Pocket warming of bupivacaine with fentanyl to shorten onset of labor epidural analgesia: A double-blind randomized controlled clinical trial. oleh Tyler M Balon, Yun Xia, Johnny McKeown, Jack Wang, Justin J Abbott, Marilly Palettas, Alberto Uribe, Marco Echeverria Villalobos, John C Coffman, Ling-Qun Hu