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pearls on Renal Consults from @NityaSrialluri and @JohnSperati this week! Here's a 
about adequacy of hemodialysis:
Look at these lytes! First set are shortly before HD and 2nd set are shortly after. Is this patient getting enough HD? 1/
#tweetorial #FOAMed
pearls on Renal Consults from @NityaSrialluri and @JohnSperati this week! Here's a about adequacy of hemodialysis:Look at these lytes! First set are shortly before HD and 2nd set are shortly after. Is this patient getting enough HD? 1/
#tweetorial #FOAMed
Some context: this patient is chronically on HD via AV fistula & has not missed any sessions. I often take it for granted when patients are on HD and admittedly don't think about whether they are being over- or under-dialyzed? Is this patient getting enough HD? 2/
To answer this question, let's go back to basics. HD removes waste products (e.g. urea) from the blood. In order to assess whether someone is getting adequate dialysis, we can calculate how much urea is being removed by a session of HD. 3/
To determine how effectively one session of dialysis removes BUN from the patient's blood, we can compare the level of blood urea (BUN) pre- and post-HD by calculating the urea reduction ratio (URR)!
URR = (pre-dialysis BUN - post-dialysis BUN) / pre-dialysis BUN
4/
URR = (pre-dialysis BUN - post-dialysis BUN) / pre-dialysis BUN
4/
Let's apply this equation to our patient! Technically his labs were drawn a bit before and a bit after HD, but we will guesstimate here.
URR for our patient (101 - 80) / 101 = 0.208 or 20.8%
So...are we removing enough urea? 5/
URR for our patient (101 - 80) / 101 = 0.208 or 20.8%
So...are we removing enough urea? 5/
The answer is it depends! Patients have better long-term outcomes (fewer hospitalizations, improved mortality) if URR is >60%. Some experts recommend a minimum URR of 65% to show that enough urea is being removed from the blood, aka that the patient is receiving adequate HD... 6/
...BUT URR can vary greatly from one HD session to next, so you would want to check URR over multiple sessions to determine whether HD is adequate. We generally say a paitent's HD is adequate if URR is consistently 65% or higher. 7/
Ok, but how does this relate to our patient? We noted 1) their initial BUN was very high despite having not missed any HD, 2) URR was low over multiple sessions, 3) AVF had weak thrill and 4) arterial pressures during HD were 
(suggesting possible AVF occlusion/stenosis). 8/
(suggesting possible AVF occlusion/stenosis). 8/
All of this data suggested that the patient was being UNDER-dialyzed, aka not allowing for adequate removal of waste products such as urea from the blood! We are working to troubleshoot their HD and determine why this occurred 
.
/fin
./fin
