SURFACE-ANALYSIS OF CLINICALLY USED EXPANDED PTFE ENDOSCOPIC TUBING TREATED BY THE STERIS PROCESS

The repeated use of semicritical and critical medical instruments in c linical procedures carries an inherent risk of subsequent patient infe ction, necessitating ''high-level'' disinfection or sterilization. How ever, residual bio-organic contamination may hinder the ability of suc h processes to efficiently destroy infectious microbes. In this study, the inner surfaces of three clinically used expanded polytetrafluoroe thylene endoscope tubes treated with glutaraldehyde disinfectant solut ions were analyzed to quantify the efficacy of a buffered peracetic ac id sterilization procedure, the STERIS PROCESS(TM), in removing this c ontamination. Samples of the flexible distal biopsy channel of colonos cope tubes were examined before and after a variable number of STERIS processing cycles by three complementary surface characterization tech niques: Fourier transform infrared spectroscopy (FTIR), electron spect roscopy for chemical analysis (ESCA), and atomic force microscopy (AFM ), Glutaraldehyde fixed protein deposits identified on the tubing surf ace decreased with increased STERIS cycles. After 20 STERIS cycles, FT IR data indicated that approximately 30% of the contamination was remo ved, whereas ESCA indicated that 50% of the contamination was removed. AFM images showed considerable variation between control and processe d samples, including evidence for tracks 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.