inability to flex the knee; and 3, inability to flex the ankle) INCLUSION CRITERIA: patients with American Society of Anesthesiologists(ASA) physical status I and II, undergoing elective cesarean section