PATIENT AND STAFF EXPOSURE TO GLUTARALDEHYDE FROM KEYMED AUTO-DISINFECTOR ENDOSCOPE WASHING MACHINE

Activated glutaraldehyde (2 %) is the recommended agent for disinfecti on of endoscopic equipment. Exposure to the disinfectant is associated with side-effects and guidelines have been set to avoid these complic ations. Endoscope washing machines are used to provide automated high level disinfection of endoscopes as well as reduce exposure to the irr itant aldehyde. We report a design fault in an endoscope washing machi ne which results in patients and staff being exposed to activated glut araldehyde. The Auto-Disinfector (KeyMed) comprises a washing chamber supplied by three separate reservoirs (detergent, disinfectant, and ri nse water) via a common channel. After the first cycle endoscopes are processed using previously used detergent and rinse water. Rinse water glutaraldehyde concentrations were measured in four machines during r outine endoscopy lists on at least two occasions and showed a progress ive rise in glutaraldehyde concentration up to 0.1 % after two to six cycles. This results in staff being exposed to glutaraldehyde present on the processed instrument and the disinfectant being pumped from the internal channels of the endoscope into direct contact with the gastr ointestinal mucosa during endoscopy at concentrations of 200-1000 ppm. The present atmospheric limit for glutaraldehyde is 0.2 ppm. Skin and mucosal irritation occur at concentrations of 0.3 ppm and severe syno vitis in experimental animals at 100 pm. Tongue swelling and bloody di arrhoea with characteristic mucosal histological changes have been rep orted in patients exposed to activated glutaraldehyde on inadequately rinsed equipment. To reduce this problem the rinse water should be cha nged after every cycle and the endoscope should be dried thoroughly be fore use.