Patient is ~90 year old male with a history of atrial fibrillation and severe aortic stenosis who presented to the hospital for an elective right and left heart catheterization. The patient’s procedure was complicated by significant difficulty crossing his aortic valve, however he remained hemodynamically stable throughout the procedure. After being brought to the recovery area post-operatively, the patient became suddenly hypotensive and bradycardic followed by a short period of asystole for which CPR was briefly performed before return of spontaneous circulation (ROSC). The patient was thereafter transferred to the emergency department as no ICU bed was available.
When this patient arrives to the ED, where should we start?
Given the patient’s arrest, we need to start with the ABC’s. Fortunately, the patient had no evidence airway compromise and bilateral breath sounds. However, on evaluation of circulation, he was noted to have weak pulses and a systolic blood pressure in the 90s with pulses in the 60s. We start fluids and move forward.
Where should we go next? Fortunately, in the setting of undifferentiated hypotension, we have a great tool in ultrasound, and the Rapid Ultrasound for Shock and Hypotension (RUSH) exam (a bit more about this later).
On parasternal long axis of the heart, this is what we see:
A pericardial effusion is noted of about 1.5cm. While our bedside echocardiogram was not initially diagnostic of tamponade, he was noted to have an echo one month prior which showed no pericardial effusion. Shortly thereafter the patient worsened becoming more hypotensive and bradycardic, for which a subxiphoid pericardiocentesis was performed. Echocardiogram during the procedure now did show right atrial collapse consistent with tamponade, and 300cc of blood was immediately drained with prompt resolution of the patient’s hypotension and confusion.
What can we learn from this case?
Ultrasound is a great tool in the setting of undifferentiated hypotension. The RUSH exam was created by Rose et al. in 2001 in order to establish a protocol for the evaluation of a hypotensive patient. This exam allows for rapid assessment of the heart, IVC, abdomen, and thorax. In our patient, assessment of the cardiac window allowed for immediate identification of the source of the patient’s hypotension.
Regarding pericardial effusions and tamponade, ultrasound is a very sensitive tool in order to detect even small amounts of fluid. Effusions less than 1cm are considered small, moderate for 1-2cm, and greater than 2cm are large. However, in the acute setting the rate of accumulation is more important.
During tamponade, we can see right atrial systolic collapse, right ventricular diastolic collapse and an enlarged IVC with little respiratory variation. Remember to have a high clinical suspicion in early tamponade as all these signs may not be visible. While these cases are rare, you should have a high suspicion for complications from cardiac intervention such as myocardial infarction, stroke, arrhythmias, or even perforation of the heart (such as suspected in our case) or great vessels. A subxiphoid pericardiocentesis was performed in this case, although an ultrasound guided parasternal approach is also an excellent option.
One last interesting fact:
While there are a number of findings on physical exam for tamponade, the classic findings are jugular venous distension, hypotension, distant hart sounds, pulsus paradoxus, hypotension and tachycardia. Now why was our patient bradycardic? Per UpToDate, “cardiac perforation is generally heralded by bradycardia and hypotension due to vagal stimulation induced by blood in the pericardium.”
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