To demonstrate that external drainage of thoracic duct lymph during sepsis results in a reduction in circulating pro-inflammatory cytokines.

To demonstrate safety and feasibility of early thoracic duct cannulation and external lymph drainage for up to 7 days in adult surgical intensive care patients.

To explore other biochemical and physiological endpoints that can be used for the design of future randomized controlled trials and estimate effect size of external drainage.

This is an interventional cohort study that will involve external drainage of thoracic duct lymph in Surgical ICU patients with septic shock. The lymph drainage will continue for up to a maximum of 7 days and will be continued in those interventional group patients discharged from ICU back to the ward before that time. The lymph (and time-matched blood) will be periodically sampled to detect changes in composition which will be correlated with changes in disease severity and outcomes, as well as patient physiology and biochemistry. This pilot study is not powered to detect changes in hospital/ICU stay, major complications or mortality. The primary endpoint of interest is the pro-inflammatory cytokine profile and concentrations in lymph and peripheral blood.

Inclusion Criteria:

• Adult (18-80 years) patients in Surgical ICU with suspected or documented infection on antibiotics and septic shock defined as hypotension requiring vasopressor therapy to maintain MAP > 65mmHg (modified from Sepsis-35).

Participants will fulfill the inclusion criteria not only at recruitment and consent, but also be confirmed to still meet those criteria immediately prior to transfer to IR for the procedure.

The patient will not be recruited if he or she no longer meet these criteria.

Patients experiencing hemodynamic instability, defined as (1) MAPs < 65 despite ongoing up-titration of pressors and volume resuscitation or (2) active titration of vasopressors (more than 2 increases in past hour) or active volume resuscitation (more than 1-liter bolus in past hour) that precludes travel to IR during the intervention window will be excluded from the study and considered screen fails

Exclusion Criteria:

1. Open abdomen
2. Intra-abdominal sepsis preventing access to the lymphatic system
3. Prior instrumentation of the lymphatic system
4. Known occlusion of the left subclavian vein
5. Known malformation of the lymphatic system
6. Previous left axillary node dissection ± left upper limb lymphoedema
7. Class 4 heart failure
8. Any chronic medical condition for which the patient is expected to have <6-month survival
9. Decompensated liver failure with ascites
10. Portal hypertension with history of variceal bleeding
11. Severe allergy to contrast agents
12. Need for continuous anticoagulation (that cannot be stopped for procedure)
13. Uncorrectable coagulopathy or INR >1.5
14. Uncorrectable thrombocytopenia (platelet count less than 50,000)
15. Immunocompromised state (active cytotoxic chemotherapy or transplant recipient)
16. Pregnancy
17. DNR ('do not resuscitate') status
18. Subject or authorized representative not willing to provide consent (unconscious patient will need to countersign prior to analysis of samples)
19. Unable to have central venous line or arterial line in place