Standard subcutaneous dosing of unfractionated heparin for venous thromboembolism prophylaxis in surgical ICU patients leads to subtherapeutic factor Xa inhibition.

Purpose: To assess coagulation status and factor Xa inhibition in surgical intensive care unit (ICU) patients administered prophylactic unfractionated heparin for venous thromboembolism (VTE) prophylaxis.

Methods: We conducted a randomized, single-blind study at a tertiary academic medical center. Included were patients 18 years and older admitted to the surgical ICU directly after major abdominal surgery.