ABSTRACT
Approximately, 40% of patients admitted to critical care units require ventilatory support (1) and the incidence of mechanical ventilation (MV) is increasing (2,3). Most mechanically ventilated patients are easily and rapidly liberated from the ventilator after improvement or resolution of the acute precipitating illness. Five large trials conducted in the 1990s demonstrated that 65-85% of patients satisfying readiness criteria of adequate oxygenation, hemodynamic stability, and favorable respiratory physiology tolerate their first trial of spontaneous breathing and undergo extubation (4-9). Up to 20% of patients require days or weeks before they can be liberated from invasive ventilatory support and 40% of their time on MV is consumed by efforts to wean [60% for chronic obstructive pulmonary disease (COPD) patients] (10,11). In a smaller percentage of cases it is impossible to remove the patient from MV, resulting in ventilator dependence. This cohort of difficult-to-wean patients experiences prolonged ICU stays and consume a disproportionate amount of resources of up to 40% of ICU costs (12-15).
