Frequency of Screening and SBT Technique Trial - North American Weaning Collaboration (FAST-NAWC): a protocol for a multicenter, factorial randomized trial oleh K. E. A. Burns, Leena Rizvi, Deborah J. Cook, Andrew J. E. Seely, Bram Rochwerg, Francois Lamontagne, John W. Devlin, Peter Dodek, Michael Mayette, Maged Tanios, Audrey Gouskos, Phyllis Kay, Susan Mitchell, Kenneth C. Kiedrowski, Nicholas S. Hill, For the Canadian Critical Care Trials Group