The use of a nursing-directed and/or respiratory therapist-directed protocol in many intensive care units for weaning from mechanical ventilation is associated with a shorter duration of ventilation and length of stay in the ICU. Most protocols have two formal components: the daily screening of a set of simple observations or interventions to identify readiness to proceed, followed by a spontaneous breathing trial that tests the patient's ability to breathe independently. The daily screen is designed to identify potential barriers regarding medical stability, level of consciousness, oxygenation, ventilation, and airway patency and protection. However, one must avoid selecting criteria that are too restrictive, potentially delaying the discontinuation of ventilation.