ASA Member
7+ Year Member
Nov 10, 2010
Resident [Any Field]
I don't quite understand this concept.

"The slower the rate and extent of tissue uptake, the greater the difference in anesthetic gas tensions between arterial and venous blood, the more time it will take to achieve equilibrium with brain tissue.”

"Since anesthetics must be carried from the tissues to the lungs for primary elimination, larger A-V concentration differences means less drugs are returning for elimination, which may increase the time for awakening"

If less is taken up by the tissue, wouldn’t the anesthetic gas tension between arterial and venous blood be very minimal and more would be readily eliminated via the lungs?

Thank you!
Aug 10, 2015
I was thinking the same thing in this. The tension should be similar to both the arterial and venous blood. What is the source of this explanation?


5+ Year Member
Dec 16, 2013
It is saying a larger A-V gradient, meaning the body is holding onto the drug. The gas is inhaled and then handed to the arterial system, then the body quickly absorbs it and the blood returning to the lungs is low in concentration. So if body is holding onto it longer than you have a longer recovery time..the body is quick to retain it but then slowly lets it seep out to be eliminated through exhalation.
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