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Old 07-23-2011
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Question Valsalva Maneuver and preload

Can someone please explain how exactly the valsalva maneuver decreases preload? thanks
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Old 07-23-2011
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When you blow out against closed glottis you will increase the intrathoracic pressure.

This pressure will be exerted on the pericardium and this in turn compress the superior and inferior vena cava and less blood will return to the heart.

Did you take Step 1 exam? This is one of the reasons that you should not start with Step 2 CK exam, you should start with Step 1 exam.
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Old 07-24-2011
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When a person tries to blow against closed glottis--->increased intrathoracic positive pressure-->thoracic wall exerts more pressure on vessels and cardiac chambers--->so increased pressure in rt atrium-->increase intramural pressure -->so it impedes flow into rt atrium--> so low preload-->pressure will be on aorta as well and low preload -->low cardiac output
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