The Use of Thrombin Generation Assay in Detection of Central Line Related Thrombosis (CRT) in Critically Ill Patients

To study thrombin generation parameters in critically ill patients with and without central line related thrombosis (CRT).

Inclusion Criteria: * Age ≧ 18; AND * Admitted to the mixed medical-surgical intensive care units of Queen Mary Hospital in Hong Kong; AND * Clinically indicated for central catheter insertion, which includes central venous catheters and dialysis catheters; AND * Expected to have the central catheter in place for at least 5 days in their ICU stay. Exclusion Criteria: * Patients known to have active venous thromboembolism including deep venous thrombosis or pulmonary embolism; * Patients known to have hypercoagulable states, e.g., hereditary thrombophilia, antiphospholipid syndrome; OR * Patients with active solid organ or hematological malignancies; OR * Patients already receiving therapeutic anticoagulation prior to study recruitment; OR * Patients with thrombosis detected in the insertion site before central catheter insertion; OR * Patients with a central venous catheter already in place prior to ICU admission; OR * Patients admitted to the ICU for post-operative care; OR * Patients admitted to the ICU for trauma care; OR * Patients requiring extra-corporeal life support (ECLS); OR * Patients with poor window or inaccessible for ultrasonographic examination; OR * Pregnancy/post-partum within 6 weeks