Comparison of Experimental Chest Compression Data to a Theoretical Model for the Mechanics of Constant Peak Displacement Cardiopulmonary Resuscitation

Abstract

The objective was to validate an existing theoretical model for the mechanics of constant peak displacement cardiopulmonary resuscitation (CPR) using experimental data taken using various back support surfaces at different chest compression (CC) rates. A CPR simulator was used to perform constant peak displacement CC on a weighted full-body CPR training manikin supported on surfaces of varying stiffness at different CC rates. The net sternum-to-spine displacement, combined chest and mattress displacement, and axial reaction force were measured during each test. The experimental results were compared to theoretical predictions from the constant peak displacement CPR model. The theoretical model predictions matched the experimental data to within a mean difference of 11.7% at a CC rate of 42 compressions per minute (cpm), 10.0% at a CC rate of 60 cpm, and 10.1% at a CC rate of 96 cpm, for a target maximum sternal displacement of 5.0 cm. The model predictions also show that when the back support stiffness is less than 250 N/cm, the benefit of using a backboard is greater than for stiffer support surfaces. Good quantitative agreement between the experimental data and the theoretical model suggests that the constant peak displacement CPR model provides reasonable prediction of CC mechanics during CPR over a wide range of CC rates. Conflicts in the literature are also explained by showing that backboards can significantly enhance CPR CC performance when the back support stiffness is less than 250 N/cm, while for surfaces with higher stiffness, the benefit of using a backboard is reduced.