Figure 1.

Recommendations for optimizing respiratory rate in patients with acute respiratory failure/acute respiratory distress syndrome. The clinician should increase respiratory rate while looking at inspiratory and expiratory flows displayed on the screen of the ventilator. In (a) too low a respiratory rate has been set: the expiratory flow ends 0.5 s before the inspiratory flow. In (b) the respiratory rate has been increased without generating intrinsic positive end-expiratory pressure: the end of the expiratory flow coincides with the beginning of the inspiratory flow. In (c) the respiratory rate has been increased excessively and causes intrinsic positive end-expiratory pressure: the inspiratory flow starts before the end of the expiratory flow. The optimum respiratory rate is represented in (b).