What is NOT normal?
Subxiphoid View
A pericardial effusion will first be visible in the posterior part of the pericardium given the patient is laying supine. The fluid will be seen between the myocardium and the liver. As fluid accumulates, the effusion will progress to encompass more of the heart. Effusion will be seen as an anechoic collection surround the heart, as if the heart is beating within a sac of fluid.
FIGURE 10: Pericardial Effusion Subxiphoid View
Parasternal Long View:
A pericardial effusion will be seen between the left atrium and ventricle and the descending aorta.
It will again appear as an anechoic, black, collection on your screen.
FIGURE 11: Pericardial Effusion Parasternal Long View
How to Distinguish Between Pleural Effusion and Pericardial Effusion
Pericardial Effusion
- Crosses the midline
- Separates descending aorta from pericardium
- Beware tamponade physiology
Pleural Effusion
- Accumulates posterolateral to the descending aorta
- Typically, not present in the subxiphoid view given no pleural reflection between the liver & heart
FIGURE 12: Pericardial effusion vs pleural effusion on parasternal long view [8].
Tamponade
Cardiac Tamponade is a clinical diagnosis. Hemodynamic instability within the context of pericardial effusion should be taken seriously and prompt consideration of tamponade. While there are sonographic clues to tamponade these are beyond the scope of this module and will be discussed in a future ”advanced“ module