musings of a salt whisperer
For my final lecture at Providence this academic year I did an ABG review covering all of the core concepts regarding the rapid interpretation ABGs and a touch on hyponatremia.
This seems impossible but I don’t see any holes in the logic.
Source: BestMedicalDegrees.com
For the link to work you will first need to install iBooks.
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| After next Tuesday, all that will be left will be to send out the prizes. |
NephMadness announces the finals today and the winner next Tuesday. As the field has contracted we have been feeling the pressure. People we respect have questioned our choices. Some have pointed to our final four, JNC8 and Acute PD in particular, and had some negative thoughts abut their importance.
I’m sorry they are disappointed with the final four. I personally am more concerned with the elite eight* than the final four, as the elite eight represents the champions of each region. The elite eight were:
* Any one else feel that the Final Four and the Sweet Sixteen, make it feel that eight should be an alliteration? But the sad reality is, elite and eight are not alliterative. I prefer Great Eight.
Looking over this list I am comfortable and enthusiastic about each choice (except for pericytes which I still don’t understand but Matt and I didn’t want a dream, bioartifical kidney, to win. When they can keep that Frankenstein Kidney alive for more than a few days without clotting we’ll reconsider).
JNC8 is the most important issue in hypertension because it is leading a massive sea change in the blood pressure standards of hypertension around the world. JNC8 is largely in agreement with all of the national guidelines that have been published world wide.
For one, the start-treatment threshold of >150/90 mm Hg applies to patients 80 years or older in the ASH/ISH guidelines, as opposed to 60 years or older in JNC 8.
AHA/ACC/CDC joins JN8 in not calling for stricter, lower, blood pressure targets in the presence of CKD, diabetes, or proteinuria.
JNC 8 versus KDIGO
Everywhere hypertension experts have been reconsidering previous aggressive blood pressure targets. In the end, the blood pressure targets of JN8 are not based on firm data that fit every clinical scenario and we may end up revising them in the face of future data but these guidelines will determine the future of stroke, coronary disease, heart failure and kidney failure for millions of people being treated for hypertension.
Additionally, JNC8 and the ACC/AHA cholesterol guidelines together usher in a new era where observational data is no longer considered acceptable data to base guidelines. This resulted in a relaxation in both cholesterol and blood pressure targets. This is a sea change in how guidelines are developed. This is important. JNC8 also grades the evidence. E level evidence, i.e. expert opinion, on such a fundamental question as systolic blood pressure target, should be humiliating to the hypertension community. I believe that letter grade will stimulate the community to find the answers definitively. I salute the guideline writers for having the courage to admit that the emperor wears no clothes.
Urgent PD triumphed in the renal replacement therapy region. We chose this because it is the first innovation in peritoneal dialysis in the last 20 years that seems capable of moving the needle and reversing the trend of dwindling number of patients on home therapy.
Two years ago there were one or two programs in the country, today there are over 100 urgen PD programs. PD, according USRDS is $20,000 a year cheaper to administer than HD and considering that 115,000 people initiate dialysis every year the savings quickly exceed my ability to track the zeros (9, I think). No one knows if PD is better than HD, and it probably is roughly equivalent, but it is definitely cheaper. Urgent PD is an innovation that shows promise in increasing the numbers of people in PD. After starting an urgent PD program we doubled our PD population after years of decline. When I mentioned that story to others who had urgent start PD programs they nodded their head and say the same was happening at their centers.
We did not make our decisions without thought and it is inevitable that others will have different values when it comes to these ambiguous and irrational comparisons. I am comfortable with the decisions that we made and do not feel we are limping to the finish line.
The fall of the serum anion gap.
Serum anion gap – out. MUD PILES. if god forbid anyone actually diagnose anything that causes ARF. #Employment #NephMadness
— Michael Katz (@MGKatz036) March 31, 2014
The serum anion gap was an entry on the electrolyte region of NephMadness. It won it’s opening round over urine anion gap and advanced to the Sweet 16 by beating hypertonic saline but failed to win the electrolyte region when it fell to Bicarbonate in CKD.
CJASN did a recent review of the anion gap and they were frank with its limitations:
Some interesting notes about the anion gap: though the serum potassium was included in the original derivation of the calculation, none of the major U.S. textbooks include it. The upper limit of normal anion gap from the 8 sources included in the paper is much higher than I teach. I use 12 and after the ASN Board Review Class, I remember feeling that was too high.
The article then discusses the fact that ion selective electrodes are more sensitive for chloride so they detect higher chloride concentrations so that average and pathologic anion gaps are lower.
The article discusses the importance of albumin in the normal anion gap. As albumin falls, either the limit for a pathologically elevated anion gap needs to fall or the calculated anion gap needs to be adjusted upwards. The article recommends the latter. The anion gap should rise 2.5 for ever 1 g/dL the albumin falls below normal (presumably 4 g/dL). The authors recommend that albumin adjustments be incorporated into laboratory reporting so clinicians do not need to worry about this.
@kidney_boy Ah yes, correcting the gap for low albumin. #ubergeek
— rob rogers (@EM_Educator) April 1, 2014
@EM_Educator the way to turn the anion gap from an abysmal test for lactic acidosis to merely a bad test for lactic acidosis
— Joel Topf (@kidney_boy) April 1, 2014
The meat of the article is contained in table 3 where the authors review 5 studies that looked at the sensitivity of an increased anion gap for lactic acidosis. It’s not a pretty picture.
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| Both James and Jean Luc start with normal anion gaps, though James is at the upper limit and Jean Luc is at the lower limit of normal. |
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| Both patients develop equivalent and significant lactic acidosis but only James develops an anion gap |
Nice lecture that dove tails with my herbal toxin lecture.
I just heard about this yesterday and loved the irony. The NRMP which toys with the emotions of med students everywhere by holding back match results until that wonderfully cinematic moment on Match Day, accidently leaked the match results. Shoddy programming.
Here is the thread from redddit.
Here is a blog post about the slip up:
As you can imagine, this created QUITE a stir, as medical students around the country have been waiting, stressed out of their minds, about where they will be assigned to go to residency for the next 4-7 years. A flurry of online activity ensued, as medical students already pushed to the brink took to their browser’s source codes to figure out their futures. Apparently the programmers “preloaded” the match homepage source code with the information of where people match, so that once the magic time hits on Friday, they can easily change everyone’s NRMP homepages to reveal the new result. What they didn’t realize? That there are medical students out there who are combing every detail of the site to figure out anything they can ahead of time. Several took it upon themselves to poll all of their friends to assess the accuracy of this method.
So today’s match day will have a little less drama, for every fourth year who was not obsessing over the match results.
Happy Match Day. Good luck and “…may the odds be ever in your favor.”
Last year, NephMadness came together in about 4 weeks from concept to Selection Sunday. Because of the short time available, and the fact that we had no idea what we were doing, somethings worked and others flailed. Since we are in the middle of a bracket fever epidemic, let’s take a critical look at last year’s brackets with a focus on the changes we made in 2014.
The most important thing we got right, was dividing the field into 8 regions of 8 teams and assigning unique themes to each of these regions. In 2013 the 8 themes were:
When we started thinking about assembling the field for 2014, we decided to get outside help. The plan was to work with experts in various corners of nephrology to unearth some gems that the core editors of NephMadness would never have considered.
David Goldfarb, immediately grokked the game and over the course of an hour long phone call filled his brackets with great pairings that hit on stone issues relevant to nephrologists. He selected teams that represented diagnosis, treatment, the future and the past. He built a bracket that we, literally, could not have done without him.
Why I love twitter.
Intermittent HD superior to CVVHD in removing methanol and formate in methanol poisoning. http://t.co/8sHi23RnLu cc: @kidney_boy
— Bryan D. Hayes (@PharmERToxGuy) March 17, 2014
Immediate download.
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| See if you can get a few more authors next time. |
Interesting introduction in the article about the disparity betweeen cases and resources for treating methanol. Most resources are available in the developed world (dialysis, fomepizole) but most cases occur in the developing world. Also interesting note was that some Islamic Countries have social bans on the medicinal use of alcohol. That could make treatment pretty dicey.
They prospectively observed 24 cases of methanol ingestion out of 121 cases in a mass methanol poisoning in the Czech Republic. Looks like it was due to contamination of spirits with industrial methanol. Apparently this is a relatively common problem.
41 deaths. All patients in the observation cohort were treated with ethanol (17 patients) or fomepizole (4) or both (3) to prevent conversion of methanol to the downstream toxic metabolite, formic acid.
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| 15 years old and this page still stands-up. Some stuff never changes. Page 358 of the Fluids Book. . |
The authors present clearance data on 11 patients treated with conventional dialysis and 13 treated with continuous dialysis.
The half life of methanol with conventional dialysis was 3.7 hours and 8.1 hours with continuous dialysis. Not suprisingly all of the componants associated with more efficient dialysis were associated with with faster clearance of methanol: increased dialyzer surface area, increased blood flow and increased dialysate flow. Those half-lifes are remarkably shorter than the half life of methanol in the body using renal and pulmonary clearance.
On the other hand folate supplementation, the pre-dialysis methanol level and the nature of the antidote (ethanol versus fomepazole) made no difference.
The shorter half-life with intermittent conventional dialysis did not transplant into better patient survival.
They turned their math into specific treatment guidelines.
Some interesting tidbits. You know that graft that shows that the osmolar gap falls as the anion gap rises?
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| Canadian Family Physician |
That wasn’t the case so much here, they found simultaneous high anion and osmolar gaps.
