Influence of switching connection ports of double-lumen permanent tunnelled catheters on total solute removal during dialysis.

Introduction: Catheter dysfunction is a concern when using double-lumen catheters in hemodialysis (HD). Reversing the connection mode results in higher blood flows, but also enhanced recirculation. We evaluated total solute removal (TSR) of different uremic retention solutes during a complete HD session, once with reversed (RL) and once with correctly connected lines (CL).

Methods: Genius dialysis was performed in 22 HD patients at maximum blood flow (QB), once with CL and once with RL. TSR was determined for urea, creatinine, phosphate and ß2-microglobulin (ß2M). Using a kinetic model, we simulated TSR and reduction ratio (RR) for urea for different percentages of access recirculation and different QB during CL vs. RL.

Results: RR and TSR of the tested solutes were not different in clinical practice between CL and RL. Mathematically, urea RR did not differ with CL or RL, but TSR decreased by 4.5%-23.3% when changing from CL to RL for a recirculation of 5%-25%, respectively. For a recirculation of 5%-25%, QB in RL should be increased by 6.7% and 52.0%, 8.5% and 72.0%, and 10.0% and 115.2%, respectively, for a blood flow in CL mode of 150, 200 or 250 ml/min.

Conclusions: Connecting patients to double-lumen dialysis catheters in RL does not impair TSR in clinical practice. Mathematically, TSR during RL was dependent upon the obtained QB and degree of recirculation. A nomogram indicating the increase in QB needed in RL to obtain equal TSR as in the CL mode, at different degrees of recirculation, is provided.