Postpartum Women's Dexmedetomidine Sedation
Condition: Cesarean Section
Study type: Interventional
Phase: Phase 4

Summary: 
      Currently, spinal anesthesia is most commonly used for cesarean section.But spinal anesthesia
      can not block the visceral vagus nerve, and the patients are prone to nausea, vomiting, chest
      tightness or other discomfort when the uterus is stretched .For parturients who have poor
      uterine contractions and are bleeding larger, obstetricians often use oxytocin to strengthen
      the contraction of the uterine,which also would increase the parturients'
      discomfort.Anesthesiologists often intravenous sedative hypnotics (eg.propofol or midazolam)
      to alleviate the fear of the parturients after the baby is delivered.One of the side effects
      of propofol or midazolam is that they would lead to the respiratory depression.For the poor
      respiratory reserve of the parturients, functional residual capacity(FRC) of this group could
      be reduced by up to 20%, and the oxygen consumption was also increased.The SPO2 could decline
      quickly intraoperatively.Dexmedetomidine is a novel , highly selective α2 adrenergic receptor
      agonists , and its selectivity for α2 receptor is 1600 times higher than α1.It also could
      provide dose-dependent sedation , analgesia , anti-anxiety and inhibition of sympathetic
      nerves and other effects.Because of its minimal impact on the respiratory , it could safely
      and effectively used to sedate patients undergoing cesarean section.But the change of
      endocrine system and hemodynamic of the parturients may affect the pharmacokinetics and
      pharmacodynamics of some anesthetic drugs.Currently studies have demonstrated the increased
      sensitivity of some anesthetic drug in parturients, such as lidocaine and isoflurane.The
      study is aim to explore the optimal dexmedetomidine dose to produce suitable sedation in
      parturients ,and compared with norman nonpregnant women.
    

Detailed description: 
      Parturients undergo cesarean section and normal nonpregnant women undergo lower abdominal
      surgery were scheduled . All patients accepted spinal anesthesia first.And then an dose of
      dexmedetomidine would be performed after umbilical cord was clapped in the parturients and in
      non-pregnant women group the dose of dexmedetomidine would be performed after the spinal
      anesthesia was conducted.Initial doses was 1.0μg/kg,with dose adjustment intervals of
      0.1μg/kg in first three turning points and 0.05μg/kg in the last four turning points. Each
      patient's sedation state was assessed using the modified observer's assessment of awareness
      /sedation (OAA/S) scale every 5 min after starting the dexmedetomidine infusion for 30 min.
      Adequate sedation was defined as an OAA/S≤3 at any assessment time point during the 30 min
    

Intervention name(s): Dexmedetomidine 01; Dexmetomidine 02
Intervention type(s): Drug; Drug
Intervention description(s): Initial dose of dexmedetomidine was 1.0 μg/kg, with dose adjustment intervals of 0.1μg/kg in first three turning points and 0.05μg/kg in the last four turning points,after the umbilical cord was clapped.The wight used to calculate the dose of dexmedetomidine would be that the total weight of the mother minus the weight of the placenta, amniotic fluid and fetal.; Initial dose of dexmedetomidine was 1.0 μg/kg, with dose adjustment intervals of 0.1μg/kg in first three turning points and 0.05μg/kg in the last four turning points,as soon as the spinal anesthesia
Intervention MeSH terms: Dexmedetomidine
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: dexmedetomidine; parturient; nonpregnant women; sedation