• Survival to hospital discharge with good neurologic recovery (measured by Modified Rankin Score 3 or less) [ Time Frame: Hospital discharge ] [ Designated as safety issue: Yes ]
  

• Rate of adverse events [ Time Frame: Cardiac arrest through hospital discharge ] [ Designated as safety issue: Yes ]
  
• Return of spontaneous circulation (ROSC) [ Time Frame: Time of cardiac arrest until discontinuation of efforts ] [ Designated as safety issue: Yes ]
  
• Survival to 1 hour [ Time Frame: One hour after cardiac arrest ] [ Designated as safety issue: Yes ]
  
• Survival to hospital (e.g., intensive care unit) admission [ Time Frame: Cardiac arrest through hospital admission ] [ Designated as safety issue: Yes ]
  
• Survival to 24 hours [ Time Frame: 24 hours following cardiac arrest ] [ Designated as safety issue: Yes ]
  
• Survival to 30 days [ Time Frame: 30 days following cardiac arrest ] [ Designated as safety issue: Yes ]
  
• Survival to 90 days [ Time Frame: 90 days following cardiac arrest ] [ Designated as safety issue: Yes ]
  
• Survival to 365 days [ Time Frame: 365 days following cardiac arrest ] [ Designated as safety issue: Yes ]
  
• Neurological recovery at hospital discharge, 30 days, 90 days, and 1 year [measured by Cerebral Performance Category (CPC), Overall Performance Category (OPC), and Health Utilities Index Mark 3 (HUI3); Cognitive Abilities Screening Instrument (CASI)] [ Time Frame: Various: hospital discharge through 1-year survival ] [ Designated as safety issue: Yes ]
  

Despite receiving conventional, standard CPR (S-CPR), most patients who experience out-of-hospital cardiac arrest die prior to arriving at a hospital. At the present time, the hospital discharge rate following out-of-hospital, nontraumatic cardiac arrest in adults in the United States is estimated to be less than 5%. Many factors contribute to the current poor survival statistics, including the inefficiency of the technique itself. CPR provides only 10% to 20% of normal myocardial perfusion, and only 20% to 30% of physiologically normal cerebral perfusion.

A new method of CPR that combines ACD and an ITD (ACD-CPR+ITD) has been shown in animal models and in clinical trials conducted in Europe to provide significantly more blood flow to the vital organs and to improve survival rates when compared to S-CPR or ACD-CPR alone.

ACD-CPR+ITD works by decreasing intrathoracic pressure during the chest wall recoil (or decompression) phase of CPR, creating a vacuum within the thorax relative to the rest of the body. When compared with controls, use of ACD-CPR+ITD (a) enhances blood return to the thorax during the chest wall recoil phase, (b) enhances blood flow to the heart and brain, (c) provides real-time feedback to rescuers to maintain high-quality CPR, (d) improves overall CPR efficiency and, as a result of the forgoing, (e) improves short-term survival rates.

The sponsor and others recently evaluated the effectiveness of the combination of conventional, manual standard CPR±ITD in animals and humans. The ITD increased short-term survival rates in these studies as well. Two clinical trials were performed in Milwaukee, Wisconsin, under IDE (#G980125). Both compared S-CPR with either a sham (nonfunctional or placebo) or active (functional) ITD. The results from the hemodynamic study demonstrated that systolic blood pressure, the primary end point, increased from approximately 45 mmHg with the sham ITD to approximately 85 mmHg with the active ITD (P less than 0.05). Intensive care unit admission rate was the primary end point of the clinical outcome study.

Comparisons: The objective of this two-arm, multisite, randomized, pivotal IDE clinical trial is to compare survival to hospital discharge with neurologic recovery rates in subjects receiving S-CPR compared to ACD-CPR+ITD following out-of-hospital cardiac arrest in well-established American emergency medical services systems.