This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Anaesthesia
A 27-year-old man was assaulted and stabbed on the left side of the chest between the areola and the sternum. He is hemodynamically unstable with jugular venous distention, distant hea sounds, and hypotension. Which of the following findings would be consistent with a diagnosis of hemodynamically significant cardiac tamponade? 
Select and explain. 
A. More than a 10 mm Hg decrease in systolic blood pressure at the end of the expiratory phase of respiration, B. Decreased right atrial pressures on Swan-Ganz monitoring, C. Equalization of pressures across the 4 chambers on Swan-Ganz monitoring, D. Compression of the left ventricle on echocardiography
C: Equalization of pressures across the 4 chambers on Swan-Ganz monitoring
Answer: C: Equalization of pressures across the 4 chambers on Swan-Ganz monitoring 
Explanation: On physical examination, cardiac tamponade may manifest with Beck triad (systemic hypotension, jugular venous distention, and distant hea sounds). Also, the patient may have pulsus paradoxus, which is manifested by a decrease in systolic blood pressure by more than 10 mm Hg at the end of the inspiratory phase of respiration. On echocardiogram, there will be pericardial fluid and right atrial collapse. On Swan-Ganz monitoring, there will be equalization of pressures across the four chambers. The right atrial pressures and central venous pressure are increased and cardiac output is decreased.