The nurse must assess the patient for readiness for early extubation. Extubation should be considered when the patient is arousable, able to follow commands, hemodynamically stable, and initiating spontaneous ventilations without excessive respiratory effort. Typical intensive care protocols for the cardiac surgery patient include preprinted orders that facilitate the weaning process. As the patient is being weaned from the ventilator, ventilatory support is gradually withdrawn and the patient must sustain spontaneous ventilations. Physical assessment of effective ventilation, and laboratory analysis of arterial blood gases and specific ventilatory parameters must be completed prior to extubation. Protocols may vary, but some standards require a PO2 > 80 mm Hg on a FIO2 of 0.40 or less, a PCO2 less than 45 mm Hg, a pH between 7.35 and 7.45, and an oxygen saturation (SaO2) >92%. Ventilatory parameters include a maximum inspiratory pressure of at least -20, a tidal volume of at least 5 mL/kg body weight, and aminute volume of at least 5 liters per minute - See more at: http://www.nursingcenter.com/lnc/journalarticle?Article_ID=638956#sthash.bVxDHL6e.dpuf