Optimization of debris removal during bladder irrigation.

Debris build-up within the bladder is one of the main problems encountered by patients undergoing long term catheterization. One of the methods of ameliorating this is to wash out the bladder at regular intervals. In this paper, an alternative method of bladder irrigation is investigated experimentally. The effectiveness of several possible catheter designs has been examined, together with other relevant variables such as the proximity and alignment of the tube tip to the debris and the irrigation flow rate. Results show that debris removal is very sensitive to tube design, with best designs achieving almost complete removal and the worst practically none. The proprietary continuous irrigation catheter used was particularly poor for the type of debris used. Removal is insensitive to the distance of the tube tip from the bladder base up to a limiting value, above which it reduces rapidly. Where misalignment causes the inlet jet to miss the debris, removal rates are very low. Increasing flow rate increases removal up to a limiting value, above which it remains constant. Although the results show the general trends, to optimize the system requires further understanding of the detailed flow patterns within the bladder. A theoretical study using computational fluid dynamics is thus being undertaken.