Unexpected Increase in Survival Rates in ROC Study

Yesterday, the National Heart, Lung, and Blood Institute (NHLBI) announced that the ROC PRIMED clinical trial ended its enrollment period early and that preliminary data suggested neither strategy under investigation significantly improved survival. For those of us following the ROC studies, our ears pricked up at this news.

As background, the large, multicenter clinical trial, which involves approximately 280 EMS agencies, is comparing two resuscitation strategies delivered by EMS providers to increase blood flow during cardiac arrest.

The first part of the study compares early versus delayed defibrillation, and the second part involves a double-blind assessment of the impedance threshold device (ITD) during CPR. (Read more about the trial at JEMS.com.)

After a prescheduled review, the study's Data and Safety Monitoring Board (DSMB) recommended the NHLBI stop enrollment because sufficient data had been collected on approximately 11,500 study participants.

However, the principal investigators (PIs) haven’t analyzed all the data yet. They will remain blinded until they can assess the six-month neurological outcome of last patient enrolled.

"We expect to find interesting details in the data," says Ahamed Idris, MD, professor of surgery and medicine at the University of Texas Southwestern Medical Center at Dallas and PI for the Dallas ROC site. "We may find that the ITD worked better in some cities than others or find some EMS agencies where it didn’t work as well."

Idris explains that the DSMB just looked at the average outcomes for all 10 cities involved. "We really need to get into the data to get the final answer."

He also noted a very interesting point: The DSMB found an unexpected increase in survival to hospital discharge in all ROC sites, higher than previously reported in JAMA in 2008.

In Dallas, for example, Idris says they've found a 50% to 300% increase in their survival rates compared to the 2006 data that was published in 2008 JAMA.

Idris attributes the significant increase to two factors: 1) intensive training on providing excellent BLS care and 2) monitored performance for quality improvement efforts.

He explains that as part of study, they were required to monitor CPR performance, collecting files from defibrillators that showed compressions, ventilations and shocks. With this data, they were able to re-train and improve performance, which led to improved patient outcomes. He notes that he can’t speak for other cities because he hasn't seen their data, but he believes this is probably true for them.

The message to all EMS providers and system leaders, says Idris, is that any system can achieve significant improvements in save rates by focusing on effective CPR in the field.