Out-of-hospital cardiac arrest (OHCA) is a growing threat to public health all over the world. Two studies were published this week showing that bystander intervention involving cardiopulmonary resuscitation and/or automated external defibrillators help in increasing chances of survival and better outcomes in individuals who experience OHCA.

The studies, one carried out in Japan and the other in the United States, examined associations between the number of bystander interventions and the kind of progress people who undergo OHCA after they receive medical attention. The Japanese study used information from Japan's OHCA registry and worked with 167,912 patients who experienced bystander-witnessed cardiac arrest away from the hospital, while U.S. researchers turned to the Cardiac Arrest Registry to Enhance Survival which include 4,961 patients of the same type.

In the U.S., OHCA claims the lives of about 200,000 Americans each year. According to background information involving bystander intervention, early CPR and defibrillation may aid in improving outcomes if adopted more widely.

The Japanese study yielded a very modest improvement in surviving neurologically intact, which went from 3.3 percent to 8.2 percent, with age adjusted for proportion. The U.S. study's results were more positive, with the combination of CPR and defibrilation resulting in a 9 percent increase.

In Japan, over 1.4 million people are trained every year to integrate basic skills in resuscitation procedures, like the use of automated external defibrillators and chest compressions. According to Shinji Nakahara and colleagues, more bystanders may hesitate less to use CPR now that the procedure no longer necessitates mouth-to-mouth breathing. Chest compression also has an economic edge over automated external defibrillators because not using equipment is cheaper overall.

"Despite increased knowledge and use of bystander CPR as well as improved survival over time, ongoing efforts are needed to improve outcomes after OHCA," reminded an editorial that accompanied the studies.

Both studies were published in the journal JAMA.

Aside from Nakahara, Tetsuya Sakamoto, Jun Tomio, Naoto Morimura, Masao Ichikawa, Hideto Takahashi, Fumiaki Nakamura and Masamichi Nishida also participated in the Japanese study.

The U.S. study listed Carolina Malta Hansen, Christopher Granger, Kristian Kragholm, Bryan McNally, David Pearson, Monique Anderson, Clark Tyson, Benjamin Strauss, Lisa Monk, James Jollis, Brent Myers, Emil Fosbol, Darrell Nelson and Matthew Dupre as authors.

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