Mouth-to-mouth rescue breathing should accompany chest compressions when performing CPR on a child, the study suggests. (CBC)

The old-fashioned version of cardiopulmonary resuscitation (CPR) with mouth-to-mouth and chest compressions may work better for children in cardiac arrest, a new Japanese study suggests.

Since 2008, the American Heart Association has recommended compressions alone for someone outside of hospital whose heart stoppage is of presumed cardiac origin, based on studies showing mouth-to-mouth or ventilation didn't improve overall survival and reduced the likelihood that a bystander would help.

In Wednesday's issue of the Lancet, Japanese researchers examined the medical records of 5,170 patients aged 17 and younger who had a cardiac arrest outside of the hospital — the first comparison of compression-only versus compression-with-ventilation CPR in children.

The combination approach was linked with greater survival and better neurological outcome (good performance or moderate neurological disability on a standard scale) after one month.

A "favourable neurological outcome" was more likely for children who received any CPR by a bystander (4.5 per cent or 110 out of 2,439 patients) than no CPR (1.9 per cent or 53 out of 2,719 patients), Dr. Taku Iwami of Kyoto University Health Service and co-authors found.

Conventional CPR with mouth-to-mouth was more likely to preserve neurological function (7.2 per cent or 45 out of 624 patients) than compression-only CPR (1.6 per cent or six out of 380).

The value of rescue breathing or mouth-to-mouth during CPR by bystanders depends on the cause of the cardiac arrest, the study's authors noted.

CPR can be effective with chest compressions and rescue breathing or chest compressions alone after ventricular fibrillation cardiac arrest, where the heart's ventricles or lower chambers contract in a rapid, unsynchronized way so that little or no blood gets pumped. Without immediate medical treatment, people with ventricular fibrillation can die.

In contrast, for cardiac arrest brought on by lack of oxygen in the blood, conventional CPR with chest compression and rescue breathing is more effective than just compressions.

Not surprisingly, the study's authors said, conventional CPR with mouth-to-mouth this study seemed to be most important for cardiac arrests after hanging, drowning, drug overdose and acute respiratory problems, which account for about 70 per cent of cases in children.

Approach for parents, teachers, lifeguards

Based on the new data, the researchers said they strongly recommend that conventional CPR with rescue breathing continue to be the standard treatment for children who have cardiac arrests outside of hospital with presumed non-cardiac causes, such as drowning.

"Our data lead us to lend support to a double CPR training strategy: compression-only CPR training for most people to increase bystander CPR by bystanders, and conventional CPR (chest compression plus rescue breathing) training for individuals who are most likely to witness children who have cardiac arrests with non-cardiac causes, such as medical professionals, lifeguards, school teachers, families with children, and families with swimming pools," the study's authors concluded.

The researchers acknowledged limitations of the study, including that people who provide rescue breathing might have been better trained to give compressions, and the lack of longer followup. Age, sex, time from collapse to first resuscitation attempt and time of arrival at hospital were taken into account in the analysis.

In a commentary that accompanies the study, Dr. Jesus Lopez-Herce and Dr. Angel Carrillo Alvarez of the pediatric intensive care service at Hospital General Universitario Gregario in Madrid said the "data underlines the importance of not extrapolating findings from adults to children, because cardiac arrest in children has specific characteristics."

"Although further studies are necessary, we believe that no changes should be made to recommendations for pediatric bystander-initiated CPR. Chest compression plus ventilation should continue to be the standard, a technique that should be taught to the whole population," the pair said.

For people trained in CPR, the Heart and Stroke Foundation of Canada recommends conventional CPR with chest compressions and mouth-to-mouth, while hands-only CPR is a potentially life-saving option for untrained bystanders.

"Hands-only CPR should not be used for infants or children, for adults whose cardiac arrest is from respiratory causes (like drug overdose or near-drowning), or for an unwitnessed cardiac arrest," according to the Heart and Stroke Foundation's online position statement.

"In these situations, evidence shows that the victim would benefit most from the combination of chest compressions and mouth-to-mouth breaths that are performed using conventional CPR."