Login to Access Video or Poster Abstract: MP23-04
Sources of Funding: This work is supported by the University of Florida Research Opportunity Seed Fund.

Introduction

Within 4 weeks, 90% of long-term catheterized patients will develop bacteriuria, and 50% will experience encrustation and marked elevation of urine pH. Urease-producing bacteria have been linked to elevated urine pH, catheter-associated urinary tract infection (CAUTI), encrustation, and struvite renal calculi. We propose a method to monitor alkalinization of urine as part of a multimodal system which could play a role in prevention of catheter encrustation. Reversibility of the colorimetric membrane acts as a form of biofeedback to allow for modification of oral intake with acidifying agents and control urine pH to prevent encrustation.

Methods

To create a pH-sensitive, reversible colorimetric porous membrane with immediate detection of alkaline urine, high molecular weight polymer was solvated in organic solvent. A quaternary ammonium salt and indicator dye were then added for pH sensitivity and electrostatic retention of the dye. Addition of plasticizer followed to modify the membrane mechanical properties. This solvated mixture was stored under 4°C refrigeration until casting.

Results

The solvated membrane blend was drop cast onto the inside of catheter tubing for demonstration. Basic solution (pH 7.5 / NaOH) was passed through and a distinct and visible change of color to green (see Figure 1) was observed upon exposure. Dilute acidic solution was then passed through (pH 4 / H₂CO₃) and there was a rapid reversal (< 5 seconds) to original yellow color. The urinary pH range from 4.0 to 9.0 can be monitored by this system.

Conclusions

The clear colorimetric indication afforded by this membrane provides a robust system for the reversible detection of real-time changes in urine pH. As a component of a multipart system, this provides rapid biofeedback that allows for informed and directed intervention. This system may also assist in the detection of elevated urine pH secondary to urease-producing bacteria responsible for encrustation and recurrent struvite kidney stone formation.

Funding

This work is supported by the University of Florida Research Opportunity Seed Fund.