Combined Use Of Hyperbaric And Hypobaric Ropivacaine For Caesarean Section: A Prospective, Double-Blind, Randomized, Controlled Study

Background: Sequential subarachnoid injection of hyperbaric and hypobaric ropivacaine was evaluated during spinal anesthesia for caesarean section. The effects of different contents of the hyperbaric ropivacaine on the hemodynamic characteristics of the parients were also explored. Methods: The patients meeting inclusion criteria (n=120) were randomly allocated into either the 5 mg hyperbaric ropivacaine + 5 mg hypobaric ropivacaine group (Group A, n=40), 4 mg hyperbaric ropivacaine + 6 mg hypobaric ropivacaine group (Group B, n=40), or 3 mg hyperbaric ropivacaine + 7 mg hypobaric ropivacaine group (Group C, n=40). The primary endpoint was the incidence of hypotension, with secondary endpoints including maximum height of sensory block and the time to reach sensory block to the T8 level. Results: The incidence of hypotension was significantly lower in Group C compared to Group A (8% vs. 45%, P<0.001). The time to reach sensory block to T8 level was 6.4 +/- 1.5, 7.5 +/- 1.4 and 9.2 +/- 2.0 in each group, respectively (P<0.001). Maximum height of sensory block decreased following the reduction of the content of hyperbaric ropivacaine. The median (first quartile-third quartile) [(Q1-Q3)] were T3 (T2.5-T4), T4 (T3-T5), and T6 (T4-T6) in each group, respectively (P<0.001). Group A and Group B had higher incidences of nausea compared to Group C (36% and 25% vs 5%, P<0.001 and P=0.012, respectively). Conclusions: Decreased content of the hyperbaric ropivacaine in the combined group resulted in an increased anesthesia induction time, decreased sensory blockade plane and incidence of hypotension.