Conditions: Pregnant Women
Keywords: scheduled cesarean delivery spinal anesthesia local anesthesia
Allocation: NON_RANDOMIZED | Intervention model: SEQUENTIAL
Enrollment: 40
Healthy volunteers: no

Brief summary:
Hyperbaric bupivacaine 0.5% associated with opioids is the local anesthetic the most commonly used for spinal injection in cesarean section. Nevertheless, its use often results in a long duration of motor nerve block and a haemodynamical instability. Recently developped, the Prilocaine, with its new 2% hyperbaric formulation, seems to offer a good alternative for hyperbaric bupivicaine. A first study has determined the ED95 of hyperbaric prilocaine 2% for intrathecal anesthesia in scheduled cesarean delivery. As opioid adjuvants potentiate the effect of the local anesthetics while decreasing their dose-related side effects, the aim of this study is to determine the ED95 of hyperbaric prilocaine 2% with sufentanyl for scheduled cesarean delivery under spinal anesthesia,by using the Continual Reassessment Method (CRM)

Detailed description:

Arms:
arm 1: Dose-finding study with 4 subjects per dose and a maximum of 40 parturients.To identify the dose to give for reaching the ED95 (effective dose for 95% subjects), Hyperbaric prilocaine 2%, associated with sufentanyl, will be administrated at the dose initial of 45 mg in the cohort 1 (4 subjects), then the dose will be adjusted in the next cohorts using the Continual Reassessment Method (CRM). Possible dose levels are 30, 35, 40, 45, 50, 55mg. arm 2: Dose-finding study with 4 subjects per dose and a maximum of 40 parturients.To identify the dose to give for reaching the ED95 (effective dose for 95% subjects), Hyperbaric prilocaine 2%, associated with sufentanyl, will be administrated at the dose initial of 45 mg in the cohort 1 (4 subjects), then the dose will be adjusted in the next cohorts using the Continual Reassessment Method (CRM). Possible dose levels are 30, 35, 40, 45, 50, 55mg. arm 3: Dose-finding study with 4 subjects per dose and a maximum of 40 parturients.To identify the dose to give for reaching the ED95 (effective dose for 95% subjects), Hyperbaric prilocaine 2%, associated with sufentanyl, will be administrated at the dose initial of 45 mg in the cohort 1 (4 subjects), then the dose will be adjusted in the next cohorts using the Continual Reassessment Method (CRM). Possible dose levels are 30, 35, 40, 45, 50, 55mg. arm 4: Dose-finding study with 4 subjects per dose and a maximum of 40 parturients.To identify the dose to give for reaching the ED95 (effective dose for 95% subjects), Hyperbaric prilocaine 2%, associated with sufentanyl, will be administrated at the dose initial of 45 mg in the cohort 1 (4 subjects), then the dose will be adjusted in the next cohorts using the Continual Reassessment Method (CRM). Possible dose levels are 30, 35, 40, 45, 50, 55mg. arm 5: Dose-finding study with 4 subjects per dose and a maximum of 40 parturients.To identify the dose to give for reaching the ED95 (effective dose for 95% subjects), Hyperbaric prilocaine 2%, associated with sufentanyl, will be administrated at the dose initial of 45 mg in the cohort 1 (4 subjects), then the dose will be adjusted in the next cohorts using the Continual Reassessment Method (CRM). Possible dose levels are 30, 35, 40, 45, 50, 55mg. arm 6: Dose-finding study with 4 subjects per dose and a maximum of 40 parturients.To identify the dose to give for reaching the ED95 (effective dose for 95% subjects), Hyperbaric prilocaine 2%, associated with sufentanyl, will be administrated at the dose initial of 45 mg in the cohort 1 (4 subjects), then the dose will be adjusted in the next cohorts using the Continual Reassessment Method (CRM). Possible dose levels are 30, 35, 40, 45, 50, 55mg. arm 7: Dose-finding study with 4 subjects per dose and a maximum of 40 parturients.To identify the dose to give for reaching the ED95 (effective dose for 95% subjects), Hyperbaric prilocaine 2%, associated with sufentanyl, will be administrated at the dose initial of 45 mg in the cohort 1 (4 subjects), then the dose will be adjusted in the next cohorts using the Continual Reassessment Method (CRM). Possible dose levels are 30, 35, 40, 45, 50, 55mg. arm 8: Dose-finding study with 4 subjects per dose and a maximum of 40 parturients.To identify the dose to give for reaching the ED95 (effective dose for 95% subjects), Hyperbaric prilocaine 2%, associated with sufentanyl, will be administrated at the dose initial of 45 mg in the cohort 1 (4 subjects), then the dose will be adjusted in the next cohorts using the Continual Reassessment Method (CRM). Possible dose levels are 30, 35, 40, 45, 50, 55mg. arm 9: Dose-finding study with 4 subjects per dose and a maximum of 40 parturients.To identify the dose to give for reaching the ED95 (effective dose for 95% subjects), Hyperbaric prilocaine 2%, associated with sufentanyl, will be administrated at the dose initial of 45 mg in the cohort 1 (4 subjects), then the dose will be adjusted in the next cohorts using the Continual Reassessment Method (CRM). Possible dose levels are 30, 35, 40, 45, 50, 55mg. arm 10: Dose-finding study with 4 subjects per dose and a maximum of 40 parturients.To identify the dose to give for reaching the ED95 (effective dose for 95% subjects), Hyperbaric prilocaine 2%, associated with sufentanyl, will be administrated at the dose initial of 45 mg in the cohort 1 (4 subjects), then the dose will be adjusted in the next cohorts using the Continual Reassessment Method (CRM). Possible dose levels are 30, 35, 40, 45, 50, 55mg.

Interventions: intervention 1: HB Prilocaine 2% (varying dose) intervention 2: HB Prilocaine 2% intervention 3: Sufentanil intervention 4: Morphine
Intervention descriptions: intervention 1: Varying dose of hyperbaric (HB) prilocaine 2% according to sensitive response of previous subjects. The dose of hyperbaric prilocaine 2% will be administrated intrathecally with 100µg of morphine and 2.5µg of sufentanyl intervention 2: The dose of 45mg of hyperbaric (HB) prilocaine 2% will be administrated intrathecally with 100µg of morphine and 2.5µg of sufentanyl intervention 3: 2.5µg sufentanyl intervention 4: 100 µg Morphine

Protocol document: