Analysis of the urine flow characteristics inside catheters for intermittent catheter selection

Abstract

Abstract In this study, we conducted a numerical analysis on catheter sizes using computational fluid dynamics to assess urinary flow rates during intermittent catheterization (IC). The results revealed that the fluid (urine) movement within a catheter is driven by intravesical pressure, with friction against the catheter walls being the main hindrance to fluid movement. Higher-viscosity fluids experienced increased friction with increasing intravesical pressure, resulting in reduced fluid velocity, whereas lower-viscosity fluids experienced reduced friction under similar pressure, leading to increased fluid velocity. Regarding urine characteristics, the results indicated that bacteriuria, with lower viscosity, exhibited higher flow rates, whereas glucosuria exhibited the lowest flow rates. Additionally, velocity gradients decreased with increasing catheter diameters, reducing friction and enhancing fluid speed, while the friction increased with decreasing diameters, reducing fluid velocity. These findings confirm that flow rates increased with larger catheter sizes. Furthermore, in terms of specific gravity, the results showed that a 12Fr catheter did not meet the ISO-suggested average flow rate (50 cc/min). The significance of this study lies in its application of fluid dynamics to nursing, examining urinary flow characteristics in catheterization. It is expected to aid nurses in selecting appropriate catheters for intermittent catheterization based on urinary test results.