| 摘要 |
Pulsatile cardiopulmonary flow closely approximating a natural heartbeat is generated in a heart-lung machine by using a proportioning valve (38) to partly convey blood in the machine's cardiopulmonary circuit to the arterial supply line (32), and to partly recycle that blood into the cardiopulmonary circuit upstream (48) of the arterial pump. The relative proportions of conveying and recycling are varied in accordance with a waveform approximating the waveform of a human heartbeat.
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