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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
A randomised single-blind comparison of the effectiveness of the high-level disinfectants Tristel Fusion (chlorine dioxide) and Cidex OPA (ortho-phthaldehyde) for use with flexible cystoscopes
Scientific title
A randomised single-blind comparison of the rate of urinary tract infections in participants undergoing flexible cystoscopy when the flexible cystoscope is disinfected with Tristel Fusion (chlorine dioxide) compared with Cidex OPA (ortho- phthaldehyde)
Secondary ID [1] 262174 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Effectiveness of high level disinfectants for flexible cystoscopes 243486 0
Condition category
Condition code
Infection 239786 239786 0 0
Other infectious diseases

Study type
Description of intervention(s) / exposure
Tristel Fusion consists of 100 ml chlorine dioxide in aqueous solution. This is diluted in five litres of water. The flexible cystoscope is then immersed in this solution for five minutes and then rinsed thoroughly.
Intervention code [1] 237104 0
Comparator / control treatment
Cidex OPA is a solution containing ortho-phthaldehyde which is used in conjunction with a Medivator (specialised cleaning machine). The flexible ctstoscope in placed in the Medivator and the cleaning cycle initiated. The cycle consists of a 10 minute soaking and soak rinse phase in Cidex OPA, a rinse 1 phase for 7 minutes in potable water, a rinse 2 phase for 6 minutes in potable water, a 30 second alcohol rinse and then a three minute air purge to dry the instrument.
Control group

Primary outcome [1] 240554 0
The Primary Endpoint is the rate of acquired urinary tract infections as determined by a mid-stream urine test (MSU) 3-7 days post intervention in the participants undergoing flexible cystoscopy when the cystoscope is disinfected with Tristel Fusion compared with Cidex OPA.
Timepoint [1] 240554 0
A single measurement at 3-7 days post intervention
Secondary outcome [1] 257139 0
Clinical Endpoints:
Urethra / bladder irritation and quality of life 3-7 days post-cystoscopy compared with baseline using the following questionnaires:
-The Short Form Urogenital Distress Inventory (UDI-6)+2 questions
-The American Urological Association Symptom Index (AUA-7)
-Single Question Quality of Life Score (QoL)
Timepoint [1] 257139 0
A single measurement at 3-7 days post intervention which is then compared with baseline
Secondary outcome [2] 257140 0
Microbiology Endpoints:
-Microbiological culture of washings and brushings from the flexible cystoscopes working channel and equipment. Samples of the washings and brushings are inoculated onto each of Blood Agar and MacConkey Agar and incubated aerobically.
Timepoint [2] 257140 0
Post disinfection
Secondary outcome [3] 257141 0
Cost-effectiveness of the 2 disinfectants will be assessed:
- The total per-patient cost of high-level disinfection with the Tristel Fusion system and the Cidex OPA system will be calculated using data collected from the participants undergoing cystoscopy. These costs will include a per-procedure estimate of machine and tray cost, all disposables, irrigation fluids, nursing time and any scope damage caused by the disinfecting agents.
-Timing of the two processes and measurement of patient through-put; time needed for the cleaning process as an indicator of relative efficiency.
Timepoint [3] 257141 0
Cost effectiveness will be analysed from data from all participants in the trial
Secondary outcome [4] 257142 0
Ease-of-use and odour will be assessed using a 5 point Likert scale
Timepoint [4] 257142 0
These will be rated by the nurses using the disinfection equipment on each study day

Key inclusion criteria
Participants requiring a flexible cystoscope and who provide written informed consent will be eligible to participate. Other inclusion criteria are a negative MSU at baseline, no symptoms of urinary tract infection (UTI) on the day of investigation, no specific indication for parenteral antibiotic prophylaxis (e.g. artificial heart valve), no current indwelling urinary catheter and no recent surgery on the urogenital tract.
Minimum age
No limit
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Exclusion criteria include the requirement of a biopsy during the procedure.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Participants will be allocated to the next available cystoscopy clinic day. When all the available spaces for a clinic day are filled, the randomised high level disinfectant (i.e. either Tristel Fusion or Cidex OPA) for that day will be determined by the study statistician and relevant staff notified. In this way, investigators allocating participants to a cystoscopy clinic study day do not know which disinfectant will be used on that day. While each individual participant is not randomly allocated to disinfectant type with this approach, it has the advantage that each participant is allocated to the next available cystoscopy clinic. It is anticipated that there will be at least 8 clinic study days. The randomisation process will be constructed by the independent statistician to ensure there are equivalent numbers of Tristel Fusion and Cidex OPA study days.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation by using a randomization table created by a computer software (i.e., computerised sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

Intervention assignment
Other design features
It is not possible to blind the people conducting the disinfection since the two products are different in appearance and procedures required. However the urologists conducting the cystoscopes; the participants reporting the symptoms and the lab staff analysing the mid-stream urine samples will be blinded
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 1942 0
New Zealand
State/province [1] 1942 0
Bay of Plenty

Funding & Sponsors
Funding source category [1] 237476 0
Commercial sector/Industry
Name [1] 237476 0
Tristel Solutions Ltd
Address [1] 237476 0
Lynx Business Park
Fordham Road
Cambridgeshire CB8 7NY
Country [1] 237476 0
United Kingdom
Primary sponsor type
Commercial sector/Industry
Tristel Solutions Ltd
Lynx Business Park
Fordham Road
Cambridgeshire CB8 7NY
United Kingdom
Secondary sponsor category [1] 236961 0
Name [1] 236961 0
Address [1] 236961 0
Country [1] 236961 0

Ethics approval
Ethics application status
Ethics committee name [1] 239600 0
Northern Y Regional Ethics Committee
Ethics committee address [1] 239600 0
354 Victoria Street
Hamilton 3140
Ethics committee country [1] 239600 0
New Zealand
Date submitted for ethics approval [1] 239600 0
Approval date [1] 239600 0
Ethics approval number [1] 239600 0

Brief summary
There are several methods and agents which can be used to provide high-level disinfection of ‘semi-critical’ instruments such as flexible cystoscopes, however non-corrosive methods are required because of the composition of the instrument.
Cidex OPA (ortho-Phthalaldehyde; 1,2 – benzenedicarboxaldehyde) has been widely used for high level disinfection but may elicit an allergic reaction in workers if protective equipment is not used and the vapours produced may be an irritant to the respiratory tract and eyes (Cidex OPA Directions for Use; 2004).
Tristel Solutions Limited (UK) produces a range of high level disinfectant products which use chlorine dioxide chemistry and the products have also been used as a disinfectant for a wide variety of instruments and surfaces without safety issues (Tristel data on file). Therefore the use of Tristel is expected to pose a very low risk to patients, surgeons and nurses.
If Tristel Fusion is shown to be at least as effective as Cidex OPA in terms of post-intervention complications (infection/inflammation) for patients, less in-use problems for the surgeons and nurses, then it may be a preferable product to use for high-level disinfection of flexible cystoscopes.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 30029 0
Address 30029 0
Country 30029 0
Phone 30029 0
Fax 30029 0
Email 30029 0
Contact person for public queries
Name 13276 0
Rana Reuther
Address 13276 0
Research Manager
Tauranga Urology Research Ltd
Promed House
71 10th Avenue
Tauranga 3001
Country 13276 0
New Zealand
Phone 13276 0
+64 7 5782561
Fax 13276 0
+64 7 5784717
Email 13276 0
Contact person for scientific queries
Name 4204 0
Peter Gilling
Address 4204 0
Promed Urology
Suite 6
Promed House
71 10th Avenue
Tauranga 3001
Country 4204 0
New Zealand
Phone 4204 0
+64 7 5782561
Fax 4204 0
+64 7 5784717
Email 4204 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary