is it appropriate to take ABG sample from dorsal pedis artery?

SummitRN, BSN, RN · Jun 7, 2012

Would venous pooling or venous insufficiency alter ABG values? Otherwise, I see no problem with the values you'd get.

However, the infection risk seems much higher for the foot... but if you need an ABG you need an ABG.

Curious to see what the experienced people say.

jkr2020788 · Jun 7, 2012

I really do not think that it would make any difference at all. Think about the art/veno system on a very small scale. 1) You have the big arteries which get smaller and smaller 2) At the destination sites, the arteries turn into capillaries 3) At this point, deoxygenated blood goes into veno system- none is returned to arterial. At this point you are saying "well duh!", but think about it like this- no oxygen is lost until the RBCs reach the destination site (capillaries), so even at the furthest point in the body, the oxygen sat/ partial pressure will be the same. Remember that Pa02 is the amount of O2 bound to 1 gram of hemoglobin. 1 gram of hgb in the radial is the same as 1 gram of hgb in the foot.

Biffbradford · Jun 7, 2012

Guess I don't understand why you can't get a radial ABG stick. Why not?

I've heard of patients getting badly infected feet (to the point of gangrene)

from just glucose sticks. I'd avoid it as much as possible.

Do you REALLY need that ABG?

tri-rn · Jun 7, 2012

Do you ever try the brachial artery?

ktliz · Jun 9, 2012

I've heard of patients getting badly infected feet (to the point of gangrene)
from just glucose sticks. I'd avoid it as much as possible.
Do you REALLY need that ABG?

I'm wondering the same thing... is the ABG really necessary? If so, could the patient benefit from an a-line instead of repeated sticks?

Biff, would you be more likely to stick certain patients in the foot? e.g. previously healthy vs. uncontrolled diabetic

Disclaimer: I'm a student just here to learn! I have very little idea what I'm talking about. :)

ktliz · Jun 9, 2012

I did a quick google.

According to

Drawing blood for ABGs - - ModernMedicine)

in order of preference

1)radial

2)brachial

3)femoral

They don't even mention pedal, but note that femoral sites are associated with increased infection. I wonder how femoral infection rates compare to pedal?

Ah, but according to UpToDate (http://www.uptodate.com/contents/arterial-blood-gases):

Site selection — The initial step in percutaneous needle puncture is locating a palpable artery. Common sites include the radial, femoral, brachial, dorsalis pedis, or axillary artery. There is no evidence that any site is superior to the others. However, the radial artery is used most often because it is accessible, easily positioned, and more comfortable for the patient than the alternative sites.

justatraveler · Jun 9, 2012

I would expect that rates of infection at femoral sites are higher than pedal. Femoral sites are just harder to keep clean.

ICU4U · Jun 19, 2012

How about vbs.. we use them all the time.. they work just fine.