How can the peristaltic pump pressure fluctuations be minimized?
These pulsations are due to tube expansion when one of the rollers moves off the tube. First of all, use as large a tube set (e.g., the FC-TS-093 tube set) in the pump as possible when the pump is providing a controlled pressure at the distal end of the cannulated vessel system. A simple windkessel may also be placed in series between the system’s distal end and the pump. The windkessel is a ‘tee’ connector with the branch at right angles to the flow path having a closed-off tube which traps some air. The larger the air trap volume, the more the pulsations are diminished, but at the expense of slowing the response time from 1–3 seconds to 15 seconds. It is possible in this way to reduce pulsations to as much as ±1 mmHg. Alternatively, the pulsations may sometimes be minimized by raising or lowering the pump height to closely match the inlet and outlet pressures of the pump.
