Utility of portable continuous-wave Doppler examination in screening for postoperative deep vein thrombosis.

BACKGROUND Early and accurate diagnosis of post-surgical deep vein thrombosis (DVT) can be difficult and time-consuming, even with duplex ultrasonography. Portable continuous-wave Doppler ultrasonography may be useful in screening patients for postoperative DVT. Further confirmation of Doppler-positive cases by duplex ultrasound might then be more cost-effective. METHODS All major post-surgical patients from the departments of general surgery, orthopaedic surgery and colorectal surgery were screened on the third postoperative day for DVT by assessing the quality of the flow signal ("whoosh") obtained by placing the probe over the femoral vein and subsequently over the popliteal vein, both with a distal squeeze, as well as assessment of phasic flow with respiration. An absent or attenuated "whoosh" was judged to be suspicious for DVT and required formal duplex ultrasonography. The first 800 consecutive patients were studied to determine the sensitivity, specificity and accuracy of portable Doppler ultrasonography for DVT screening. RESULTS Twenty-four cases of DVT were diagnosed, comprising seven cases in the proximal veins and 17 cases in the calf veins. The sensitivity of Doppler ultrasonography was 12.5% and the specificity was 96.8%. The positive and negative predictive values were 10.7% and 97.3%, respectively. CONCLUSIONS Portable Doppler ultrasonography does not have adequate accuracy to be used as a quick screening tool for DVT.