Large Multisite Clinical Field Study Characterizing Contamination Levels in Patient Used Endoscopes After Manual Cleaning

Abstract

Background: Multiple outbreaks multidrug-resistant organisms (MDROs) have been associated with flexible endoscopes resulting in unacceptable patient mortality and morbidity. Evidence highlights the importance of effective cleaning to achieve effective high-level disinfection (HLD). This study presents an analysis of >700,000 measurements of adenosine-triphosphate (ATP) contamination levels found in flexible endoscopes after manual cleaning. Method: This 2018–2019 study consists of 702,768 measurements of ATP levels found in the suction/biopsy channel of instruments used on patients after manual cleaning: gastroscopes (267,533 measurements from 223 sites), duodenoscopes (123,697 measurements from 161 sites), colonoscopes (252,249 measurements from 229 sites), and bronchoscopes (59,289 measurements from 107 sites). Sites were located across the United States and employed protocols that included routine cleaning verification performed by the reprocessing technicians using a handheld luminometer and the associated ATP water test (3M Clean-Trace). Results: Figure 1 shows a boxplot analysis of the ATP levels by endoscope type. Upper gastrointestinal (GI) endoscopes (gastroscopes and duodenoscopes) show a significantly (P < .005) greater level of ATP contamination after manual cleaning. The pairwise mean differences are all significant (P < .005) except for colonoscopes when compared to bronchoscopes (P = .203). Also shown on Fig. 1 is a literature supported adequate cleanliness value of 200 RLUs [=2.3log(RLUs)] (MJ Alfa et al.; Am J Infec Control 2013;41:245–253 and ANSI/AAMI ST91; 2015). A 95% confidence interval analysis performed against this literature value (Table 1) showed that a high number of gastroscopes (12%) and duodenoscopes (10%) are not adequately clean. Figure 2 shows a box-plot analysis of the data set by endoscope type and by site. There is significant (P < .005) site-to-site variability for all endoscope types as demonstrated by variation in mean values, box size, and many outliers. Conclusions: This study highlights the importance of using a quantitative cleaning verification method to better understand process capability and to provide more robust quality assurance for manual cleaning. Significant differences were detected in the level of cleanliness between upper GI scopes and lower GI scopes and bronchoscopes. When compared to a literature-supported level for adequate cleanliness, upper GI scopes exhibited failure rates in excess of 10%. Furthermore, significant site-to-site variability occurred, and many outliers fell well beyond the normal process envelope, representing significant cleaning lapses. Root causes to these concerning findings could range from inadequate execution of the cleaning protocol, to device design, to age and existing damage that could prevent achieving adequate cleaning and possibly impair the effectiveness of HLD.

Funding: None

Disclosures: Marco Bommarito, 3M (salary)