Use of Bedside Ultrasound in Emergency Department Patients With Concern for Pulmonary Embolism to Reduce CT Imaging

At most institutions, the average patient with clinical concern for PE(pulmonary embolism) will have a CT angiogram(CTA) with contrast of the lungs performed to evaluate for a clot. However, CTA has risks including contrast- induced allergic reactions and nephropathy, as well as radiation which has been linked to development of cancer later in life. There is literature that has looked at using lower extremity doppler ultrasound first to evaluate for a DVT (deep venous thrombosis) in patients where there is concern for a PE. There is also literature showing that emergency medicine physicians can perform adequate lower extremity compression ultrasounds (LCUS), at the bedside with results similar to that of the ultrasound tech. The goal of this project is to fuse both principles by having emergency medicine physicians perform LCUS at the bedside, to help reduce CTA utilization in the evaluation of PE.

In this study, the subgroup of hemodynamically stable patients felt to be at moderate to high risk for PE will receive a bilateral LCUS before possible CTA/VQ imaging. The LCUS of the entire proximal leg including the popliteal fossa will be performed by an emergency medicine resident provider in conjunction with their attending. All positive studies will then be confirmed with a second ultrasound by the Albany Medical Center's vascular laboratory service. Patients with confirmed acute positive studies identifying a DVT will be treated for a presumed PE, which is the same treatment as that for the DVT. No CTA will be ordered from the ED. They will be anticoagulated and admitted to the hospital, with further management as per the inpatient hospital team. Patients with a negative emergency department LCUS done by the resident will receive either a CTA or a VQ (ventilation/perfusion) scan as per the initial treatment plan established by the attending physician.

According to this protocol, patients discharged home by default must have had a negative CTA or VQ scan, and so PE was effectively ruled out. Therefore they will not require further follow up after discharge. However, we will follow patients who were admitted throughout their admission course. Through review of medical records, we will take note of any complications such as any issues with starting anticoagulation treatment without a CTA, misdiagnoses, whether a CTA was ordered later as a part of their course and why, and further details.

Eligibility Criteria:
Inclusion Criteria:

* Clinical Concern for PE (moderate to high risk) that warrants imaging of the chest

Exclusion Criteria:

* Age less than 18
* nidus for DVT in upper extremity (eg. PICC (peripherally inserted central Cather) line, etc)
* already anti-coagulated at presentation
* above the knee- leg cast
* prisoners
* DVT ultrasound or CTA prior to presentation
* Hemodynamically unstable:
* SBP (systolic blood pressure) \<90 for \>15min
* Drop of SBP by at least 40mmHG for \>15mins
* Organ hypoperfusion (eg cold extremities, mental confusion, low urine outpt \<30cc/hr, etc
* need for pressors
* Other concerns in thorax necessitating inevitable CT chest imaging.