None listed
Conditions
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.
Interventions
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 proced
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.
Sponsors
University of Auckland
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Diagnosis
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 80 Years
Healthy volunteers
No
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.
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.
Outcome results
None listed