Sterile water in endoscopy: habit, opinion, or evidence

Should sterile or tap water be used in irrigation bottles during endoscopy? The use of sterile water obviously increases the cost of endoscopy, not only in terms of actual costs, but also in terms of the costs to society and the environment because the plastic containers it comes in are discarded. Given the recent focus on the skyrocketing cost of health care and on the environment, this issue, although raised before, seems to be more controversial than ever. The American Society for Gastrointestinal Endoscopy (ASGE), the Society of Gastroenterology Nurses and Associates (SGNA), and The Society for Healthcare Epidemiology of America” (SHEA) have recommended using sterile water in sterile bottles during endoscopy. These recommendations form the basis of “standard protocol” at most endoscopy units. Herein, we discuss the evidence behind these recommendations. In their practice guidelines on infection control, the ASGE states that “water bottles should be disinfected or sterilized, and sterile water should be used in the water bottle.” However, the basis for this recommendation seems to stem from a study that addresses the importance of endoscope drying after endoscope reprocessing rather than the use of sterile water in bottles. This was confirmed with a personal communication with the author (LF Muscarella, February 16, 2010). The SGNA, in their position statement, comments that “sterile water should be used in the water bottle for all endoscopic procedures.” They reference the ASGE guidelines and the Association for Professionals in Infection Control (APIC) guidelines from 2000. The APIC guidelines recommend sterile water in bottles because “the water bottle and connecting tubes are difficult to clean and disinfect and are often colonized with Pseudomonas species and may serve as important reservoirs of crossinfection.” The 2000 APIC guidelines’ references include 2 articles on disinfection of endoscopes, from 1974 and 1978. In 1 study, the efficacy of ethyl alcohol and glutaraldehyde to disinfect fiberoptic endoscopes was compared. The wash bottles were disinfected by soaking them in the disinfectant for 10 minutes. The study was not designed to assess the use of sterile water, nor does it conclude anything about the use of sterile water. Interestingly, the tap water that was used in this study did not grow any bacteria. The second study addressed the efficacy of a 2-stage disinfecting procedure for the endoscopes, a short intermediate disinfection using polyvidoneiodine between 2 procedures and a main disinfection at the end of a series of procedures using glutaraldehyde. After disinfection with polyvidone-iodine (but not after glutaraldehyde), Pseudomonas aeruginosa was grown from the channels of the endoscope. The bacteria were also grown from the water bottle and the connection tube. The source was ultimately traced to a contaminatedmovable water tap. So this also is not pertinent to our question. Case reports from the 1970s and 1980s have reported Pseudomonas infections after ERCP and EUS. In these cases, although Pseudomonas was cultured from the endoscopy water bottles, it was unclear whether the source of infection was the endoscope or the water bottle. This study also predated current endoscope reprocessing guidelines. The above studies are all many years old, used dated disinfection techniques, and did not establish tap water or the bottle as the source of infection. We have gained valuable knowledge about disinfection in the past few years and have far better technology Abbreviations: APIC, Association for Professionals in Infection Control; ASGE, American Society for Gastrointestinal Endoscopy; SGNA, Society of Gastroenterology Nurses and Associates; SHEA, Society for Healthcare Epidemiology of America.