Comparative evaluation of straight and curved extension dialysis catheters for continuous renal replacement therapy in dogs with acute kidney injury

A patent dual lumen dialysis catheter is one of the basic requirements for efficient extracorporeal (EC) therapy. The objective of this study was to measure resistance to blood flow offered by straight and curved extension dual lumen dialysis catheters used for continuous renal replacement therapy (CRRT). Twenty dogs suffering from acute kidney injury (AKI) were subjected to CRRT. The dogs were allocated randomly to Group-I (Curved extension catheter, n=12) or Group-II (Straight extension catheter, n=8), based on the type of dual-lumen catheter used in CRRT. The catheter outflow and inflow pressures were recorded at blood pump speeds of 50 mL/min and 99-100 mL/min. Data were tested for normality and differences in mean inflow and outflow catheter resistances were evaluated for statistical significance using independent samples t tests. Straight extension catheters offered lower inflow resistance than curved extension catheters at both 50 mL/min (41.50 ± 5.84 mm Hg and 63.75 ± 6.88 mm Hg, respectively; P =0.03) and 99-100 mL/min (63.00 ± 8.11 mm Hg and 86.92 ± 7.02 mm Hg, respectively; P =0.04) blood flow rates. Straight extension catheters also offered lower outflow resistance than curved catheters at 99-100 mL/min (−94.12 ± 7.91 mm Hg and -128.25 ± 7.56 mm Hg, respectively; P =0.01; the negative signs only indicate the direction of blood flow). These findings suggest that straight extension dual lumen dialysis catheters would likely perform better than the curved model in extracorporeal renal replacement therapy.