Residual glutaraldehyde levels in fiberoptic endoscopes: measurement and implications for patient toxicity

Most gastroenterology societies recommend glutaraldehyde for fiberoptic end oscope disinfection. However, glutaraldehyde toxicity has been suspected in patients examined with endoscopes disinfected with this compound. The aim of our study was to determine the residual levels of glutaraldehyde in fibe roptic endoscopes after either manual or automatic disinfection and to eval uate the extent of toxicity Furthermore, the procedures for disinfection cu rrently performed by the department a ere compared with the new French guid elines. We used both manual and automatic disinfection procedures and flushed steri le distilled water through the lumens of endoscopes before use. Residual gl utaraldehyde levels were determined using liquid chromatography coupled to spectrophotometric detection. In a total of 92 measurements it was found that residual glutaraldehyde lev els were higher and more variable after manual disinfection (< 0.2-159.5 mg /L) than after automatic disinfection (< 0.2-6.3 mg/L). We conclude that lo cal procedures for disinfection need to be improved to conform to the new F rench guidelines. Since thresholds for the toxic dose of glutaraldehyde and international norms for levels of residual glutaraldehyde in equipment hav e not been defined, additional studies combining accurate measurements in f iberoptic endoscopes and clinical observations of endoscopy patients will b e required to draw more definitive conclusions. (C) 1999 The Hospital Infec tion Society.