摘要 |
A chest drainage apparatus (CDU) and method is disclosed for accurately measuring gas flow or leakage from a patient's chest cavity even at very low or near zero flow rates. The CDU has a collection chamber for receiving fluid and gas to be drained from a pleural cavity of a patient, a vacuum source for applying suction to the collection chamber and a valve for connecting the CDU to the vacuum source. A pressure transducer measures the gas pressure in the collection chamber. A microcomputer controller, responsive to the pressure measured by the pressure transducer, causes the valve to disconnect the vacuum source from the CDU when the gas pressure in the collection chamber is less than a first predetermined threshold and connects the CDU to the vacuum source when the gas pressure in the collection chamber exceeds a second predetermined threshold. The time period during which the vacuum source is disconnected from the CDU is measured as an indication of the rate of gas flow into the CDU.
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