Depending on the chosen weaning technique, the RT will set the ventilator to the desired mode or place your patient on a T-piece. Once the SBT begins, pay particular attention to oxygenation status. His mental status should not change. For example, if he becomes somnolent or shows signs of agitation, discontinue the trial. Your patient's oxygen saturation should remain above 85% – 90%, PaO2 should be greater than 60 mm Hg, and pH should be in the range of 7.25 – 7.40, according to baseline values.