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Trial registered on ANZCTR


Registration number
ACTRN12622000296730
Ethics application status
Approved
Date submitted
17/12/2021
Date registered
16/02/2022
Date last updated
14/07/2023
Date data sharing statement initially provided
16/02/2022
Date results provided
27/01/2023
Type of registration
Prospectively registered

Titles & IDs
Public title
A comparison of high and low level disinfection for ultrasound probes which have been used on human skin.
Scientific title
Non-inferiority of low-level versus high-level disinfection for elimination of bacteria on contaminated transcutaneous ultrasound transducers: A randomised controlled trial.
Secondary ID [1] 306039 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Disinfection of ultrasound transducers 324680 0
Condition category
Condition code
Infection 322125 322125 0 0
Studies of infection and infectious agents

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Ultrasound (US) contamination will be simulated through the application of US transducers on the arms of hospital staff and patients. Research team members will recruit participants as a convenience sample according to set inclusion and exclusion criteria. To control for individual patient variation in baseline skin colonisation, once participants have consented, they will be randomised into one of two groups: Group A- Right arm High Level Disinfection (HLD) & Left arm Low Level Disinfection (LLD); Group B- Right arm LLD & Left arm HLD; thereby allowing participants to act as their own control. Two identical linear US transducers will be used throughout the study, one labelled “HLD” and the other “LLD”. This will be allocated prior to study commencement and based upon which disinfection process will be repeatedly used on it.

After applying 5g aliquot of sterile US gel from the same single use sachet to each transducer a research staff member will perform a mock vein localisation procedure on the arms of the recruited participant according to their group allocation. This will entail ten continuous back and forward tracing movements made on the volar and dorsal aspects of the forearm from the cubital fossa to the wrist aiming to contaminate the transducer with microorganisms. Following enrolment this process of completing a mock vein localisation procedure on recruited participants would take approximately 5 minutes in total. The same research staff member will collect the study samples from each transducer for baseline bacterial contamination. This will be determined by swabbing the area of each transducer that has encountered the participant’s skin using a standardised method involving a pre-moistened sterile cotton tip swab.

Following contamination US cleaning and disinfection will occur at the point of collection by the same research staff member. Once each transducer has been reprocessed accordingly, they will be swabbed again using a sterile pre-moistened cotton tip swab. LLD will be with Clinell universal wipes ® and HLD will be with Tristel Trio wipes ® both of which have been approved by the Therapeutic Goods Administration as LLD and HLD systems respectively.

To ensure that disinfection instructions are followed as per manufacture's recommendations all research staff members undertaking transducer reprocessing will be trained using manufacturer training videos in both methods of disinfection. They will also be required to demonstrate that their technique is satisfactory to the chief investigator prior to commencing any participant recruitment. Evidence of training and demonstrating a satisfactory disinfection technique will be recorded in a research training log kept by the investigator team. During training and recruitment a stopwatch will be provided at the workstation where disinfection is to occur so as to ensure that the minimum contact times of the disinfectant solutions are adhered to as per manufacturers recommendations.
Intervention code [1] 322438 0
Prevention
Comparator / control treatment
One contaminated US transducer will be treated with LLD, which will act as the control group, while the other US transducer will be disinfected using HLD.
Control group
Active

Outcomes
Primary outcome [1] 329895 0
The primary outcome will be the number of ultrasound transducers which have had all bacterial colonies eliminated (Colony forming units =0) following treatment with LLD or HLD wipes. The presence of bacterial colonies will be assessed both pre- and post- disinfection by swabbing the area of the US transducer that contacted the participants skin with a sterile cotton-tip swab. Swabs will then be streaked across agar plates and incubated at 37°C before being examined at 24 and 120hrs for growth.
Timepoint [1] 329895 0
Samples will be collected at baseline (i.e. immediately after contact with participant's skin, before disinfection), and immediately after disinfection with LLD or HLD wipes. The sample swabs will be delivered to the microbiology laboratory and processed on the same day as they are collected.
Secondary outcome [1] 406229 0
Colony Forming Unit (CFU) present on contaminated and disinfected ultrasound transducers. CFU counts will be summarised on a scale of 0-3. All plates will be assessed qualitatively and bacterial growth recorded where: 0 = no growth; 1 = 1–3 colonies; 2 = 4–10 colonies; and, 3 = > 10 colonies and up to confluent growth. This will be assessed by swabbing the area of the US transducer that contacted the participants skin with a sterile cotton-tip swab, which will then be streaked across agar plates and incubated at 37°C before being examined at 24 and 120hrs for growth.
Timepoint [1] 406229 0
Samples will be collected at baseline (i.e. immediately after contact with participant's skin, before disinfection), and immediately after disinfection with LLD or HLD wipes. Swabs will. be streaked on agar plates on the same day they are collected and the number of colony forming units will be assessed after an incubation period of 24hrs and 120hrs
Secondary outcome [2] 406254 0
Microbial identification, genus and species of colonies identified on both contaminated and disinfected ultrasound transducers, will be assessed by swabbing the area of the US transducer that contacted the participants skin with a sterile cotton-tip swab, which will then be streaked across agar plates and incubated at 37°C for 120hrs.
Timepoint [2] 406254 0
Samples will be collected at baseline (i.e. immediately after contact with participant's skin, before disinfection), and immediately after disinfection with LLD or HLD wipes. Microbial identification analysis will be conducted at the conclusion of the agar plate incubation period of 120hrs.

Eligibility
Key inclusion criteria
• Age greater than or equal to 18 years
• Willing and able to expose both arms from hands to above the elbow
• Have only healthy intact skin between the wrist and elbow on both arms
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
• Any area of infection or damaged skin between the elbow and wrist on either arm
• Any injured or painful areas on either arm
• Performed a surgical scrub on the day of the eligibility assessment
• Have had any skin disinfectants applied above the wrist within the last hour
• Known colonisation with resistant bacteria ie Methicillin Resistant Staphylococcus Aureus (MRSA).

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation concealment will be ensured at the time of recruitment through the utilisation of a computer based centralised randomisation system which will allocate a participants group only upon successful screening and written consent to participate in the study. Research staff members recruiting for the study will not know which arm of the study participants will be in until study enrolment. Randomisation will be conducted through REDcap - Research Electronic Data Capture software which will be utilised for data capture in the study
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Prior to the study commencing a sequence of 600 participants, each with a unique identification number, will be generated based on a non-factorial trial with 2 treatment groups. The sequence of treatment groups will be randomly permuted in blocks of size 2 or 4 in equal proportion.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?


The people assessing the outcomes
Intervention assignment
Other
Other design features
Each patient will act as their own control in this study. Each of the patients arms will have a cleaned and disinfected US transducer applied to it so that contamination will be equal (from the same person) on each ultrasound transducer prior to disinfection with either LLD or HLD. To ensure equal distribution of left and right arms between the two disinfection treatments (LLD and HLD) each participant will be randomised into one of two groups upon recruitment. This allocation will determine how the ultrasound transducer contaminated by being applied to the left and right arms are subsequently disinfected: Group A- Right arm = High Level Disinfection (HLD) & Left arm = Low Level Disinfection (LLD); Group B- Right arm = LLD & Left arm = HLD. Swabs will labelled in manner so that the microbiology staff will be blinded to which swabs have been collected from the HLD and LLD treated ultrasound transducers.
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
The dependant variable will be the elimination of all bacteria by the disinfectant solutions such that: no (CFU >0); and, yes (CFU =0). The expected proportion of US transducers with eliminated bacterial loads following LLD was estimated to be 96% (i.e. 4% (2/58) of transducers had >0 CFU bacteria detected based on previous published research). The proportion of US transducers with eliminated bacterial loads following HLD is generally unreported, but estimated to be twice as effective as LLD at the elimination of bacteria resulting in an estimate of 98%. The non-inferiority margin of -5% was selected as the smallest clinically important difference in the proportion of US transducers with eliminated bacterial loads where LLD would be considered non-inferior to HLD (i.e. the lower confidence interval (LCI) of the LLD estimate excludes this -5% margin, or 93%).

A proportion of US transducers up to 10% are expected to have absent bacterial load in the pre-sample. Sample size calculated will be inflated by this ‘dropout’ factor to ensure sufficient sample size to achieve stated power.

Statistical analysis will be using the Nam Score or Wald score non-inferiority test. The null hypothesis is that the difference in the proportion of US transducers with no bacterial present between LLD and HLD is less than or equal to -0.05 (LLD – HLD), with the alternate hypothesis that this difference is larger than -0.05.

For a one-sided non-inferiority test of the difference between two correlated proportions with a non-inferiority margin of -5%, a sample size of 522 subjects is required to attain the 470 subjects required to achieve 80.0% power at a 2.5% significance level, assuming 10% of subjects will have no growth and with LLD and HLD bacterial load absent proportions of 96% and 98%, respectively. These results assume that the proportion of both methods that result in absent bacterial loads are equal to 95%.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
1/03/2022
Actual
28/05/2022
Date of last participant enrolment
Anticipated
2/02/2023
Actual
15/12/2022
Date of last data collection
Anticipated
2/02/2023
Actual
19/12/2022
Sample size
Target
470
Accrual to date
Final
476
Recruitment in Australia
Recruitment state(s)
QLD
Recruitment hospital [1] 21319 0
Royal Brisbane & Womens Hospital - Herston
Recruitment postcode(s) [1] 36209 0
4029 - Herston

Funding & Sponsors
Funding source category [1] 310375 0
Charities/Societies/Foundations
Name [1] 310375 0
Australasian Society For Ultrasound In Medicine
Country [1] 310375 0
Australia
Primary sponsor type
Hospital
Name
Department of Anaesthesia and Perioperative Medicine
Address
Royal Brisbane and Women's Hospital, Butterfield Street, Herston QLD, 4029
Country
Australia
Secondary sponsor category [1] 311520 0
None
Name [1] 311520 0
Address [1] 311520 0
Country [1] 311520 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 310028 0
Royal Brisbane and Women's Hospital Human Research ethics Committee
Ethics committee address [1] 310028 0
Ethics committee country [1] 310028 0
Australia
Date submitted for ethics approval [1] 310028 0
24/07/2021
Approval date [1] 310028 0
05/08/2021
Ethics approval number [1] 310028 0
HREC/2021/QRBW/77718

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 116238 0
Dr Nathan Peters
Address 116238 0
Department of Anaesthesia and Perioperative Medicine
Royal Brisbane and Women's Hospital
Butterfield Street, Herston, QLD, 4029
Country 116238 0
Australia
Phone 116238 0
+61439997304
Fax 116238 0
Email 116238 0
[email protected]
Contact person for public queries
Name 116239 0
Nathan Peters
Address 116239 0
Department of Anaesthesia and Perioperative Medicine
Royal Brisbane and Women's Hospital
Butterfield Street, Herston, QLD, 4029
Country 116239 0
Australia
Phone 116239 0
+61439997304
Fax 116239 0
Email 116239 0
[email protected]
Contact person for scientific queries
Name 116240 0
Nathan Peters
Address 116240 0
Department of Anaesthesia and Perioperative Medicine
Royal Brisbane and Women's Hospital
Butterfield Street, Herston, QLD, 4029
Country 116240 0
Australia
Phone 116240 0
+61439997304
Fax 116240 0
Email 116240 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Individual participant data will not be available from this study.


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.