Calculate what your human crave online https://radioxoma.github.io/heval/
Heval is an advanced medical calculator and decision support system for intensive care units. It is available as a web app, a desktop app, and a Python package for integration with existing medical information systems.
Heval aims to achieve an ambitious goal: unifying multiple calculations within a single robust human model.
When the model properties are populated with anthropometric and laboratory data, it derives additional human features (calculated properties) and executes a comprehensive rule set of validation and diagnostic checks. Found issues are represented as broad text report and set of flags. The flag is a short distinct warning with a reason, description, color coded severity and action required.
Main features:
- Minimal user input — unknown values estimated automatically whenever possible (e.g. weight by height)
- Only measurable parameters — no need to speak with a human of interest, no opinion controversy
- No "Calculate" button — evaluated data changes immediately with your input
- Every calculation referenced and explained in source code, so everyone can reproduce it
- Python package can be integrated into medical information system
- It's got electrolytes
There are overwhelming amount of model properties, but filling them all is not required. Only sex and height are mandatory.
Tip: Get yourself a ruler or Broselow tape, not all humans are able to talk.
Just enter sex and height. That's it! Ideal body weight is used by default - uncheck Use IBW and enter real body weight if known. Age, even for children, is not mandatory because it has poor prediction power.
- Anthropometry. IBW, BMI, BSA, blood volume. Broselow-Luten color zones for children.
- Respiratory. Use as start ventilator settings for adults and children.
- Nutrition
- Generic approximation for healthy human. Real demands are unpredictably dependent on body fat/muscle compound, fever, sepsis, burns etc. REE formulas has been taken from original papers, so your lovely Harris-Benedict equation don't have dubious correction coefficients, leading to irreproducible result.
- Based on ESPEN 25-30 kcal/kg recommendation and nitrogen balance. Use indirect calorimetry if you need a real tool.
- Fluid demands. Generic approximation for healthy human. Pathologic fluid loss must be taken into account
- Urinary output, dialysis dose. Simple ml/kg/h approach for adults and children, though eGFR estimation may be necessary
Tip: You can test Heval's ability to interpret ABG with case studies. Some books provide case studies with invalid data (see below).
ABG test reveals main and mixed acidosis-alkalosis, suggests urgent correction measures and infusion therapy. Prefer arterial blood sample, but venous will work too.
- Enter pH and pCO2 for simplest acid-base status assessment.
- pH correction. Papers deny benefit from iv bicarbonate if BE >-15 mEq/L. Mortality decrease is possible in AKI patients. No validated formula found.
- Enter Na+, Cl-, K+ to reveal hidden processes (via anion gap, delta-gap) and general electrolyte disturbances
- Algorithm is able to detect mixed acid-base disorders, vomiting etc
- Excellent prediction, but please USE REAL DATA
- Hi-low electrolytes correction strategies (sex and weight used only for dosage calculations, not for ABG diagnostics itself). Exact depletion/excess estimation is impossible due to multiple body compartments. High/low warnings still usable though.
- K+ — no reliable model, use daily requirement and standard iv replacement rate for hypokalemia.
- Na+ — Adrogue and classic one compartment model.
- Cl- — no model at all. Multiple calculation methods in books, few applicable in real world.
- Tips for emergency cases
- Enter albumin and glucose for complex cases
- If there are metabolic acidosis and patient is starved, enter albumin for anion gap correction
- DKE/HHS detection
- Hyperosmolar pseudohyponatremia estimation
- Na and glucose used for serum osmolarity estimation
Warning: Blood management is a serious deal and anyone involved must be trained and certified.
Enter Hb, PLT, Fib, INR to estimate overall recommendations and transfusion dose for a stable patient without continuous bleeding. Heval will point at obvious issues, but normal lab values of routine coagulation tests won't reveal impact of modern drugs (anti-Xa, antiplatelet) and have nothing to do with surgeon hands curvature.
Human model has many other properties, but filling them manually may not worth time spent. They exist for completeness and medical information system integration.
- eGFR Cockcroft-Gault, CKD-EPI 2021 for adults, Schwartz revised 2009 for children.
Please use a real patient's data: all electrolytes interconnected by electroneutrality law, Henderson-Hasselbalch equation. So even if you enter values in reference range, calculations can produce a broken result, especially anion gap (e.g. 149 - (101 + 24) = 24 which is >16 mEq/L!).
Some imagined case studies from books aren't designed well and will fail too.
Heval is an experimental software. Whatever it calculates, it's your decisions will affect your human's live longevity. I have no responsibility for your collateral damage.
Since 2026 development switched towards web app. Desktop app is obsolete.
Details
Download exe file from the releases page. Just run it — installation is not required.
- v0.1.5 is last compatible with Windows XP SP3 x86 and python 3.4.3.
- Latest version can be installed with
pip install https://github.com/radioxoma/heval/archive/main.zip.
Download dmg file (Apple Disk Image with 64-bit Heval.app) from the releases page. Unpack Heval.app from dmg. Application unsigned, so warning "macOS cannot verify the developer of 'Heval'" will appear if you try to run it. You can overcome this in one of two ways:
- Press Control and simultaneously click on unpacked Heval.app. Click Open in appeared context menu. Click Open in appeared window
- Run in terminal
xattr -dr com.apple.quarantine "Heval.app". Now "Heval" can be run by click
Heval is written in python and uses tkinter for GUI.
$ sudo apt install git python3-tk # Debian / Ubuntu $ sudo pacman -S git python tk # Archlinux
$ git clone https://github.com/radioxoma/heval.git $ cd heval $ pip install . $ python -m heval # Run code directly
Instead of executing python -m heval it's possible to double-click 'heval.desktop'.
