Circadian Variation of Anti-Factor Xa in Hospitalized Trauma Patients

Inclusion Criteria: * Inpatient admission for acute traumatic injury ≥72 hours * Prescribed LMWH subcutaneous for VTE chemoprophylaxis Exclusion Criteria: * Pregnancy * Brain hemorrhage or non-survivable injury * Chronic Kidney disease ≥ 3b estimated Glomerular Filtration Rate (eGFR) less than 30 interferes with coagulation * Chronic liver failure •-Acute stimulant use of cocaine and methamphetamine * Active VTE or ongoing anticoagulation at admission * History of coagulopathy or inherited bleeding disorders * Chronic alcohol as defined as a documented diagnosis of alcohol use disorder or alcohol consumption exceeding established risk thresholds (men \>14 drinks/week; women \>7 drinks/week) within the prior 3-6 months * Unmanaged psychiatric conditions as defined as diagnosed psychiatric disorder with evidence of inadequate or no active treatment or documented poor symptom control * Neurologic injury involving hypothalamic or circadian regulatory centers