Spinal Marginally Hyperbaric Ropivacaine for Cesarean Delivery

BACKGROUND: One previous study has confirmed that the marginally hyperbaric solutions of bupivacaine can maintain good quality of anesthesia and get a more steadily hemodynamic status than commonly hyperbaric solutions, some authors confirmed the plain ropivacaine for cesarean section have a higher failure rate and commonly hyperbaric solutions of ropivacaine have a higher incidence of side reaction. It is unclear what the efficacy of spinal marginally hyperbaric ropivacaine for elective cesarean delivery.We hypothesized that the marginally hyperbaric ropivacaine will get a similar efficacy to commonly hyperbaric solutions but a more steadily hemodynamic status. OBJECTIVE In this prospective, randomized, double-blinded study, Investigator will compare the clinical efficacy and adverse effect of spinal anesthesia with commonly hyperbaric and marginally hyperbaric ropivacaine for elective cesarean delivery. Main outcome measures: The maximum cephalad sensory block level; the change of continuous cerebral oxygen desaturation (ScO2) over time; the incidence of hypotension and nausea and vomiting; the change of invasive arterial pressure; the consumption of ephedrine; the incidence of shivering; the onset time to T8 dermatome; the quality of anesthesia (efficacy of motor block and sensory block)