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Surface analysis of clinically used expanded PTFE endoscopic tubing treated by the STERIS PROCESS
R C Tucker1, B J Lestini, R E Marchant
1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA.
Abstract:
The repeated use of semicritical and critical medical instruments in clinical procedures carries an inherent risk of subsequent patient infection, necessitating "high-level" disinfection or sterilization. However, residual bio-organic contamination may hinder the ability of such processes to efficiently destroy infectious microbes. In this study, the inner surfaces of three clinically used expanded polytetrafluoroethylene endoscope tubes treated with glutaraldehyde disinfectant solutions were analyzed to quantify the efficacy of a buffered peracetic acid sterilization procedure, the STERIS PROCESS, in removing this contamination. Samples of the flexible distal biopsy channel of colonoscope tubes were examined before and after a variable number of STERIS processing cycles by three complementary surface characterization techniques: Fourier transform infrared spectroscopy (FTIR), electron spectroscopy for chemical analysis (ESCA), and atomic force microscopy (AFM). Glutaraldehyde fixed protein deposits identified on the tubing surface decreased with increased STERIS cycles. After 20 STERIS cycles, FTIR data indicated that approximately 30% of the contamination was removed, whereas ESCA indicated that 50% of the contamination was removed. AFM images showed considerable variation between control and processed samples, including evidence for cracks in the residual contamination layer. Clinical glutaraldehyde treatment and subsequent device drying are suggested to be two majors factors that limit effective cleaning of endoscopic tubing.
Insights
High-level disinfection of medical endoscopes is crucial but hindered by residual bio-organic contamination. The STERIS PROCESS shows limited efficacy in removing glutaraldehyde-fixed protein deposits from endoscope inner surfaces.
Area of Science:
- Medical device reprocessing
- Infectious disease control
- Surface science
Background:
- Semicritical and critical medical instruments require high-level disinfection or sterilization to prevent patient infections.
- Residual bio-organic contamination on instruments can impede the effectiveness of disinfection and sterilization processes.
- Endoscopes, frequently reused, pose a risk of transmitting infections if not adequately cleaned.
Purpose of the Study:
- To quantify the removal of bio-organic contamination from endoscope inner surfaces using the STERIS PROCESS.
- To evaluate the efficacy of buffered peracetic acid sterilization in cleaning clinically used endoscope tubes.
- To identify factors limiting the effective cleaning of endoscopic tubing.
Main Methods:
- Analysis of inner surfaces of expanded polytetrafluoroethylene endoscope tubes after glutaraldehyde treatment.
- Application of the STERIS PROCESS (buffered peracetic acid sterilization) for variable cycles.
- Utilized Fourier transform infrared spectroscopy (FTIR), electron spectroscopy for chemical analysis (ESCA), and atomic force microscopy (AFM) for surface characterization.
Main Results:
- Glutaraldehyde-fixed protein deposits decreased with an increasing number of STERIS processing cycles.
- FTIR indicated approximately 30% contamination removal after 20 STERIS cycles.
- ESCA indicated approximately 50% contamination removal after 20 STERIS cycles, with AFM revealing cracks in the residual layer.
Conclusions:
- The STERIS PROCESS demonstrates partial efficacy in removing glutaraldehyde-fixed contamination from endoscope inner surfaces.
- Clinical glutaraldehyde treatment and device drying are significant factors limiting effective cleaning of endoscopic tubing.
- Further optimization of cleaning protocols is necessary to ensure complete removal of bio-organic contamination from medical endoscopes.