Chest compression-only CPR better for cardiac arrest patients

Myocardial infarction patients suffering sudden cardiac arrest have a better chance of survival when they receive chest compression only cardiopulmonary resuscitation (CPR), according to a study led by researchers at the Washington University School of Medicine in St. Louis. 

Conventional CPR involves alternating chest compression with rescue breaths or mouth-to-mouth breathing has been found in a number of studies to be inferior to chest compression only CPR when it comes to reviving cardiac arrest patients.

The current study published online on Oct. 15 in The Lancet reviewed three studies and confirmed that the chest compression-only CPR improved survival rates over conventional CPR.

Principal investigator Peter Nagele, MD. said each individual study did not show a statistically significant improvement in the rate of survival because the cardiac arrest patients involved in the study were not enough to have a significant improvement.

But he said when three studies were combined, "there was a significant increase in survival when witnesses were told by 911 dispatchers to provide chest compression only."

Bagele ameta-analysed data from the three studies of more than 3,700 cardiac arrest patients who received either the conventional CPR or chest compression only CPR and found overall the survival improved by 22 percent when bystanders called 911 and were advised by the dispatcher to do chest compression only cardiopulmonary resuscitation.

"When a person goes into cardiac arrest because of a problem with the heart, that individual normally has plenty of oxygen in the body," Nagele explained. 

"So rescue breaths aren't as vital to survival as trying to keep blood flowing as regularly as possible. However, if cardiac arrest is secondary to trauma, drowning or a problem not directly related to heart function, then it is advisable to do standard CPR that includes rescue breaths. In those cases, getting oxygen into the system is crucial."

The findings do not apply to children with cardiac arrest, Nagele said.  He recommended chest compression and rescue breaths for children who experience cardiac arrest, which is very unlikely to occur as people experience cardiac arrest are likely in their 30s or 40s. 

Negeles said it does not make any difference in the survival rate whether a bystander had previous training in CPR or not. 

Sudden cardiac arrest is a condition in which the heart suddenly stops beating. Death is imminent if this condition is not normalized in three to five minutes due to massive brain damage from lack of oxygen.

Cardiac arrest is often times caused by arrhythmias meaning that the heart beats too fast, too slow or with an irregular rhythm. The condition differs from myocardial infarction or heart attack which occurs when blood flow to part of the heart muscle is blocked.

Cardiac arrest kills about 325,000 people each year in the United States.  Cardiopulmonary resuscitation or CPR can only revive a small percentage of the patients.

Jimmy Downs and editing by Rachel Stockton