Welcome to the inaugural post for an exciting new ultrasound-based case series called “Ultrasound For The Win!” (#US4TW). In this peer-reviewed case series, we will focus on real clinical cases where bedside ultrasound changed the management or aided in the diagnosis. In our first case, we present a 28-year-old female with shortness of breath.
A 28-year-old female with active cancer on chemotherapy presents to the ED with 1-week of progressively worsening shortness of breath. On examination, the patient appears distressed, tachypneic, and requires 15L O2 via non-rebreather to maintain a normal oxygen saturation.
- BP 102/69 mmHg
- P 142 bpm
- RR 22 respirations/min
- O2 100% saturation on non-rebreather mask
- T 36.9
- Congestive heart failure
- Pericardial effusion
- Pleural effusion
- Pulmonary embolism (PE)
Immediately evident on bedside echocardiogram are distinct ultrasonographic findings that are highly suggestive of pulmonary embolism:
- An intra-ventricular thrombus within a dilated right ventricle (blue arrow), with an RV to LV size ratio greater than 1:1 indicative of right heart strain. Visualization of a clot is a rare (estimated to be present in only 4-18% of acute PE1) but specific echocardiographic finding.
- Right ventricular hypokinesis with apical sparing (McConnell Sign).
In this clinical context, the bedside echo findings are highly suggestive of an acute PE.
Ultrasound Image Quality Assurance
An important aspect of ultrasonography is appropriate and optimal image acquisition. The ultrasound clip shows an apical view of the heart with appropriate depth and gain. While the providers were not able to obtain an apical 4-chamber view, the right and left ventricles are clearly demonstrated, and the clip is of sufficient quality to provide valuable diagnostic information. Patients with acute respiratory distress can be challenging to image due to tachypnea and the inability to turn to a left lateral decubitus position.
Of note, the probe indicator-to-screen orientation is oriented to the patient’s right, which is the reverse of the cardiology convention.2 Whether you use the ED or cardiology convention, it is important to know how you are oriented so that you are properly identifying the right and left sides of the heart especially when trying to identify pathology such as right heart strain. In this case, the right side of the heart is on the left side of the screen. If the probe is reversed, one can misinterpret a normal LV as being a RV.
The clip could be improved by attempting to better visualize both atria so that all four chambers are in view. In addition, the interventricular septum should be ideally oriented vertically down the screen rather than on an angle as in the clip. Sliding the transducer laterally so that the septum is centered on the screen, and angling the beam back towards the inferior tip of the right scapula will result in a more vertical orientation to the interventricular septum.
Disposition and Case Conclusion
A CT angiogram of the chest was obtained which revealed a massive PE extending from the right ventricle causing near-total occlusion of bilateral pulmonary arteries extending to all segmental pulmonary arteries.
Heparin was started in the ED, and the patient was admitted to the medical ICU. The patient continued to decompensate during her admission, and tPA was administered with subsequent clinical improvement.
The patient was discharged home after a full recovery with normal oxygen saturations on enoxaparin.
Take Home Points
- Bedside echocardiogram, in correlation with the appropriate clinical picture, can be a beneficial diagnostic tool in the unstable patient with suspicion for acute PE.
- Echocardiographic features of PE can be classified into direct (high specificity, low sensitivity) and indirect (low specificity, moderate sensitivity) findings3:
|Echocardiographic Findings in Acute PE|
|Direct||Right heart thrombus
DVT on lower extremity US
|PA = pulmonary artery; DVT = deep vein thrombosis; US = ultrasound|
- McConnell sign, which is RV hypokinesis with apical sparing, in its original description was found to be 77% sensitive and 94% specific for diagnosing PE.4 However, more recent literature has shown that McConnell sign is non-specific, found in 2/3 of patients with RV infarction,5 and should not be used in isolation for the diagnosis of PE, nor for the decision to adminster thrombolytics.
- Be aware of the differences between the ED and cardiology echo conventions to avoid confusion and potential misinterpretation of findings.
Special thanks to Dr. Chris Moore for permission to use the included ultrasound clips and images!
*Note: All identifying information and certain aspects of the case have been changed to maintain patient confidentiality and protected health information (PHI).