1443. Utility of Twice-Weekly Deep Vein Thrombosis Screening in Detecting Pulmonary Embolus Among Neurosurgical Patients

Authors: Nikki M. Barrington; Mandana Behbahani, MD; David Rosenberg, BS; Nauman Chaudhry, MD; Ankit Mehta, MD (Waukegan, IL)

Introduction: Neurosurgical patients are a complex population wrought with risk factors for venous thromboembolism (VTE), including both deep vein thrombosis (DVT) and pulmonary embolus (PE). These patients are at higher risk of VTE due to long duration of both surgical intervention, postoperative immobility, and prolonged need for mechanical ventilation and sedation. Previous studies have suggested that twice-weekly DVT surveillance with bilateral lower extremity venous duplex ultrasound (VDUS) has increased rates of DVT detection and reduced the rate of PE occurrence. Here we sought to characterize the utility of twice-weekly VDUS in screening for and detecting PE in neurosurgical patients. Methods: Medical records of patients admitted to the neurological surgery service at the University of Illinois hospital from 2014-2017 were reviewed. Patients were categorized based on DVT/PE status, and characterized in terms of demographics, comorbidity, and adverse events. Results: A total of 3000 patients were identified which met inclusion criteria. Of these patients, 85 had a positive DVT screening and 11 of these patients ultimately developed a PE. Nineteen patients who were not identified as having a DVT developed a PE. The sensitivity and specificity of DVT screening at predicting PE occurrence was 36.7% and 97.5% respectively. The positive predictive value was 12.9%; the negative predictive value was 99.3%. The number needed to treat was 8.1. In comparing screened patients with and without pulmonary embolus, a comorbid diagnosis of hypertension was associated with lower rates of PE (p = 0.008627). Conclusion: These results suggest that the sensitivity and positive predictive value of a positive DVT screening in predicting PE are low among neurosurgical patients. This population warrants further study to determine whether alternate PE detection methods such as CT PE rather than twice-weekly DVT screening would result in reduced neurosurgical morbidity and mortality.