Date of Award

8-17-2009

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

First Advisor

Mark D. Siegel

Second Advisor

Leora Horwitz

Third Advisor

Lloyd Cantley

Abstract

VENOUS THROMBOEMBOLISM: A CASE-CONTROL STUDY OF PATIENTS IN THE NEUROSCIENCE INTENSIVE CARE UNIT Rachel H. Wolfson, Mark D. Siegel. Section of Pulmonary and Critical Care, Department of Internal Medicine, Yale University, School of Medicine, New Haven, CT. Venous Thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is a significant source of morbidity and mortality in hospitalized patients. However, despite ample research into VTE in hospitalized subpopulations, critically ill patients with primary neurological disorders have been insufficiently studied. We hypothesized that there is a high incidence of VTE in the NICU despite a high thromboprophylaxis rate and that this population would carry a unique set of risk factors. Our goal was to identify those patients at higher risk for VTE who may then be served by more aggressive screening and thromboprophylaxis. We performed a retrospective chart review and case-control study of patients admitted to the NICU of a major urban hospital for three or more days, between 2001 and 2005. The two groups were matched, 2:1 (two controls per case), based on year of hospital discharge and presence of surgical intervention. The incidence of VTE in the NICU was 9.5% (125 of 1,318 patients), despite an overall thromboprophylaxis rate of 97.6%. 55% of DVTs were in the upper and 45% in the lower extremity. 48 PE patients had PE. Univariate analysis utilizing p<0.05 as a statistical threshold revealed 12 factors associated with VTE. These factors were entered into a multivariable analysis logistic regression, which yielded 5 factors that remained independently with VTE: higher rates were associated with use of a central-venous catheter (OR:2.5, CI: 1.4 4.6, p=0.003), arteriovenous malformation (OR:4.9, CI: 1.2 20.1, p=0.026), prior VTE (OR:5.6, 1.4 22.4, p=0.014), and mechanical ventilation (OR:2.1, CI: 1.1 4.2, p=0.036). VTE prophylaxis was protective (OR:0.8, CI: 0.0 0.9, p=0.043). In conclusion, VTE remains common among NICU patients despite a high rate of prophylaxis. Several factors appear to be associated with VTE in this population. Future studies are needed to validate the association between these factors and VTE and to determine if more aggressive surveillance and prophylaxis can decrease the frequency and complications associated with VTE.

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