elevated pro-bnp

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I'm working on my large care plan for my critical care rotation. As I'm going through my pt's lab values, I'm trying to explain why some would be elevated and some would be low. This is all making sense for the most part.....pt was experiencing kidney failure so high K+ (8.1) and was found in a house that was near 100 degrees so Na+ was high as well (152). What I can't explain is his elevated pro-bnp. This was 3815 (normal 0.0-1800)! I know this is used in relation with heart failure. This pt has no history of heart failure, although he was not a reliable historian (neither were his ex-wife or ex sister in law). Could this lab test be elevated due to the renal failure? I know that BNP relies on the kidney for excretion, but would failure lead to such a high number? All other heart values came back normal so I know there wasn't an MI that occurred. His EKG did show a 1st degree heart block and prolonged q-t interval but I don't think that would effect the bnp that much. Does anyone have any ideas, or am I thinking right with the kidney failure reason?

Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

Have you looked up what the BNP signifies? Is it always correlated to heart failure?

http://www.clinchem.org/content/55/7/1271.full

Specializes in Family Practice, Urgent Care.

BNP can be increased in Acute coronary syndrome, LV dysfunction, CAD, pulmonary embolism and MI. BNP is secreted by the ventricles in response to volume expansion and pressure. So...BNP is from the myocardial cells. Changes in the body pressures due to KF may have caused the BNP to increase. I would guess this patient has some LV dysfunction.

Thank you for your responses, and also thank you for the article Esme. It took me a bit to read, but it was interesting. I'm thinking that this leads back to my Pt's uncontrolled blood pressure. When contacted, his daughter stated that she knew he hasn't been taking his meds. the friend that called EMS said that there were full bottles of pills at the house, but he forgot to bring them, so I am unsure of what they really are. I'm kind of going off daughter stating they were blood pressure pills. BP at ER arrival was 170/109, 166/112, 177/126, and right before transfer to ICU 185/109. I thinking he probably stopped taking meds, BP became even more elevated (who knows how compliant he was or how the meds were working) which has led to some LV problems. No ECHO or ultrasound was performed, so I don't know what the heart really looks like or ejection fractions or the like. I'm thinking these previous problems complicated by the decreased renal clearance may have caused the increase.

Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

right....and remember renal patients have hypertension that is poorly controlled. BNP can be elevated in renal failure. Pro-BNP is reliant solely on the kidney for excretion. When interpreting an elevated BNP level, it is useful to remember that values may be elevated due to factors other than heart failure. Lower levels are often seen in obese patients. Higher levels are seen in those with renal disease, in the absence of heart failure.

It is the kidney failure itself that causes fluid retention and the failure to excrete pro-BNP

Phew, thank you so much for your guidance. This patient's picture is finally starting to fall into place.

Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

It takes time.....and experience. That is what we are here for...((HUGS))

Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

What's next....LOL

I agree with Esme, the pro BNP is elevated but just slightly. Probably r/t renal function. My last Acute HF pts BNP was like 49,000

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