Resident-Performed evaluation for deep venous thrombosis reduces time to diagnoses “After-Hours”

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Study objectives: The vascular laboratory may not be available 24 hours a day to evaluate patients with suspected lower extremity deep venous thrombosis (DVT). We assess the impact of resident-performed compression ultrasonography on the time to diagnosis for patients treated “after hours” with suspected DVT. Methods: This was a prospective study of patients treated after hours with suspected DVT during a 6-month period in an urban, academic emergency department (ED). Patients were enrolled only when a study physician was available in the ED. Informed consent and compression ultrasonography without color Doppler were done by 1 of 8 participating resident sonographers not responsible for the care of the patient. Treating clinicians were blinded to the results of this examination and determined treatment course with private physicians when available. Results: Forty-eight patients were enrolled with suspected DVT and underwent resident-performed compression ultrasonography for DVT before evaluation by the vascular laboratory. There were 23 true positives, 1 equivocal examination considered a “false positive” for the sake of analysis, 24 true negatives, and no false negatives, corresponding to a sensitivity of 100% (95% confidence interval [CI] 82% to 100%) and specificity of 96% (95% CI 78% to 100%) for lower extremity DVT. Eleven patients were admitted, presumptively anticoagulated, and had inpatient evaluation by the vascular laboratory an average of 23 hours (95% CI 14.2 to 32) after compression ultrasonography in the ED. Thirty-seven patients were held overnight in the ED and underwent vascular laboratory evaluation an average of 7.7 hours (95% CI 5.3 to 10.2) after compression ultrasonography in the ED. Discussion: Our only equivocal examination occurred in a patient with tender lymphadenopathy caused by unilateral cellulitis, preventing the resident from performing adequate compression pressure for an adequate examination. Conclusion: Resident-performed compression ultrasonography for DVT was accurate and associated with a decrease in time to diagnosis for patients treated after hours.