Ineffectiveness of Reprocessing Techniques Sustains Focus on Need for Improved Quality, Resources

By Kelly M. Pyrek

Several years following a widely publicized series of outbreaks related to contaminated and improperly reprocessed duodenoscopes, re-searchers are reporting that current techniques used to clean endoscopes for reuse are not consistently effective. However, some experts say that slow progress is underway.

"I believe we have made some strides in improving the reprocessing of duodenoscopes -- at least from a guideline perspective," says IAHCSMM president Steven J. Adams, RN, BA, CRCST, CHL, RN, manager of central sterile processing at Sinai Hospital of Baltimore. "Certainly, the CDC and FDA have shared some recommendations -- along with our professional associations, such as AAMI, AORN and SGNA; however, I believe everyone needs to understand that the landscape continuously changes as new information is obtained from case studies and other recent research endeavors. We must remain vigilant and aware of these ongoing changes as they occur."
A recent study published in the American Journal of Infection Control identified the need for careful visual inspection and cleaning verification tests to ensure that all endoscopes are free of damage and debris before they are high-level disinfected or sterilized and used on another patient.

“APIC is concerned about the risk of infections related to endoscopic procedures, says Linda Greene, RN, MPS, CIC, FAPIC, the 2017 president of the Association for Professionals in Infection Control and Epidemiology (APIC). “This study reinforces the importance of having strong infection prevention and control programs at all types of facilities, led by highly trained infection preventionists, to ensure that facilities are following the latest evidenced-based guidance.”

The study, conducted by Ofstead & Associates, Inc., suggest that even more rigorous reprocessing techniques of endoscopes are not consistently effective, and organic residues often remain. “Understanding issues with the effectiveness of reprocessing techniques is critically important as institutions seek to improve the quality of endoscope cleaning and disinfection,” says lead study author Cori L. Ofstead, MSPH, Ofstead & Associates, Inc. “Even though top-notch methods were used, the endoscopes in this study had visible signs of damage and debris, and tests showed a high proportion were still contaminated.”

Using a longitudinal study design, Ofstead, et al. (2017) performed three assessments of 20 endoscopes over a seven-month period. The assessments involved visual inspections with a tiny camera, microbial cultures, and biochemical tests to detect protein and adenosine triphosphate (ATP) – a marker that identifies organic matter. These assessments were used to identify endoscopes that required further cleaning and maintenance. During the final assessment, the researchers found that all 20 endoscopes examined had visual irregularities, such as fluid, discoloration and debris in channels. Furthermore, samples from 12 of 20 reprocessed endoscopes (60 percent) had microbial growth, indicating a failure of the disinfection process. Of note, endoscopes reprocessed using current recommended guidelines and those that were cleaned at least twice before high-level disinfection exhibited similar culture results.

Further results indicated that about 20 percent of endoscopes in each group exceeded post-cleaning benchmarks for ATP and protein residue. Moreover, ATP levels were higher for gastroscopes, which are used for upper GI procedures, than the endoscopes used for colonoscopy. “Since the same technicians used the same techniques to clean and disinfect these scopes, the findings and our visual observations suggest that something is happening to gastroscopes during procedures that changes the surfaces and causes reprocessing failures,” says Ofstead.

This study comes on the heels of a 2015 report of Carbapenem-resistant Enterobacteriaceae (CRE) infections related to Endoscopic Retro-grade Cholangio-Pancreatography (ERCP) duodenoscopes - devices that are threaded through the mouth, throat, and stomach into the top of the small intestine (duodenum) for examinations and treatment. No breaches in reprocessing were identified and yet infections related to the duodenoscopes were uncovered, raising concerns that current reprocessing techniques were ineffective, and illuminating the challenges in re-processing of such intricate medical devices.

“The finding of residual fluid in 95 percent of endoscopes tested was significant because moisture fosters microbial growth and the development of biofilm-which can be difficult or impossible to remove,” says Ofstead. “This confirms the importance of cleaning, disinfecting, and drying to ensure patient safety.”

The 2017 study is preceded by a number of studies performed by Ofstead and colleagues that demonstrate the bioburden left behind in endoscopes following cleaning and high-level disinfection. For example, Visrodia and Ofstead, et al. (2014) took samples from endoscopes used for gastrointestinal procedures after bedside cleaning and again after manual cleaning by a technician (prior to HLD). In addition to visual inspections, rapid indicator tests were used to detect residual protein, blood and adenosine triphosphate (ATP). These tests were conducted by sampling external surfaces with swabs and using a flush-brush-flush method on one channel of each endoscope. The researchers inspected 121 components for visible residue and 249 rapid indicator tests were conducted during a total of 37 encounters with 12 endoscopes. All bedside-cleaned endoscopes (N=15 encounters) tested positive for organic residue using rapid indicators, whether or not there was visible residue. After manual cleaning, there was no visible residue on any endoscopes (N=22 encounters), yet 82 percent had at least one positive rapid indicator test. Contamination reflected by the presence of blood (9 percent), protein (27 percent), and high ATP levels (64 percent) was detected on multiple endoscope components. More biopsy ports (64 percent) and suction/biopsy channels (41 percent) had ATP levels exceeding benchmarks after manual cleaning compared to distal ends (15 percent) and control handles (9 percent). The researchers emphasized that, "Despite passing visual inspections, most manually-cleaned endoscopes tested were contaminated with organic residue (e.g., blood, protein, ATP). Visual inspections are difficult to perform on biopsy ports and suction/biopsy channels, and these components were positive for organic residue more frequently than the control handles and distal ends. Relying on visual inspection is inadequate for confirming decontamination of complex endoscopic instruments. These results demonstrate the need for alternative indicators to identify contaminated endoscopes before they are subjected to HLD and subsequently used in patients. More research is needed to determine optimal methods of ensuring endoscopes are free of con-tamination prior to patient use."

In another study, Ofstead and Tosh, et al. (2014) sought to evaluate the effectiveness of endoscope reprocessing when guidelines are fol-lowed. The researchers directly observed endoscope reprocessing during 60 encounters with 15 clinically-used colonoscopes and gastroscopes at a large, tertiary care medical center. Researchers documented adherence with guidelines. Surface swabs were used to sample distal ends, con-trol handles, ports, caps and buttons. Water samples were obtained from suction-biopsy channels and auxiliary water channels. Samples were tested for protein, blood, carbohydrates, and adenosine triphosphate (ATP) using rapid indicator tests. Aerobic cultures were performed, and positive cultures were sent to a reference lab for species identification. The researchers visually inspected 500 endoscope components and con-ducted 588 rapid indicator tests, including surface protein (78), surface ATP (334), water ATP (88), and dipsticks for protein, blood, and carbohydrates (88). Cultures were performed on 88 channel effluent samples. No residue was visible on endoscopes after manual cleaning. Residue was seen on swabs or in effluent for 31 percent of post-manual cleaning samples and zero post-HLD samples. After manual cleaning, samples exceeded benchmarks for ATP (46 percent biopsy ports) and protein (75 percent handles). Post-HLD tests revealed persistent contamination (p<.05). Colony counts from bedside-cleaned channel samples were higher than manually-cleaned and disinfected counts. As the researchers concluded, "Despite guideline adherence by technicians, endoscopes remained contaminated with debris and microorganisms. Visual inspections performed during manual cleaning did not identify debris that researchers could visualize on white swabs during data collection. Rapid indicator tests detected contamination on endoscopes with and without visible debris. Cultures confirmed viable microorganisms after manual cleaning and HLD. Quality assurance initiatives involving rapid indicator tests can detect non-visible endoscope contamination to help ensure effective reprocessing."

Dirlam-Langlay and Ofstead, et al. (2013a) acknowledge that duodenoscopes are notoriously difficult to clean and disinfect, and residual bio-burden has been found on 19 percent of elevator guidewires and 12 percent of channels. However, they emphasize, "…current guidelines assert there is little to no risk of endoscopy-associated infection (EAI) and suggest that infections are largely due to endogenous microbial flora introduced via mucosal trauma." The researchers sought to examine the association between post-ERCP infections and endoscope reprocessing lapses; they identified recent reprocessing lapses that involved patient exposure to contaminated endoscopes through searches of PubMed, governmental documents, conference abstracts, and media reports. A subset of reports describing post-ERCP infection was reviewed to evalu-ate the merit of evidence linking infection transmission to duodenoscopes that were not properly cleaned or disinfected. The researchers found that post-ERCP infections associated with reprocessing lapses occurred in several institutions. Visually-apparent residue and viable microbes, including multiple gram-negative pathogens and multidrug resistant organisms (MDROs), were found on individual patient-ready duodenoscopes. Epidemiological investigations and active surveillance determined that 42 patients acquired Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae during outbreaks tied to reprocessing lapses in three geographic regions. Among 461 patients exposed to con-taminated duodenoscopes, attack rates ranged from 7 percent to 41 percent. Asymptomatic gastrointestinal colonization was common. A Pseudomonas outbreak attributed to reprocessing errors resulted in patient hospitalization and notification of 536 exposed patients. In all of these cases, genetic testing confirmed transmission of pathogens to patients via contaminated duodenoscopes. Various lapses were discovered in institutions with confirmed EAIs, including failure to preclean duodenoscopes after procedures, fill channels with detergent before brushing, remove gross contamination from elevator guidewires and channels, and dry devices after disinfection. Lapses continued undiscovered for 2 to 20 months. Consequences included increased morbidity, mortality, and healthcare utilization among case patients, and secondary transmission to other patients.

Following up on that 2013 initial research, Dirlam-Langlay and Ofstead, et al. (2013b) published a study that reaffirmed (via their literature review) that lapses occurred in various types of facilities and involved errors in all major steps of reprocessing. The researchers report that each lapse continued for several months or years until the problem was discovered except for one that was described as a single incident. As the researchers note, "Improper cleaning occurred on multiple occasions, and employees detected visually apparent residual matter on endoscopes during several of these lapses. At three hospitals, residue on duodenoscopes was associated with bacterial infections. At one of the hospitals, guidelines were violated over a period of 20 months when contaminated duodenoscopes were allowed to dry before cleaning. MAUDE reports described multiple lapses involving detection of debris or residue in various endoscope channels or components. Other lapses described in MAUDE reports involved broken cleaning brushes that were left in endoscopes and found during subsequent procedures, occasionally after being expelled into patients. Errors in disinfection often involved lack of HLD for entire endoscopes or certain channels. For example, endoscopes at a large medical center received no HLD during an eight-month period. At another large center, HLD was not performed on an endoscope channel for nearly three years because of misinformation from the manufacturer.23 MAUDE reports discussed incorrect connectors used to attach endoscopes to automated endoscope reprocessors (AERs) or flushing aids, resulting in no HLD of certain channels. Other failures involved inadequate HLD time or temperature, and errors in disinfectant concentration or water quality during reprocessing. At one hospital, only 25 percent of the required amount of disinfectant was used over a period of 17 months. Expired disinfectant was used for over one year at each of four other facilities. In addition, one MAUDE report described a lapse where water was used in place of disinfectant, and problems with endoscope flushing or rinsing were found when residual chemicals caused chemical colitis."

The researchers continue, "Improper endoscope storage was also reported. One lapse involved patient exposure to a damaged, contaminated colonoscope that was hung unlabeled in a cabinet with clean endoscopes. Other errors involved equipment problems, including AER mal-function or incorrect programming. In some cases, inadequate staff training was recognized as an underlying problem. VAOIG investigations revealed insufficient documentation of staff competency at several VA medical centers. One state agency reported receiving three notifications when staff knowingly used incompletely reprocessed endoscopes on patients. Certain individual lapses involved multiple reprocessing errors. At one private endoscopy clinic, reprocessing errors involved expired chemicals, inadequate cleaning and HLD, and cross contamination of clean and dirty endoscopes. At a large general hospital, failure to preclean duodenoscopes contributed to problems cleaning them. Multiple cleaning and HLD errors also occurred at another general hospital."

Dirlam-Langlay and Ofstead, et al. (2013b) emphasize that adherence to reprocessing guidelines must be improved: "In a multi-site study [Of-stead and Wetzler, et al. (2010)] that revealed poor adherence, staff reported that they did not like to do various reprocessing tasks, felt pressure to work quickly, and attributed health problems to working with endoscopes. The link between reprocessing errors and factors that may influence healthcare worker behavior suggests that training and competency testing need to be supplemented with accountability measures and active surveillance of reprocessing effectiveness so that contaminated endoscopes can be identified before they are used on patients."

Tony Thurmond, CRCST, CHL, CIS, CS, manager at The Christ Hospital Health Network in Cincinnati, Ohio, and an IAHCSMM executive board member, echoes the researchers' message: "There must be more stringent guidelines on the approval of medical devices, and those guidelines must include all the involved parties involved with the use and reprocessing of the device," he says. "The design of the mechanism in the ERCP scope made it difficult to clean the scope properly. If the people who clean and process these scopes had been involved earlier, they may have identified challenges much earlier. The obstacles that remain are proper education and training from the manufacturer, and the information provided should be consistent. Instructions for use must be referred to constantly, and when changes are made, it must go out to all customers/users."
As for potential solutions, Dirlam-Langlay and Ofstead, et al. (2013b) suggest that, "Enhanced training and accountability, combined with in-creased automation, may ensure guideline adherence and patient safety while improving employee satisfaction and health."

Adams says that much work needs to be done to address lingering human factors-related issues. "I am personally grateful for the recom-mendations and guidelines that have been established thus far regarding duodenoscopes; however, efforts have been focused on these specific scopes and not necessarily all endoscopes (or surgical instruments), in general," he says. "One issue in our country is that we react to situations once a patient or many patients are infected or harmed in ways that should never happen. The result is that we develop guidelines specific to those incidents and do not expand it to the processes as a whole. We must be more proactive in identifying risks and developing solutions before the risks become actual issues that impact people. Additionally, the next challenging issue is getting hospital administrators to not only under-stand the criticality of instrument and device reprocessing, but to also understand the costs associated with requiring products and services in order to be compliant with best practices (let alone having and maintaining a skilled, proficient and certified labor force). Facilities will not always develop best practices for sterile processing -- and other hospital areas -- until they are cited by surveyors from the Joint Commission and/or Centers for Medicare and Medicaid Services (CMS). This is definitely a practice that must be addressed and overcome."
Thurmond says that, "Continuous improvement in the forms of education provided to all staff is critical. As items become more complex, the more time is necessary to properly clean and reprocess them. This will affect SPD/CS departments with the staffing needed and the equipment necessary to carry out the process.  Often, we feel rushed to get an item reprocessed and when you rush, mistakes are bound to happen. We will need all parties involved to have an understanding of the time needed and to plan accordingly.  If not, we increase the risk and patient safe-ty is compromised."

In late 2016, the Association for the Advancement of Medical Instrumentation (AAMI), with collaborating organizations (the American Hospital Association, the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA)’s Center for Devices and Radio-logical Health and the Joint Commission) convened last September a forum titled Medical Technology and HAIs. During the event, which served as a follow-up to the 2011 summit on medical device reprocessing convened by AAMI and the FDA, experts were tasked with identifying a list of HAI hazards and articulating potential solutions and mitigation strategies.

The HAI risk factors they identified included facility design, water quality, device reprocessing, and competency and training. Other factors-which were named by a diverse group of clinicians, sterilization and reprocessing professionals, microbiologists, regulators, healthcare technology management professionals, representatives from accreditation bodies, and other experts-included:
- Inadequate facility design
- Inadequate surface/fixture disinfection
- Inadequate risk management practices
- Issues with steam/water quality
- Aged/outdated facilities
- The actions of healthcare providers, housekeeping and environmental services staff, as well as the C-suite
- Failure to consider reprocessing requirements when purchasing equipment
- Inadequate resources and training for sterilization and reprocessing staff
- The complexity of reusable devices and other design issues that make them difficult to clean
- Issues with instructions for use
- Inadequate point-of-use treatment, such as decontamination
- Insufficient maintenance and repair of equipment and devices

"The event was intended to examine the causes of HAIs associated with medical devices and other healthcare equipment," says Joe Lewelling, vice president of emerging technologies and health IT at AAMI. "We conducted a systems approach looking at the issue to come up with what the problems are, the contributing factors, and what the solutions are. At the forum, we divided the world into people, places and things: 'things' meaning problems originating with devices, their use and their maintenance; 'people' meaning problems originating with the actions of the people involved, whether they are clinicians, members of the public, or patients; and 'places' being facilities and facilities management where devices are used. We identified hazardous situations that can cause transmission of infectious agents from one person to another, either by direct contact, or indirectly by dispersing them into the atmosphere."

Lewelling continues, "We found a lot of hazardous uses and contributing factors, which included things such as insufficient resources, either in terms of equipment or reprocessing equipment; it included insufficient training in infection control practices not only among the clinicians but also among reprocessing staff and others who play a role in transmitting or preventing infections. We also looked at the role of the layout of a hospital can play, whether it is the positioning of sinks and toilets, or a physical layout preventing proper cleaning. We also looked at the designs of devices and the instructions for reprocessing and how those contribute. We essentially came up with the proposal that we can address all of these problems with simple actions, but there is a systems problem in inadequate allocation of resources and inadequate training, and also the lack of a pervasive safety culture in many ways. There are certainly people in the healthcare organization whose job it is to prevent infections but to really do that it has to come from the top and it has to be on the minds of every clinician and every worker -- everyone plays a role in preventing the spread of infection."

As we have seen, forum participants were divided into three groups, people, places and things, and asked to identify factors relating to risk in each category. According to the post-forum report from AAMI, Preventing Device-Related Healthcare-Associated Infections: Issues and Out-comes from the September 2016 Forum, Medical Technology and HAIs, the top-ranked factors in the "People" category that contribute to the risk for HAIs are:
1. Inadequate resources and training
2. Failure of healthcare providers to implement best practices (practices based on scientific evidence that they will produce the desired out-come)
3. Environmental services practice failure
4. Actions of patients
5. Actions (or inaction) of governance/leadership

The top factors in the "Places" category were ranked as follows:
1. Inadequate disinfection of surfaces, fixtures, crevices and hinges
2. Inadequate quality systems and risk management practices
3. Issues with the HVAC (heating, ventilation and air conditioning) system and filters
4. Inadequate facility design
5. Issues with facility management
6. Improper sink and toilet placement
7. Special issues in ambulatory settings
Additional factors identified by stakeholders were issues with waste disposal, inadequate environmental monitoring, issues with steam and water quality, aged or outdated facilities, and inadequate signage, labeling, written instructions and standard operating procedures.

The top factors in the "Things" category were ranked as follows:
1. Inadequate cleaning/disinfection of reusable devices
2. Poor device management at point of use
3. Device design issues
4. Device management issues
5. Non-adherence to manufacturer’s instructions for use (IFUs)
6. Improper maintenance/repair of devices
7. Lack of cleaning/disinfection of non-patient care devices (e.g. phones, electronics, etc.)
8. Poor device tracking and monitoring
9. Improper device disposal

Other factors included delays in treatment and reprocessing, insufficient inventory for case load, incompatibilities in disinfection or sterilization processes, transportation of contaminated devices, inadequate or improper storage, single-use devices, and Spaulding’s Classification scheme

For many in attendance at the 2016 forum, implementing a quality management system seemed like the most effective way to structure solutions to many of these problems. In fact, a new standard-ST90-that adapts the quality management system guidance found in AN-SI/AAMI/ISO 13485 to device processing in healthcare facilities is expected to be published sometime this year. However, fixing the issue of de-vice-related HAIs does not rest solely on the shoulders of standards developers or central sterile processing staff ? everyone has a role to play, Suzanne Schwartz, MD, MBA, associate director for science and strategic partnerships at CDRH, articulated during her keynote speech. Schwartz described a shift from passive surveillance to a proactive approach based on using real-world evidence to support regulatory decisions. She emphasized the need for collaboration. Leveraging the healthcare ecosystem-including patients, clinicians, providers, payers, and device manufacturers-enhances the flow of information that informs FDA surveillance, facilitates the clearance and approval of new devices, and enhances oversight of device-related events.

“Solutions are needed at an ecosystem level,” she said at the forum. “Until we change our model to more of a systems approach, our siloed efforts will only get us so far.”
As AAMI's post-forum report summarizes, "Focusing on people, places, and things provided structure to the workshop and helped organize discussions and recommendations. But it also served to identify the important concepts that are essential to the success of any program. The most important observation was the systems nature of infection prevention. Contamination and transmission are rarely isolated events; they are the product of a complex, interactive environment (system) that was not adequately designed to prevent them. Collaboration and communication are integral to infection prevention. Finally, education and training, oversight and validation of knowledge and performance were elements captured in the recommendations from all three focus groups."

The report emphasizes further, "Infection prevention requires 'big picture' thinking. A patient’s device-related infection results from contamination that could have come from numerous sources. Because so many factors impact the potential for contamination and transmission related to a device, effective strategies must address the device as a process, including purchase, maintenance/reprocessing, use, and storage. That approach to prevention requires collaboration and commitment from everyone involved, support from the facility for the resources required for implementation, acknowledgement and reward for achievements, and a commitment to improvement when performance falls short."

This forum was a first step in gaining the consensus needed to take such a systems approach.

"We are going to continue to work with stakeholders to try to create tools that will help enable healthcare delivery organizations tackle some of the problems identified in our report," Lewelling adds.

The recommendations for preventing device-related HAIs created by forum attendees was published in early 2017. These recommendations will represent the opinions of highly qualified experts constituting all disciplines involved in the design, development, purchase, use, and reprocessing of medical devices and associated equipment, and the systems in which they are used. A summary report of the proceedings is available from AAMI at: http://s3.amazonaws.com/rdcms-aami/files/production/public/FileDownloads/Summits/161227_AAMI_HAI_Forum_Report.pdf.

The long list of challenges that sterile processing departments face must be shared with hospital administration so that it can be addressed financially and from the perspective of an institutional culture of safety.

"The simple but extremely difficult-to-accomplish answer to improving collaboration is persistent and consistent fact-based communication," says Adams. Utilizing the infection prevention department as a collaborative force definitely offers some support. Additionally, we cannot over-look getting key individuals from other departments involved. A recommendation would be to get key personnel who comprise the value analysis committee/purchasing department and give them a tour of the CS department. Explain the importance behind the equipment and products being used and explain what works well and what does not. At the same time, relate that information to the instruments that could be used on them personally, as a patient, and ask which product they would prefer to have used on them."

Adams continues, "There are many staff to communicate with across the facility. What CS managers need to understand is that not all of these people in these various departments understand what we do. If you do not have that expectation, then we can put on our education and training hats to help these key personnel better understand what we do and what our needs are. In other words, we must stretch out beyond our comfort zones and directly reach out to these individuals to offer tours and education. It will eventually be a win-win situation. The last important factor is we must have our facts in hand. Top-level administrators are not going to make decisions based on hunches or opinions, or just because we believe it is the best thing to do. We need to make sure we have the most current standards and guidelines to support our needs and requests. Documented evidence that is current and accurate is our best friend when communicating to facility administrators. We must always make sure we keep a documented record of the discussions had and the areas we are wanting to improve. Leadership changes happen more often than we anticipate. Having all the previous facts and discussion-based information at hand will prevent a lot of anxiety and frustration when the leadership team undergoes some changes."

Thurmond recommends collaboration with the infection prevention and control department. "If a CS/SPD department is not working closely with their infection control personnel, they are missing out on a great collaboration.  An example, I recently toured our department with our Infection Control team and we spoke about the new Xenex disinfection robots our hospital just purchased.  While walking through our decontamination room, I asked about the possibility of getting them used in our department, and they all agreed it was a definite necessity and it is being scheduled. We need to be very open and discuss our concerns and successes with our administration. Our department is critical to patient safety and the success of each patient's full recovery." 

References:

Association for the Advancement of Medical Instrumentation (AAMI). Preventing Device-Related Healthcare-Associated Infections: Issues and Outcomes from the September 2016 Forum, Medical Technology and HAIs. December 2016.

Dirlam-Langlay AM, Ofstead CL,  Wetzler HP, Tosh PK and Baron TH. Abstract 1468: Transmission of Multidrug-Resistant Organisms via Con-taminated Duodenoscopes. Gastrointestinal Endoscopy. Volume 77, No. 5, Supplement, May 2013(a), Pages AB394.

Dirlam-Langlay AM, Ofstead CL, Mueller NJ, Tosh PK, Baron TH and Wetzler HP. Reported gastrointestinal endoscope reprocessing lapses: The tip of the iceberg. Am J Infect Control. Vol. 41, No. 12, December 2013(b), Pages 1188-1194.

Ofstead CL, Wetzler HP, Heymann OL, Johnson EA, Eiland JE and Shaw MJ. Longitudinal assessment of reprocessing effectiveness for colono-scopes and gastroscopes: Results of visual inspections, biochemical markers, and microbial cultures.  Am J Infect Control, Volume 45, No. 2. Feb-ruary 2017.

Ofstead CL, Tosh P, Yellin HL, Doyle E, Rocco C, Baron T, Visrodia K and Wetzler HP. Persistence of Organic Residue and Viable Microbes on Gastrointestinal Endoscopes Despite Reprocessing in Accordance with Guidelines. Am J Infect Control. Volume 42, Issue 6, Supplement Pages S41. June 2014.

Ofstead CL, Wetzler HP, Snyder AK and Horton RA. Endoscope reprocessing methods: a prospective study on the impact of human factors and automation. Gastroenterol Nurs, 33 (2010), pp. 304–311.

Visrodia K, Ofstead CL, Tosh PK, Baron TH, Yellin HL and Wetzler HP. ASGE oral abstract 214: Evaluating Contamination on Gastrointestinal Endoscopes in Clinical Use Before and After Manual Cleaning. Gastrointestinal Endoscopy. Vol. 79, No. 5, Supplement, May 2014, Pages AB119–AB120.