Assessment of access recirculation during haemodialysis.

With dialysis lines in the correct alignment, access recirculation only occurs when the access blood flow rate is exceeded by the extracorporeal blood flow rate. The degree of access recirculation is accurately measured by non-urea-based methods using indicator dilution or differential conductivity methods. The classical urea-based methods have inherent inaccuracies. Access flow rate can be calculated from an accurate measurement of the access recirculation induced by dialysis line reversal. Access flow rate monitoring can detect early access dysfunction; the existence of access recirculation indicates severe access dysfunction.