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Abstract 20905: The Force-Displacement Relationship in Commonly Used Resuscitation Manikins: Not Very Human


 Introduction:
 Manikins are widely used for CPR training and designed to simulate a human in cardiac arrest. Previous studies show a non-linear force-displacement relationship in the human chest. This may not be the case for resuscitation manikins. The aim of this study was to investigate the force-displacement relationship in commonly used resuscitation manikins.
 
 
 Methods:
 Commonly used infant and adult manikins for resuscitation training were included in the study. Manikins were tested by placing them in a material testing machine (ProLine Z050, Zwick/Roell, Ulm, Germany). A piston was placed on lower half of the sternum of the manikin. The testing machine applied a constant growing force downwards on the manikin chest while recording the force-displacement relationship. The test was stopped when either the manikin was nearly fully compressed or the displacement exceeded 7 cm. On manikins with adjustable compliance of the thorax, the medium setting was used. The force needed to achieve the recommended compression depth i.e. 3 cm and 5 cm were compared for infant and adult manikins respectively.
 
 
 Results:
 Seven different resuscitation manikins were included in the study; two infant manikins: Resusci Infant (Laerdal) and CPR Anytime® Infant (inflatable; American Heart Association) and five adult manikins: Mini Anne (inflatable), Little Anne®, Resusci Anne, Resusci Anne Advanced(Laerdal) and Ambu® Man (Ambu). Infant manikins required a force of 57 N and 34 N to compress the chest 3 cm. The force required to compress the adult manikins to a depth of 5 cm ranged from 195 N to 543 N. The force-displacement curve is shown in the Figure.
 
 
 Conclusions:
 Four out of five adult resuscitation manikins and one infant manikin had a nearly linear force-displacement curve different from the human chest. The Mini Anne and Resusci Infant showed a non-linear curve more like the human chest. The force needed to compress the chest to the recommended chest compression depth varied between manikins.
 
 
 
