Calculating the total volume of reflux in venous insufficiency

Currently, the only duration of reflux is used in grading venous insufficiency of lower extremities, ignoring the flow rate. But current technology allows us to acquire more information than just the duration of insufficiency. The total volume of reflux can be more useful than just knowing the duration. Duration can be misleading when just a tiny amount of blood is continuously finding a way through out the valves. Total volume allows us to account for duration x flow rate.

Calculating the total amount of reflux is easy.

Total volume = Flow rate (Litre/min) x duration (Second) / 60 Second

In the example above:
  • Flow rate: 0,105 litres / minute
  • Reflux duration: 2,24 second
  • Reflux volume = 0,105 x 2,24 / 60 = 0.00392 litres or 4ml
In the case of continuous reflux, a maximum arbitrary limit of ten seconds can be set since most patients have difficulty in sustaining Valsalva longer than ten seconds.

The total amount of reflux to the lower extremity can be calculated by addition of reflux from Saphenous system + Common femoral vein.  

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