Prolonged Bed Rest: An Indication for Venous Duplex Scanning?

Fred W. Rushton, MD, Steven D. Taylor, MD, and  Marc E. Mitchell, MD
University of Mississippi, Jackson, MS

Objective(s):
Prolonged bed rest has been considered to be a significant risk factor for the development of lower extremity deep venous thrombosis (DVT). Venous duplex ultrasound of the lower extremities is the standard means of non-invasively confirming the presence or absence of DVT. This study was undertaken to determine the incidence of lower extremity DVT, as determined by venous duplex ultrasound, in neurosurgery patients requiring prolonged bed rest.
Methods:
A retrospective review of 753 bilateral venous duplex ultrasound examinations of the lower extremities performed on neurosurgery patients admitted to the University of Mississippi Medical Center between January 1 and December 31, 2004 was conducted. The majority of patients were hospitalized because of neurologic injury. Prolonged best was the sole indication for 433 of the studies. Indications for the remaining 320 studies included: shortness of breath, lower extremity swelling or pain, fever of unknown origin, or follow-up of a previously positive duplex scan. Studies performed on patients with lower extremity trauma were excluded from the study.
Results:
Of the 433 bilateral lower extremity duplex scans performed because of prolonged bed rest, no significant iliac vein, common femoral vein, superficial femoral vein, deep femoral vein or popliteal vein thromboses were discovered. One non-occlusive superficial femoral vein thrombosis (0.1% of studies) was identified. A subsequent study performed four days later failed to demonstrate the thrombosis. Three non-significant thromboses involving the calf veins, one peroneal vein and two posterior tibial veins, (0.9%) were detected. In 320 studies done because of shortness of breath, lower extremity pain or swelling, fever of unknown origin, or follow-up of a previously positive duplex scan, 45 (14.1%) demonstrated the presence of significant DVT and 22 (6.9%) had thromboses involving the calf veins.
Conclusions:
The incidence of DVT in asymptomatic neurosurgical patients on bed rest is extremely low. Prolonged bed rest without associated symptoms of DVT or pulmonary embolus is not an indication for routine lower extremity venous duplex scanning.