Access recirculation in temporary hemodialysis catheters as measured by the saline dilution technique

Ultrasound dilution technology is emerging as the standard for measuring ac cess recirculation and blood flow in hemodialysis patients. In temporary di alysis catheters, studies using the traditional two-needle urea method have suggested that short femoral catheters are associated with an unacceptably high degree of recirculation. This problem has never been assessed using u ltrasound dilution technology. We performed a prospective observational stu dy of consecutive patients undergoing dialysis through a temporary catheter , Measurements were made on 49 catheters; 10 catheters were excluded becaus e poor flow necessitated reversal of the dialysis ports. Thirty-nine cathet ers in 33 patients were included in this analysis, of which 26 catheters we re located in the femoral vein, and 13 catheters, in the internal jugular v ein. Dialyzer blood flow was adjusted to give an ultrasonic flow rate of 25 0 mL/min (actual mean blood flow, 234.3 mL/min; 95% confidence interval [CI ], 228 to 241). Overall mean recirculation rate was 8.9% (95% CI, 4.8 to 13 .0). Multivariate analysis showed catheter location and length to be indepe ndent predictors of recirculation. Blood flow (within the range tested), du ration into dialysis, time since catheter insertion, cardiac rhythm, and ca theter type had no significant effect on recirculation rates. Recirculation in femoral catheters (13.1%) was significantly greater than that in intern al jugular catheters (0.4%; P < 0.001). Femoral catheters shorter than 20 c m had significantly greater recirculation (26.3%) than those longer than 20 cm (8.3%; P = 0.007). We conclude that temporary femoral catheters shorter than 20 cm are associated with increased recirculation rates. In addition, when dialysis dose delivery is a priority, locating the temporary catheter in the internal jugular vein is an advantage. (C) 2000 by the National Kid ney Foundation, Inc.