Characteristics of atmospheric pressure plasma decontamination of endoscopic channels

This paper reports an electrical and optical characterization study of an atmospheric pressure plasma generator used for decontaminating endoscopic channels. In order to sustain such plasma in a narrow channel of up to one meter, two electrode configurations are discussed. Plasma characteristics such as the discharge current, dissipated power, gas temperature are measured, together with optical emission spectroscopic measurements. These are used to seek the optimal plasma conditions by means of scoping the range of the gas composition, the gas flow rate, and the excitation frequency as well as different electrode designs. Results of electrical and optical measurements are then linked to efficacy data of plasma inactivation of bacteria and proteins that are common contaminants on medical instruments following surgery. Based on these relationships, discussions are made of possible scope of decontamination efficacy.