Screening for asymptomatic deep vein thrombosis in surgical intensive care patients

Purpose: To identify the presence of occult deep vein thrombosis (DVT) in surgical intensive care unit (SICU) patients and to avoid unnecessary screening, we reviewed our experience with routine duplex screening for DVT in SICU patients. Methods: Over a 24-month period, all patients who were admitted to an SICU with an anticipated length of stay greater than 36 hours were studied to determine the prevalence of risk factors for asymptomatic proximal DVT. Risk factors, demographics, and operative data were collected and analyzed with multilinear regression, t tests and χ² analysis. Results: There was a 7.5% prevalence of major DVT in the 294 patients studied. APACHE II scores (14.5 ± 6.24 vs 10.3 ± 3.15; p < 0.0001) and emergent procedures (45.5% vs 23.2%; p > 0.0344) were associated with DVT by multifactorial analysis. Age was significant by univariate analysis. An algorithm based on the presence of any one of the three risk factors identified (APACHE II score 12 or more; emergent procedures; or age 65 or greater) could be used to limit screening by 30% while achieving a 95.5% sensitivity for identification of proximal DVT. Conclusion: Absence of all three risk factors indicates a very low risk for DVT (1.1%). Screening of SICU patients is indicated because of a high prevalence of asymptomatic disease. Patients who have proximal DVT require active therapy and not prophylaxis. Costs and resources may be contained by using the above risk factors as a filter for duplex screening.