Method and arrangement for evaluating effective flow resistance of a patient breathing circuit

摘要

in a method and arrangement for evaluating effective flow resistance of a patient breathing circuit connected to a mechanical breathing assist device, a flow controller is operable to temporarily introduce an occlusion to the gas flow within the breathing circuit at a time after the end of an inspiration phase of a breathing cycle provided by the breathing assist device. A sensor unit 34 has a flow sensor for measuring gas flow within the circuit and a pressure sensor for measuring gas pressures within the circuit. An evaluating unit receives measurements from the sensor unit, to determine for a measured gas flow a value of a pressure drop within the breathing circuit after the introduction of the occlusion, and establishes a relationship between the calculated pressure drop and the measured gas flow, such as based on the known Blasius formula.