Clinically important deep vein thrombosis in the intensive care unit: a survey of intensivists

INTRODUCTION Outside the intensive care unit (ICU), clinically important deep vein thrombosis (DVT) is usually defined as a symptomatic event that leads to objective radiologic confirmation and subsequent treatment. The objective of the present survey is to identify the patient factors and radiologic features of lower limb DVT that intensivists consider more or less likely to make a DVT clinically important in ICU patients. METHODS Our definition of clinically important DVT was a DVT likely to result in short-term or long-term morbidity or mortality if left untreated, as opposed to a DVT that is unlikely to have important consequences. We asked respondents to indicate the likelihood that patient factors and ultrasonographic features make a DVT clinically important using a five-point scale (from 1 = much less likely to 5 = much more likely). RESULTS Of the 71 Canadian intensivists who responded, 70 (99%) rated three patient factors as most likely to make a DVT clinically important: clinical suspicion of pulmonary embolism (mean score 4.6), acute or chronic cardiopulmonary morbidity that might limit a patient's ability to tolerate pulmonary embolism (score 4.5), and leg symptoms (score 4.2). Of the ultrasound features, proximal (score 4.7), large (score 4.2), and totally occlusive (score 3.9) thrombi were considered the three most important. CONCLUSION When labeling a DVT as clinically important, intensivists rely on different patient specific factors and thrombus characteristics than are used to assess the clinical importance of DVT outside the ICU. The clinical importance of DVT is influenced by unique factors such as cardiopulmonary reserve among mechanically ventilated patients.