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.
Phase:
Phase 4
Details
Lead Sponsor:
Guangzhou General Hospital of Guangzhou Military Command