Comparison of cleaning effects of vacuum-assisted boiling washer-disinfectors on rigid endoscopic instruments: impact of cleaning cycle parameters.

Background: Vacuum-assisted boiling washer-disinfectors are widely favoured for cleaning rigid endoscopic instruments, but the standard cleaning cycle is time-consuming, which affects the turnover of instruments.

Aim: To compare the cleaning effects of different cleaning cycle parameters on rigid endoscopic instruments and determine parameter settings that balanced effectiveness and efficiency.

Methods: 600 rigid endoscopic instruments that had been used in laparoscopic cholecystectomies were randomly divided into four groups, including one control group (standard parameters) and three experimental groups which differed in enzymatic washing time, temperature, or detergent concentration. The cleaning quality was assessed via visual inspection with a 5x magnifier and borescope, adenosine triphosphate (ATP) bioluminescence assay, and residual protein detection.

Findings: No significant difference was found in the cleaning qualification rate among the four groups using a visual inspection with either the 5x magnifier or the borescope (all P > 0.05). However, significant differences were observed in the ATP bioluminescence assay and residual protein detection (all P < 0.05). Pairwise comparisons revealed group A had higher qualification rates than groups C or D (P < 0.0167). Significant differences in relative light unit (RLU) values were observed between groups in the ATP bioluminescence assay (P < 0.05): group A showed lower RLU values than groups B and C, and group D showed lower RLU values than group C (all P < 0.001).

Conclusion: Increasing the enzymatic washing temperature of the vacuum-assisted boiling washer-disinfector to compensate for the flushing and rinsing steps shortened the cleaning time and improved the reprocessing efficiency of rigid endoscopic instruments while maintaining high cleaning quality.