Patent ID: 8685320

Claim:
A method of performing gas exchange for blood comprising: introducing blood into a housing in which are positioned a plurality of hollow fiber membranes each having a lumen so that the blood flows exteriorly of the hollow fiber membranes, the housing defining a blood flow path between a blood inlet and a blood outlet port; introducing gas into the lumens of the hollow fiber membranes and subjecting the blood flowing exteriorly of the hollow fiber membranes to gas exchange with the gas flowing through the lumens of the hollow fiber membranes; passing the blood through a filter member having a mesh size of approximately 15-60 Î¼m, the filter member being positioned in the housing directly contacting the hollow fiber membranes at a position downstream of the hollow fiber membranes, thus removing bubbles in the blood while the blood is in the housing and after the blood has been subjected to the gas exchange; passing the blood through a blood passage downstream of the filter member, the blood passage being defined by a gap having a predetermined width between an outer surface of the filter member and an inner surface of the housing; passing the blood through a passage enlargement positioned between the blood passage and the blood outlet port, the passage enlargement having an enlarged width defined between the outer surface of the filter member and the inner surface of the housing, the enlarged width being greater than the predetermined width of the blood passage such that the passage enlargement provides an increased passage cross-sectional area relative to the blood passage, thereby decelerating the blood from which bubbles have been removed as the blood approaches the blood outlet port in the housing; and discharging from the housing by way of the blood outlet port the blood which has been decelerated.