Computer Simulation Of The Mathematical Model Of Physical Procedures Of Time-Cycle Mechanical Ventilation

Objective To simulate the mathematic expressions of the five subfunctions of one total time-cycle ventilatory period dynamically by computer programming and build a platform for rapid demonstration and analysis of the theoretical curves, and to discuss the feasibility of the simulation of ventilation based on other cycling principles.Methods All the five subfunctions were determined to be five-section expressions after analyzing the whole period of mechanical ventilation. The initializing period, inspiratory period, switch period, expiratory period and end-expiratory period of mechanical ventilation were further analyzed with Bernoulli equation, by which the expressions of time-velocity curve, time-flow rate curve, time-pulmonary volume curve, time-alveolar pressure curve and time-airway pressure curve were derived respectively. The functions were then simulated statically with Excel and demonstrated dynamically with Borland Delphi 6. The simulated curves were compared with those obtained from clinical monitoring.Results The simulative curves of the five subfunctions were highly similar to those captured from monitors. While subtle differences still exists. Conclusion Theoretical curves of various kinds of ventilators can be analyzed and simulated on the basis of the five subfunctions of the physical procedures of mechanical ventilation. The changes of the curves and their relations with physical factors can be explained with the five subfunctions. They also have guiding significance for the design and improvement of ventilators. The simulation of different kinds of clinical condition is important for clinical practice of mechanical ventilation. The demonstration software can be put into use inmedical education as a multimedia tool.