The Resuscitation Outcomes Consortium
ROC PRIMED - Overview (page 2)
Impedance Threshold Device (ITD)
One experimental device, called an impedance threshold device or ITD, is being studied in this clinical trial. The ITD is a device smaller than your fist that attaches to the end of the breathing bag used by EMTs and paramedics. The ITD works to bring more oxygen-poor blood back to the heart so that ultimately more oxygen-rich blood is available to be pushed forward.
The timing of the CPR compressions is also being studied in this trial. Some evidence indicates that the period right before the heart is shocked may be especially important for the heart to have the best chance to regain its own natural heart beat. Experts have long believed that the first priority when trying to restart the heart was to shock the abnormal heart rhythm. More recently however some evidence has indicated that CPR should be the priority before delivering the shock. The research indicates that delaying the shock a few minutes to provide CPR may actually help the heart. The CPR seems to prime the heart pump so that after a few minutes of CPR the shock is more likely to produce a natural heartbeat than if the heart was shocked right away.
A study is planned involving the Emergency Medical Services of Portland and Multnomah County to evaluate whether either of these strategies -- the ITD or priming the heart with CPR before the shock -- will improve survival following cardiac arrest. The study is entitled ROC-PRIMED (Resuscitation Outcomes Consortium Prehospital Resuscitation using an Impedance threshold device and Early versus Delayed rhythm analysis), is supported by the National Institute of Health and will involve 10 communities from across the United States and Canada. Portland and greater Multnomah County are one of the 10 communities. Although these approaches appear promising and safe, they are yet to be proven to save lives.