| 摘要 |
A method and an apparatus are provided for preventing retrograde flow of fluid, e.g., blood products, into a source of sterile substitution fluid ( 50 ). The apparatus of the present invention includes a controllable pinch valve member ( 110 ) that is placed on a section of a conduit ( 90 ) which carries sterile substitution fluid to an extracorporeal circuit ( 30 ). In one embodiment, control over the valve member ( 110 ) is based on a control unit ( 120 ) using fluid pressures that are sensed upstream and downstream of the valve member ( 110 ) by upstream sensor ( 121 ) and downstream pressure ( 122 ) respectively. The valve member ( 110 ) is preferably opened only when the upstream pressure is greater than the downstream pressure. This assures that the substitution fluid flows only in a single direction when the pinch valve member ( 110 ) completely occludes the conduit ( 90 ) when in a closed position. Therefor, blood will not contaminate the sterile fluid by being drawn into the conduit ( 90 ) due to pressure differences. |
