Blood Flows and Recirculation Rates in Temporary Niagara® and Long-Term Opti-Flow® Hemodialysis Catheters Assessed by Ultrasound Dilution

Real blood flows (Qb in mL/min) and blood recirculation rates (R in %) were assessed using the ultrasound dilution technology (Transonic Systems Inc, Ithaca, NY, USA) in internal jugular and sub-clavian catheters inserted for chronic hemodialysis. A total of 14 Niagara temporary catheters and 17 Opti-Flow long-term catheters (both by Vas-Cath, distributed by Bard, Mississauga, Canada) were evaluated. Real Qb and R were measured for each catheter at set Qb of 250 (not shown), 300, 350, 400, and 450 mL/min, as indicated by the dialysis machines and under 0 ultrafiltration. Arterial and venous pressures (PA and PV in mmHg) were recorded with each measure (not shown). There were 13 Niagara® catheters with non-reversed lines, 1 with reversed lines, and 12 Opti-Flow® catheters with non-reversed lines, and 5 with reversed lines at the time of measurements. Only 2 Niagara® and 4 Opti-Flow® with non-reversed lines showed evidence of R; R was found in all catheters with reversed lines. Results are shown as mean ± SD:TableWe conclude that both types of catheters provide effective Qb above 400 mL/min with absent or low R for the majority. R seems higher in Opti-Flow® with reversed lines. When it occurs, R can not be predicted by significantly altered PA and PV (not shown), and Qb is maintained.