av shunt VS av fistula?

[MoscowAbe]

Please someone explain the difference in the findings. Do they both have the same a-v o2 difference?

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[PokerDoc]

Please someone explain the difference in the findings. Do they both have the same a-v o2 difference?

hmm good question.. well i think the AV fistula is easy to answer, since youre bypassing the capillary beds you wont have the same gas exchange as normal so your A-V 02 difference will definitely decrease.

for the AV shunt, i never even heard of it terminology wise, but wouldnt that just be a synonym? did you mean to compare a fistula to something else? a fistula essentially is a shunt because youre shunting your blood around the capillaries.


i might be off base though but ive never heard of an 'av shunt' as something separate from an av fistula

 

[Vikingwizardguy]

def weird terms. I thought AV fistula was systemic while AV shunting was pulmonary. An AV shunt would bypass the capillary and thus have a large A-a gradient while an AV fistula (after like a knife fight or something) would result in a larger venous PO2 since you're bypassing the capillaries. I know AV fistulas are often ask about in physio when discussing CO and venous return.

 

[aashkab]

I thought that an AV shunt was a mechanism of bypassing capillary beds when you don't need those regions perfused. For example, when you are cold, your glomus body "shunts" blood directs from the arteriole to the vein instead of trickling through the capillaries.

In an AV fistula, I assume its an irregular connection formed from some irregular process connecting an artery and vein together.

It would increase preload in both I think and have the same lessened A-V O2 difference. It also increases resistance because you are converting a parallel circuit into a series circuit.

These are just my guesses/ideas. Not sure if they are right.