Nursing staff will be provided with a documentation form (Data sheet 1) and asked to annotate heart rate, blood pressure, respiratory rate, tidal volume, oxygen saturation, and RASS score at 0, 15, 30, 60 minutes and at the conclusion of the SBT.They will be inserviced on the protocol prior to the start of the study. The study investigators will collect demographic information and record it on Data sheet 2. In addition to the primary endpoint(changes in cardiopulmonary parameters and RASS collected by the nursing staff), secondary endpoints will include outcome of first SBT(pass or fail), time from randomization to extubation, outcome of the first extubation (Data sheet 1). As stated earlier, there are no clearly defined cut-off values for any of the monitored variables that define failure of an SBT.