Patent ID: 7347205

Claim:
A method for providing a reference pressure level for the pressure responsive triggering of a mechanical ventilator to assist a spontaneously breathing effort by a patient, a breathing circuit for the ventilator having a gas flow path extending from the ventilator to an exhaust port and along which breathing gases flow through the breathing circuit, the breathing circuit having a patient connection interposed along the gas flow path of the breathing circuit downstream from the ventilator and upstream from the exhaust port, said method comprising the steps of: configuring the breathing circuit to dispose at least one pressure transducer along the gas flow path: limiting the gas flow properties of the patient connection while maintaining gas flow properties in the gas flow path of the breathing circuit; providing a gas flow along the gas flow path of the breathing circuit from the ventilator to the exhaust port; sensing the gas pressure generated in the breathing circuit by the gas flow along the gas flow path and through the flow resistance of the gas flow path with the pressure transducer disposed along the gas flow path; and ascertaining when the gas flow along the gas flow path is in an amount sufficient to cause the flow resistance properties of the gas flow path of the breathing circuit to generate a desired gas pressure in the breathing circuit suitable for use as a reference pressure level for the pressure responsive triggering action, gas flow in a corresponding amount serving as a bias flow through the gas flow path of the breathing circuit in the subsequent operation of the ventilator.