The impact of increased blood flow rates on recirculation in central venous hemodialysis catheters

A recent practice change in our unit from Quinton dual lumen PermCaths to Vas-Cath Optiflow central venous catheters resulted in the routine achievement of bloodflow rates (BFR) of 500 ml/min. Previously BFRs of 300-400 ml/min were the norm. The increased BFR was achieved without any apparent increase in venous pressure, prompting us to consider the possibility that increased recirculation was occurring. This paper presents the results of a study designed to answer the following questions: (a) What is the difference in recirculation rates between Quinton dual lumen PermCaths and Vas-Cath Optiflow dual lumen catheters? and (b) What is the impact of increased BFR on recirculation rates in Optiflow hemodialysis catheters? The study documented recirculation rates in two groups of patients. In Group 1, the Optiflow group, recirculation rates were calculated for 10 subjects, first at 350 ml/min and then at 500 ml/min. In Group 2, the PermCath Group, recirculation rates were calculated for 10 subjects at 300 ml/min. Paired t-tests were performed to compare Group 1 at 350 ml/min with Group 2. No significant differences were found within or between groups suggesting that recirculation rates were not affected by increased BFR.