November 17, 2013
38 Minutes Worth Of CPR Improves Cardiac Arrest Survival Rate
redOrbit Staff & Wire Reports - Your Universe Online
Sustaining CPR for at least 38 minutes can improve a person’s chances of surviving a heart attack and increase the odds that a cardiac arrest survivor will have regular brain function, according to research presented Saturday at the American Heart Association’s Scientific Sessions 2013 conference in Dallas.
“Cardiac arrest occurs when electrical impulses in the heart become rapid or chaotic, causing it to suddenly stop beating,” the heart-health organization explained in a statement, adding that “about 80 percent of cardiac arrests - nearly 288,000 people - occur outside of a hospital each year, and fewer than 10 percent survive.”
Previous research has shown that it is critical to resume spontaneous circulation (the name for the condition during which the body pumps blood on its own) as early as possible to preserve normal brain function. However, the American Heart Association points out that few studies have examined the period between the start of a heart attack and the point to which spontaneous circulation is re-established.
In their new study, Dr. Ken Nagao, a professor and the director-in-chief of the Department of Cardiology, CPR and Emergency Cardiovascular Care at Surugadai Nihon University Hospital in Tokyo, and his colleagues used data from a registry tracking all non-hospital cardiac arrests that occurred in Japan between 2005 and 2011.
Specifically, they looked at the amount of time that passed between the initial collapse and the return of normal blood flow, as well as how well the brain function of the survivors was preserved one month after their heart attacks. They determined that those who were alert and able to resume regular activities has fared well neurologically, as well as those who had moderate disability but could work part-time or take part in day-to-day activities independently.
According to Nagao’s team, 13 minutes passed between the onset of the heart attack and the return of spontaneous circulation for those who fared well. In comparison, those who suffered severe neurological damage as a result of their heart attack had to wait approximately 21 minutes for normal blood flow to be restored.
“After adjusting for other factors that can affect neurological outcomes, researchers found that the odds of surviving an out-of-hospital cardiac arrest without severe brain damage dropped 5 percent for every 60 seconds that passed before spontaneous circulation was restored,” the American Heart Association said.
“Based on the relationship between favorable brain outcomes and the time from collapse to a return of spontaneous circulation, the researchers calculated that CPR lasting 38 minutes or more was advisable,” the agency also said. Their standards advise those administering CPR to continue doing so until emergency crews arrive on the scene.
The study was conducted by the Japanese Circulation Society Resuscitation Science Study and presented during the conference on Saturday. Co-authors of the research included Dr. Eizo Tachibana, Dr. Tukasa Yagi, Dr. Naohiro Yonemoto, Dr. Morimasa Takayama, Dr. Hiroshi Nogoni, Dr. Shinichi Shirai, and Dr. Takeshi Kimura.