Lower extremity DVT is common among critically ill patients. The clinical consequences of DVT can be serious and are often unrecognized. A rapid and accurate diagnosis is needed although delays in obtaining studies are encountered. We assessed the accuracy and timeliness of compression ultrasound studies (CUS) performed by critical care physicians in the ICU by comparing results with the radiology department study.
Study participants were recruited from a pool of critical care fellows and attendings at the New York City (NYC) Fellows Ultrasound Course in 2007 and 2008. Fellow training consisted of a one hour didactic lecture on CUS followed by two hours of hands-on experience using live models. Attending experience varied from 1–20 years. CUS protocol consisted of three compressions along the common femoral vein (CFV), 2 compressions along the popliteal vein (PV), followed by sequential compressions along the superficial femoral vein if the CFV and PV were negative. A CUS was done on any ICU patient suspected of having DVT. A confirmatory study was simultaneously ordered through the department of radiology. Sensitivity and specificity were calculated using the radiology department study findings as the “gold standard”. Time delays between the respective studies were calculated.
A total of 11 critical care physicians agreed to participate from three university affiliated urban hospitals. A CUS of the lower extremity was performed on a total of 57 patients. Prevalence of DVT was 17%. Study member findings included 1 false positive and 2 false negatives yielding a sensitivity of 83% and a specificity of 98% with a diagnostic accuracy of 95%. Time delay between ICU physician CUS and the radiology department study averaged 42 hours.
Critical care clinicians can achieve high accuracy in diagnosing lower extremity DVT in the ICU. Clinician performed CUS can be obtained more rapidly than traditional radiology department studies.
The use of bedside US in the diagnosis of DVT can lead to earlier recognition and treatment if performed by critical care clinicians.
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