Metabolic, hemodynamic, and respiratory responses to performing cardiopulmonary resuscitation

The purpose of this study was to evaluate the cardiorespiratory demands inherent to the maintenance of continuous one- and two-man cardiopulmonary resuscitation (CPR) for 10 min. Ten male paramedics (X age = 26 yrs) certified to perform CPR participated. Each subject assumed the three possible roles for administering CPR: ventilator, compressor, and one-man technique. Cardiorespiratory responses were determined by impedance cardiography and open-circuit spirometry at 2 min intervals while performing CPR with a resuscitation manikin. Left ventricular performance was evaluated by impedance ventricular function indices (VFI) and systolic time intervals (STI). All three roles elicited an increase in oxygen uptake compared to kneeling rest, with the roles of one-man and compressor being the most demanding. There were moderate increases in cardiac output and heart rate during the exercise roles, but stroke volume remained similar to resting values. Pulmonary ventilation increased during exercise, with the greatest increase occurring for the one-man role. STI and impedance VFI reflected an enhanced ventricular performance while performing the roles of one-man and compressor. These findings suggest that the energetic demands placed on the rescuer depend upon the specific role assumed. Properly trained and experienced individuals can perform CPR efficiently for at least 10 min while eliciting only moderate physiological stress.