Subxiphoid Cardiac Exam

Clinical question	Does my patient have a pericardial effusion (or are they in tamponade)?
Patient positioning	Supine with knees bent if patient can tolerate
Supplies needed	No special supplies required
Probe	Phased array (cardiac probe)
Normal findings	No or trace pericardial effusion
Sensitivity & specificity	A study of 515 patients showed a sensitivity of 95% and specificity of 98%
Contraindications	No real contraindication to subxiphoid ultrasound, but there are contraindications to pericardiocentesis (insertion of a needle to drain a pericardial effusion or tamponade).
Alternate diagnostic modalities	CXR (not sensitive for acute effusions), Cardiac CT (not suitable for hemodynamically unstable patients), Cardiac MRI (slow)

*Note: if your patient is in tamponade, there are classic physical exam findings (Beck’s Triad) that may indicate this, in which case, ultrasound will become a therapeutic tool for pericardiocentesis, rather than diagnosis.

How to perform this exam

1. Prepare your supplies:

Obtain an ultrasound machine with a cardiac probe, ultrasound gel, and a chuck or towel.

2. Explain the purpose of the exam (if patient is conscious)

Position your patient for comfort
Supine with knees bent (can place a pillow under the knees) and elevate the head for patient comfort

3. Apply copious ultrasound gel to the probe.

4. Select the abdominal view

We are using the liver as an acoustic window to avoid bowel gas.

5. Obtain a subxiphoid cardiac view

Begin scanning through the liver with the probe in a coronal orientation on the right side of the abdomen - increase your depth and/or ask the patient to inhale to better visualize the heart. Aim the probe toward the left shoulder (about 15–30° angle upward) and apply steady pressure to displace any bowel gas - this may cause some discomfort as you are pressing up on the diaphragm.
Visualize cardiac anatomy by obtaining a four-chamber view: RA, RV (closest to probe), LA, LV. Identify the pericardium as a bright echogenic line around the heart.
Evaluate for Pericardial Effusion. Look for an anechoic (black) space between the heart and pericardium. Effusion typically starts posterior to the heart behind the left ventricle. A circumferential effusion suggests a larger collection.

6. Evaluate for tamponade physiology

Check for Right atrial collapse in late diastole/early systole, which is the earliest sign of tamponade.
Right ventricular collapse in early diastole which is most easily assessed in parasternal long-axis view with M-mode overlying the mitral valve.
Dilated IVC with poor respiratory variation (suggests high right-sided pressure).
Swinging heart in a large effusion = classic tamponade finding.