1. A method for respiratory support, the method comprising: providing a measured pressure; calculating a net flow based on at least one measured inlet flow and at least one measured outlet flow; using a relationship between a first value related to the measured pressure, a second value related to the measured net flow and a third value related to patient effort to provide a prediction of patient effort; updating an interim value based at least in part on the prediction of patient effort, wherein the interim value is one of a covariance matrix and a parameter vector; calculating a computed patient effort based at least in part on the interim value; and utilizing the computed patient effort to trigger a ventilation cycle.