One of the first tasks many medical students are told to interpret on wards are the ever intimidating arterial blood gas or ABG. Interpretation of ABG’s can cause even the most confident student or junior resident to get sweaty palms along with X-ray and EKG interpretation. Over the years, many facilities (usually ER’s) are using less painful and easier to obtain venous blood gases. Some forgo the classic ABG interpretation sequence altogether and claim that “hard” base deficit calculations are the way to go. With the advent of the smartphone, many developers have created acid-base apps. eBloodGas, favorably reviewed on iMedicalApps, ABG eval by Dr Joshua Steinberg, ABG, Acid Plus, and many others are available for iOS and some for Android. One of the latest entries to the ABG evaluation field is Friendly Base Deficit Calculator from the Medical College of Wisconsin. The app was developed via a contest between physician-student teams; undergrads from the University of Wisconsin-Milwaukee worked with physicians and scientists at the Medical College of Wisconsin.

The app claims its “friendly” title because instead of using the traditional bicarbonate based approach to acid-base calculations, the app uses a base deficit based approach. This supposedly makes it simpler in that you only need three values: pH, PaCO2, and the base deficit. Most ABGs and VBGs obviously include this information plus the bicarbonate. When you open the app it states the “One Easy Rule”: PaCO2 of 12=pH of 0.1=Met Ac of 6. The app does allow the user to input the patient’s Na, Cl, lactate, albumin, and Cr. The more data you have the more information the app can analyze.

Clinical Scenario:

You are the intern on the medical wards taking care of a 65 year old male with a worsening COPD exacerbation. You are concerned the patient may need rescue bi-level (BiPap) or even intubation. You order a STAT ABG. The respiratory therapist hands you the results. You think you know how to interpret the information, but consult Friendly Base Deficit Calculator to see if it can help you with the interpretation. Let’s take a look at the app in action and see how it compares to the competition.

Login to iMedicalApps in order to view the following video review of Friendly Base Deficit Calculator. Registration for iMedicalApps is free.

Evidence based medicine

The Friendly Base Deficit app clearly contains a good deal of acid base evidence. Unfortunately, the app does not include any links to this evidence or references in the app. There is nothing showing/proving this approach is a more evidence based or superior approach to the traditional bicarbonate based approach.

What providers would benefit from this App?

Students, residents, mid-levels, nurses, physicians or anyone working in critical care medicine.

Disclaimer: The views expressed are those of the author(s) and do not reflect the official policy of the Department of the Army, the Department of Defense or the U.S. Government.

  • Price
    • Free
    • User interface accepts data easily.
    • Permits graphing of individual and multiple patient data over time .
    • Impressive detail on the results the more data is entered into the app.
  • Dislikes
    • No directions or references on use of app.
    • Uncertain utility compared to more traditional ABG interpretation.
    • Built in information windows not helpful.
    • The “One Easy Rule” is neither easy or friendly.
  • Overall

    The apps strictly base deficit approach to acid-base dilemmas will be foreign to many practicing providers limiting its effectiveness at the point of care. May be useful to those first learning acid-base, but without any directions or references, the app fails to make its case as “friendly”.

  • Overall Score
  • User Interface

    Simple to enter data into the UI and robust data on the results just minimal explanation of its meaning.

  • Multimedia Usage

    The app includes a nifty graphing function for patient data over time, but no links to information on the advantages, pearls/pitfalls of the “hard” base deficit approach.

  • Price

    App is free and certainly worth a look for those interested in a different approach to acid base calculations.

  • Real World Applicability

    The app simply doesn’t make itself user friendly enough to supplant any number of alternative acid-base apps such as Dr Joshua Steinberg’s excellent ABG eval app which teaches as you input information into the app.

  • Device Used For Review

    iPhone 6 running iOS 8.4

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