Overview
THIS IS A STUDY IN WHICH YOU CAN BE ENROLLED WITHOUT YOUR CONSENT
Cardiac arrest is the sudden, abrupt loss of heart function. Death usually occurs within minutes unless cardiopulmonary resuscitation (CPR), rapid defibrillation, and paramedic interventions are available. CPR consists of pumping on the patient’s chest and delivering breaths to produce some circulation until the heart can be restarted. When the chest is compressed, oxygen-rich blood is pumped forward. When the chest is released, oxygen-poor blood is brought back to the heart and lungs where it can be restored with oxygen before being pushed out to the body with another compression. Both actions – pushing oxygen-rich blood forward and bringing oxygen-poor blood back to the heart and lungs - are important. CPR however produces only about 30% of normal circulation. Methods to improve the circulation produced by CPR may lead to better survival.
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.
CPR
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 Seattle and King 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. Seattle and greater King County are one of the 10 communities. Although these approaches appear promising and safe, they are yet to be proven to save lives.
If you still have questions after reviewing the website, please contact us via e-mail at kcroc@u.washington.edu. (Note that the confidentiality of e-mail communications cannot be guaranteed) or at 206-447-5671 where you will be able to leave a voice message. The e-mail and voice mails are checked regularly and you can expect to receive a reply within 3 days.