title: A Novel Nonlinear Mathematical Model of Thoracic Wall Mechanics During Cardiopulmonary Resuscitation Based on a Porcine Model of Cardiac Arrest.
abstract: Cardiopulmonary resuscitation (CPR) is used widely to rescue cardiac arrest patients, yet some physiological aspects of the procedure remain poorly understood. We conducted this study to characterize the dynamic mechanical properties of the thorax during CPR in a swine model. This is an important step toward determining optimal CPR chest compression mechanics with the goals of improving the fidelity of CPR simulation manikins and ideally chest compression delivery in real-life resuscitations. This paper presents a novel nonlinear model of the thorax that captures the complex behavior of the chest during CPR. The proposed model consists of nonlinear elasticity and damping properties along with frequency dependent hysteresis. An optimization technique was used to estimate the model coefficients for force-compression using data collected from experiments conducted on swine. To track clinically relevant, time-dependent changes of the chest's properties, the data was divided into two time periods, from 1 to 10 min (early) and greater than 10 min (late) after starting CPR. The results showed excellent agreement between the actual and the estimated forces, and energy dissipation due to viscous damping in the late stages of CPR was higher when compared to the earlier stages. These findings provide insight into improving chest compression mechanics during CPR, and may provide the basis for developing CPR simulation manikins that more accurately represent the complex real world changes that occur in the chest during CPR.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA, 19104-4399, USA. jalaliA@email.chop.edu.|Villanova Center for Analytics of Dynamic Systems (VCADS), Villanova University, Villanova, PA, 19085, USA. jalaliA@email.chop.edu.
authors.forename: Ali
authors.initials: A
authors.lastname: Jalali
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine at the University of Pennsylvania and The Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA, 19104-4399, USA.
authors.forename: Allan F
authors.initials: AF
authors.lastname: Simpao
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine at the University of Pennsylvania and The Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA, 19104-4399, USA.
authors.forename: Vinay M
authors.initials: VM
authors.lastname: Nadkarni
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine at the University of Pennsylvania and The Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA, 19104-4399, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Berg
authors.affiliation: Villanova Center for Analytics of Dynamic Systems (VCADS), Villanova University, Villanova, PA, 19085, USA.
authors.forename: C
authors.initials: C
authors.lastname: Nataraj
mesh_terms: D000465:Algorithms; D000818:Animals; D001696:Biomechanical Phenomena; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D004195:Disease Models, Animal; D005260:Female; D006323:Heart Arrest / Q000503:physiopathology* / Q000628:therapy*; D008954:Models, Biological; D017711:Nonlinear Dynamics; D013552:Swine; D035441:Thoracic Wall / Q000378:metabolism*
keywords: Biomechanical modeling; Cardiopulmonary resuscitation; Chest compression; Chest wall properties; Hysteresis; Parameter estimation