| 摘要 |
A pump used to infuse a medical liquid into a patient is autoprimed under th e control of a microprocessor that monitors and adjusts a priming sequence to minimize the accumulation of small air bubbles within a pumping chamber of t he cassette. Small air bubbles can be created by the agitation of liquid and ai r within the cassette during priming, and as a result of changing pressure conditions within the cassette. Adherence of the air bubbles on the walls of the pumping chamber can negatively affect performance of the pump. The microprocessor controls the flow of liquid into the pump cassette from a liquid supply to establish a layer of liquid at the bottom of the air trap, thereby preventing air bubbles within the air trap from moving into the pumping chamber. The layer of liquid acts as a one-way value, allowing air t o rise up from the pumping chamber and pass through the liquid layer into the air trap, but preventing air from passing through the liquid layer and down into the pumping chamber. The microprocessor then back primes the cassette until air is removed from the proximal liquid line connecting the liquid supply to the cassette. At that point, liquid is pumped from the liquid supp ly to forward prime the cassette until air is removed from the pumping chamber and a distal liquid line.
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