AnaSim

AnaSim is a real-time adult anesthesia simulator for teaching and model exploration. It combines published pharmacokinetic, pharmacodynamic, and cardiorespiratory models with a patient monitor and anesthesia machine.

Run AnaSim

In the browser: open robche.com/AnaSim. It runs on your device through Pyodide. The first visit downloads about 23 MB.

Locally (Python 3.10 or later):

python3 -m venv .venv
source .venv/bin/activate      # Windows: .venv\Scripts\activate
python -m pip install anasim-simulator
anasim

anasim opens the simulator in your browser and runs it in Python on your computer. It works offline. Stop it with Ctrl+C.

To begin, choose Guided scenario and TIVA induction, then Start simulation. The clock runs once you press Start simulation again below the monitor. Each objective has a button that opens the controls it needs.

What's included

• Drugs: propofol, remifentanil, sevoflurane, rocuronium, sugammadex, norepinephrine, epinephrine, phenylephrine, vasopressin, dobutamine, and milrinone, given by infusion, bolus, or effect-site TCI.
• Machine: facemask or tracheal tube, fresh gas flow, vaporizer, bag-mask ventilation, and VCV, PCV, PSV, or CPAP.
• Monitor: ECG, SpO₂, arterial line, NIBP, capnography, BIS, TOF, temperature, fluid balance, and alarms.
• Events: fluids and blood, surgical stimulation, airway obstruction, bronchospasm, laryngospasm, hemorrhage, anaphylaxis, sepsis, and arrhythmias.
• Guided scenarios: TIVA and inhalational induction and emergence, hemorrhage, anaphylaxis, septic shock, and oxygen supply failure.

Record CSV saves the simulation as a time series. The local version writes it to recordings/ in the directory where you ran anasim; the browser version downloads it.

Limits

Patients must be adults aged 18 to 70 years, weighing 50 to 100 kg, 150 to 200 cm tall, with a BMI of 18 to 32 kg/m². These are the ranges of the volunteer studies used to build the hemodynamic and norepinephrine models.

Respiratory drug effects, neuromuscular block, the baroreflex, and vasoactive responses use AnaSim calibrations fitted to published data. The model references list the sources.

Displayed values include monitor lag and artifact. Acid-base balance, lactate, tissue oxygen debt, machine pneumatics, and resuscitation are not modeled.

Headless use

anasim --mode headless --duration 60 --record

This runs 60 simulated seconds without the interface and writes a CSV to recordings/. Use --config to set the patient, models, and starting state from a JSON file; the CLI guide lists the fields.

Documentation

• CLI usage
• Model references
• Architecture
• Contributing
• Changelog

Citation and license

Cite AnaSim using CITATION.cff. AnaSim is released under the MIT License. The first TIVA implementation was derived from Python Anesthesia Simulator.