To understand the importance of this study, we must first understand the role of weaning parameters in patient care. Weaning parameters assess a patient’s ability to oxygenate and/or ventilate spontaneously. Oxygenation parameters are generally permissive; that is, a patient is considered ready to wean from ventilation, from an oxygenation perspective, once the Pao2/fraction of inspired oxygen ratio is > 120 (some say 150). Most weaning parameters index the likelihood of sustained unassisted ventilation as follows: respiratory muscle capacity; respiratory loads; or the balance thereof. It is not surprising that the ƒ/Vt has emerged as the simplest and most predictive tool. It is the end-product of the capacity-load relationship. When capacity is insufficient to readily meet loads, patients breathe rapidly and shallowly. Does the use of weaning parameters to guide weaning decisions affect outcomes? In a seminal study, Ely and colleagues5demonstrated that when the ƒ/Vt was used to determine when to begin spontaneous breathing trials (SBTs), the duration of mechanical ventilation could be reduced compared to the situation with patients who received routine ad hoc physician-directed weaning. This important study may suggest, at first glance, that use of the ƒ/Vt accounted for the observed positive result. However, another study, by Kollef and colleagues,6 yielded similar results, and the treatment arm (ie, patients assigned to a variety of weaning protocols) did not include the use of the ƒ/Vt. Finally, preliminary data by Tanios and colleagues,9demonstrated that a ƒ/Vt-centered weaning protocol was no better than simply performing daily SBTs in patients who were hemodynamically stable (ie, Pao2/fraction of inspired oxygen ratio, ≥ 150). These results suggest the same conclusion: the intervention that reduces the duration of mechanical ventilation is not the weaning parameter that was used. Rather, the weaning parameter used was allowing patients who are hemodynamically stable and adequately oxygenated to perform daily SBTs until they pass. This approach focuses attention away from the numbers and toward the patient. In my opinion, the ƒ/Vt is not so much a weaning parameter as it is a physiologic description of a 1- to 2-min SBT. If patients look good (ie, if the ƒ/Vt is favorable), then simply extend the SBT to 30 to 120 min. If the patient “passes,” he or she no longer needs the ventilator, assess whether an airway is still required,10 and if it is not, perform a trial of extubation. One of the primary problems with using weaning parameters, even the ƒ/Vt, is that false-negative results bind patients to ventilators needlessly. Patients whose ƒ/Vt is not favorable ought not necessarily be precluded from undergoing an SBT. Some would argue that, in light of the above result,9 and the risks inherent in prolonged intubation, we should err on the side of giving patients every possible opportunity to prove they are ready to be extubated. There is little potential harm if an SBT is carefully observed, and in our hands one half of those with ƒ/Vt of 100 to 125 breaths/min/L were successfully liberated from ventilation.,8 After all, protocols (and the weaning parameters therein) are meant to help guide and expedite, and they never should substitute for common sense.