In Vivo Trial of a Novel Atraumatic Urinary Catheter Design for Prevention of Catheter-Induced Trauma

Innovating Indwelling Catheter Design to Counteract Urinary Tract Infection

BACKGROUND AND OBJECTIVE

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.

METHODS

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

KEY FINDINGS AND LIMITATIONS

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.

CONCLUSIONS AND CLINICAL IMPLICATIONS

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.

PATIENT SUMMARY

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.

In vivo catheterization study of chlorhexidine-loaded nanoparticle coated Foley urinary catheters in male New Zealand white rabbits

Foley urinary catheters were coated with chlorhexidine-loaded nanoparticles (CHX-NPs), encapsulated in the form of micelles and nanospheres. Both of nanoparticles were deposited by multilayer nanocoating through dip and spray coating on the catheter surface both inner and outer surface. In our previous studies, the nanocoating of Foley urinary catheters was studied for chlorhexidine release, degradation, antibacterial evaluation, cytotoxicity assessment, hemocompatibility, skin irritation, skin sensitization, and stability during storage. The results demonstrated the antimicrobial functions and biocompatibility of the coated catheters. In this study, coated urinary catheters were inserted in the bladders of rabbits for 7 day to investigate their efficacy. Histopathology results showed no inflammation, redness, or swelling on bladder and urethra tissues. Surface morphology comparison of uncoated catheters in the control group and coated catheters in the treatment group revealed more encrustation and crystallization on uncoated catheter than on coated catheter, indicating that catheters coated with CHX-NPs showed efficacy in delaying encrustation and bacterial colonization. These findings suggest that nanocoating of urinary catheters can potentially enhance the biocompatibility of medical devices.

Innovations in indwelling urethral catheterisation

The indwelling urethral catheter remains an integral part of contemporary medical care, despite its significant design shortcomings. Urethral catheterisation is responsible for well-recognised complications including catheter-associated urinary tract infection (CAUTI), catheter-associated urethral injury (CAUI), catheter blockage, and bladder mucosal irritation. In this narrative review, we provide an update on current innovations in urethral catheter design, aimed at safeguarding against these complications. There is an obvious need to improve catheter technology and urologists should support the translation of innovations into clinical practice.

Clinical Evaluation of a Safety-device to Prevent Urinary Catheter Inflation Related Injuries

OBJECTIVE

To evaluate the feasibility of a novel "safety-valve" device for preventing catheter related urethral trauma during urethral catheterization (UC). To assess the opinions of clinicians on the performance of the safety-valve device.

MATERIALS AND METHODS

A validated prototype "safety-valve" device for preventing catheter balloon inflation related urethral injuries was prospectively piloted in male patients requiring UC in a tertiary referral teaching hospital (n = 100). The device allows fluid in the catheter system to decant through an activated safety threshold pressure valve if the catheter anchoring balloon is misplaced. Users evaluated the "safety-valve" with an anonymous questionnaire. The primary outcome measurement was prevention of anchoring balloon inflation in the urethra. Secondary outcome measurement was successful inflation of urinary catheter anchoring balloon in the bladder.

RESULTS

Patient age was 76 ± 12 years and American Society of Anaesthesiologists grade was 3 ± 1.4. The "safety-valve" was utilized by 34 clinicians and activated in 7% (n = 7/100) patients during attempted UC, indicating that the catheter anchoring balloon was incorrectly positioned in the patient's urethra. In these 7 cases, the catheter was successfully manipulated into the urinary bladder and inflated. 31 of 34 (91%) clinicians completed the questionnaire. Ten percent (n = 3/31) of respondents had previously inflated a urinary catheter anchoring balloon in the urethra and 100% (n = 31) felt that a safety mechanism for preventing balloon inflation in the urethra should be compulsory for all UCs.

CONCLUSION

The safety-valve device piloted in this clinical study offers an effective solution for preventing catheter balloon inflation related urethral injuries.

Cateter urinário: o tempo de exposição e calibre podem influenciar na formação de biofilme?

Resumo Objetivo: Avaliar a influência do tempo de exposição e calibre na formação de biofilme em cateteres urinários de Foley (CUFs). Método: Pesquisa in vitro com amostras de fragmentos de CUFs em látex siliconizado de diferentes calibres (n° 14 e n° 16 Frenchs). A urina artificial foi confeccionada, inoculada com bactérias-padrão Staphylococcus aureus (ATCC 25923) e Pseudomonas aeruginosa (ATCC 27853) e incubada a 37 °C por 24 horas e 72 horas. As análises foram realizadas por meio de cultura (carga bacteriana) e microscopia eletrônica de varredura. Resultados: Não houve diferença na carga bacteriana dos biofilmes formados nas superfícies dos CUFs com relação aos diferentes calibres (p > 0,05). Por outro lado, o tempo de exposição (24 horas e 72 horas) foi o fator determinante para formação do biofilme de P. aeruginosa nos CUFs (p < 0,05). Conclusão: O tempo de exposição influenciou a formação do biofilme de P. aeruginosa nos CUFs, independentemente dos calibres.