Adaptive: A targeting scheme that allows the ventilator to automatically set one target (eg, pressure within a breath) to achieve another target (eg, average tidal volume over several breaths). Optimal: A targeting scheme that automatically adjusts the targets of the ventilatory pattern to either minimize or maximize some overall performance characteristic (eg, minimize the work rate done by the ventilatory pattern). Intelligent: A targeting scheme that uses artificial intelligence programs such as fuzzy logic, rule based expert systems, and artificial neural networks.