This month’s excellent save goes to… Dr. Steven Greenstein!
Dr. Greenstein was working during a particularly busy shift in the Critical Care / Trauma area when EMS brought in a patient with a history of prostate cancer and a chief complaint of shortness of breath. Triage vital signs were notable for a borderline BP (106/70) but were otherwise normal. Dr. Greenstein astutely brought over the ultrasound to help guide the diagnosis in a patient with “undifferentiated dyspnea” and immediately found a pericardial effusion with signs of tamponade. Upon recognition of this, he quickly got our cardiologists and cardiothoracic surgeons consulted, and less than 2 hours after arrival, the patient was in the OR for a pericardial window. In the meantime, the patient was stabilized with fluids that normalized the BP, but Dr. Greenstein was also prepared for a bedside pericardiocentesis if the patient started to decompensate. When not acutely diagnosing cardiac tamponade, Dr. Greenstein can be found putting out fires (literally) in Room 26, playing basketball, and hanging out with his adorable daughter. Strong work, Dr. Greenstein!
Just what did Dr. Greenstein see on ultrasound? The classic triad of muffled heart sounds, jugular venous distention and hypotension is not always present in tamponade.
Let’s learn how to distinguish uncomplicated pericardial effusions from tamponade on ultrasound…
1 – Pericardial fluid
There should be anechoic free fluid between the pericardial sac and the heart. This fluid should be seen surrounding the entire heart if it significant enough to cause tamponade. Pericardial fat can mimic hypoechoic fluid, but the fat is isolated to the anterior aspect of the pericardium and there will be brighter speckles within the fat. You may also be tricked by a pleural effusion posteriorly. When pericardial effusions layer out posteriorly, the anechoic fluid will be seen anterior to the aorta (above the aorta on the screen). Don’t be confused by pleural effusions that are also posterior to the heart, but will be posterior to the aorta as well (below the aorta on the screen). [1]
[photo from Goodman A, Perera P, Mailhot T, Mandavia D. “The role of bedside ultrasound in the diagnosis of pericardial effusion and pericardial tamponade.” J Emerg Trauma Shock. 2012; 5(1): 72-75.]
2 – Right ventricle collapse during diastole
The external pressure of the effusion overcomes the diastolic pressure in the RV causing collapse. This can be difficult to assess in a tachycardic patient. One method is to use the M-mode in the parasternal long view to assess them movement of both the mitral valve and the right ventricular wall (much like we do when estimating EF using end-point septal separation). Place the M-mode cursor over the anterior leaflet of the mitral valve and the right ventricular free wall and follow the tracing to see if the RV collapses when the mitral valve is open during diastole. [2]
[photo from Goodman A, Perera P, Mailhot T, Mandavia D. “The role of bedside ultrasound in the diagnosis of pericardial effusion and pericardial tamponade.” J Emerg Trauma Shock. 2012; 5(1): 72-75.]
[photo from Nagdev A, Stone MB. “Point-of-care ultrasound evaluation of pericardial effusions: Does this patient have cardiac tamponade?” Resuscitation. 2011; 82(6): 671-673.]
3 – Plethoric Inferior Vena Cava (IVC)
A plethoric IVC can be an indication of obstructive shock due to tamponade. To assess the IVC, find your cardiac subxiphoid window then angle the probe inferiorly to catch the IVC in short axis view before it enters the right atrium. Then rotate the probe 90 degrees (probe marker facing superiorly) with the probe pointed inferiorly to catch the IVC entering the right atrium in long axis. If the IVC collapses less than 50% with inspiration and is larger than 2cm, it is considered plethoric, correlating to a central venous pressure > 10 cm H2O. [2]
[photo from Goodman A, Perera P, Mailhot T, Mandavia D. “The role of bedside ultrasound in the diagnosis of pericardial effusion and pericardial tamponade.” J Emerg Trauma Shock. 2012; 5(1): 72-75.]
Fun Fact! Size does NOT matter!
The rate of effusion development is more important than its size. Effusions as small as 50 mL may cause tamponade, depending on the timing of the fluid accumulation. When fluid accumulates quickly, there is no time for the pericardial sac to expand, and cardiac filling is then reduced. In chronic effusions, the pericardial sac can stretch to accommodate more fluids without causing hemodynamic compromise.
Once you have identified a pericardial effusion and signs of tamponade, you should be prepared for a emergent pericardiocentesis if your patient is unstable. For more on that procedure, check out this excellent post from our alumni, Dr. Corburn and Dr. Bogoch. For an interesting case of pericarditis-turned-tamponade, check out this post by another alumnus, Dr. DiMare.
References and further reading / watching/ listening:
[1] Nagdev A, Stone MB. “Point-of-care ultrasound evaluation of pericardial effusions: Does this patient have cardiac tamponade?” Resuscitation. 2011; 82(6): 671-673.[2] Goodman A, Perera P, Mailhot T, Mandavia D. “The role of bedside ultrasound in the diagnosis of pericardial effusion and pericardial tamponade.” J Emerg Trauma Shock. 2012; 5(1): 72-75.
[3] “Pericardial Tamponade. Learn this. Know This. FOAMed.”
http://www.ultrasoundpodcast.com/2013/11/pericardial-tamponade-learn-know-foamed/
Kylie Birnbaum
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1 Comment
Dorothy Salmon-Lindsay · August 7, 2017 at 7:39 pm
Strong work Dr. Greenstein, you are an excellent doctor. Most of the nurses in the ED will agree with me.