Med-Surg Pathophys question

[Tweety, BSN, RN]

I was on the phone on a consult with a surgeon I had a patient who had a small bowel obstruction on cat scan and the MD was wondering if it was ischemic bowel, as the patient began to report some pain after a few days. He had me do an ABG to, I believe, check for acidosis which would be indicative of ischemic bowel.

None of my peers could explain why the pathophys behind it. Does anyone know?

Complicating it was his renal insufficiency. Indeed he was slightly metabolic acidosis which is renal doc treated with bicarb.

So what's the connection between an ABG and ischemia, specifically bowel ischemia? I have an idea in my head, but don't want to articulate and haven't had time to research it.

Thanks!

[PJMommy]

Ischemia which results in an infarcted area will cause increased lactic acid (did they get a lactate level?). The ABG will reflect this change as metabolic acidosis -- pH decreased, bicarb decreased (as it is used up to buffer the lactic acid), pCO2 might be lowered if pt is compensating respiratory-wise.

Is this what you are looking for?

[suzanne4, RN]

But you also have another problem involved, nephrology is already treating your patient with bicarb, so the ABG will not show specifically what the surgeon is looking for. If he/she knew that the patient was already receiving bicarb, I am sure that the test would not have been ordered for that reason.

[Tweety, BSN, RN]

Suzanne, the bicarb was ordered by the nephroligist after the abg the surgeon ordered. The patient wasn't on bicarb before that.

But we don't know was the metabolic acidosis renal caused, or ischemia caused.

Thanks PJMommy for the response. No lactate level, only the abg.