A novel method to simulate force-chest displacement relationship during cardiopulmonary resuscitation

摘要

Survival from cardiac arrest is dependent on timely cardiopulmonary resuscitation (CPR). Experimental and modeling work had shown that the relationship between compression force and sternal displacement had a tendency of hysteresis curve, which in manikins was rather lineal. A novel method was introduced to improve the mechanical characteristics of the manikins using a variable-stiffness springs group-damper structure, in which the spring's group and the damper simulate the elastic and damping of human chest respectively. To do the simulation, the model of the human chest's mechanical during CPR based on Gruben's pre-result was modified and the elastic part was fitted by piecewise linear function to get the springs' stiffness. The variable-stiffness springs group system was designed accordingly to simulate the human chest' stiffness during CPR, and a damper was designed to simulate the damping of chest. The damper and the variable-stiffness springs group were paralleling combined, forming a mechanical system. A sample system was realized and the test results showed that there were nonlinear elasticity and adequate viscosity in this system, whose coefficients were adjacent to Gruben's 'typical' human. According to the method, the mechanical system could be changed to accurately simulate different models, and its stiffness could be easily adjusted by varying the interval between the nest springs' top. The simulation method could be used directly in manikin, whose mechanical character would be improved and then more adequate training would be provided.