Disinfection of anesthesia and respiratory therapy equipment with acid glutaraldehyde solution

The dilution of acid glutaraldehyde solution and its effect on microbiological effectiveness were investigated using Sonacide and the Cidematic Decontamination System under normal use conditons at 18 hospitals over a 4-week period. The dilution of Sonacide was found to follow first-order kinetics and is described by the equation, ln C = ln Co-KT, where K is the apparent dilution-rate constant. The average dilution-rate constant under normal use conditions was 0.015/day. It takes an average of 47 days under normal hospital-use conditions to reduce its potency to half its original strength. The average glutaraldehyde concentration after 28 days' use was found to be approximately 66% of the initial concentration. The AOAC use-dilution test was employed to evaluate the microbiological effectiveness of the Sonacide samples collected weekly for four weeks. Results showed that all the Sonacide samples from 18 hospitals passed the AOAC use-dilution test for Pseudomonas aeruginosa (ATCC 15442). Based on this study, it is apparent that Sonacide can be used to disinfect various anesthesia and respiratory therapy equipment for up to 4 weeks in the Cidematic machine.