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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
Date results information initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Avoidance of endotracheal suction in routine, post operative cardiac patients.
Scientific title
Avoidance of endotracheal suction in routine, post-operative cardiac patients. A single centre, non-inferiority, randomised controlled trial assessing the safety and efficacy of avoiding endotracheal suction on patients having planned cardiac surgery who are ventilated for less than 12 hours.
Secondary ID [1] 287195 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Endotracheal Suction 295775 0
Post Operative Cardiac Surgery 295778 0
Artificial Ventilation 295779 0
Condition category
Condition code
Surgery 296052 296052 0 0
Other surgery

Study type
Description of intervention(s) / exposure
The avoidance of endotracheal (ETT) suction in patients undergoing planned cardiac surgery,who are ventilated for less than 12 hours. ETT suction is normally performed "as required". It is at the discretion of the bedside nurse and can vary from 2 hours to 4 hours. The aim of ETT suction is to maintain pulmonary hygiene, clear any secretions that the patient cannot remove by coughing. It also aims to maintain integrity of the the ETT.
Those patients in the intervention group, i.e. no suction, will have all the usual care of the post operative cardiac patient, however with no ETT being performed. All the usual ICU monitoring will be in use and there are no plans for earlier extubation of this group. There are predefined criteria for the non-suction group to receive suction if required and for patient safety.
It is intended that a data safety committee will be established and review the first 20 patients to ensure protocol compliance and patient safety.
Intervention code [1] 292477 0
Treatment: Other
Intervention code [2] 292576 0
Treatment: Surgery
Intervention code [3] 292577 0
Treatment: Devices
Comparator / control treatment
ETT suction is performed on all ventilated patients. A suction catheter, attached to a negative pressure vacuum, is inserted into the ETT and any excess secretions are removed. This is performed "as required" and can vary from 2 to 4 hours. "As required" is usually influenced by the training and experience of the bedside nurse. Suction is also frequently performed at the point of extubation, the aim being to prevent aspiration during the procedure. The bedside nurse usually decides upon when suction is performed as well as doing the intervention.

Control group

Primary outcome [1] 295718 0
PaO2/FiO2 ratio 6 hours after extubation. This is 6 hours after extubation, as long as the patient is extubated within 12 hours of return to ICU. The outcome will be measured from the results of arterial blood gases, these provide data about the PaO2 and FiO2 that the patient is receiving. The primary outcome is the difference between the two groups.
Timepoint [1] 295718 0
6 hours after extubation.
Secondary outcome [1] 316300 0
1. Complications at extubation; defined as laryngeal spasm, vomiting, aspiration, oxygen de-saturation (SaO2 <90%). This data is recorded on the ICU chart and in the patient record. The data will be collected by research nurses who are also ICU nurses and familiar with ICU practice and procedures. When required that outcome will be assessed by the treating intensivist.
Timepoint [1] 316300 0
This will be collected from the time of extubation, up to 6 hours after extubation.
Secondary outcome [2] 316301 0
2. Requirement for the escalation of oxygen therapy; this is defined as increasing dyspnoea, tachypnoea (respiratory rate>25 breaths per minute) in the first 6 hours after extubation. This outcome will be assessed by reviewing the ICU chart and patient record. Any desaturation and action taken will be documented on the ICU chart. The number of episodes will be collected.
Timepoint [2] 316301 0
This will be collected from the time of extubation, up to 6 hours after extubation.
Secondary outcome [3] 316302 0
3. Oxygen saturation <90%. This will be the number of episodes of oxygen saturation below 90% from the time of extubation to 6 hours later. The patients have continuous pulse oximetry measured and recorded on the ICU chart. The data will be collected from reviewing the ICU charts and patient records.
Timepoint [3] 316302 0
This will be collected from the time of extubation, up to 6 hours after extubation.
Secondary outcome [4] 316303 0
4. Tachycardia (>100 bpm), this is the number of episodes of tachycardia during the 6 hours following extubation. This will be assessed from the ICU chart. The patients have continuous ECG monitoring while in the ICU.
Timepoint [4] 316303 0
This will be collected from the time of extubation, up to 6 hours after extubation.
Secondary outcome [5] 316304 0
5. Increased mean arterial pressure (>85mmHg). This is part of the routine monitoring for patients in ICU and is recored on the ICU chart. The number of episodes of increased MAP in the 6 hours after extubation will be collected. The outcome will be assessed from reviewing the ICU chart.
Timepoint [5] 316304 0
This will be collected from the time of extubation, up to 6 hours after extubation.
Secondary outcome [6] 316305 0
6. Re-intubation rates. This will be assessed from a review if the ICU chart and the patient record. It will be documented on both records.
Timepoint [6] 316305 0
This will be collected from the time of extubation, up to 6 hours after extubation.

Key inclusion criteria
1. Equal to or greater than 16 years old,
2. Patients having cardiac surgery with cardiopulmonary bypass (CPB),
3. Extubation expected within 12 hours of admission to CVICU
Minimum age
16 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Documented difficult intubation
2. Expected ventilation >12 hours
3. Clinician preference for the patient to receive ETT suction.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Patients will be screened and seen preoperatively to gain consent for participation in the study. Patients will be randomised 1:1 to either ETT suction or no ETT suction. Randomisation will be performed once the patient is admitted to the ICU post operatively. Patients will not be randomised if on admission to the ICU it is thought likely that they will remain intubated for > 12 hours.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Allocation sequence will be generated using computer software. This will provide computerised sequence generations and allocation concealment will be achieved through the use of sequentially numbered, opaque, sealed envelopes. The envelopes will contain the unique patient identifier code and the allocated treatment group. Block randomisation will ensure even allocation across both groups and minimise predictability of the allocation sequence.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Non-inferiority study
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The non-inferiority margin has been set at 10%, this has been assessed as clinically acceptable, The sample size calculations have been base upon data available from a similar patient cohort who were receiving supplemental oxygen. There is no available data for patients not receiving supplemental and we judged a 10% change clinically acceptable, that is a change in P/F ratio from 301 to 270. To ensure adequate power the sample size was increased to 100 participants in each arm of the study. This will allow for those who will not be randomised on return to the unit or who are ventilated for >12 hours. The non-inferiority margin has been set as 10%.

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] 7064 0
New Zealand
State/province [1] 7064 0

Funding & Sponsors
Funding source category [1] 291755 0
Name [1] 291755 0
Auckland District Health Board Charitable A+ Trust
Address [1] 291755 0
Auckland District Health Board Charitable Trust
Private Bag 92024
Auckland 1023
Country [1] 291755 0
New Zealand
Primary sponsor type
Eileen Gilder
CVICU Research
Auckland City Hospital
Level 4, Building 32,
2 Park Road
Auckland 1142
New Zealand
Secondary sponsor category [1] 290427 0
Name [1] 290427 0
Address [1] 290427 0
Country [1] 290427 0

Ethics approval
Ethics application status
Ethics committee name [1] 293278 0
Northern B Health and Disability Ethics Committee
Ethics committee address [1] 293278 0
Ministry of Health
Freyberg Building
20 Aitken Street
PO Box 5013
Wellington 6011
Ethics committee country [1] 293278 0
New Zealand
Date submitted for ethics approval [1] 293278 0
Approval date [1] 293278 0
Ethics approval number [1] 293278 0

Brief summary
Cardiac surgery utilising cardiopulmonary bypass (CPB) is one of the most common forms of major surgery, with more than 1 million patients undergoing this surgery worldwide each year, including around 2500 in New Zealand (MOH 2008). After cardiac surgery the patients are admitted to the Intensive Care Unit, where they remain until ready for transfer to the surgical ward. The uncomplicated patient is ventilated for between 3-12 hours and woken up once they are cardiovasculary stable. When patients are ventilated part of the routine care includes nurses performing endotracheal suction (ETT Suction). The principle of ETT suction is to maintain pulmonary hygiene in patients who have lost the natural ability to cough and protect their airway as a result of the ETT being in place. Other principles include maintaining patency of the ETT tube, preventing aspiration and removing secretions. One of the main complications of the ETT is the increased risk of infection, e.g. pneumonia, but it can also lead to trauma to the lung tissue, hypoxia, bradycardia and hypertension. The bulk of the current evidence for performing ETT suction in ICU has been based upon patients who have been ventilated for longer than 3 days and frequently have underlying lung disease or injury. Both these conditions require long-term ventilation and have specific oxygenation requirements.
The uncomplicated postoperative cardiac patient is ventilated for a few hours after surgery, usually until they are warm and cardiovascularly stable. The aim is to extubate these patients as soon as it is safe and appropriate to do so. There is some recent evidence that the effect of ETT suction is longer lasting than anticipated particularly in the spontaneously breathing patient
ETT suction causes a loss of lung volume and positive end expiratory pressure.
There appears to be no evidence about the safety and efficacy of not performing ETT suction in this group of patients. This study aims to determine if avoiding ETT suction in the routine postoperative cardiac patient ventilated for less than 12 hours has a deleterious effect.
Hypothesis: Avoiding ETT suction in patients following cardiac surgery is not inferior to usual care of mandated suction prior to extubation.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 59238 0
Mrs Eileen Gilder.
Address 59238 0
CVICU, Ward 48,
Auckland City Hospital,
2 Park Road.
Grafton, 1142
Country 59238 0
New Zealand
Phone 59238 0
Fax 59238 0
Email 59238 0
Contact person for public queries
Name 59239 0
Mrs Eileen Gilder
Address 59239 0
CVICU, Ward 48,
Auckland City Hospital,
2 Park Road.
Grafton, 1142
Country 59239 0
New Zealand
Phone 59239 0
Fax 59239 0
Email 59239 0
Contact person for scientific queries
Name 59240 0
Mrs Eileen Gilder
Address 59240 0
CVICU, Ward 48,
Auckland City Hospital,
2 Park Road.
Grafton, 1142
Country 59240 0
New Zealand
Phone 59240 0
Fax 59240 0
Email 59240 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
This has not been stated in the ethics application and would need review by ethics.
What supporting documents are/will be available?
Statistical analysis plan
How or where can supporting documents be obtained?
Type [1] 2080 0
Statistical analysis plan
Citation [1] 2080 0
Link [1] 2080 0
Email [1] 2080 0
Other [1] 2080 0
Summary results
Have study results been published in a peer-reviewed journal?
Journal publication details
Publication date and citation/details [1] 12279 0
Respir Care 2020;65(12):1838–1846.
Attachments [1] 12279 0
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary
Avoidance of endotracheal suction in cardiac surgical patients who are expected to be ventilated for 12 hours or less can be safely avoided or minimized.