Made a radiologist go red with rage recently? If not, you could try showing them this paper1 in this month’s Annals of Emergency Medicine that describes accurate emergency physician ultrasound diagnosis of deep vein thrombosis after just ten minutes training!
ED patients with a suspected lower extremity deep venous thrombosis were assessed using a bedside 2-point compression technique by emergency physicians using a portable US machine and all patients subsequently underwent duplex ultrasonography performed by the Department of Radiology.
The emergency physicians had a 10-minute training session before enrolling patients
The techinque involved 2 specific points: the common femoral and popliteal vessels, with subsequent compression of the common femoral and popliteal veins. The study result was considered positive for proximal lower extremity deep venous thrombosis if either vein was incompressible or a thrombus was visualised.
A total of 47 physicians performed 199 2-point compression ultrasonographic examinations in the ED.
There were 45 proximal lower extremity deep venous thromboses observed on Department of Radiology evaluation, all correctly identified by ED 2-point compression ultrasonography. The 153 patients without proximal lower extremity deep venous thrombosis all had a negative ED compression ultrasonographic result. One patient with a negative Department of Radiology ultrasonographic result was found to have decreased compression of the popliteal vein on ED compression ultrasonography, giving a single false-positive result, yet repeated ultrasonography by the Department of Radiology 1 week later showed a popliteal deep venous thrombosis. The sensitivity and specificity of ED 2-point compression ultrasonography for deep venous thrombosis were 100% (95% confidence interval 92% to 100%) and 99% (95% confidence interval 96% to 100%), respectively.
These figures may appear to fail the ‘sniff test’, ie. seem too good to be true. Not surprisingly Annals acknowledge this by providing an accompanying editorial2 by emergency ultrasound heavyweight Michael Blaivas, MD, who is healthily skeptical of such a minimal training program but is overwhelmingly supportive of the principle. Dr Blaivas also provides a fantastic summary of the existing evidence base on ED ultrasound for DVT. To me he hits the nail on the head when with a philosophical point on the practice of EM: ‘One common challenge proponents of any new application or procedure face in emergency medicine is overcoming the inertia of comfort with the status quo.’ Spot on, Dr B.
1. Compression Ultrasonography of the Lower Extremity With Portable Vascular Ultrasonography Can Accurately Detect Deep Venous Thrombosis in the Emergency Department
Annals of Emergency Medicine 2010;56(6):601-10
2. Point-of-Care Ultrasonographic Deep Venous Thrombosis Evaluation After Just Ten Minutes’ Training: Is This Offer Too Good to Be True?
Annals of Emergency Medicine 2010;56(6):611-3
The guys at ‘EM Live’ have a short video on how to do DVT ultrasound:
