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Trial registered on ANZCTR


Registration number
ACTRN12623000143628
Ethics application status
Approved
Date submitted
9/01/2023
Date registered
10/02/2023
Date last updated
10/02/2023
Date data sharing statement initially provided
10/02/2023
Type of registration
Retrospectively registered

Titles & IDs
Public title
Cerebral Oximetry when VEntilated oR Spontaneously breathing: The COVERS trial
Scientific title
Cerebral oximetry, in healthy subjects undergoing arthroscopic shoulder surgery in the beach-chair position, when using intermittent-positive-pressure ventilation compared to spontaneous ventilation.
Secondary ID [1] 308386 0
Nil known
Universal Trial Number (UTN)
U1111-1284-9475
Trial acronym
COVERS
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Shoulder pathology including but not limited to shoulder instability and rotatory cuff tears 328184 0
Condition category
Condition code
Anaesthesiology 325237 325237 0 0
Anaesthetics
Surgery 325822 325822 0 0
Other surgery

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Intermittent positive pressure ventilation (IPPV) group: Post-induction and following placement of a laryngeal mask airway, patients randomized to the IPPV group will be given atracurium 0.3mg/kg via intravenous injection and receive positive pressure ventilation continuously throughout the duration of the surgery. Initial ventilator settings will be an inspired oxygen concentration of 40%, a respiratory rate of 14, an inspiratory/expiratory ratio of 1:2, and tidal volumes of 7ml/kg and a PEEP of 5cmH2O. These settings will be titrated to ETCO2 level of 5-7kPa. If capnography or airway pressure readings suggest that diaphragmatic movement is opposing the action of the ventilator, patients in the ventilated group will be given a further 0.1-0.2mg/kg of atracurium, unless surgery is nearing completion.
Anaesthetic records will be reviewed and dose of atracurium given as well as intra-operative inspired oxygen and end-tidal carbon dioxide recorded to monitor adherence.

A cerebral oximetry monitor will be applied prior to induction in both studied groups. This involves 2 sensor stickers being placed on the forehead, the data is recorded continuously throughout the duration of the surgery.
Intervention code [1] 324838 0
Treatment: Other
Comparator / control treatment
Spontaneous ventilation group: For patients randomised to the ‘spontaneous ventilation’ subgroup, the anaesthetist will confirm successful placement of the laryngeal mask airway by administering 1-2 breaths via positive pressure ventilation and examining the capnograph. A brief period of apnoea will then be tolerated to allow the patient to initiate spontaneous respiration. The anaesthetist must intervene by providing further positive pressure ventilation if pulse oximetry falls below 93%, or earlier if concerned.

A cerebral oximetry monitor will be applied prior to induction in both studied groups. This involves 2 sensor stickers being placed on the forehead, the data is recorded continuously throughout the duration of the surgery.
Control group
Active

Outcomes
Primary outcome [1] 333308 0
Mean change in cerebral oximetry during the operative period. This will be calculated as the difference between baseline cerebral oximetry values and mean intraoperative values, which are defined as:
The area under the curve (AUC) for ‘cerebral oximetry versus time’ between anaesthesia induction and wound closure, divided by duration to produce a value (AUC/t).
Cerebral oximetry data is downloaded digitally at the end of the case.
Timepoint [1] 333308 0
Time-averaged over the course of the surgery, from the start of preoxygenation to wound closure.
Secondary outcome [1] 416577 0
The incidence of cerebral desaturation events (defined as a fall of 20% below baseline values and/or an absolute measured cerebral oxygenation value of 55% or less in either hemisphere).
Cerebral oximetry data is downloaded digitally at the end of the case.
Timepoint [1] 416577 0
Over the duration of the surgery, from the start of pre-oxygenation to wound closure.
Secondary outcome [2] 416578 0
Changes in cerebral oximetry by ethnicity.
Cerebral oximetry data is downloaded digitally at the end of the case.
Timepoint [2] 416578 0
Over the duration of the surgery, from the start of pre-oxygenation to wound closure.

Eligibility
Key inclusion criteria
ASA1-2 patients aged 18-70 undergoing arthroscopic shoulder surgery in the beach chair position under general anaesthesia with interscalene blockade (either ‘single shot’ or catheter-based).
Minimum age
18 Years
Maximum age
70 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Known cerebrovascular or peripheral vascular disease, uncontrolled hypertension, a history of severe postoperative nausea and vomiting (which may mandate a total intravenous based anaesthetic).

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)
Central randomisation by statistician not involved in the analysis of the study.
Sealed opaque envelopes containing randomisation group are opened after induction of anaesthesia.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Permuted block randomisation using block size of 4 and SAS code.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis
A recent series by Cox et al presented a complete dataset of NIRS values in forty patients across multiple phases of arthroscopic surgery in the beach chair position . This information was used to derive the mean and associated standard deviations of NIRS values between the baseline (or awake) value to the conclusion of surgery which includes the operative phase during which the patient was anaesthetised and in the beach chair position. The mean change in NIRS value between these two phases was 1.65% with an associated standard deviation of 7.3%.

We consider an absolute difference in NIRS values between the two groups of 6% to be clinically relevant. This is in agreement with the power calculations provided by Picton et al5 for a study comparing the effect of anaesthetic techniques in patients undergoing shoulder surgery in the beach chair position. Here a difference of NIRS values between the two groups of 4-5% was regarded as a clinically relevant difference.

Based on a minimum clinical difference of 6%, a standard deviation of 7.3%, a power of 90% and a two sided alpha value of 0.05 we would need a sample size of 30 patients. Accounting for protocol violations and a study drop out rate of 25%, we would need 20 in each group using a 1:1 ratio. Our power calculation was completed by Christin Coomarasamay, Biostatistician with the Counties Manukau Health Research Office.

The statistical analysis will be completed on an intention to treat and per protocol basis with those completing the process blinded to group allocations. To avoid the assumption of normality of data, non-parametric statistical tests will be used to compare the two groups. Continuous variables will be compared using the Mann-Whitney U test and discrete or binomial variables compared with the Fisher Exact or the Chi Square test with or without the Yates correction as appropriate. A two-tailed p-value of less than 0.05 will define statistical significance. The statistical analysis will be completed with SPSS Version 27.0 (IBM, New York, United States) by a researcher who is versed in the analysis of trial information in Anaesthesia and Perioperative Medicine. The analysis will be completed using blinded data whereby the researcher is unaware of the group allocation meaning bias is not introduced to the analysis.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
8/06/2022
Date of last participant enrolment
Anticipated
8/06/2023
Actual
Date of last data collection
Anticipated
8/06/2023
Actual
Sample size
Target
40
Accrual to date
12
Final
Recruitment outside Australia
Country [1] 25169 0
New Zealand
State/province [1] 25169 0
Auckland

Funding & Sponsors
Funding source category [1] 312633 0
Government body
Name [1] 312633 0
Counties Manukau Health Research Office
Country [1] 312633 0
New Zealand
Funding source category [2] 312929 0
Charities/Societies/Foundations
Name [2] 312929 0
NZ Society of Anaesthetists (The John Ritchie Prize Research Award)
Country [2] 312929 0
New Zealand
Primary sponsor type
Government body
Name
Counties Manukau Health Research Office
Address
Ko Awatea
Level 1, Middlemore Hospital
100 Hospital Rd
Otahuhu
Auckland 1640
Country
New Zealand
Secondary sponsor category [1] 314245 0
None
Name [1] 314245 0
Address [1] 314245 0
Country [1] 314245 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 311950 0
Northern B Health and Disability Ethics Commitee
Ethics committee address [1] 311950 0
Ministry of Health
133 Molesworth Street
PO Box 5013
Wellington
6011
Ethics committee country [1] 311950 0
New Zealand
Date submitted for ethics approval [1] 311950 0
03/12/2020
Approval date [1] 311950 0
02/06/2021
Ethics approval number [1] 311950 0
21/NTB/10

Summary
Brief summary
The ‘beach chair’ or sitting position is commonly used during shoulder surgery. Maintenance of adequate cerebral perfusion is a key goal of anaesthetic technique. Rare but catastrophic outcomes (stroke, brain death) have been reported. Further concern has been raised that relative hypoperfusion could lead to subclinical cerebral damage in vulnerable patients.

Cerebral oximetry is a non-invasive monitor which can be used to measure cerebral oxygenation. Among patients undergoing shoulder surgery, studies have looked at the impact of position, regional techniques, and anaesthetic agent. This is the first randomised control trial looking at cerebral oximetry in ventilated vs spontaneously breathing patients in beach chair position.

The objective of our study is to compare the effect of the two ventilatory strategies on cerebral oximetry in the beach chair position. Secondary objectives are
• to see if ventilatory strategy affects the incidence of cerebral desaturation events.
• If possible, to report changes in cerebral oximetry by ethnicity
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 122942 0
Dr Andrew Cameron
Address 122942 0
Te Whatu Ora Counties Manukau Middlemore Hospital
100 Hospital Rd
Otahuhu
Auckland 1640
Country 122942 0
New Zealand
Phone 122942 0
+64 212378437
Fax 122942 0
Email 122942 0
Andrew.Cameron@middlemore.co.nz
Contact person for public queries
Name 122943 0
Dr Jennifer Stephens
Address 122943 0
Te Whatu Ora Counties Manukau Middlemore Hospital
100 Hospital Rd
Otahuhu
Auckland 1640
Country 122943 0
New Zealand
Phone 122943 0
+64 211486420
Fax 122943 0
Email 122943 0
jennyclare2@gmail.com
Contact person for scientific queries
Name 122944 0
Dr Jennifer Stephens
Address 122944 0
Te Whatu Ora Counties Manukau Middlemore Hospital
100 Hospital Rd
Otahuhu
Auckland 1640
Country 122944 0
New Zealand
Phone 122944 0
+64 211486420
Fax 122944 0
Email 122944 0
jennyclare2@gmail.com

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
17973Study protocol    384971-(Uploaded-09-01-2023-13-05-11)-Study-related document.docx
17975Informed consent form    384971-(Uploaded-09-01-2023-13-05-43)-Study-related document.doc
17976Ethical approval    384971-(Uploaded-09-01-2023-13-05-57)-Study-related document.pdf



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.