Optimization of colonoscope bedside precleaning protocol: an orthogonal experimental study

This study utilized an orthogonal experimental design to optimize the bedside precleaning protocol for colonoscopes. It evaluated the correlation between adenosine triphosphate (ATP) bioluminescence testing and microbial culture results, thereby establishing an evidence-based foundation for quality control in endoscopy.

Four factors affecting colonoscope bedside precleaning were selected, each with three levels, and arranged into nine protocols using an L9(3⁴) orthogonal design. One hundred eighty colonoscopes were assigned to nine groups (n = 20) for different bedside precleaning protocols after the procedure. ATP levels (RLU) and microbial counts (CFU/mL) were measured after bedside precleaning, cleaning, and disinfection. Spearman correlation analysis was performed using GraphPad Prism 10.1.2, and cost-effectiveness was assessed.

Factors A (types of detergents) and C (suction duration) demonstrated statistically significant effects on post-precleaning ATP values and microbial counts (P = 0.035 and P = 0.048, respectively), with alkaline solution (A₃) and 20-second suction (C₂) showing optimal efficacy. No factors significantly influenced postcleaning ATP levels or microbial counts (P>0.05).

The optimized colonoscope bedside precleaning protocol for reducing biopsy channel contamination includes: alkaline solution (A₃), solution replacement every four hours (B₂), 20s suction (C₂), and a clinically appropriate delay (≤3h). ATP testing and microbial culture exhibit high consistency in assessing biopsy channel cleanliness during cleaning, which can serve as a useful screening tool for immediate process intervention during endoscope cleaning. However, its utility post-HLD is limited.