Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12621001065886
Ethics application status
Approved
Date submitted
6/07/2021
Date registered
12/08/2021
Date last updated
7/02/2022
Date data sharing statement initially provided
12/08/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
Testing a new method for measuring lymphatic fluid using blood sampling.
Scientific title
Measuring Thoracic Duct Lymph Composition during Acute and Critical Illness: A Novel Central Venous Sampling Technique.
Secondary ID [1] 304707 0
None
Universal Trial Number (UTN)
U1111-1267-5582
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Lymphatic sampling in acute and critical illness patients 322726 0
Condition category
Condition code
Cardiovascular 320315 320315 0 0
Diseases of the vasculature and circulation including the lymphatic system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Central venous sampling for measurement of thoracic duct lymph composition.
The study is a pilot cohort study to confirm the feasibility of a novel technique to measure changes in venous blood due to thoracic duct lymph drainage. The plan is to recruit 10 patients in the Cardiovascular ICU unit in Auckland City Hospital, who are undergoing pre-planned elective cardiac surgery and will act as their own control. Peripheral and central venous catheters are inserted as part of normal surgical procedure. In addition to this, after the surgery the cardiac anaesthetist will insert an enteral feeding tube and a second central venous catheter into the left internal jugular vein (around where the thoracic duct joins the vein) above the pre-inserted catheter. Blood will be sampled using syringes by a research team member or a research nurse from the peripheral catheter and the two central catheters. Blood is taken and compared across two different timepoints (end-inspiration and end-expiration). The sampling procedure is done twice over 2 hours (before and after ingestion of lipid-rich cream via the feeding tube to promote lymph flow). The blood will be analysed for lymphatic biomarker concentrations. Consent from the patients will be obtained prior to the surgery, and the study procedures will be conducted post-surgery while the patient is still under anaesthetic and on ventilator. No further contribution is needed from the patient once the blood samples have been taken.
Intervention code [1] 321090 0
Treatment: Other
Comparator / control treatment
No control group. Patients will act as their own control.
Control group
Uncontrolled

Outcomes
Primary outcome [1] 328164 0
Detection of a difference between central blood samples in the concentration of Apolipoprotein ApoB48 (lymphatic biomarker) using an ELISA ApoB48 assay.
Timepoint [1] 328164 0
Post surgery, when the patient is in the post-surgical ward but still under anaesthetic, the blood samples will be collected. Simultaneous sampling will be performed using syringes attached to the relevant catheters. During end-inspiration, blood will be drawn simultaneously from each catheter. This is done until a total of 2.5mL of blood is obtained from each catheter. The syringes are then replaced and the procedure is repeated at end-expiration.
Lipid-rich cream will then be administered via a nasogastric/enteral feeding tube.
After waiting 30mins to allow for uptake of the lipids into the lymphatic system, sampling will be repeated for both end-inspiration and end-expiration to obtain "post-cream" samples.

After all blood samples have been taken from the patient, they will be taken to be centrifuged to separate the plasma, which will be stored in a -80°C freezer in the hospital.

Once plasma from 10 patients has been collected (done within ~1 month), the samples will be transferred to labs at the University of Auckland to be analysed.
Primary outcome [2] 328165 0
Detection of a difference in Total Triglyceride concentration between central blood samples via a lipid profile analysis.
Timepoint [2] 328165 0
When the patient is in the post-surgical ward but still under anaesthetic, the blood samples will be collected. During end-inspiration, blood will be drawn simultaneously from each catheter. This is done until a total of 2.5mL of blood is obtained from each catheter. The procedure is then repeated at end-expiration.
Lipid-rich cream will then be administered via a nasogastric/enteral feeding tube.
After waiting 30mins to allow for uptake of the lipids into the lymphatic system, sampling will be repeated for both end-inspiration and end-expiration to obtain "post-cream" samples.

After all blood samples have been taken from the patient, they will be taken to be centrifuged to separate the plasma, which will be stored in a -80°C freezer in the hospital.

Once plasma from 10 patients has been collected (done within ~1 month), the samples will be transferred to labs at the University of Auckland to be analysed.
Secondary outcome [1] 397907 0
Nil
Timepoint [1] 397907 0
Nil

Eligibility
Key inclusion criteria
Participant will be recruited from cardiac patients undergoing planned elective surgery (e.g. CABG procedures or similar).
Inclusion criteria:
• Patients aged 18-80 years
• Peripheral venous line
• Multi-lumen left internal jugular or subclavian venous catheter
• NG or NJ tube or willing to have a NG tube placed during anaesthetic to allow the giving of enteral cream to augment TD lymph flow. An existing PEG or PEJ tube would also work.
• Expected to be on mechanical ventilation following the completion of the operation, which is preferred. But the study can be done on patients breathing spontaneously.
Minimum age
18 Years
Maximum age
80 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Exclusion criteria:
• Pregnancy
• Intrinsic lung disease
• Severe congestive heart failure (leading to high right atrial pressure)
• Moderate-severe tricuspid incompetence (leading to high right atrial pressure)
• Chronic renal/liver conditions
These conditions may affect lymph flow and disrupt the measurement procedure.

Study design
Purpose of the study
Diagnosis
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Not RCT.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Single group
Other design features
This study evaluates the outcome of a technique, not clinical outcomes in patients.
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis
This small pilot study does not have any precedent, being a novel sampling technique with no preliminary data on which to calculate the power of the study. The decision was that the study 10 patients will be sufficient, as each patient will acts as their own control. The primary endpoint will be any detectable difference in the concentration of lymphatic tracers between the proximal and distal central blood samples at two phases of the respiratory cycle.

The results from the assays will be analysed by statisticians and pharmacokinetic experts in Monash University. Concentration differences between central and peripheral blood samples, as well as between pre and post lipid-ingestion samples will be compared as baseline/background tracer levels in blood. The samples with the greatest difference in concentrations of ApoB48 and TTG levels between proximal and distal samples will be from the timepoint with greatest lymphatic flow and contribution.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
28/02/2022
Actual
Date of last participant enrolment
Anticipated
28/03/2022
Actual
Date of last data collection
Anticipated
28/03/2022
Actual
Sample size
Target
10
Accrual to date
Final
Recruitment outside Australia
Country [1] 23944 0
New Zealand
State/province [1] 23944 0
Auckland

Funding & Sponsors
Funding source category [1] 309077 0
Government body
Name [1] 309077 0
Health Research Council of New Zealand
Country [1] 309077 0
New Zealand
Primary sponsor type
University
Name
University of Auckland
Address
Office of Research Strategy and Integrity
University of Auckland
Private Bag 92019
Auckland Mail Centre
Auckland 1142
Country
New Zealand
Secondary sponsor category [1] 310023 0
None
Name [1] 310023 0
Address [1] 310023 0
Country [1] 310023 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 308951 0
Health and Disability Ethics Committee (HDEC)
Ethics committee address [1] 308951 0
Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140
Ethics committee country [1] 308951 0
New Zealand
Date submitted for ethics approval [1] 308951 0
09/08/2021
Approval date [1] 308951 0
30/09/2021
Ethics approval number [1] 308951 0
21/NTB/222

Summary
Brief summary
The overall aim of the project is to evaluate a new technique to sample thoracic duct lymph without relying on direct surgical cannulation. This will allow for a less invasive and more readily available method to determine compositional changes in lymph in patients with critical illness.

The study involves recruiting elective surgical patients in CVICU (cardiovascular intensive care unit) at Auckland City Hospital. Post-elective cardiac surgery, ingestion of lipid rich cream (orally or via nasogastric tube) will promote production of lymph and lymphatic markers such as Apolipoprotein ApoB48 or Triglyceride levels, the increase of which can be detected in blood. Central venous catheters can then be used to sample blood from the Internal Jugular vein upstream and downstream of where the thoracic duct drains into the vein. The blood will then be examined for concentration of lymphatic markers, and differential composition upstream vs downstream will be compared to determine contribution by thoracic duct lymph. Blood sampling will be done at different points in the respiratory cycle to help ascertain period of maximal lymph flow.
The endpoint of the study is to show that this technique is effective in measuring differences in blood concentration due to lymphatic contribution, and that blood sampling can therefore be used to monitor compositional changes in lymph with critical illness.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 112446 0
Prof John Windsor
Address 112446 0
University of Auckland
Room 2004, Level 2, M&HS Building 507
28 Park Avenue
Grafton
Auckland 1023
Country 112446 0
New Zealand
Phone 112446 0
+64 99239791
Fax 112446 0
Email 112446 0
[email protected]
Contact person for public queries
Name 112447 0
Prof John Windsor
Address 112447 0
University of Auckland
Room 2004, Level 2, M&HS Building 507
28 Park Avenue
Grafton
Auckland 1023
Country 112447 0
New Zealand
Phone 112447 0
+64 99239791
Fax 112447 0
Email 112447 0
[email protected]
Contact person for scientific queries
Name 112448 0
Prof John Windsor
Address 112448 0
University of Auckland
Room 2004, Level 2, M&HS Building 507
28 Park Avenue
Grafton
Auckland 1023
Country 112448 0
New Zealand
Phone 112448 0
+64 99239791
Fax 112448 0
Email 112448 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
Some relevant patient information such as age, sex, ethnicity, and medical history will be published with the main study. Further data may be shared with researchers performing further research, e.g. future studies by members of the same research team on the same topic. All shared data will be de-identified. No information that could reasonably identify the patient will be shared/published.
When will data be available (start and end dates)?
After conclusion of the study and publication of the study results. No end date.
Available to whom?
Researchers performing future studies on lymphatic composition and monitoring. It may include members of the current research team who go on the do further studies into this area, and wish to compare/build upon data from the current study. Availability will be on a case-by-case basis at the discretion of Primary Sponsor.
Available for what types of analyses?
The data and results from this study can be used to help design and inform new studies that test for different lymphatic biomarkers. The results of these future studies may be cross-referenced with the results from the current study (e.g. comparing efficacy of different methods, testing for repeatability, etc.), and relevant de-identified patient information linked to the study may be used.
How or where can data be obtained?
Future research will require starting a new study for the purposes of further analysis. Access to data and information linked to the current study beyond that in published reports of the study will be subject to approval by the Principal Investigator ([email protected])


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
12437Study protocol  [email protected]



Results publications and other study-related documents

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