Whether hemodialysis is performed through a fistula, graft, or a dialysis catheter, it is a common practice to lower the dialyzer blood flow in patients who develop intradialytic hypotension. Lowering dialyzer blood flow is assumed to reduce AV access blood flow and thus increase peripheral vascular resistance tending to raise blood pressure. As a general rule, however, such a reduction in dialyzer blood flow does not lower access flow; only in the case of an intra-access stenosis could this be the case. Reducing access blood flow (in both catheter and AV accesses) did ameliorate a number of potential contributors to intradialytic hypotension when older dialysis technologies were routinely used. A lower dialyzer blood flow reduced acetate influx, decreased extracorporeal blood volume, and decreased the release of vasodilatory products of blood-membrane interactions. However, none of these considerations are applicable to current dialysis practice.
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