Anesthesiology APPLIED Exam › OSCE: echocardiography and POCUS

Pericardial effusion and tamponade

OSCE: echocardiography and POCUS·~5 min read· Physician-reviewed✓ Sourced · 3

Stem

Monitors and echo station. A 58-year-old woman, 64 kg, with metastatic lung cancer is short of breath and scheduled for a pericardial window. Blood pressure is 88/62, heart rate 116. The loop is a subcostal four-chamber view: a black, circumferential space about 2.4 cm deep surrounds the heart, the right atrial wall folds inward from late diastole well into systole, and the RV free wall indents in early diastole. The IVC is 2.5 cm and barely changes with breathing.

Question

Describe what you see. Does she have tamponade?

Ideal answer

HeadlineA large circumferential pericardial effusion with right atrial and right ventricular collapse and a plethoric IVC; with her hypotension and tachycardia, this is tamponade. I drain it.

Find the fluid and size it: subcostal four-chamber, an anechoic space between the heart and the bright pericardium, measured at end-diastole.
Then its consequences: RA collapse from end-diastole for more than a third of the cycle, RV diastolic collapse, IVC over 2.1 cm with less than 50% collapse;¹ I also look for a septum swinging with breathing.
Keep her full, fast and constricted, because a fixed stroke volume leaves her output on rate and tone; avoiding sudden positive-pressure breaths, which cut venous return.
Ultrasound-guided pericardiocentesis, or surgical drainage under local with spontaneous ventilation.²
General only with the surgeon scrubbed, because lost sympathetic tone and venous return at induction can arrest her.

Breaking down the answer

Pericardial versus pleural — in the parasternal long-axis, pericardial fluid lies anterior to the descending aorta, between it and the left atrium; pleural fluid lies posterior. The wrong call sends a needle into the wrong space.¹
Fluid versus fat — epicardial fat sits mostly anteriorly over the RV, is often brighter than myocardium rather than black, and moves with the heart.¹ A true effusion is dependent first, posterior in a supine patient, and anechoic.
Size is not severity — echo supports a physiological diagnosis the patient makes. A 1 cm effusion accumulating in minutes after a line perforation causes tamponade; a 3 cm chronic effusion stretches the pericardium and can be tolerated.
RA collapse is the most sensitive sign — atrial pressure is lowest in late diastole and early systole. A brief inversion occurs without tamponade; longer than a third of the cycle is nearly 100% sensitive and specific.¹
RV diastolic collapse: less sensitive, more specific — first only in inspiration, then throughout the cycle; may be absent with prior high RV pressure (pulmonary hypertension, RV hypertrophy).¹
The IVC — plethoric in more than 90% of tamponade, but not specific; a small collapsing IVC makes it unlikely, except low-pressure tamponade from hypovolemia, where chamber collapse is the key sign.¹
After cardiac surgery — loculated clot can compress a single chamber, often an atrium behind the heart; transthoracic windows miss it, so I ask for TEE and look specifically behind the atria.¹

Follow-up question

The next loop is a subcostal view in a different patient who became hypotensive after a central line was placed. It shows a circumferential effusion with right atrial and right ventricular collapse. The facilitator asks: if she needs general anesthesia for drainage, how will you give it?

Follow-up answer

HeadlineTamponade from perforation. I tell the team drainage is the treatment and induction is the most dangerous moment.

Fluid for preload, heart rate maintained, norepinephrine or epinephrine for pressure; I prefer pericardiocentesis under local with her sitting up. If general is necessary: surgeon prepped and draped first, ketamine or etomidate, spontaneous ventilation or small tidal volumes with no PEEP until the pericardium is open, because positive pressure cuts venous return to an underfilled heart.² After drainage the chambers re-expand, and I watch for re-accumulation, rebound hypertension, bleeding and decompression pulmonary edema.²

Pitfalls that cost points

Calling tamponade on effusion size without chamber collapse or hypotension.
Calling a left pleural effusion pericardial.
Trusting a normal transthoracic study after cardiac surgery.
Offering mitral inflow Doppler variation when the station does not show Doppler; I describe the 2D signs.³

Rapid-fire

Q: Why does the right atrium collapse first? A: It has the thinnest wall and the lowest pressure, so it is the first chamber whose transmural pressure becomes negative.

Q: Why is positive-pressure ventilation dangerous? A: It raises intrathoracic pressure, cuts venous return and removes the inspiratory filling the right heart depends on.

Q: Why does a rapid small effusion cause tamponade? A: The pericardium is stiff over minutes; it stretches only over weeks, so the pressure-volume curve is steep for acute fluid.

Q: Why is the IVC plethoric? A: Right atrial pressure equals pericardial pressure, which is high, so venous return backs up into the cava.

Numbers to know

Item	Value
Small effusion	<1 cm at end-diastole¹
Moderate effusion	1–2 cm
Large effusion	>2 cm
RA collapse, specific	>1/3 of the cardiac cycle¹
Plethoric IVC	>2.1 cm, <50% collapse¹
Pulsus paradoxus	>10 mmHg systolic fall¹

Sources

1.Clinical Recommendations for Multimodality Cardiovascular Imaging of Patients with Pericardial Disease · ASE, 2013 · asecho.orgEffusion sizing, descending-aorta sign, RA collapse >1/3 cycle, IVC plethora.
2.Cardiac tamponade: Anesth management · OpenAnesthesia · openanesthesia.org
3.APPLIED Exam Objective Structured Clinical Examination (OSCE) Content Outline · ABA · theaba.org

Facts on this page were checked against these sources on Oct 14, 2026. Guidelines change; confirm doses against current institutional protocols.