Patient selection: patient in the Emergency Department with possible pulmonary embolism
A D-dimer is indicated if none of the following are present (these conditions are associated with a moderate pre-test probability):
(1) age >= 70 years of age
(2) duration of symptoms >= 4 days
(3) unexplained hypoxemia (pulse oximetry < 95%)
(4) unilateral leg swelling
(5) surgery within the past 4 weeks
(6) hemoptysis
(7) pregnancy (or postpartum)
If the D-dimer test is positive or if any of the conditions above is present then consider:
(1) CT angiography (default)
(2) combined CT venography and pulmonary angiography (subsegmental pulmonary embolus suspected)
(3) ultrasound of the lower extremities
