Novel flexible bronchoscope and single-use disposable-sheath endoscope system. A preliminary technology evaluation

Duodenoscope-Associated Infections: Update on an Emerging Problem

The duodenoscope is among the most complex medical instruments that undergo disinfection between patients. Transmission of infection by contaminated scopes has remained a challenge since its inception. Notable risk factors for pathogen transmission include non-adherence to disinfection guidelines, encouragement of biofilm deposition due to complex design and surface defects and contaminated automated endoscope reprocessors. The most common infections following endoscopy are endogenous infections involving the patient's own gut flora. Exogenous infections, on the other hand, are associated with contaminated scopes and can theoretically be prevented by effective reprocessing. Pseudomonas aeruginosa is currently the most common organism isolated from contaminated endoscopes. Of note, reports of multidrug-resistant duodenoscopy-associated outbreaks have surfaced recently, many of which occurred despite adequate reprocessing. The FDA and CDC currently recommend comprehensive cleaning followed with at least high-level disinfection for reprocessing of flexible GI endoscopes. Reports of duodenoscope-related outbreaks despite compliance with established guidelines have prompted professional and government bodies to revisit existing guidelines and offer supplementary recommendations for duodenoscope processing. For the purposes of this review, we identified reports of duodenoscope-associated infections from 2000 till date. For each outbreak, we noted the organisms isolated, the number of cases reported, any possible explanations of contamination, and the measures undertaken to end each outbreak. We have also attempted to present an overview of recent developments in this rapidly evolving field.

A Systematic Review of Disposable Sheath Use During Flexible Endoscopy

Flexible endoscopes are exposed to blood, mucus, and other secretions during procedures. Single-use sheaths are designed to prevent contact between contaminants and reusable endoscope components. This systematic review examined findings from 22 studies that assessed endoscopic sheath use during urologic, gastrointestinal, or respiratory procedures. The evidence showed that sheaths were durable and yielded faster endoscope turnover times because their reusable components did not require high-level disinfection or sterilization. After a brief learning period, health care providers successfully assembled and maneuvered sheathed endoscopes. Patients generally did not experience greater discomfort during procedures in which sheaths were used. Microbial cultures of sheathed endoscopes were negative or similar to unsheathed endoscopes. More research is needed to evaluate the potential effect of disposable sheaths on infection risks. The evidence suggests that sheaths are a viable option for reliably providing a barrier between endoscopes and patients without affecting the quality of endoscopic procedures.

Single use and conventional bronchoscopes for Broncho alveolar lavage (BAL) in research: a comparative study (NCT 02515591)

Background

Broncho alveolar lavage (BAL) is widely used for investigative research to study innate, cellular and humoral immune responses, and in early phase drug trials. Conventional (multiple use) flexible bronchoscopes have time and monetary costs associated with cleaning, and carries a small risk of cross infection. Single use bronchoscopes may provide an alternative, but have not been evaluated in this context.

Methods

Healthy volunteers underwent bronchoscopy at a day-case clinical research unit using the Ambu® aScope^TM single-use flexible intubation bronchoscope. Broncho alveolar lavage was performed from a sub segmental bronchus within the right middle lobe; a total of 200 ml of warmed normal saline was instilled then aspirated using handheld suction. BAL volume yield, cell yield and viability were recorded.

Results

Ten volunteers, (mean age 23 years, six male) participated. Bronchoscopies were carried out by one of two senior bronchoscopists, experienced in the technique of obtaining BAL for research purposes. The results were compared to 50 (mean age 23, 14 male) procedures performed using the conventional scope by the same two bronchoscopists. The total volume yield was significantly higher in the disposable group median 152 ml (IQR 141–166 ml) as compared to conventional 124 ml (110–135 ml), p = <0.01. The total cell yield and viability were similar in both groups, with no significant differences.

Conclusions

With single use bronchoscopes, we achieved a larger BAL volume yield than conventional bronchoscopes, with comparable cell yield and viability. Better volume yields can potentially reduce post procedure side effects such as pleuritic chest pain and cough. The risk of cross infection can be eliminated, providing reassurance to researchers and participants. Reduced maintenance requirements can be cost effective. These could potentially be used for early phase drug development studies.

Trial registration

This trial was registered prospectively in July 2015 with the National Clinical Trials register, with the following registration number assigned: NCT 02515591.

An evaluation of a new single-use flexible bronchoscope with a large suction channel: reliability of bronchoalveolar lavage in ventilated piglets and initial clinical experience

A single-use flexible bronchoscope with a large suction channel has become available recently and we have evaluated this innovative device. Firstly, bronchoalveolar lavage was performed and quantified in ventilated piglets. Next, the bronchoscope was evaluated in three intensive care units and a satisfaction questionnaire was carried out. Sixteen bronchoalveolar lavages were performed in piglets with a recovery rate of 83 (79-86 [72-89])% of the instilled volume. Quality and performance of all devices tested was identical. The medical satisfaction questionnaire was as follows: 'acceptable' to 'very good' for quality of aspiration, manoeuvrability and quality of vision; 'very good' to 'perfect' for setting up and insertion. This encouraging preliminary evaluation demonstrates the effectiveness of this new single-use device, which may obviate the need for disinfection procedures and, thereby, eradicate a potential vector of patient cross-contamination.

Transmission of infection by flexible gastrointestinal endoscopy and bronchoscopy

Flexible endoscopy is a widely used diagnostic and therapeutic procedure. Contaminated endoscopes are the medical devices frequently associated with outbreaks of health care-associated infections. Accurate reprocessing of flexible endoscopes involves cleaning and high-level disinfection followed by rinsing and drying before storage. Most contemporary flexible endoscopes cannot be heat sterilized and are designed with multiple channels, which are difficult to clean and disinfect. The ability of bacteria to form biofilms on the inner channel surfaces can contribute to failure of the decontamination process. Implementation of microbiological surveillance of endoscope reprocessing is appropriate to detect early colonization and biofilm formation in the endoscope and to prevent contamination and infection in patients after endoscopic procedures. This review presents an overview of the infections and cross-contaminations related to flexible gastrointestinal endoscopy and bronchoscopy and illustrates the impact of biofilm on endoscope reprocessing and postendoscopic infection.

Microbiologic assessment of disposable sterile endoscopic sheaths to replace high-level disinfection in reprocessing: a prospective clinical trial with nasopharygoscopes

BACKGROUND

Conventional reprocessing of endoscopes with high-level disinfection is labor intensive, expensive, delays the turnover of instruments, and involves potential exposure of personnel to toxic chemicals. We report a prospective clinical trial with rigorous microbiologic assessment of a novel disposable, sterile, polyurethane sheath, which can be easily and snugly applied over a nasopharyngoscope before performing the endoscopic procedure, with enzymatic cleansing and disinfection of the instrument with 70% ethanol following the procedure to determine whether the use of the novel sheath can provide reliable protection against bacterial contamination and obviate the need for routine high-level disinfection in reprocessing.

METHODS

Baseline cultures were obtained at 3 time periods from the control heads and insertion shafts of nasopharyngoscopes used in 100 clinical examinations: before application of the protective sheath and execution of the procedure; immediately after the procedure and removal of the sheath; and after enzymatic cleaning, disinfection with 70% ethanol, and drying. All 100 used sheaths and 20 unused sheaths were subjected to high-pressure leak testing to assess barrier integrity.

RESULTS

Bacteria were detected on 16 control heads and 6 shafts prior to the procedure; from 13 heads and 1 shaft immediately following the nasopharyngoscopic procedure and sterile sheath removal; and none of the instruments following cleaning, ethanol disinfection, and drying. No sheath showed loss of barrier integrity on leak testing.

CONCLUSION

Use of a high-quality, snugly fitting, sterile, disposable polyurethane sheath on a nasopharyngoscope during a clinical examination, combined with enzymatic detergent cleaning and disinfection with 70% ethanol, can provide a reliably decontaminated, patient-ready instrument, eliminating the need for high-level disinfection of endoscopes.

A potential danger of flexible endoscopy sheaths: a detached tip and how to retrieve it

Objective:

To report an unrecognised complication of fibre-optic nasendoscopy, and its management.

Case report:

A protective, transparent nasendoscopy sheath is often used to reduce nasendoscope ‘downtime’ and to prevent cross infection, with minimal effect on the obtained image quality. We report the case of a subcutaneous tracheostomy procedure during which, without undue strain, the tip of the sheath became detached and acted as a foreign body within the trachea. A urological stone retrieval basket was used to retrieve the sheath, after failure of conventional methods.

Discussion:

Clinicians should be aware that any instrument introduced into the airway has the potential to fail and in the process produce a foreign body which may cause serious complications. The urological stone retrieval basket may be a useful addition to the current set of instruments used to deal with difficult airway foreign bodies.

Out-patient flexible cystoscopy using a disposable slide-on endosheath system

INTRODUCTION

The aim of this study was to investigate the feasibility of out-patient flexible cystoscopy.

PATIENTS AND METHODS

Twenty-seven patients awaiting diagnostic or check cystoscopy in Leeds, UK were invited to undergo out-patient flexible cystoscopy using a CST-2000 Flexible Cystoscope (Vision Sciences; Natick, MA, USA) using the sterile single-use slide-on(trade mark) disposable endosheath endoscope system (EndoSheath); Vision Sciences). The performance of the cystoscope was evaluated, and the patients' experiences were documented using a questionnaire.

RESULTS

The out-patient setting proved to be ideal for flexible cystoscopy. The cystoscope was rated highly for image quality, ease of use and handling. All patients complimented us on the service and preferred out-patients to a day-ward or theatre attendance.

CONCLUSIONS

This study demonstrates that it is possible to perform out-patient flexible cystoscopy safely, economically and efficiently with the aid of a disposable endoscope system.

Sterile disposable sheath system for flexible cystoscopes

Flexible cystourethroscopy is an accepted routine procedure in urology. The sterilization of instruments is time consuming and may damage flexible instruments. However, it must be performed to prevent contamination of the endoscopes. This study is the first to document experience using a flexible cystoscope with a disposable sheath in a urologic setting.

Evidence based guidelines for the prevention, identification, and management of occupational asthma

BACKGROUND

Occupational asthma is the most frequently reported work related respiratory disease in many countries. This work was commissioned by the British Occupational Health Research Foundation to assist the Health and Safety Executive in achieving its target of reducing the incidence of occupational asthma in Great Britain by 30% by 2010.

AIM

The guidelines aim to improve the prevention, identification, and management of occupational asthma by providing evidence based recommendations on which future practice can be based.

METHODS

The literature was searched systematically using Medline and Embase for articles published in all languages up to the end of June 2004. Evidence based statements and recommendations were graded according to the Royal College of General Practitioner's star system and the revised Scottish Intercollegiate Guidelines Network grading system.

RESULTS

A total of 474 original studies were selected for appraisal from over 2500 abstracts. The systematic review produced 52 graded evidence statements and 22 recommendations based on 223 studies.

DISCUSSION

Evidence based guidelines have become benchmarks for practice in healthcare and the process used to prepare them is well established. This evidence review and its recommendations focus on interventions and outcomes to provide a robust approach to the prevention, identification, and management of occupational asthma, based on and using the best available medical evidence. The most important action to prevent cases of occupational asthma is to reduce exposure at source. Thereafter surveillance should be performed for the early identification of symptoms, including occupational rhinitis, with additional functional and immunological tests where appropriate. Effective management of workers suspected to have occupational asthma involves the identification and investigation of symptoms suggestive of asthma immediately they occur. Those workers who are confirmed to have occupational asthma should be advised to avoid further exposure completely and early in the course of their disease to offer the best chance of recovery.

Bronchoscopy with the Vision Sciences BF100 Disposable-Sheath Device: French Experience after 328 Procedures

BACKGROUND

In spite of adhesion to recommended disinfection procedures, the transmission of infections by bronchoscopes is a permanent problem.

OBJECTIVE

The new device may prevent nosocomial infections because it consists of two parts: a specific bronchoscope Vision Sciences BF100 and a single-use protective sheath for each procedure. The aim of this paper is to report our practice and the difficulties encountered when using this system.

METHODS

We report our experience from 1997 to 2002 after 328 elective and emergency endoscopic procedures with the BF100 device. In a retrospective study, we describe the population and the incidents during procedure. We discuss the impact of the use of BF100 on the cost of bronchoscopies.

RESULTS

The major constraint is the care required in assembling the optical device and disposable sheath. The intrinsic qualities of the optics are confirmed; any sample may be taken although image quality and suction capacity are inferior to videoscopes. Maneuverability is inferior to videoscopes, but improves with a short experience. In addition, this device is expensive.

CONCLUSIONS

The technical performances of the BF100 device are inferior to those of videoscopes but the concept of sterile single-use sheaths is able to prevent the nosocomial infections related to bronchoscopes. Because of the cost, examination with the BF100 should be reserved to patients with proved or suspected infection (multiresistant bacteria, tuberculosis, hepatitis C and B virus, HIV, prions) and immunosuppression (hematologic diseases).

Epidemiology and Prevention of Infections Related to Endoscopy

Contaminated endoscopes are the most common cause of device-related nosocomial outbreaks in the United States. Because almost all outbreaks are related to breaches in reprocessing techniques, it is crucial that endoscope cleaning and disinfection are performed carefully. Key elements that should be emphasized are availability of and adherence to guidelines, thorough staff training, and ensuring proper equipment is used in the reprocessing. Encouraging endoscopists to notify infection control when they see unexpected postprocedure complications and document which endoscopes are used in each case are key elements in limiting the impact of outbreaks.

An outbreak of Pseudomonas aeruginosa infections associated with flexible bronchoscopes

BACKGROUND

Endoscopes, including bronchoscopes, are the medical devices most frequently associated with outbreaks of nosocomial infections. We investigated an outbreak of Pseudomonas aeruginosa infections after bronchoscopic procedures.

METHODS

Microbiologic results were reviewed to determine the rates of recovery of P. aeruginosa from bronchoalveolar-lavage specimens. Environmental samples from endoscopes and the endoscopy suite were cultured. Medical records were reviewed to identify infections in the 14 days after a bronchoscopy.

RESULTS

The rate of recovery of P. aeruginosa from bronchoalveolar-lavage specimens obtained with use of endoscopy-suite bronchoscopes increased from 10.4 percent at base line to 31.0 percent during the outbreak (relative risk, 2.97; 95 percent confidence interval, 2.28 to 3.90). Cultures of samples from three bronchoscopes grew P. aeruginosa, whereas cultures of samples from the environment, instrument-cleaning machines, and gastrointestinal endoscopes did not. The three bronchoscopes had been part of a nationwide recall. A total of 414 patients underwent bronchoscopy during the outbreak, and there were 48 respiratory tract and bloodstream infections among 39 of these patients (9.4 percent). In 32 infections (66.7 percent), P. aeruginosa was confirmed as a potentially causative organism. Exposure to a potentially contaminated bronchoscope may have had a role in the death of three patients. The rate of recovery of P. aeruginosa returned to base line after the instruments were removed from service.

CONCLUSIONS

This large outbreak of P. aeruginosa infections related to bronchoscopy was apparently caused by a loose biopsy-port cap in the bronchoscopes. Instrument safety and surveillance methods for bronchoscopy must be improved, and better recall procedures are needed for medical devices.

Flexible nasendoscope with a disposable-sheath system versus standard nasendoscopy: a prospective, randomized trial

There are no published guidelines for the sterilization of the flexible nasendoscope and various techniques exist. We have conducted a randomized, prospective, blinded trial of the barrier Endosheath system versus immersion in Cidex disinfectant. Using a visual analogue assessment, there were no differences at a 99% confidence interval (CI) between the two techniques from the nursing assistant and patient perspectives. Image quality was assessed blinded and no difference could be detected at a 99% CI. The Endosheath offers the advantage of increasing the productivity of each nasendoscope as the sterilization time is reduced. It also provides barrier protection against cross-contamination, including prion diseases.