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.
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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.
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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:
- the primary disorder
- additional primary disorders, altering compensation
- If you add the sodium it will calculate the anion gap
- It will calculate the delta ratio to determine if there is an additional non-anion gap metabolic acidosis or metabolic alkalosis.
Pretty slick. It is by far the fastest ABG calculator I have seen. My position on ABGs can be summed up here:
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| Page 13, Acid Base Haggadah |
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.
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| 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.
- Dialyzing the highest potassium
- There once a dialysis patient from Nantucket…
- Cool Wikipedia page of the day: Hickam’s Dictum.
- When 1A evidence is not 1A evidence.
- Shame on you US News and World Report
- Do we need to EVOLVE our views on EBM in dialysis
- Team based learning, reason for optimism about medical education
- You hear about the kid who sold his kidney for an iPad?
- Three of them with each meal…
- Salty dog, the highest sodium I ever saw
- Dogs, squirrels and evolution
- The agony and ecstasy of of secondary hyperparathyroidism
- How the kidney works, a primer for non-medical folks
- One of my friends had a heart attack
- Celebrity interaction: How I “met” Margaret Atwood on Twitter
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.