Innovating Indwelling Catheter Design to Counteract Urinary Tract Infection

Bacteriuria is anticipated in long-term indwelling catheter (IDC) use, and urinary tract infections (UTIs) and related issues are common. Defence mechanisms against infection are undermined by the presence of a Foley catheter, and adjustments to design could influence UTI risk.

We reviewed the various aspects of IDCs and ureteric stent designs to discuss potential impact on UTI risk.

Design adaptations have focussed on reducing the sump of undrained urine, potential urinary tract trauma, and bacterial adherence. Experimental and computational studies on ureteral stents found an interplay between urine flow, bacterial microcolony formation, and accumulation of encrusting particles. The most critical regions for biofilm and crystal accumulation are associated with low shear stress. The full drainage system is the functioning unit, not just the IDC in isolation. This means reliably keeping the drainage system closed and considering whether a valve is preferred to a collection bag. Other developments may include one-way valves, obstacles to "bacterial swimming", and ultrasound techniques. Preventing or clearing IDC blockage can exploit access via the lumen or retaining balloon. Progress in computational fluid dynamics, energy delivery, and soft robotics may increase future options. Clinical data on the effectiveness of IDC design features are lacking, which is partly due to reliance on proxy measures and the challenges of undertaking trials.

Design changes are legitimate lines of development, but are only indirect for UTI prevention. Modifications may be advantageous, but might potentially bring problems in other ways. Education of health care professionals can improve UTIs and should be prioritised.

Catheters used to help bladder drainage can cause urinary infections, and improvements in design might reduce the risk. Several approaches are described in this review. However, proving that these approaches work is a challenge. Training professionals in the key aspects of catheter care is important.