Clinical Research| Volume 24, ISSUE 3, P388-392, April 2010

The Impact of a Systemwide Policy for Emergent Off-Hours Venous Duplex Ultrasound Studies

Published:September 11, 2009DOI:


      We evaluated the impact of an after-hours policy regulating venous duplex ultrasound (VDU) for deep vein thrombosis (DVT) diagnosis on resource utilization and patient care.


      On July 1, 2007, we altered the approach to emergent VDU of patients with potential DVT during off-hours (defined as 5:00 p.m. to 7:00 a.m. weekdays, after 3:30 p.m. Saturdays and Sundays). Instead of 24 hr access, we permitted a venous duplex study in the noninvasive vascular laboratory (NIVL) only after meeting set criteria developed collaboratively across services. In the emergency department (ED), we based all VDU requests on a preset modified Wells score (MWS) as determined by the ED physician. Those patients with MWS 0 or 1 and those above 1 who could receive empiric single-dose low–molecular weight heparin (LMWH) received next-morning imaging unless consultation with a vascular surgeon created an emergent imaging plan. In parallel, inpatient emergent VDU was permitted only after contact with an attending vascular surgeon and where empiric short-term anticoagulation could not occur safely. We tracked NIVL utilization, patient morbidity, sonographer retention, and satisfaction.


      The number of overall off-hours emergent VDUs decreased from 59 to 19/month after implementation. Testing was deferred in 52 ED patients: 15 stayed in the ED for testing in the morning and 37 were discharged to be tested the following day. Thirty-one of 37 patients returned for testing as outpatient follow-up. Twenty-eight received ED LMWH while awaiting testing. No adverse events were noted with the delay. The mean MWS for ED after-hours studies was 2.9±1.6 and that for deferred ER studies was 2.4±1.3 (p=0.005). Incidentally, overall off-hours inpatient and ED VDU requests decreased 64% with no clinical adverse events in the first year. The rate of overall positive studies done off-hours increased from 6.7% to 20% (p<0.0001). Sonographer satisfaction was maintained with regulation of call.


      Our collaborative approach allowed off-hour VDU utilization to decrease without any measurable negative care impact.
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