Apparatus for determining when a partially or completely collapsed lung has been opened up

摘要

In the course of opening up an alveolus by supplying a gas pressure the alveolus will generate a crackle sound. By listening to the crackle sounds via microphones (6) an apparatus (4) can determine when the lung is completely open. The apparatus (4) comprises a filter (10) for filtering out the relevant frequencies for the crackle sounds and a determination unit (12) for identifying the crackles and for determining when the lung is open based on the filtered out sounds.