High-frequency oscillation patient ventillator system

A breathing assist system comprising:

• a patient circuit adapted for connection to airways of a patient;
• a high-frequency oscillation ventilator connected to said patient circuit and operable to induce oscillations in gas in said circuit at a predetermined high frequency;
• a gas supply connected to the patient circuit for supplying breathing gas thereto;
• a detection device which monitors operation of the high-frequency oscillation ventilator comprising a gas sensor which produces an output signal representing at least one parameter selected from the group consisting of gas pressure and gas flow, said analyzer emitting and an analyzer which receives said output signal and which calculates from said output signal at least one average periodic value for said at least one parameter, a trigger signal dependent on a deviation of said calculated at least one average periodic value from an associated predetermined value indicating a spontaneous breathing effort;
• and
• said trigger signal being supplied from said analyzer to said gas supply and said gas supply, upon receipt of said trigger signal, supplying breathing gas to said circuit at a level to assist said spontaneous breathing effort.