I just had a question about a client that i had in clinical the other day.
She is 87, and was admitted with hypoxia and pneumonia. Her BNP on day one was 0, on day 2 was 398 and on day 3 was 727. CHF was ruled out and her BP was only 100/60 on average, but she had bounding pulses. Her troponin I also went from 0 to .4 in 24 hours.
Her history also includes hypothyroidism, mild mitral regurgitation that causes stable a-fib. While at the hospital that afib was less stable as her heart rate was over 100. At one point she had a tachycardic episode related to a bad reaction to the duo-neb treatments which caused her Hr to increase to 150-170. The duo nebs had been initiated on the first day of her admission.
The doctors weren't concerned with the cardiac values and were just monitoring the situation and focusing on treating the pneumonia with antibiotics.
Im just trying to figure out then What caused the high bnp and increase of troponin...and what does this value then tell us about this clients heart?
Based on the fact that CHF was ruled out and the troponin was too low for a MI, my theory is that the troponin could have be caused by ischemia related to hypoxia, related to pneumonia and perhaps the high BNP could have been caused by the fluid bolus that the client recieved in the ED....Which leads me to my final question...can a client have a BP of 100/60 and have fluid volume overload?
Mar 13, '09
BNP is excreted renally, so in the context of renal failure/insufficiency it could be elevated as well.
Other than that, BNP is fairly specific to ventricular stretching (call it CHF, call it what you will).
edit to add: Apparently BNP levels can be elevated in the presence of atrial fibrillation without heart failure:
Last edit by hypocaffeinemia on Mar 13, '09
I am curious how the CHF was ruled out. Was an echocardiogram performed to evaluate ejection fraction? A person can certainly have a big, boggy heart that is only squeezing out 10% and have clear lungs on XR and to auscultation. Then when they get a fluid bolus, uh, oh.
It is my understanding that mitral regurg. can be both a result and a cause of heart failure (stretched LV pulls the valve so it can't close or non-closing valve allows back flow during systole).
I also would suspect right sided HF and pulm. HTN in this pt. How were her neck veins? Any peripheral edema or ascites?
I have never heard of measuring BNP 11 minutes apart. We usually don't do it amy more often than once a day.
Last edit by nursej22 on Mar 13, '09
: Reason: Not finished
The purpose of BNP is to help regulate blood volume, the work that the heart must do in pumping blood throughout the body. Both BNP and NT-proBNP are produced mainly in the left ventricle. So when the left ventricle is "stretched" from having to work harder, the BNP concentrations can increase markedly. A person who is given a fluid bolus, such as 500 ml's of saline into the circulation, for example, it affects all the fluid compartments of plasma, extracellular and intracellular compartments (increased blood volume). If that person does not have sufficient oxygenation, myocardial performance and vascular tone, all results in "stretching" of the LV. In simple terms, it is as nursej22 stated, CHF.
But, lung disease such as COPD, or Renal disease, Chronic Hypertension call all cause elevated BNP, but generally you will see this elevated on admit, not suddenly.
CHF makes more sense considering the information you provided. We also do not draw BNP's that closely together. Because of the fluid administration, and the bout of fast heart rate, could have been the cause of the elevation, which may acount for the reasons the hospitalist wasn't concerned. A CXR is not the ideal test to rule out CHF. A echo would have been more conclusive. And hopefully, they ordered another BNP later to help distinguish the cause. I am curious as to what the hospitalist documented what he thought the cause was for the elevated BNP?
Last edit by Over-the-hill-Nurse on Mar 13, '09
: Reason: corrected spelling