Clinical trial day is held on May 20th in honor of the first clinical trial, James Lind’s 1747 Trial on the treatment of Scurvy. The ironic thing is how shoddy the study design was. He took 12 sailors with scurvy and divided them into 6 groups of 2. He then treated each group with a different dietary supplement:
quart of cider
sulfuric acid
vinegar
seawater
oranges and lemons
spicy paste and barley water
By the time they ran out of lemons, six days the two sailors in group 5 showed remarkable improvement. No other group showed any improvement. I guess with an N of 2 you better hope for an NNT of 1.
Read the wikipedia page, it has a fascinating account of how this medical breakthrough was ignored and missed for 47 years until lemon juice was issued as part of provisions in 1794.
Patient comes to the ER. She has a a sodium of 119.
Four days earlier the sodium was 134.
ER provides normal saline and the sodium falls to 114.
This is classic SIADH. If you see the serum sodium fall with normal saline, SIADH is your diagnosis.
The fellow ordered all the right tests:
Urine Sodium: 81
Urine Potassium: 87
Urine osmolality: 583
Uric acid: 2.6
BUN: 13
Cr: 0.95
She had negative free water clearance, and a lot of it. For every liter of urine she made it was like she had a 400 mL glass of water.
The patient was on doxepin for mastocytosis. Doxepin is a known cause of SIADH. She also took anti-histamines which cause dry mouth so she was always thirsty. Cruel disease.
That was stopped and the patient was put on a fluid restriction. She almost immediately turned around and his sodium started to rise. By the following morning the SIADH had completely resolved. Without the inappropriate ADH the pituitary looked at the serum osmolality of 250 and shut down all ADH secretion. This turns the urine to almost pure water. Here are her urine electrolytes from the following morning:
Urine Sodium: less than 10
Urine Potassium: 10
Urine Osmolality: 111
Her electrolyte free water was 87% of urine output.
If you need refresher, here is a video, different numbers but the concept hold.
Sodium rose to 120 the next morning. The patient was making 250 mL per hour of 87% free water. We were concerned about over correction and decided to start D5W at 100 mL per hour to slow the rate of correction. Her sodium rose at a measured pace after that. We planned on adding DDAVP if the sodium went up to fast. Not needed.
Blogged with patient permission. Release on file at PBFluids world headquarters.
So bad you need to read it to believe it. The NKF has this ask the doctor article by
Look at all those paper charts! How 2007 of you.
Dr Spry on the effects of alcohol on the kidney.
His first point is that drinking alcohol suppresses ADH. You know what other beverage suppresses ADH? All of them. Because that’s what drinking does. Alcohol may have some aditional ADH suppressing property but it is not clinically relevent because being drunk doesn’t cause hypernatremia.
Here is what UpToDate has to say about the electrolyte abnormalities of alcohol:
So beyond some increase in thirst from the suppression of ADH, this is a side show.
Then Spry confuses that point by saying that drinking beer to excess can cause hyponatremia as part of beer drinkers potomania (BTW: Best name for a disease ever). To say that beer-drinkers potomania is a consequence of alcohol misses the point, the disease comes from a bizarre diet that is void of protein and salt. These people exist on carbohydrates alone.
Then he mentions that excessive drinking can cause high blood pressure, but fails to mention that not drinking is associated with increased mortality, in fact being a teetotaler has the same relative risk of death as drinking a sixer every night. Seems like an important omission.
Alcohol can also cause significant drug interactions with medication that you are taking for chronic kidney disease (CKD) and lead to complications with the drugs that you are taking.
What CKD drug interacts with alcohol? Am I an idiot (likely) or is he just making shit up?
How can some one spend almost two thirds of a short essay talking about irrelevent (suppression of ADH) or seldom seen (beer drinkers potomania) sodium abnormalities but fail to even mention what any internal medicine intern knows are are the most common electrolyte abnormalities of alcoholism:
hypokalemia
hypomagnesemia
hypophosphatemia
These are common and have real patient consequences.
Thank-god his final sentence has some wisdom, god knows the rest of the post is crap.
Drinking alcohol to excess can also lead to liver disease which could cause serious complications with underlying CKD.
Med calc received an incremental update this week to 2.7.1. The purported reason for the update was to fix a crash on start bug. An additional gift was to update the notes to detect UID and create links.
Here is what the notes looked like in my last review:
Here is what it looks like now:
Press that blue number and then you get a dialog box asking what program you want to visit the link in and then boom you’re at your reference.
Apparently I was the inspiration for the feature:
@kidney_boy Notice anything when looking at your transtub K gradient note in MedCalc 2.7.1? 😉 — Pascal Pfiffner (@phaseofmatter) May 14, 2013
I recently heard a great example of failed sharing. USMLE World is a question bank designed for students preparing for USMLE Step 1. The questions can be viewed through the website or via an iPad. Here is what the iPad version looks like.
The curious bit comes when you look at their iTunes ratings:
They are getting slammed for requesting access to you photos. My sentiments are precisely with the raters, “Why the hell would a question bank need access to my photos?” Here is the explanation from the iTunes description:
NOTE: Users running iOS 6.0 and higher will need to enable access to ‘Photos’ as all screen captures are automatically stored in that section. The application will track the number of stored images only to determine whether screen captures are being performed and stored while a test is being taken or reviewed. Tests will not launch without this access. USMLEWorld does not sample, transfer, or save images at any time. USMLEWorld is committed to ensuring the privacy of all users, and any identifying information will be used only in accordance with the Privacy Policy as outlined on our website.
They are so afraid of their own customers that they spy on the user’s photos stream to make sure they are not taking screen shots of the questions or answers. Absurd. I have heard that when you do take a screenshot you get a very scary message, if anyone has a screen shot of that message I’d love a copy.
A reader of PBFluids, forwarded me an e-mail that came from USMLE World. She used the desktop version and they have the same possessive mentality. Apparently after she took a screen shot she received the following e-mail:
Hi,
Our records indicate that you are having problems accessing the USMLEWorld Software because you have an incompatible application/process running on your computer. Please disable the application before using our software by following the instructions below
If you are using a Mac computer, please follow these instructions:
Exit from the USMLEWorld software completely by closing any open tests and/or by clicking on the close icon (X).
Go to “Mac HD”
Select “Applications”
Click on “Utility” and double click on “Activity Monitor”
Select process ” screencapture”
Click on “Quit Process”.
Close Activity Monitor and “Applications” window and try launching the software again
If you are using a Windows computer, please follow these instructions:
Exit from the USMLEWorld software completely by closing any open tests and/or by clicking on the close icon (X).
Press “Ctrl + Alt + Del”
Select “Task Manager”
Click on “Processes” tab and then locate the incompatible process. Inyour case, ” screencapture”
Select the Process and Hit “End Process” on the bottom.
Close task manager and try launching the software again.
If you are accessing our software from a computer that you do not have sufficient rights on (such as a public terminal at hospital, library, etc), you may need to seek assistance from the computer administrator to resolve this issue or use it from a computer on which you have full administrative rights.
You’re the man. Just as it was done to me, I direct any student on my rotation to “The Whole Enchilada.” (warning 28 mb PDF)
I’m in my second year in private practice, and I get to teach students and residents through the osteopathic school in Philly (PCOM).
As a 4th year student, a renal attending put me onto your book. I had to special order it from alibris or one of those sites. My wife also used your microbiology book often when we were 2nd year students in medical school.
Anyways, I’m a big fan and supporter of all your varied output (books, blogs, lectures, etc). Early on, it made a big difference in how I synthesized a lot of daunting content, and it continues to affect how I communicate and teach others. But I’m not at the point where I can hand out sodium ninja badges…
A couple of months ago, Jeff Zonder was stroking my ego telling me how much he loved PBFluids and how it inspired him to begin blogging (check out his blog, Amyloid Planet). One of the aspects of PBFluids that he liked was how I freely shared my teaching materials.
A bit later I was invited to write a post for Wing of Zock, a blog about academic medicine in transformation and decided to write about the the value of sharing. The essence of the post is that it is not enough to just post a PDF of your presentation or paper, what you should post, to be truly useful to your audience, is the native, editable files. From the post:
The NYU Division of Nephrology has weekly renal grand rounds done by the fellows. In the spirit of Internet sharing, they post every presentation on the division’s website. Every presentation is available only as a PDF. This form of sharing is strictly Read Only; providing the information only as a PDF limits users from remixing your content. Posting a presentation as a PDF says to users, “You can use my material, but only if you use all my information. The way I teach this subject is the only way to teach this subject and my information is eternal and infallible.”
However, the Internet is inherently a Read/Write culture. The optimal way to post those presentations is as native PowerPoint files (or Google Docs Presentations or Apple Keynote presentations) so future fellows can leverage previous work, adding new data, correcting mistakes, and reworking the old into the new. Make the materials you provide online flexible to make them more useful, because the source of your satisfaction is usefulness to others. Provide the Power Point file so the user can grab what they like, skip what they don’t and fix the mistakes you made. We should readjust our sensibilities regarding ownership and intellectual property to recognize the Read/Write culture of the internet.
I am a big fan of MedCalc. I have used it since the early days of the Palm PDA. The program rocks on the iPhone. The authors, Pascal Pfiffner and Mathias Tschopp, have added both the KDIGO AKI and RIFLE criteria for acute kidney injury. But the tentpole feature of 2.7 is the ABG analyzer. The ABG analyzer uses Androgue’s 2009 review paper in KI to create a mathematical framework to fully interpret ABGs. This has been done before, I recommend ABG in my lectures and there are 6 programs in the iTunes store whose name starts with “ABG” and appear to do the same thing. MedCalc offers a few features that set it apart. First, data entry is very slick. The keypad is well designed and other programs that use a wheel or + and – buttons are exercises in frustration.
Lots of clever ideas to speed entering data, MedCalc bests them all with a device called a “keypad.”
The other MedCalc innovation is requiring only the pH and pCO2 and then calculating and autofilling the only possible HCO3 for those independent variables. Clever.
The Henderson-Hasselbalch equation: not just a good idea, it’s the law.
The other nifty feature is the application is live. You enter the pH and pCO2, and it immediately fills the HCO3 based on a Henderson-Hasselbalch calculation. No calculate button or analyze button. Instant interpretation. It will immediately interpret the ABG and provide:
I will update the document to include MedCalc as my suggested tool. My final thoughts on MedCalc is that it is a delight to use. The keypad can be swept away to see the data underneath. You can get to the supporting data for any equation by tapping on the ‘i” in the upper right corner (a very Palm-esque method) or by swiping to the right. Tap on the wrong formula from a list? Swipe left to go back. Entering multiple variables for a calculation, swiping on the keypad advances you to the next field. If you want to add your own notes on on any formula, you can do that.
My notes on the TTKG formula in the yellow
The handsome and generous authors have given me 15 codes so you can get the program for FREE! The standard calculator is $1.99 and the pro version is $4.99. Here’s what you need to do:
Apologize to Pfiffner and Tschopp for not having purchased their superior program before now.
You can do this by twitter (Pascale and/or Mathias) please tag @Kidney_boy or use the hashtag #ImOnlyDoingThis4TheFreeSoftware in your apology so I know you did it.
Alternatively you can also apologize by e-mail, remember to cc me (joel.topf at gmail dot com).
Then vote for your favorite post on PBFluids. Use the form below. I ask for your twitter name or email just to match it up to the apologies. I have neither the time or inclination to spam you. I will destroy that info after the contest.
I have codes for both the regular version and the pro version. If you are already rocking the original version, mention that and I’ll send you a code for the pro version.
I received no money or payment for this promotion. The MedCalc guys offered the codes and I had to make it as complex as possible (I am a nephrologist).
I want to add more interactivity to my lectures. Gary Abud, a friend and former mentee, told me that about GoSoapBox that he is using in his class room. He showed me how it works for 15 minutes earlier this week and I put together a board review style lecture that I did on Friday morning.
What immediately attracted me to GoSoapBox was that it was a web app. I did not need to hand out or customize my presentation for an Audience Response System with little remote controls for every student. All I did was flash a website and log in number on the opening slide. The residents then logged into my event on their phone or iPad or laptop. No one needed to download an app.
Then I went through a series of questions. These were questions I found in the dark bowels of the internet, they are not mine and I don’t know where they came from.
The Keynote is here (Keynote | PDF). The quiz is still open so you can down load the quiz and answer the questions if you like.
The residents had no trouble logging in when I flashed the website and access code on the screen. I tagged most slides with the log on information so late comers could join.
My first issue was I did not get good feedback on how many people had logged on. No messages flashed on my screen showing successful log ons. There is a box at the bottom of the event manager that showed number of people logged in, but with my iPad in landscape orientation, I could not see it unless I scrolled down. I would have liked a window listing the people who had logged on, right at the top.
When I started the lecture and we came to a question I received no feedback of the number of people who had answered it and could not get realtime feedback on how they answered. I can see the answers after the fact. GoSoapBox packages a beautiful spreadsheet of the questions and answers for download, but I did not get any realtime feedback. I needed simple things, like what percentage of people had answered the question so I could know when to reveal the answer and begin explaining the physiology.
I also could not see what answers people putting in to guide my explanation to what people found tricky.
Also the residents receive no feedback on whether they were right or wrong. It would be nice for them to get a score when they were done or even to enable question by question feedback.
In the end I tried to use GoSoapBox in a way that it was not intended. I made a quiz which is designed for students to plow through it from beginning to end and then I can evaluate it after the lecture. It looks like the feature I should have used was Polls. Here are the help videos for both tools.
Quiz
Poll
My feeling is that GoSoapBox looks like a promising tool but that I need more experience and knowledge on how to use it properly. I will keep posting my experience with it as I move forward. Smartphones and iPads are in the morning report classroom we just need to start leveraging them for education rather than fighting their primary use, distraction.
I wrote about similar technologies that I was introduced to at Med 2.0 at eAJKD.com.
I gave my healthcare and social media talk today at Grand Rounds at Providence Hospital. Great turnout. Good questions.
Some observations
People are concerned about the ubiquitous text messaging of clinical images. This is an opening for the forthcoming Figure 1.
Doctors are nervous about patient portals. No new observations here but I received a number of questions about this after my talk. Maybe my next talk should be Ready of Not Here Comes Meaningful Use Phase 2.
Clinical trial day is held on May 20th in honor of the first clinical trial, James Lind’s 1747 Trial on the treatment of Scurvy. The ironic thing is how shoddy the study design was. He took 12 sailors with scurvy and divided them into 6 groups of 2. He then treated each group with a different dietary supplement:
