An arrangement and method for detecting spontaneous respiratory effort of a patient (11) receiving ventilatory support via a breathing circuit (12). A patient/breathing circuit interface (10) is adapted to provide a closed connection between a breathing passage (20) of the patient (11) and the breathing circuit (12). A sensor (28) is disposed at least partially in the breathing passage (20) of the patient (11) and arranged to sense flow of gas through the breathing passage (20). The arrangement and method individually or in addition to the airway pressure measurement promotes reliable and rapid detection of breathing efforts of a non-intubated patient to promote efficient augmentation of patient breathing.
