A method for controlling mechanical lung ventilation is described. The method may include intermittently switching the airway pressure of the patient from a substantially constant high baseline pressure level to a substantially constant low baseline pressure and vice-versa such that the patient is able to breathe spontaneously in both high and low baseline pressure levels; detecting an inspiration effort by the patient inside a trigger time window that immediately precedes a switching event of the intermittently switching the airway pressure; maintaining a baseline pressure at the level in which the inspiration effort was detected so that the patient can complete the inspiration-exhalation cycle; and switching the baseline pressure level after a delay time.