Chest Compression-Only CPR Improves Survival in Heart Attack Patients

Researchers at Barnes-Jewish Hospital (St. Louis, MO, USA) combined the data from three studies in a meta-analysis to analyze survival rates in more than 3,700 cardiac arrest patients who received either standard CPR or chest compression only. By analyzing all three studies, the researchers were able to determine that survival improved by 22% when bystanders called 911 and were advised by the dispatcher to do chest compression-only CPR; whether a bystander had previous training in CPR had no effect on patient survival. The researchers also found that the benefit occurred only when dispatchers actually coached bystanders to use chest compression-only CPR.

In several uncontrolled studies that simply asked bystanders whether they did only chest compressions or standard CPR, the investigators found no survival benefit with the chest compression-only technique. The researchers explained that part of the reason earlier studies could not verify a statistical benefit from the chest-compression-only technique was that overall patient survival rate hovers around 10%. Even with 1,000 or 2,000 patients in a study, the total number of survivors was small, and thus was "underpowered” statistically and could not show a survival benefit. Only by combining data from all three studies to generate larger numbers were the investigators able to confirm improved survival. The study was published on October 15, 2010, in the Lancet.

"The heart doesn't literally stop during cardiac arrest,” said lead author Peter Nagele, M.D. "It gets super excited and electrically very active, and the only way to get it back into rhythm is with an electrical shock, a defibrillation. By doing chest compression-only CPR, a bystander is basically buying time until a paramedic with a defibrillator can jump-start the heart.”

The researchers stress that the findings do not apply to children with cardiac arrest, since it is very uncommon for children to go into cardiac arrest due to a primary heart problem. If cardiac arrest does occur, it is likely to be secondary to a severe asthma attack, an allergic reaction, or something else unrelated to the heart. Under those circumstances, the body needs oxygen, and the researchers therefore strongly recommend chest compression and rescue breaths in these children.

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