Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2022, 166(2):204-210 | DOI: 10.5507/bp.2021.031

Fixed-dose enoxaparin provides efficient DVT prophylaxis in mixed ICU patients despite low anti-Xa levels: A prospective observational cohort study

Jan Benes^{a, b}, Roman Skulec^{a, b, c, d, h}, Jakub Jobanek^b, Vladimir Cerny^{b, c, e, f, g}

^a Faculty of Medicine in Hradec Kralove, Charles University in Prague and University Hospital Hradec Kralove, Czech Republic

^b Deartment of Anesthesiology, Perioperative Medicine and Intensive Care Masaryk Hospital, J.E. Purkinje University, Usti nad Labem, Czech Republic

^c Faculty of Health Studies, J.E. Purkinje University, Usti nad Labem, Czech Republic

^d Department of Anesthesiology and Intensive Care, Faculty of Medicine in Hradec Kralove, Charles University in Prague and University Hospital Hradec Kralove, Czech Republic

^e Center for Research and Development, Department of Anesthesiology and Intensive Care, Faculty of Medicine in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic

^f Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, Canada

^g Constantine the Philosopher University in Nitra, Faculty of Social Sciences and Health Care, Slovak Republic

^h Emergency Medical Service of the Central Bohemian Region, Czech Republic

Background: Deep vein thrombosis (DVT) is a serious but preventable complication of critical illness with a reported incidence from 4 to 17%. Anti-Xa activity in critically ill patients achieved with standard dosing of low-molecular-weight heparins (LMWH) is often below the target of 0.2-0.5 IU/mL. However, the clinical significance of this finding is unclear. The quality of thromboprophylaxis also strongly impacts the incidence of DVT. We performed a prospective observational study to evaluate the incidence of DVT in a mixed medical-surgical-trauma intensive care unit (ICU) using a thromboprophylaxis protocol with a fixed dose of enoxaparin. We also explored the relation between DVT incidence and anti-Xa activity.

Method: All consecutive patients with expected ICU stay ≥72 hours and without evidence of DVT upon admission were included. They underwent ultrasound screening for DVT twice a week until ICU discharge, death, DVT or pulmonary embolism. Peak anti-Xa activity was measured twice a week. Patients received 40 mg of enoxaparin subcutaneously (60 mg in obese, 20 mg in case of renal failure). Graduated compression stockings were used in case of LMWH or another anticoagulant contraindication.

Results: A total of 219 patients were enrolled. We observed six cases of DVT (incidence of 2.7%). The agreement between expected and delivered DVT prophylaxis was 94%. Mean peak anti-Xa activity level was 0.24 (SD, 0.13) IU/mL. There was no significant difference in anti-Xa activity in DVT and non-DVT group.

Conclusion: A low incidence of DVT was achieved with meticulous adherence to the standard prophylactic protocol. The low incidence of DVT was observed despite low levels of anti-Xa activity. Our findings suggest that enoxaparin dose adjustment based on regular monitoring of anti-Xa activity is unlikely to result in further reduction of DVT incidence in a mixed ICU population. Trial registration: ClinicalTrials.gov, NCT03286985.

Keywords: venous thrombosis, thromboprophylaxis intensive care units, anti-Xa, enoxaparin, pulmonary embolism, compression ultrasound test

Received: October 19, 2020; Revised: May 4, 2021; Accepted: May 7, 2021; Prepublished online: May 27, 2021; Published: May 13, 2022  Show citation