Feasibility and efficacy of newly developed eco-friendly, automatic washer for endoscope using electrolyzed alkaline and acidic water

Introduction: As well as preventing nosocomial and healthcare-associated infections, a reliable and eco-friendly washer for medical equipment would also be safe for the global environment. The aim of this study was to evaluate the efficacy of a newly developed automatic washing system (Nano-washer) that uses electrolyzed water and ultrasonication without detergent for washing endoscopes.Methods: Patients who underwent laparoscopic lobectomy or laparoscopic colectomy at Nagasaki University between 2018 and 2022 were included. A total of 60 cases of endoscope use were collected and classified according to endoscope washing method into the Nano-washer group (using no detergent) (n = 40) and the manual washing group (n = 20). Protein and bacterial residues were measured before and after washing, using absorbance spectrometry and 16S rRNA polymerase chain reaction. The effectiveness of protein and bacterial removal and endoscope surface damage after washing were compared under specular vision between the groups.Results: Nano-washer did not use detergent unlike manual washing. There was no difference in demographic or clinical characteristics between the groups except for the presence of comorbidities in the lobectomy group (Nano-washer, 85%; manual washing, 40%, P = .031). Compared with the manual washing group, residual protein levels in the Nano-washer group were significantly reduced after washing (lobectomy, 0.956 mg/mL vs 0.016 mg/mL, P < .001; colectomy, 0.144 mg/mL vs 0.002 mg/mL, P = .008). Nano-washer group showed a significant reduction in bacteria between before and after lobectomy (9437 copies/cm(2) vs 4612 copies/cm(2), P = .024).Conclusion: Nano-washer is a promising, effective, and eco-friendly automatic washing device that is safer and more efficient than manual washing.