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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
A bundle for anaethetists to reduce postoperative infection: the Anaesthetists Be Cleaner (ABC) study
Scientific title
The effect of implementing a bundle for anaesthetists to reduce postoperative infections: a stepped wedge cluster randomised multi-site trial. The Anaesthetists Be Cleaner (ABC) Study
Secondary ID [1] 291870 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Postoperative infection 303160 0
Condition category
Condition code
Anaesthesiology 302603 302603 0 0
Other anaesthesiology
Infection 302630 302630 0 0
Other infectious diseases

Study type
Description of intervention(s) / exposure
The intervention will involve the implementation of the bundle outlined below.
1. Wipe skin with 70% alcohol (with or without 2% chlorhexidine) and allow to dry before inserting any IV line.
2. Inject all IV bolus medications except propofol through a 0.2micron filter incorporated into each patient’s IV line.
• Use aseptic technique when attaching the filter to the IV and, unless it has been freshly opened from sterile packaging, wipe the IV injection port with 70% alcohol (with or without 2% chlorhexidine) for 15 seconds and allow to dry.
• If the filter is moved from one access point to another during the case the new access point should first be wiped with 70% alcohol (with or without 2% chlorhexidine) for 15 seconds and allowed to dry.
• Use more than one filter if necessary or desired (e.g. for cardiac patients, one filter in the peripheral line, one on a central line port where bolus medications may be given, and a third onto the medication injection port on the bypass machine for the perfusionist to use when administering medications).
• Remove the filter(s) on discharge from the Post Anaesthesia Care Unit or on admission to the Intensive Care Unit.
3. Use meticulous aseptic technique when drawing up or injecting propofol, and discard syringes, needles or the medication in the event of any suspected contamination:
• Note that the rubber bungs on propofol vials are not sterile even with the cap in place, so they should be wiped with alcohol (with or without chlorhexidine) for 15 seconds and allowed to dry before propofol is drawn up. If the medication is supplied in an ampoule, wipe the outside of the neck and surrounding part of the ampoule with alcohol (with or without chlorhexidine) before opening.
• Use a new needle or spike for each occasion.
• Cap the syringe with a syringe cap or capped needle.
• Administer as soon as possible and discard propofol after one hour if not used.
• Do not reuse syringes or needles for propofol, even for the same patient.
• Flush IV port with sterile sodium chloride 0.9% or sterile water for injection after propofol has been administered to ensure no residual propofol remains to support bacterial growth.
4. Perform hand hygiene:
• Before and after interacting with each new patient (i.e. on entering the operating room and on leaving a patient in the Post Anaesthesia Care Unit).
• Before and after any procedure creating risk of infection (e.g. IV insertion, airway manipulation, administering propofol, etc).
• After blood and body fluid exposure (e.g intubation, IV line insertion etc); remove gloves (if they have been worn) and, if practicable, perform hand hygiene before spreading contamination to the work station, computer key board and other surfaces.
5. Maintain clean working surfaces:
• Place used laryngoscopes, masks and other contaminated objects into a tray designated for this exclusive purpose; maintain strict separation of clean and contaminated areas - do not use this tray for clean instruments, swabs or other items even at the start of a procedure.
• Wipe the anaesthetic machine bench top and the circuit pressure-relief valve with alcohol (with or without chlorhexidine) once the patient has settled into the maintenance phase of anaesthetic (i.e. after intubation of the trachea if this is done).
• Propofol should not be injected through the filter.
• The filter has a dead space of 0.45 mL and the injection port has a dead space of 0.11 mL (= 0.56 mL in total); therefore, as with any IV setup, it is necessary to prime the filter with sterile sodium chloride 0.9% or sterile water for injection to eliminate air, and it is also necessary to ensure that medications are flushed through.
• Hand hygiene implies either hand washing with medicated soap and water or using alcohol-based hand rub; it is important for hands to dry properly.
• Provided the medications are injected through a 0.2micron filter, the study does not ask for hand hygiene in relation to the injection and drawing up of medications other than propofol.
The bundle will be presented to each study site by the investigators and site champions (we already have anaesthetists who have volunteered to be site champions for the study) and additional information in the form of emails to each department, study information sheets, videos and a study website will also be used.
Evaluation of current aseptic practices and changes to these after implemetnation of the bundle will be observed by indepentent medically trained personnel e.g. medical students. Aseptic processes defined in the bundle will be measured using a simple behaviourally anchored scale developed for the study.
Intervention code [1] 297988 0
Comparator / control treatment
The study is controlled by using a stepped wedge design so that each site starts the study with usual care (defined as the practices usually used by each participating anaesthestist, notably in relation to asepsis).
Control group

Primary outcome [1] 302016 0
Days alive and out of hospital. This will be determined from the Minimum National Data Set from the Ministry of Health, New Zealand.
Timepoint [1] 302016 0
90 days following surgery
Secondary outcome [1] 334520 0
The rate of surgical site infection (SSI) in patients undergoing hip or knee arthroplasty or cardiothoracic surgery. This is a composite outcome and includes a) superficial incisional SSI; b) deep incisional SSI; and (c) organ/space SSI. The information regarding these infections will be obtained from the National SSI Improvement programme from the Health Quality and Safety Commison in New Zealand.
Timepoint [1] 334520 0
Occurring within 30 (superficial incisional) or 90 days of surgery while in hospital after surgery, or requiring re-admission to hospital

Key inclusion criteria
All patients undergoing hip or knee arthroplasty or cardiothoracic surgery (as defined by the Surgical Safety Infection Improvement programme) in the study hospitals during the active phase of the study under general anaesthesia with or without regional anaesthesia, or under regional anaesthesia with sedation.
Minimum age
No limit
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Heart and lung transplants will be excluded from the study because of their complexity and the use of immunosuppression in these cases.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
All sites will be included in the intervention but in a randomly allocated sequence. Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people analysing the results/data
Intervention assignment
Other design features
Our study does not lend itself to the randomisation of individual patients - it would be unreasonable to ask that practices widely accepted as desirable be done in a haphazard fashion. Instead, we will randomise departments and use a real world, multi-site (five departments in four hospitals), stepped wedge, cluster randomised quality improvement design to compare participants’ usual anaesthetic practices with practices that include our bundle.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The primary outcome for the study is days alive and out of hospital (DAOH) within the first 90 days after the procedure. Pilot data for DAOH within 90 days for 150 patients who had procedures as defined for the proposed study provided data upon which to estimate the sample size for this study. Sample size was calculated (by our study statistician) using iterative simulation. A total sample of 5,000 (2,500 per group) would provide sufficient power (>80%) to show an increase of one day in the DAOH within 90 days as statistically significant (two-tailed P<0.05). A difference of one day would represent a clinically significant improvement of importance to patients and of economic relevance. Conversely (and importantly), a difference less of less than one day in an adequately sized study would arguably be of little clinical relevance, particularly from the perspective of health economics.

Recruitment status
Not yet recruiting
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] 8880 0
New Zealand
State/province [1] 8880 0
Auckland District Health Board
Country [2] 8881 0
New Zealand
State/province [2] 8881 0
Waitemata District Health Board
Country [3] 8882 0
New Zealand
State/province [3] 8882 0
Counties Manukau District Health Board

Funding & Sponsors
Funding source category [1] 296370 0
Name [1] 296370 0
Austalia New Zealand College of Anaesthestists
Address [1] 296370 0
PO Box 6095,
Melbourne, Victoria, 3004
Country [1] 296370 0
Primary sponsor type
University of Auckland
Private Bag 92019
Auckland 1142
New Zealand
Secondary sponsor category [1] 295313 0
Name [1] 295313 0
Professor Alan Merry
Address [1] 295313 0
Department of Medicine
the University of Auckland
85 Park Road
Auckland 1142
Country [1] 295313 0
New Zealand

Ethics approval
Ethics application status
Ethics committee name [1] 297608 0
Northern B Health and Disabilities Ethics Committee
Ethics committee address [1] 297608 0
Ministry of Health
No 1 The Terrace
PO Box 5013
Wellington 1601
Ethics committee country [1] 297608 0
New Zealand
Date submitted for ethics approval [1] 297608 0
Approval date [1] 297608 0
Ethics approval number [1] 297608 0

Brief summary
The problem
Postoperative infection.

We know that anaesthetists inadvertently inject potentially pathogenic micro-organisms into about 6% of patients. We do not know whether this matters clinically, but it is a plausible cause of post-operative infections in operations such as major hip and knee arthroplasty and cardiac surgery.

To demonstrate the clinical importance of inadvertent intravenous (IV) injection of micro-organisms during anaesthesia using two endpoints:
1. Days alive and out of hospital (DAOH) at 90 days post-surgery.
2. Rates of surgical site infection (SSI) from the National Surgical Site Infection Improvement programme reports.

Our primary end-point is the patient-centred measure, days alive and out of hospital in the 90 days following surgery.

As a secondary endpoint we will also measure the rate of SSI in patients undergoing hip or knee arthroplasty and cardiothoracic surgery. These infections include a) superficial incisional SSI; b) deep incisional SSI; (c) organ/space SSI; (d) pneumonia; and (e) septicaemia, all occurring within 30 days (superficial incisional) or 90 days of surgery, while in hospital, after surgery, or requiring re-admission to hospital.

These are important explanatory measures, but will not capture all forms of infection. By contrast, quantifying the difference between groups in days alive and out of hospital will provide a compelling quantification, the practical clinical importance of all manifestations of infection, and of the potential benefit of our proposed intervention.

We will use a service-based, “real world”, prospective, modified stepped-wedge, quality improvement design to evaluate a bundle of measures for improving key anaesthetic practices related to the aseptic drawing up and administering of IV medications, to hand hygiene, and to maintaining a clean work space to prevent injection of micro-organisms, by anaesthetists, on postoperative infection, and hence the clinically relevant and patient-centred measure, days alive and out of hospital, in the 90 days following surgery.
Trial website
Trial related presentations / publications
Public notes
Attachments [1] 2493 2493 0 0

Principal investigator
Name 74574 0
Prof Alan Merry
Address 74574 0
School of Medicine
the University of Auckland
Private Bag 92019
Auckland 1142
Country 74574 0
New Zealand
Phone 74574 0
+64 9 3737599 ext 89301
Fax 74574 0
Email 74574 0
Contact person for public queries
Name 74575 0
Prof Alan Merry
Address 74575 0
School of Medicine
the University of Auckland
Private Bag 92019
Auckland 1142
Country 74575 0
New Zealand
Phone 74575 0
+64 9 3737599 ext 89301
Fax 74575 0
Email 74575 0
Contact person for scientific queries
Name 74576 0
Dr Derryn Gargiulo
Address 74576 0
School of Medicine
the University of Auckland
Private Bag 92019
Auckland 1142
Country 74576 0
New Zealand
Phone 74576 0
+64 9 3737599 ext 89321
Fax 74576 0
Email 74576 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
Our participants are the anaesthetic team members. We are not asking for consent nor gathering data from any patients.
What supporting documents are/will be available?
Study protocol
Informed consent form
Ethical approval
Type [1] 281 0
Study protocol
URL/details/comments [1] 281 0
Type [2] 282 0
Informed consent form
URL/details/comments [2] 282 0
Type [3] 283 0
Ethical approval
URL/details/comments [3] 283 0
Summary results
Not applicable