Which of the following is a sign commonly noted in pulmonary embolism?

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Multiple Choice

Which of the following is a sign commonly noted in pulmonary embolism?

When a pulmonary embolism blocks blood flow to parts of the lung, ventilation can continue in those regions but perfusion drops. That creates more physiologic dead space—air reaching alveoli that isn’t gas-exchanging because there’s no blood flow. The VD/VT ratio measures how much of each breath becomes dead space, so it rises as physiologic dead space increases. That makes an increased VD/VT ratio a classic sign of PE. Decreased VD/VT would mean less wasted ventilation, which isn’t typical with PE. A normal VD/VT doesn’t reflect the added dead space from the embolism. Decreased PaO2 can occur due to V/Q mismatch in PE, but it’s less specific than the rise in dead-space fraction.

When a pulmonary embolism blocks blood flow to parts of the lung, ventilation can continue in those regions but perfusion drops. That creates more physiologic dead space—air reaching alveoli that isn’t gas-exchanging because there’s no blood flow. The VD/VT ratio measures how much of each breath becomes dead space, so it rises as physiologic dead space increases. That makes an increased VD/VT ratio a classic sign of PE.

Decreased VD/VT would mean less wasted ventilation, which isn’t typical with PE. A normal VD/VT doesn’t reflect the added dead space from the embolism. Decreased PaO2 can occur due to V/Q mismatch in PE, but it’s less specific than the rise in dead-space fraction.

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