Blood recirculation in malfunctioning catheters for haemodialysis

Venous catheters are increasingly used for chronic haemodialysis, with dual lumen catheters being the most commonly used as blood recirculation (REC%) is relatively low. The aim of this study was therefore to evaluate blood recirculation in dual lumen catheters, both well-functioning and malfunctioning, with reversed lumens. In our study, blood recirculation in well-functioning catheters with standard lumens is similar to that found in previous studies. However, when lumens are reversed, blood recirculation increases significantly (6.7 +/- 4 vs 19 +/- 11%, p < 0.001). REC% in malfunctioning catheters (10.8 +/- 2%) was higher than normal function (p < 0.05) but lower than reversed flow in normal catheters (p < 0.01). Therefore, inadvertent reversal of lumens in a well-functioning catheter increases REC% in a significant manner, thus worsening haemodialysis efficiency. We conclude that, in inflow failure catheters, lumens can be reversed because REC% is acceptable. However, inadvertent reversal of lumens in a well-functioning catheter increases REC% to a level which may compromise the adequacy of haemodialysis.