2.2. Study participants
coagulation abnormalities
The first patient is enrolled on 31st December 2021 and the last patient is enrolled on 24th July 2022. The last observation is collected on 31st July 2022. We state that our CT registration was later that the date of enrolling the first patient because of the delay caused by the COVID-19 pandemic. Our CT registration actually was first submitted before December 31st, 2021, but it was not approved until February 9th, 2022 due to the extended review time of the website during the pandemic. Despite the CT registration being late, the trial still was conducted according to the original trial plan. (Chinese Clinical Trial Registry, no: ChiCTR2200056615, For real-world research purposes, we relaxed the criteria and did not exclude patients on anticoagulants (Including patients treated with continuous renal replacement therapy and treated with enoxaparin). Patients aged 18 to 80 years who received CVCs infusion during their ICU stay were enrolled. We excluded women during pregnancy, perinatal or lactation, and patients with heparin or sodium citrate allergy or coagulation abnormalities. If patients withdraw their informed consent, are removed from the ICU, die, or have a catheter removed, the study is considered to be discontinued. The first placement of CVCs in each patient was recorded.