Several recent studies suggest that compression only CPR (CCPR) has similar or superior outcomes to the standard AHA guidelines CPR (S-CPR). However, it has been difficult to rigorously study the key metabolic and hemodynamic endpoints in the acute clinical environment. A systems analysis approach employing a mathematical model of human physiology (Guyton/Coleman/Summers model) was used to compare the expected physiologic perturbations of S-CPR and C-CPR strategies.