How to evaluate the work of breath in mechanically ventilated patients?

The main goal of mechanical ventilation is to restore the gas exchange and to reduce the work of breathing (WOB). However, most clinicians have only some general concepts for WOB. The WOB in mechanically ventilated patients can not only be evaluated from clinical presentations, but also from physiological methods such as the Campbell' s diagram, the pressure time product, and the oxygen cost of breathing. In addition, we also review the literatures and integrate ways to reduce the WOB in order to help clinicians providing the most effective use of mechanical ventilation.