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Adult ECMO Simulator

The effect of return cannula size on performance.

Effect Of Cannula Size

In the figure above, I've used the simulator to find out what rpm's and pressures are required to generate a flow of 5.0 lpm through a VV ECMO circuit when the size of the return cannula is varied between 15 and 23 F and drainage is unrestricted.

The data are modelled on the behaviour of a 'Rotaflow' pump and a 'Quadrox D' oxygenator.

As can be seen, when a small return cannula is selected, the driving pressure and pump speed required to generate the flow are much higher. This may be associated with:

  • Increased shear stress on the formed elements of the blood,
  • an increase in platelet activation,
  • an increased likelihood of circuit disruption,
  • an increase in the operating temperature of the pump head.