ANZCTR - Registration

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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]

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

Condition category

Condition code

Cardiovascular

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]

Treatment: Other

Comparator / control treatment

No control group. Patients will act as their own control.

Control group

Uncontrolled

Outcomes

Primary outcome [1]

Detection of a difference between central blood samples in the concentration of Apolipoprotein ApoB48 (lymphatic biomarker) using an ELISA ApoB48 assay.

Timepoint [1]

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]

Detection of a difference in Total Triglyceride concentration between central blood samples via a lipid profile analysis.

Timepoint [2]

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]

Nil

Timepoint [1]

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?

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

Accrual to date

Final

Recruitment outside Australia

Country [1]

New Zealand

State/province [1]

Auckland

Funding & Sponsors

Funding source category [1]

Government body

Name [1]

Health Research Council of New Zealand

Address [1]

Level 3 - ProCARE Building, Grafton Mews, at 110 Stanley Street (GPS: 50 Grafton Road), Grafton, Auckland 1010
New Zealand

Postal address: PO Box 5541, Victoria Street West, Auckland 1142, New Zealand

Country [1]

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]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Health and Disability Ethics Committee (HDEC)

Ethics committee address [1]

Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140

Ethics committee country [1]

New Zealand

Date submitted for ethics approval [1]

09/08/2021

Approval date [1]

30/09/2021

Ethics approval number [1]

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

Prof John Windsor

Address

University of Auckland
Room 2004, Level 2, M&HS Building 507
28 Park Avenue
Grafton
Auckland 1023

Country

New Zealand

Phone

+64 99239791

Fax

j.windsor@auckland.ac.nz

Contact person for public queries

Name

John Windsor

Address

University of Auckland
Room 2004, Level 2, M&HS Building 507
28 Park Avenue
Grafton
Auckland 1023

Country

New Zealand

Phone

+64 99239791

Fax

j.windsor@auckland.ac.nz

Contact person for scientific queries

Name

John Windsor

Address

University of Auckland
Room 2004, Level 2, M&HS Building 507
28 Park Avenue
Grafton
Auckland 1023

Country

New Zealand

Phone

+64 99239791

Fax

j.windsor@auckland.ac.nz

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 (j.windsor@auckland.ac.nz)

What supporting documents are/will be available?

Doc. No.	Type	Citation	Link	Email	Other Details	Attachment
12437	Study protocol			j.windsor@auckland.ac.nz

Results publications and other study-related documents

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No additional documents have been identified.

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