BreathSim, a mathematical model-based simulation of the anesthesia breathing circuit, may facilitate testing and evaluation of respiratory gas monitoring equipment.

BreathSim is a new computer simulation of the anesthesia breathing circuit, ventilator, and respiratory system. The system permits user-control over various respiratory parameters, ventilator functions, and the integrity and performance of the anesthesia machine and breathing circuit. Respiratory gas pressure, flow, and carbon dioxide (CO2) concentration data may be simultaneously displayed from several locations in the system. Pressure-volume and flow-volume tracings (spirometry) are displayed as well. In addition, an animation which is synchronized to the simulation displays the movement of oxygen and CO2 in the system. We propose the use of the simulator to test and evaluate the software algorithms utilized in respiratory gas monitoring equipment and anesthesia workstations. The output of the simulator can provide a "patient signal" input to the monitor and specific algorithms (e.g. breath detection, waveform recognition) could be evaluated. Rare but significant clinical states may be easily simulated, and the simulator may be driven by "scripts" to permit reproducibility.