Hemodynamic Effects of Standard Cardiopulmonary Resuscitation (CPR), Active Compression Decompression CPR With an Inspiratory Impedance Device, and Standard CPR With an Intrathoracic Pressure Regulator During Out-of-hospital Cardiac Arrest

Initial Inclusion Criteria:

• Subject is initially presumed or known to be 18 years of age or older;
• Subject presents with presumed non-traumatic, out-of-hospital cardiac arrest AND is a candidate for resuscitation attempt. [NOTE: the cardiac arrest may be witnessed OR unwitnessed];
• Subject has a secured cuffed advanced airway [e.g., endotracheal tube, Combitube, King airway].

Final Inclusion Criteria:

• Subject in whom femoral arterial access was successfully established;
• Subject remained in cardiac arrest (undergoing CPR) at the time of hemodynamic data acquisition;
• Subject in whom at least 5 minutes of continuous hemodynamic data were able to be collected, OR if ROSC occurs before 5 minutes, at least 2 minutes of hemodynamic data were able to be collected.

Initial Exclusion Criteria:

• Subject has known pre-existing DNR orders in place prior to this cardiac arrest;
• Subject has signs of obvious clinical death or conditions that preclude the use of CPR;
• Subject's family or legal guardians request that the subject not be entered in the study at the time of arrest;
• Subject has recent sternotomy, with wound not appearing completely healed (if date of sternotomy is unknown) or less than six months (if date of sternotomy is known);
• Subject has a stoma, tracheotomy, or tracheostomy prior to arrest;
• Subject is known or suspected to be pregnant;
• Subject is known/suspected to be a prisoner.

Final Exclusion Criteria:

• Subject in whom < 2 minutes of hemodynamic data were acquired while receiving CPR;
• Subject in whom an arterial pressure catheter was not placed or arterial pressure was not able to be successfully monitored;
• Subject is subsequently found to have had a traumatic arrest;
• Subject was in asystole at time of initial arrest AND remained in asystole during resuscitation effort AND arrest was unwitnessed or unknown if witnessed.