Document Type : Research Article
Purpose: To identify the presence of occult (DVT) in post op patients on DVT prophylaxis and to avoid unnecessary screening, we reviewed our experience with routine duplex screening for DVT in high risk post-operative patients on DVT prophylaxis.
Methods: Over a 2 year period, all patients who were admitted 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 7.3% prevalence of major DVT in the 100 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 60 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 (3%). Screening of post op 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.