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Old 04-08-2011
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Lungs Pulmonary Shunt and Hypoxemia

Hi everyone,

Can anyone explain the concept behind Pulmonary Shunt and Hypoxemia. I am a little confused and didn't quite pick it up while doing Kaplan. Also, why does supplemental oxygen not help in this case of hypoxia?

Thanks
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Old 04-08-2011
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Sorry about that .. I just searched and found this link Pulmonary Shunting, Please Explain? ...Going to go over but any further explanations are still welcome !
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Old 04-09-2011
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Originally Posted by Mondoshawan View Post
Attachment 1135
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I think because there is a V/P mismatch; normal perfusion with less ventilation (from fluid, chronic inflammation, tissue destruction, or whatever). The "shunt" is the blood going from pulmonary artery to pulmonary vein without ever getting oxygenated.
If the alveolus is blocked, then there is no interface between that 100% oxygen and the capillary...
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Wouldn't that be similar to Diffusion Impairment ? I think that is what is confusing me. But I think, in diffusion impairment there is some gas exchange compared to the shunt (Atelectasis) where there is none. That is why when we give 100% O2 or supplemental oxygen, it resolves the hypoxemia. Is that correct ?
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That sounds right - I think of diffusion as being the interface between perfusion and ventilation, and diffusion impairment as being diffusion through a "thicker" membrane - so increasing the FiO2 would increase the partial pressure of oxygen on the ventilation side. If the impairment is not too strong, the hypoxemia should be corrected...
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