Rationale of filtration enhancement in membrane plasmapheresis by pulsatile blood flow.

It has been demonstrated in our laboratory that blood flow pulsations enhance plasma filtration rate by 30-60 per cent. The increase in plasmafiltration over the steady flow value is found to be a function of the parameter F. delta V'/QB where F denotes the pulsation frequency, delta V' the volume amplitude of pulsed blood in the filter and QB is the time mean blood flow. The increment in plasma filtration may be related to the increase in time-mean absolute value of shear rate.