Described is an apparatus for oxygenation and/or CO2 clearance of a patient, comprising: a flow source or a connection for a flow source for providing a gas flow, a gas flow modulator, a controller tocontrol the gas flow, wherein the controller is operable to: receive input relating to heart activity and/or trachea gas flow of the patient, and control the gas flow modulator to provide a varying gas flow with one or more oscillating components with a frequency or frequencies based on the heart activity and/or trachea flow of the patient.