Clinical utility of rapid shallow breathing index in predicting successful weaning: secondary analysis of the COBRE-US trial Fabio Varón-Vega; Eduardo Tuta-Quintero; Henry Robayo-Amortegui; Adriana Rincón; Luis F. Giraldo-Cadavid; Jonathan Palacios; Stephanie Crevoisier; Diana C. Duarte; Marcela Poveda; Laura Cucunubo; Pablo Monedero;