ResQ Trial: Impact of an ITD and Active Compression Decompression CPR on Survival From Out-of-Hospital Cardiac Arrest

ResQ Trial: Comparison of Standard CPR Alone Versus Active Compression Decompression CPR Plus an ITD on Survival From Out-of-Hospital Cardiac Arrest

The purpose of this study is to determine whether performing active compression decompression cardiopulmonary resuscitation (ACD-CPR) with an impedance threshold device (ITD) compared to conventional standard cardiopulmonary resuscitation (S-CPR) will impact the neurologic recovery and survival to hospital discharge following out-of-hospital cardiac arrest.

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.

Inclusion Criteria:

• Adult subjects initially presumed or known to be 18 years of age or older
• Subjects who present with out-of-hospital cardiac arrest from presumed cardiac etiology and who receive CPR by Emergency Medical Services (EMS) personnel for at least 1 minute
• Subjects whose airways are managed with a cuffed ET tube, combitube, or laryngeal mask airway or facemask

Exclusion Criteria:

• Adult subjects presumed or known to be less than 18 years of age
• Subjects with known or likely traumatic injuries causing cardiac arrest or cardiac arrest of presumed noncardiac origin
• Subjects with preexisting Do Not Resuscitate (DNR) orders
• Subjects with signs of obvious clinical death or conditions that preclude the use of CPR
• Family or legal representative request that the subject not be entered into the study
• Subjects experiencing in-hospital cardiac arrest
• Subjects with a recent sternotomy with wound not appearing completely healed (if unknown) or less than 6 months (if known)
• Subjects who received less than 1 minute of CPR by EMS personnel
• Subjects with a complete airway obstruction that cannot be cleared or in whom attempts at advanced airway management are unsuccessful
• Subjects intubated with a leaky or uncuffed advanced airway device or presence of stomas, tracheotomies, or tracheostomies
• Subjects who rearrest and are encountered by EMS within 365 days of the index cardiac arrest