Materials and Methods: This study is a prospective, randomized, controlled trial conducted from
January 2007 to January 2009 that compared protocol-based weaning (PBW) with UC. A total of 122
patients who received invasive ventilation in the medical ICU of the Asan Medical Center were
examined. Nurses operated the mechanical ventilators according to a predesigned ventilator-weaning
protocol for the PBW group (n = 61), and intensive care unit (ICU) physicians managed weaning in the
UC group (n = 61).