How single-use is your bronchoscope



How single-use is your bronchoscope? Contamination of single-use bronchoscopes following diagnostic and therapeutic procedures in critically ill ventilated patents* Brendan A McGrath,1,2 Sarah Ruane,3 Janet McKenna,4 & Stephanie Thomas51 Consultant in Anaesthesia & Intensive Care Medicine, University Hospital South Manchester2 Honorary Senior Lecturer, Manchester Academic Health Sciences Campus3 Speciality Trainee in Anaesthesia, Health Education North West4 Senior Biomedical Scientist, University Hospital South Manchester5. Consultant Medical Microbiologist, University Hospital South ManchesterCorrespondence to B A McGrathEmail: brendan.mcgrath@manchester.ac.ukAcute Intensive Care Unit, University Hospital South Manchester, Southmoor Road, Wythenshawe, Manchester. M23 9LT*Presented in part at the Anaesthetic Research Society, Royal College of Anaesthetists, London, April 2015.Email addresses of non-corresponding authors:3. sruane@.uk4. janet.mckenna@.uk5. stephanie.thomas@uhsm.nhs.ukShort title (60 characters)Contamination of single-use bronchoscopesKey wordsNosocomial infection; Bronchoscopy; Fibre-optic intubationSummary Disposable bronchoscopes such as the Ambu aScope3TM are marketed as ‘single use.’ The risks of contamination from prolonged device storage prior to possible re-use are unknown. Following clinical bronchoscopy in ventilated patients, 20 aScope3’s received a standard ‘social clean’ and were stored. Subsequent paired saline flush and swab samples were taken at time zero, 24 and 48 hours. Positive microbiological cultures were obtained at least one time point from 16 of the 20 bronchoscopes. Seven bronchoscopes isolated pathogens considered high risk of causing pneumonia, with six in significant quantities. Our study demonstrates that aScopes should not be re-used on the same patient as clinically significant growth of microorganisms frequently occurs despite adequate social cleaning. Culture of bronchoscopes themselves may be a potentially useful diagnostic tool in the context of pulmonary infection. Our data makes it clear that these devices are single use and not single patient use.Bronchoscopy is a common diagnostic and therapeutic procedure on the Intensive Care Unit (ICU). Diagnostic uses include aspiration of sputum or cytology samples for microbiological or pathological analysis. Aspiration can be assisted by first instilling small volumes (typically 20mls) of saline during a bronchial wash (BW) or a more formal broncho-alveolar lavage (BAL) involving instilling and aspirating 50-200mls of saline from a lung segment. BW may also be used as a therapeutic maneuver for lobar collapse via the removal of mucus plugs or secretions. Relatively complex, re-useable flexible bronchoscopes are typically used for these procedures and cleaning is followed by sterilization or high-level disinfection with rinsing and drying before storage. Bronchoscopes are at a greater risk of residual contamination due to their relatively small working channel size when compared with devices such as gastroscopes. Exogenous microorganisms may be transmitted by bronchoscopes by contamination of reprocessing equipment, of the bronchoscopes themselves or of accessory equipment. Whilst relatively rare, 48 outbreaks of exogenous bronchoscopy-related infections and cross-contaminations involving 198 infected patients were reported in the literature between 1970 and 2012, and the problem is likely to be underreported [1,2]. Outbreaks of bronchoscopy-related transmission of multidrug-resistant Pseudomonas aeruginosa and carbapenemase-producing Klebsiella pneumoniae have also been published along with news reports of cross contamination [3-8]. This led the US Food and Drug Administration to publish a safety communication in September 2015 highlighting contamination of re-usable bronchoscopes [9] and to the ECRI Institute declaring ‘Inadequate cleaning of flexible endoscopes before disinfection can spread deadly pathogens’ as the top Health Technology Hazard for 2016 [10].Disposable bronchoscopes such as the Ambu aScope 3TM (Copenhagen, Denmark) have been recently introduced alongside conventional multi-use bronchoscopes, with similar functionality. Devices such as the aScope3 are designed and marketed as ‘single use’. Beyond this statement, there is currently no guidance concerning how long this single episode may last. For example, if a patient with a difficult airway was intubated at the start of a theatre case using a bronchoscope, most anaesthetists would keep the device available to troubleshoot problems with the secured airway, or to facilitate re-intubation should extubation prove problematic. Similarly, the bronchoscope used to check the placement of a double lumen endotracheal tube is usually re-used if the patient is subsequently re-positioned and there are concerns about the precise device location. This may seem entirely reasonable if the procedure lasts for one hour, but what if the procedure lasts for six or 12 hours, or if endoscopy is required the following day? The costs of single-use devices make them tempting to use as single patient device, but there are currently no data to confirm whether this is a reasonable strategy, how long a device may be kept available to be safely re-used and what the potential problems from prolonged device storage and subsequent re-use might be. Re-using a single-use device may be particularly problematic in the ICU patient. Bronchoscopy is commonly performed to investigate or treat pulmonary infection and involves aspiration of infected material through the bronchoscope’s suction channel. If the patient is critically ill, immunosuppressed or receiving potent antimicrobial agents, re-introduction of pathogens may have significant repercussions for the patient. The aim of this study was to evaluate the possible consequences of re-using stored aScope 3’s following routine clinical ICU bronchoscopy by performing microbiological analysis up to 48 hours after use.MethodsThe NHS Health Research Authority on-line tool determined that this study did not require formal ethical approval but the study was subject to local internal research governance procedures.The University Hospital South Manchester has a mixed tertiary Acute Intensive Care Unit with 17 beds, managing a wide range of adult patients. Surgical specialties supported include major vascular, general and upper gastrointestinal surgery, orthopaedics and trauma, major urology, burns, plastic surgery, and head and neck surgery. The unit admits mixed medical patients and the hospital also houses the North West Lung Centre and infectious diseases department, including the National Aspergillus Centre. Unselected ventilated patients underwent bronchoscopy at the discretion of the attending clinicians. The ICU stocks a mixture of single-use aScopes and re-useable bronchoscopes, and device choice was left entirely to the operator. If an aScope was used between Monday and Wednesday (when research staff were available to perform subsequent sampling and analysis for the following 48 hours), the device was quarantined following use and studied.The used bronchoscope was exposed to a standard ‘social clean’ by research staff. This comprised flushing of the working channel with 20mls of sterile saline, followed by external decontamination with our ICU standard proprietary non-enzymatic detergent fluid and pre-packed sponge (UNO-FLUSH? Endoscope Channel Cleanser, Medical Innovations Group, Essex, UK). The bronchoscope was then flushed with a further 20mls of sterile saline and this fluid collected for microbiological analysis. The tip of the endoscope was swabbed using our standard sample medium swabs (CultureSwab? Becton Dickinson Company? Oxford, UK) and this was also sent for analysis. Paired flush and swab samples were taken at time zero (immediately following social clean after use), at 24 hours and at 48 hours. This allowed research staff to complete the analysis within the working week following use. Collection of samples was required within a two hour window, one hour either side of the time determined by clinical first use of the bronchoscope. The aScopes were stored between samples in their original packaging on the ICU at room temperature. At 48 hours, the results of any microbiological samples taken from the patient at the time of the original clinical bronchoscopy were anonymized and recorded. This observational study did not influence the clinical management of the patient and as such, contemporary clinical microbiological samples were taken from the patient via bronchoscopy only if the attending clinician felt this was clinically indicated. No other potential clinical, laboratory or radiological markers of infection were collected.Bacterial colony count and identification were recorded for each positive patient or bronchoscope sample. Isolates were classified using a Red-Amber-Green (RAG) coding system to indicate high, intermediate or low risk respectively, for causing Hospital Acquired Pneumonia (HAP) or Ventilator Acquired Pneumonia (VAP) in our ICU patients. The RAG coding system is used by microbiologists at our hospital, based on our local microbiological profiles and knowledge of which organisms are most likely to cause invasive pulmonary infections in our critically ill patients.ResultsMicrobiological results from 20 aScope3’s were obtained. All intended flush and swab samples were acquired within the specified timeframe, resulting in analysis of 60 swab and 60 flush samples. Positive microbiological cultures were obtained in either swab or flush specimens in 16 of the 20 bronchoscopes at some point in the 48 hours following social clean. These included 11 bronchoscopes with positive flush samples, seven with positive swab samples and five where both flush and swab samples were positive. At time zero, 4/20 bronchoscopes isolated sufficient quantities of pathogens considered to be high risk for HAP/VAP with a further 4/20 isolated organisms considered medium risk. Over 48 hours, a total of seven bronchoscopes (35%) had pathogens isolated considered high risk of causing HAP/VAP, and on six occasions, these were present in significant quantities at 48 hours. Table 1 outlines the organisms isolated and the significance associated using the RAG rating scheme. There were 15 episodes of bronchoscope use that were associated with contemporaneous microbiological sampling for clinical reasons. There was no organism identified in seven of these samples after routine incubation and analysis. Of the remaining eight positive clinical cultures, the same organism was grown from the bronchoscope samples on five occasions. One bronchoscope grew a different organism to that identified from paired clinical sampling. In four bronchoscopes, all flush and swab samples were negative for any growth: two of these bronchoscope uses were associated with positive clinical microbiology, with no contemporaneous clinical samples taken during the other two uses.DiscussionOur results indicate that prolonged bedside storage of bronchoscopes after clinical use and social cleaning may encourage microbiological growth of organisms implicated in causing HAP and VAP. This finding is not surprising, but is relevant to situations where a used endoscope could be stored and potentially reused on the same patient. Following social clean, at time zero, four bronchoscopes unexpectedly grew organisms considered to be high risk for HAP/VAP in critical care populations. Worryingly, two bronchoscopes isolated Pseudomonas aeruginosa, a highly successful opportunistic pathogen, associated with a wide spectrum of conditions including nosocomial pneumonia, blood stream and respiratory infections. In both of these cases there was concordance with the clinical patient samples suggesting contamination from the bronchoscopic procedure. With the colony counts increasing significantly over the 48 hours of storage, this could infer that the social clean used was not sufficient to prevent colonization. Our intention was not to sterilize the bronchoscopes after use but to apply a recognized form of physical and enzymatic cleaning that would not preclude potential clinical reuse. A stronger anti-bacterial agent could be a source of potential harm to the patient if re-introduced into patient’s airways, and could damage the integrity of the bronchoscopes itself. The aScopes are not designed to tolerate standard decontamination treatments that non-disposable bronchoscopes are subjected to.Four bronchoscopes isolated organisms considered to be intermediate risk for respiratory infection. Viridans streptococci are commensals of the respiratory tract but can invade in certain situations, such as in neutropenic patients, and cause pneumonia. Candida albicans is not considered to be a pathogen in isolation but may encourage biofilm formation and therefore colonization with other known pathogens such as Pseudomonas aeruginosa. Paired clinical samples were only collected for two of these bronchoscopes, but in one of these, the clinical isolate was identical (Candida albicans). By 24 hours a further two bronchoscopes had isolated pathogens considered to be high risk; Staph aureus and Klebsiella pneumonia. Klebsiella is an important nosocomial and opportunistic pathogen which is known to cause bronchopneumonia. Although Staph aureus can be a colonizer of the upper respiratory tract it can also cause primary and secondary pneumonia. By 48 hours post use, six bronchoscopes remained colonised with high-risk pathogens. Re-using these colonised bronchoscopes in the immunosuppressed or critically ill would put patients at increased risk for nosocomial infection by contributing to an increased bioburden. Cross contamination has been reported with re-useable bronchoscopes. The exogenous microorganisms most frequently associated with transmission of infection during bronchoscopy are Pseudomonas aeruginosa and mycobacteria [11]. The most common factor associated with microbial transmission is inadequate cleaning and disinfection, identified in up to 60% of outbreaks [1]. Reported outbreaks were frequently related to inadequate manual cleaning and brushing, use of contaminated endoscope accessories, use of inappropriate disinfectants with low and intermediate potency, and resistance of microorganisms to disinfectants. Around one third of outbreaks are associated with contaminated or defective endoscope reprocessor, with a further third associated with inadequate drying and storage. There is also variation and inconsistency between reprocessing guidelines [12,13]. The potential for iatrogenic harm to multiple patients from contaminated bronchoscopes has led some authors to suggest additional cleaning measures and routine pre-use ‘control’ BAL samples to be taken prior to clinical use of a reusable bronchoscope [12,14]. This approach could alert departments that a scope is contaminated and also ensure that positive clinical samples are true positives, preventing unnecessary treatment. Of interest, seven bronchoscopes grew microorganisms that did not grow in paired patient samples. One possible explanation for this could be that the bronchoscopes themselves provide a good environment for sampled microorganisms to grow. Bedside storage in the original packaging may also have encouraged growth, but this was intentionally done to mirror the likely storage of a used aScope that could be potentially re-used. The bronchoscopes were all introduced via endotracheal or tracheostomy tubes and the microorganisms detected from the bronchoscopes may simply represent the biofilm within these devices. This observational study did not routinely collect paired clinical samples from all potential sources such as blood, sputum and BAL, and so it is possible that clinical infection was simply not detected. Our study did not consider other potential identifiers of clinical infection such as VAP scoring systems or X-ray interpretation. Although we did not actively investigate whether the detected microorganisms were directly associated with clinical infection, identification of pathogen colonies considered locally to be of high risk of causing subsequent infection is likely to be of clinical significance, especially in the invasively ventilated critical care population. However, given the difficulty in detecting and identifying microorganisms responsible for critical illness using standard sampling and culture techniques, even using validated multivariable scoring systems, prolonged storage and culture of bronchoscopes following use may be of diagnostic benefit. [16]ConclusionsCross contamination following bronchoscopy procedures has been widely reported due to exogenous microorganisms that are not adequately removed during reprocessing. Single-use devices such as the aScope eliminate the risk of cross contamination and these devices may be cost effective for certain services [15]. Our study demonstrates that aScopes should not be re-used on the same patient as clinically significant growth of microorganisms frequently occurs despite adequate social cleaning. Further work should evaluate the clinical significance of pathogens isolated from single use bronchoscopes at intervals less than 24 hours. Culture of bronchoscopes themselves may be a potentially useful diagnostic tool in the context of pulmonary infection. Our data makes it clear that these devices are single use and not single patient peting interestsNo external funding was used for this study. The aScopes used were purchased for routine clinical use. BAM has received travel expenses and honoraria from Ambu to speak at meetings.AcknowledgementWe are grateful to Mrs Sue Allen, Biomedical Scientist, University Hospital South Manchester, for assistance in performing microbiological analysis of the specimens.Table 1. Microbiological growth from paired flush (F) and swab (S) samples at time zero, 24 and 48 hours post use, with contemporary clinical microbiology and the RAG-rating of the organism(s).ScopeTime post use (hours)Clinical resultOverall significance(RAG*)024481F+ Non-HS No growthAmberS+ AHS + MC2F+ C alb + MCC alb BAL & sputumAmberS3F+ CNSNo growthGreenS4FNo growthGreenS+CNS 5FE coli sputumN/AS6F+ E coli++ CNS+ ASBC alb & S aur & E. coli sputumRedS7F+ MC+ CNSC alb sputumGreenS+ CNS8FNo growthGreenS+CNS9F+ CNSNo samplesAmber*S+ Ps ory10FNo samplesN/As11FNo samplesN/As12F+ CNSNo growthGreens13FC alb & S aursputumN/AS14F+ S aurNo growthRedS15F+++ AHS++ AHS+++ E cloaNo samplesRed*S16F+++ E cloa++++E cloa ++++ H flu++++ E cloa No growthRed*S+++ E cloa++++ E cloa++++ E cloa17F+ Ps aer+++ C alb+ Ps aer++ C alb++++ Ps aerE coli & Ps aer & Kleb oxy BALRedS18FNo samplesGreenS+ AHS +CNS+ AHS +CNS+MC19F+++ Ps aer++++ Ps aer+++++ Ps aerPs. aer SputumRedS+ Ps aer ++ Ps aer20F+++ Ps aer++ Ps aer+ Kleb pneu+++ Ps aer++++ Kleb pneuPs. aer SputumRedS+ Ps aer+ Kleb pneuKey to table 1.Key to micro-organismsNon-HS: Non- hemolytic StreptococcusAHS: Alpha-hemolytic streptococciMC: MicrococcusC alb: Candida albicansCNS: Coagulase negative staphylococciE coli: Escherichia coliASB: Aerobic spore bearerPs.ory: Pseudomonas oryzihabitanS aur: Staphylococcus aureusE cloa: Enterobacter cloacaePs aer: Pseudomonas aeruginosaH flu: Haemophilus influenzaeKleb oxy: Klebsiella OxytocaKleb pne: Klebsiella pneumoniaeKey to bacterial colonies/ml + : <100 colonies/ml++: >100 colonies/ml but <1,000 colonies/ml+++: >1,000 colonies/ml but <10,000 colonies/ml++++: >10,000 colonies per/ml but <100,000 colonies/ml+++++: >100,000 colonies per/ml RAG: clinical significance ratingR: Red Organisms known to cause HAP/VAPA: Amber Organisms that can in certain circumstances cause HAP/VAPG: Green Organisms where there is little or no evidence that these organism would HAP/VAPReferences1.Kovaleva J, Peters FTM, van der Mei HC, Degener JE. 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