90% effective volume of 0.1% ropivacaine combined with 0.4 µg/ml sufentanil for epidural labour analgesia with push pump at a rate of 400 mL/hr and a bolus interval of 30 min: a double-blind sequential dose-finding study. - Sun, Yuanqing; Ma, Wei; Xu, Tao; Zheng, Jing (BMC Anesthesiology, 2024)