NEW YORK (Reuters Health) - “Hands-only” CPR (cardiopulmonary resuscitation) is usually as effective as traditional CPR that includes mouth-to-mouth breathing - but the odds that cardiac arrest victims will survive with minimal brain damage are still quite low, a large study from Japan finds.

Researchers say the findings support statements from the American Heart Association and other groups that compression-only CPR can be a comparable alternative to the traditional technique of alternating chest compressions with mouth-to-mouth breathing.

Since 2008, the American Heart Association has recommended that when an adult suddenly collapses and isn’t breathing, bystanders should perform hands-only CPR -- strong, steady chest compressions, at a rate of 100 per minute -- unless they are confident in their ability to perform conventional CPR.

The reasoning is that hands-only CPR is easier for a layperson to learn and remember, and that people are more likely to administer CPR to a stranger if mouth-to-mouth contact is not required.

Moreover, studies in recent years have shown that hands-only CPR can be as effective as the traditional version for cardiac arrest caused by heart problems. (Cardiac arrest, where the heart stops pumping blood to the rest of the body, can also result from drowning, drug overdose or breathing problems; in those cases, CPR with rescue breaths is still recommended.)

But these latest results, published in the journal Resuscitation, also underscore the fact that regardless of CPR technique, the chances of surviving cardiac arrest, with or without significant brain damage, are still low.

Using national data on more than 55,000 Japanese adults who suffered a cardiac arrest in front of witnesses, the researchers found that roughly 7 percent of victims who received CPR from a bystander and were treated by paramedics within 15 minutes survived with a “favorable neurological outcome.”

There was no significant difference between those who received conventional CPR and those who received the hands-only approach: 7.1 percent and 6.4 percent, respectively, survived and had a favorable neurological outcome one month later -- meaning no greater than “moderate” brain damage that left them still able to perform routine daily activities on their own.

That compared with a rate of 3.8 percent among victims who received no bystander CPR and were treated by emergency medical services within 15 minutes of their collapse.

When treatment from paramedics was delayed for more than 15 minutes, survival with minimal brain damage was universally lower -- though somewhat higher with conventional CPR relative to hands-only and no CPR. Among victims who received no CPR, just 0.7 percent survived with no more than moderate brain damage one month later. That figure was 1.3 percent among those who received hands-only CPR, and 2 percent among victims who received conventional CPR.

Despite that small advantage, though, the findings still support the recommendation for most bystanders to perform hands-only CPR, according to the researchers, led by Dr. Tetsuhisa Kitamura of Kyoto University Health Service.

Dr. Michael Sayre, chair of the American Heart Association’s Emergency Cardiovascular Care Committee, agreed. In an interview, he noted that in most cases, paramedics will reach cardiac-arrest victims within 15 minutes.

But he said that the current findings underscore the importance of prompt action -- of bystanders not only starting CPR, but also immediately calling 911. CPR helps keep a cardiac-arrest victim’s blood flowing until emergency help arrives, but it cannot “restart” someone’s heart. An electrical shock from a device called a defibrillator can reverse cardiac arrest, but time is of the essence. It’s estimated that for every minute defibrillation is delayed, the odds of survival drop by 10 percent.

And while survival rates were low in this study, regardless of CPR technique, Sayre said that the “good news” is in the changes seen over time.

The 55,014 cardiac arrests in the study occurred between 2005 and 2007; it was in 2005 that the hands-only technique was first promoted as an “acceptable” way to perform CPR. And over that time, the proportion of cardiac-arrest victims who received CPR of any kind increased.

In the last few months of 2007, 28.5 percent received hands-only CPR -- up from 17 percent in the first few months of 2005. That was countered by only a small dip in conventional CPR -- from just under 20 percent in early 2005 to 17 percent in late-2007.

Moreover, overall survival with a good neurological outcome improved over time. In the last few months of 2007, those survival rates were 7 percent with hands-only and 6 percent with conventional CPR, compared with 3 percent and 4 percent, respectively, in early 2005.

“The good news is that it’s getting better over time,” Sayre said. And he predicted that if a greater proportion of cardiac-arrest victims got prompt CPR and emergency medical attention, more lives could be saved.

A study published last month in the Journal of the American Medical Association found that a mass campaign in Arizona to promote hands-only CPR may be paying off. Five years after the state began the effort, the percent of cardiac-arrest victims surviving to hospital discharge had more than doubled -- from less than 4 percent in 2005 to just under 10 percent in 2009.

At the same time, the rate of CPR increased from about 28 percent to 40 percent, with a steep increase in compression-only CPR and a drop in CPR with rescue breathing.

While other factors, including changes in medical care, may have been partially at work, the researchers tied hands-only CPR to a 60 percent increase in the odds of surviving cardiac arrest, versus both no CPR and conventional CPR.

“Performing hands-only CPR can be life-saving,” Sayre said, “and people should not hesitate to help.”

The American Heart Association has a Web site with information on how to effectively perform hands-only CPR, at handsonlycpr.org.

SOURCE: link.reuters.com/xyv77q Resuscitation, online November 22, 2010.