1/ #UncleBob on treating metabolic acidosis. First, get this article:
Sabatini, S., Kurtzman, N. (2009). Bicarbonate Therapy in Severe Metabolic Acidosis JASN 20(4), 692-695. dx.doi.org/10.1681/asn.20…

@UnremarkableLab @kidney_boy @hswapnil @CPSolvers
@uabimres @UAB_NRTC
2/ Here is the quick chalk talk.
For increased anion gap metabolic acidosis, treat the underlying cause. Do not give bicarbonate unless you have an extraordinarily low pH (debate whether this is < 7.2 or 7.1 or 7. And with DKA, NEVER.
3/ For normal gap metabolic acidosis ALWAYS give bicarbonate with a goal of ~ 22 for the bicarbonate.

How?

Estimate bicarbonate deficit = 22 - current bicarb
Multiply by bicarbonate space = TBW = 50% wt in kg (+/- 10%)
4/ Example:
We had a 70 kg man admitted with severe diarrhea and a bicarbonate of 17 (normal gap)
Therefore 22-17 = 5 * 35 liters = 175 mEq

So we chose 3 amps of sodium bicarbonate into a liter of D5/W. We'll check his bicarbonate today and then titrate
5/ With chronic metabolic acidoses like the NAGMA of CKD, once we return the bicarbonate to 22, then we need maintenance bicarbonate. If we assume that most people need to buffer ~ 1 mEq/kg of acid daily. Then titratable acid (phosphate) will usually handle around 50%
6/ Non-titratable acid (NH4+) is the problem. With CKD we often have decreased NH3 available for conversion to NH4+ in the distal tubule. I usually estimate about 20-30 mEq of bicarbonate daily to maintain our bicarbonate in the 22 range.
7/ We can either give sodium bicarbonate or sodium citrate. Use 650 mg tablets (~7.7 mEq per tablet) or 1300 mg tablets (~15.4 mEq per tablet) or baking soda (1 tsp ~ 60 mEq). So with a starting estimate of 30 mEq: 4 650s or 2 1300 or 1/2 tsp of baking soda. Then titrate
8/ If we give sodium citrate (Shohl's or bicitra) get converted to sodium bicarbonate - 1 mEq/ 1 cc - so 30 cc of sodium citrate to start.
Beware that this tastes horrible - imagine Rose's lime juice with too much salt added.
9/ Please ask questions or critique and make more clear.

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More from @medrants

14 Aug
1/ Thoughts on presenting on rounds #UncleBob - #5goodminutes

This is how I do rounds - would love questions and critiques.

I explain my expectations the first day on the service.

@WrayCharles @LisaWillett13 @iMedEducation #MedEd @ShreyaTrivediMD @AdamRodmanMD
2/ New patient presentations:

Deliver a succinct HPI - start with chief complaint - insert RELEVANT PMH as desired. Tell the story chronologically if possible. Include related review of systems, social history, health behavior history, medication list as pertinent.
3/ Stop after HPI and we will discuss the HPI. The goal of the discussion is to improve how each learner tells the story. The goal is complete, yet succinct. Don't give too much information. Avoid redundancy. We call this discussion IMMEDIATE FEEDBACK.
Read 7 tweets
14 Aug
1/ #UncleBob - how I use the delta gap. Hopefully worth #5goodminutes

@UnremarkableLab

Here is the idea - we have an increased anion gap and want to see if the patient also has either a normal gap metabolic acidosis or metabolic alkalosis. Here are the assumptions:
2/ Expected gap = 11 - 2.5*(albumin -4) but that is hard to remember, so we use a reasonable approximation = albumin * 3.
Example, patient has an albumin of 2.3 so we expect a gap of 7.
3/ Second assumption - the increased anion gap has replaced bicarbonate. - thus treating the gap will restore bicarbonate

2 examples to follow:
Read 5 tweets
29 Jul
1/
#UncleBob was puzzled last night by a very low A-a gradient during an @UnremarkableLab session

Patient had a pCO2 of 55 and pO2 of 76 which calculates as a gradient of 5. That is probably impossible so something must be off.

@anandiyermd @DxRxEdu
2/ Two numbers in the A-a gradient are variable: atmospheric pressure and RQ. The atmospheric pressure in Birmingham is around 745 rather than the 760 we normally use. If you plug that into the equation the A-a gradient decreases to ~2. So that does not explain it.
3/ The big variable is the respiratory quotient. What is the respiratory quotient: "Respiratory quotient, also known as the respiratory ratio (RQ), is defined as the volume of carbon dioxide released over the volume of oxygen absorbed during respiration. "
Read 5 tweets
4 Jul
1/ #UncleBob has thoughts on planning your career for young clinician-educators. Read for #5goodminutes, then consider for longer.
Do not plan your career, rather strive to be the best you. Excellence gets recognized. Opportunities will appear.
2/ Have a trusted mentor who will listen to you explain the opportunity and help you decide if it works with your goals.

I just finished listening to an episode of Broken Record - an interview with Huey Lewis. He become a very successful singer and band.
3/ As he told his story, it was clear that early in his career his goal was to make good music. Eventually, opportunity shone on him. Because he had worked on his craft he was able to both succeed and not get sucked into the fame trap.
Read 8 tweets
29 Jun
/1 #UncleBob has great optimism about Internal Medicine. My initial love started when I understood that our job was to solve the mystery for the benefit of the patient. Over the years i have had colleagues with that same passion. So why is my optimism particularly high now.
2/ What excites me is the community response to learning during COVID-19. @CPSolvers Virtual Morning Report has involved so many learners - students and young physicians. Their enthusiasm to learn tells me that so many have what I consider "the right stuff".
3/ This morning I check our YouTube video of our first @UnremarkableLab episode - and already >160 views as I type. This quest to improve is the hallmark of great physicians. Our goal as educators is to help our learners (and ourselves) regularly improve.
Read 5 tweets
28 Jun
1/ #UncleBob presents a #5goodminutes tweetorial on the FeNa. The idea is simple, with normal kidneys and volume contraction, the kidney should avidly reabsorb sodium. With acute tubular injury, the problem is that the tubules cannot reabsorb Na.
2/ Here are the cautions - with a non-oliguric patient the stimulus to reabsorb Na is either not there (patient not volume contracted) or the patient has underlying CKD. When you understand the concept of fractional excretion, this will make sense.
3/ Here (from Wikipedia) is a good definition of FeNa: The fractional excretion of sodium is the percentage of the sodium filtered by the kidney which is excreted in the urine. You can substitute any measurable for sodium.
Read 8 tweets

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