Design and development of a novel automatic valve system for long-term catheterized urinary incontinence patients

It has been estimated that over 3 million patients in the UK suffer from urinary incontinence, the result of which is often long-term catheterization. However, many catheters block prematurely through encrustation and their continuous drainage limits bladder rehabilitation. Although evidence shows that a catheter valve may overcome such weaknesses, only manual valves are currently available and many patients are not able to benefit from these owing to a lack of manual dexterity. A novel electronically controlled automatic valve system, the Shan-Lai (SL) valve system, has been designed and prototyped. The prototype is compact, reliable, and cost effective, and it has low power consumption. The mass of the overall packaged valve system is 34.2 g and it measures 4.5 cm x 4.5 cm x 1.2 cm. With an orifice of 3 mm diameter, the SL valve has achieved high flowrates with relatively low energy consumption. A flowrate-energy relationship (FER) has been introduced to assess the performance of a catheter valve, and the SL valve system prototype has achieved an FER of 0.66 m/s(-1) mJ(-1) while a commercially available electronic valve has an FER of 0.28 m/s(-1) mJ(-1). The valve demonstrated outstanding mechanical reliability after a series of performance tests and also indicated remarkable encrustation resistance in the vicinity of the valve during an in-vitro test.