Residues of ethylene oxide and chemical disinfectants in anesthesia supplies can cause side effects in patients. For this reason we intubated 37 New Zealand rabbits with PVC endotracheal tubes of 3.0-3.5 mm inner diameter. The tubes were sterilized with ethylene oxide and aerated for 24 or 48 h in room air. At this time they still held 600 resp. 80 ppm ethylene oxide as we had determined by gaschromatography. For comparison tubes were soaked in 2% activated Cidex or 10% Gigasept and watered for 1 h in sterile water. 5 not intubated animals served as controls. All rabbits were sacrificed after 48 h and larynx and trachea examined microscopically for histological changes. In all intubated animals we found hyperemia, edema formation and cellular infiltration. In addition there were epithelial erosions in about 60% and 4 uclers. The findings were considerably more pronounced in animals which had been intubated with tubes containing 600 ppm ethylene oxide. Almost all tubes cause mechanical irritation of the respiratory tract. Additional chemical trauma is not to be expected, however, if they are watered adequately after treatment with disinfecting solutions resp. aerated sufficiently after ethylene oxide sterilization.
