Low Diastolic Pressure - I mean REALLy Low

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Specializes in Peds Critical Care, Dialysis, General.

So, I have returned to Acute Dialysis after very heavy recruitment. I love it and got great hours...now for my problem.

Had a really unpleasant conversation with one of our nephrologists in regard to a specific patient. His basic complaint was that we (the Acute Dialysis Team) are stupid and incompetent. A patient' s BNP has continued to rise (except for a couple of days) despite daily dialysis. The patient came to us from a larger facility d/t problems with AVF. When pt arrived to our hospital, said patient coded, K was 6.6. Compressions and defibrillation were done and ROSC obtained in 3-4 minutes.

I have run this patient once...during treatment her SBPs were fine; however, her DBPs were in the toilet 24-32. Patient looked awful. The mean pressures didn't meet any criteria. I have just never seen such low DBPs before. The nephrologist very clearly stated DBPs did not matter, patient was in heart failure and diastolics were not an issue, that we were only to use SBP as our guide, since we were obviously pumping patient full of fluid. Again, another rant of our incompetence and need to find another job. I learned in nursing school that diastole allowed for perfusion of the coronary vasculature.

He did mention one person he wanted to run this patient. A review of treatment showed that a BP of 118/11 was recorded. The patient's BNP has climbed steadily even with his preferred nurse running the treatments.

In an effort to improve this patient's treatment, I asked some questions. I formerly worked in teaching hospital where questions were expected and welcome. Again, another unprofessional rant of the team's incompetence and stupidity.

I would love your input. BTW, the patient's BNP decreased a good bit after my one run. The patient needs CRRT, but we don't do that and I got the distinct impression the MD will not transfer patient to an appropriate facility.

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Specializes in Dialysis.

Is this low diastolic by your ears and a stethoscope or NIBP?

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Specializes in Peds Critical Care, Dialysis, General.

Both! I usually do both when I get a pressure that is questionable. This nephrologist is only concerned with systolics and MAPs and BNP (he is the only one who routinely follows the BNP and dialyzes on that basis).

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You're in a hospital setting? Are these pressures seen constantly or only during treatments?

In a simple sense, diastolic BP reflects the patient's SVR. So it could be low from hypovolemia or vasodilation, etc. And you are correct that coronary perfusion occurs during diastole. Further, coronary perfusion pressure hinges on aortic diastolic BP: CPP = aortic diastolic BP - right atrial end diastolic pressure. A CPP should ideally be at least 15. So with the values you gave the patient was not getting adequate coronary perfusion by any means. I mean, her MAP for the 118/11 would be less than 50.

It's hard to say what could have been done from such limited information, but obviously the physician was inappropriate in this scenario. Something further probably should have been done for this patient...

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Specializes in Dialysis.

I think the damage to the heart has already occurred and the doc is focused on reducing the work of the heart by pulling fluid.

UAB - The UAB Mix - Diastolic blood pressure: How low is too low?

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Specializes in Peds Critical Care, Dialysis, General.

Thank you both for your comments. Yes, patient does have CHF. He considers me to be, in this instance, very stupid and told me to find another job. My run with this patient kept said patient within the more "normal" values, SBP >90, MAP > 65. He said I was just pushing fluid into this patient. I followed protocols. I just could not see having to stand in front of the BON and try to justify anything else ie, "the doctor said so." Reviewing her treatments showed that she continued to go up on BNP with the lower pressures with more and more fluid being pulled off. He dialyzes patients based on BNP, which means most patients get daily dialysis when he is on.

BTW, I just saw in our hospital's warehouse, 3 big boxes with pictures of the Prismaflex! Dare I hope that we are adding CRRT??

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I think the damage to the heart has already occurred and the doc is focused on reducing the work of the heart by pulling fluid.

UAB - The UAB Mix - Diastolic blood pressure: How low is too low?

This thread is super interesting to me because I am just learning more about dialysis as a nurse. I have been a GI nurse, cardiac ICU nurse, left anesthesia (CRNA- another interesting thread I have recently read up on and will add to), and now this. I recently have noticed while training many patients diastolic BP are low while they are on dialysis in an outpatient setting and I am trying to figure out the physiology behind this. Any insight, input and thoughts would be appreciated. Even what you have seen. Thanks!!

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Specializes in Dialysis.

Low diastolics are seen in patients who don't have long to live because, like this one, they have crappy hearts. You mentioned the MAP but didn't say what it was. It may be the best parameter to use and should be 60. Maybe you could augment with albumin 25%, or the patient could be on some pressors during treatment. I agree that CRRT would probably benefit the patient, but if you don't do it there, you are stuck. Having a crit line also would be a great tool to document status. Unfortunate that there are still Neanderthal docs in practice.

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Specializes in Peds Critical Care, Dialysis, General.

The patient's MAP was 50, propped up by a SBP of 118/11. Wide pulse pressure, much? Patient was on pressors. She was sick and her heart was a wreck. Patient passed after about a week and a half of daily dialysis.

BellaGeorge, what is interesting is when you have a patient with a low BP and as you pull fluid off, BP actually rises.

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BellaGeorge, what is interesting is when you have a patient with a low BP and as you pull fluid off, BP actually rises.

I wonder if this is due to BP medications being dialyzed off then becoming dry and having some reserve kidney function left intact.
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When I was working cardiac ICU I asked one of the cardiovascular surgeons what very low diastolic blood pressure meant. He said if it was non-invasive (AKA using a blood pressure cuff), a very low diastolic blood pressure didn't mean much at all and was never anything to worry about. He said the only time to pay attention to a low diastolic blood pressure is if it was invasive (art line, central lines etc.).

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Specializes in Hemodialysis, Mental Health, Addictions.
I wonder if this is due to BP medications being dialyzed off then becoming dry and having some reserve kidney function left intact.

That could be part of it! One of my dialysis preceptors explained to me that at the start of dialysis, the heart is burdened down by the fluids so as we pull the fluid off, the burden decreases and the heart can pump harder.

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