- On his first ED visit he was assessed for shortness of breath. He was having no chest pain and vitals were within normal limits. The following investigations were normal: CXR, CBC, electrolytes, BUN, Creatinine, CK and TnI. The patient was discharged home pending the outpatient stress ECHO and told to return if symptoms worsened.
- On the second ED visit 6 days later, the patient complained of worsening SOBOE, no chest pain, no PND, no orthopnea, no fever or cough, no leg pain or edema. There were no known PE risk factors. He is a non-smoker, drinks ETOH occasionally.
A point-of-care ultrasound scan was done to help narrow the differential.
Below are three cardiac views. Think of what you would be looking for given the clinical scenario.
In each of these images it appears the vein fully collapses with compression. We can conclude that there is likely no DVT present within the limitations of the 2-point compression scan (see discussion for further details)
If we incorporate our Wells score for PE and our scan as above we can generate a diagnostic algorithm:
1. Your clinical gestalt must supercede your PoCUS result. If your scan is suboptimal then call it indeterminate and proceed to a definitive investigation such as the CTPE study in this case.
2. 2-Zone Lower extremity DVT PoCUS can be very helpful when it is positive for DVT. However one should not rely on a negative PoCUS DVT scan to definitively rule out a DVT. Additional investigations such as the d-dimer and radiology performed Doppler US should be performed if there is a reasonable clinical suspicion for thromboembolism.
Case by Dr. Rebecca Brown, PGY3, CCFP-EM, University of Ottawa.