Abstract
Medical equipment has become increasingly sophisticated with technological progress, with the result that sterilization is often more difficult to achieve. Much modern equipment is intricate, delicate and thermolabile. For the purposes of this research, fibre-optic endoscopes were chosen as important examples of this type of equipment. Because of their expense, individual instruments may be required more than once during a surgical list. There is thus a need for a rapid, simple, cold method of sterilizing such equipment but there are no suitable methods currently available. Physical sterilization methods and gaseous chemicals cannot be used and the sporicidal liquids available for the treatment of heat labile surgical equipment require contact periods of several hours. Previous research showed that a mixture of methanol and sodium hypochlorite had appreciable sporicidal properties. The main aim of this work was therefore the investigation of alcohol-hypochlorite mixtures and the development of a cold, quick-acting sporicidal liquid suitable for treating thermolabile instruments and other equipment. The physical, chemical and biological properties of several mixtures of sodium hypochlorite and an alcohol were studied and some were shown to be sporicidal within two minutes. The effect of changing the pH of these mixtures and of hypochlorite solution alone was investigated. The uses of such solutions were considered. Disinfection methods currently used for endoscopes in two hospitals were studied and shown to be ineffective. Following successful treatment of a laboratory contaminated fibre-optic endoscope a solution of sodium hypochlorite buffered to pH 7.6 was suggested for use with thermolabile medical equipment.