An assessment of the flow rate within peritoneal dialysis catheters, using a standardized in vitro technique

A variety of peritoneal dialysis catheters are used in clinical practice. The catheters are mainly described by their design, French number (circumference in mm) and length. However, this description does not provide information about the catheters inflow and outflow rates. We have therefore, studied flow rates of 18 adult catheters, using a uroflowmeter. Inflow rates were measured with the inflow bag 100 cm and 145 cm above the tip of the catheter, and outflow rates were measured with the flow transducer located 35 cm and 80 cm below the tip of the catheter, imitating situations where patients are sitting in a chair or laying in a bed during fluid exchanges. Ten measurements were made for each catheter at all heights. We found that catheter designs do affect flow rates. Straight catheters had statistic significantly faster inflow and outflow rates compared to curled catheters (p < 0.001). Moreover, curled catheters had statistic significantly faster flow rates than Swan Neck catheters (p < 0.001). The length and internal diameter of the catheter was found to be the determining factor for the differences in flow rates.