A Novel Urethral Catheter Design to Guide Safer Placement and Both Prevent and Minimize Risk of Urethral Balloon-Inflation Injury
Introduction and Objective: Iatrogenic urethral injury due to urethral balloon-inflation occurs regularly but with unknown incidence. Manufacturers have, to date, not incorporated any safety-oriented modifications into their catheter design. We sought to: 1) Explore the overall number of non-infectious catheter related complications in a nationally representative dataset; 2) Create novel catheter design modifications designed to guide safer catheter placement and mitigate urethral trauma caused by urethral balloon-inflation; 3). Manufacture working prototypes of our catheter; 4.) Test our catheter-prototypes on human cadavers and adult pigs.
Materials and Methods: A cross-sectional analysis of the 2006 to 2008 National Inpatient Sample was performed (a 20% stratified sampling of non-federal U.S hospitals), using ICD-9-CM diagnostic codes to identify the national annual numbers of catheter related complications in hospitalized patients. Standard (BARDTM) 16-Fr. catheters were modified by thinning out a circumferential area of the balloon-port shaft, and painting this area bright-red, so that when the retention balloon is inflated within the urethra, this thinned area (“Safety Balloon”) expands, and serves to: 1. Minimize filling and pressure upon the urethra, and 2. Visually alert the operator. We measured pressure within the balloon-port during filling within the bladder and urethra using fresh human-cadavers and live-adult pigs (N=8) under anesthesia, followed by histologic analysis. We determined the lowest filling-volume necessary to activate the “safety balloon” only when the retention balloon was filled within the urethra.
Results: Over this time period, 21,566 -111,353 patients experienced a non-infectious catheter related complication. Mean patient age was 68.4 (SD=18.8); 46.2% required a procedure such as cystoscopy or suprapubic-catheter placement. Balloon-port pressure after inflation within the bladder was similar among standard catheters and our catheter prototype. Immediately upon inflation within the prostatic and bulbar urethra of both cadavers and pigs, the “safety balloon” visibly. Mean balloon-port pressure was 60% lower in our catheter prototype. Porcine model histologic analysis showed minimal to no urethral injury using our catheter as compared to a standard BARD catheter.
Conclusions: Non-infectious catheter-related complications occur regularly and are likely under-reported. The simple, intuitive, inexpensive design modifications we describe appear to reduce the damaging pressure exerted upon the urethra during urethral balloon-inflation.
** Dr. Maurice M. Garcia and research reported in this publication was supported by the Eunice Kennedy Shriver National Institute Of Child Health & Human Development of the National Institutes of Health under Award Number K08HD069462. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.