The ventilator discontinuation process: an expanding evidence base

The ventilator discontinuation process is an essential component of overall ventilator management. Undue delay leads to excess stay, iatrogenic lung injury, unnecessary sedation, and even higher mortality. On the other hand, premature withdrawal can lead to muscle fatigue, dangerous gas exchange impairment, loss of airway protection, and also a higher mortality. Continued ventilator dependence can be a result of persistent illness or can be a result of poor management. It is obviously important for the clinician to be able to assess both of these issues. An evidence-based task force has recommended regular assessments focusing on the causes of ventilator dependence, regular assessments for evidence of disease stability/reversal, use of regular spontaneous breathing trials (SBTs) as the primary assessment tool for ventilator discontinuation potential, use of separate assessments to evaluate the need for an artificial airway in patients tolerating the SBT, and the use of comfortable, interactive ventilator modes (that do not need to be "weaned") in between regular SBTs. More recent developments have focused on the importance of linking sedation reduction protocols to ventilator discontinuation protocols. Patients with repeated SBT failures are often considered to require prolonged mechanical ventilation (PMV). These patients often receive tracheostomies and are probably better managed with more gradual reductions in support and gradually lengthened spontaneous breathing periods. PMV patients have a high 1-year mortality, and many may ultimately require lifelong support. This evidence base is growing, but the earlier guidelines are standing the test of time. Indeed, practice patterns are evolving in accordance with them. Nevertheless, there is still room for improvement, and further clinical studies, especially in the patient requiring PMV, are needed.