Chapter 26 Venous Thromboembolism and Fat Embolism
2 What are some of the risk factors for PE and deep venous thrombosis (DVT)?
Three general conditions that increase the risk of venous thrombosis are called Virchow’s triad: venous stasis, thrombophilia, and injury to the endothelium of vessel walls. Specific risk factors are listed in Box 26-1.
5 What are the signs and symptoms of an acute PE?
The symptoms of an acute PE depend on the thromboembolic burden, the degree of underlying pulmonary parenchymal disease, and the ability of the right ventricle to accommodate acute pressure changes. Patients can present with syncope, shock, tachycardia, acute right ventricular failure, increased dead space, or refractory hypoxemia. However, patients may also be relatively asymptomatic. In patients with underlying cardiac or pulmonary disease, significant hemodynamic compromise may occur with less occlusion of the pulmonary vasculature. Common signs and symptoms of PE are listed in Box 26-2.
9 When should a ventilation-perfusion (V/Q) scan be ordered in the diagnostic work-up of PE?
V/Q scans can be particularly useful:
In patients for whom computed tomography angiography (CTA) is contraindicated (renal failure, radiocontrast allergy, concern for radiation exposure)
When a concern exists for chronic PE
10 What about CTA for the diagnosis of PE?
Evaluation for alternative diagnoses in the chest
Direct visualization of emboli
Evaluation for inferior vena cava and lower extremity thromboses (when computed tomography venography is used in conjunction with CTA)