Doing CPR too fast can mean chest compressions aren't deep, a new study from Belgium suggests.
Researchers found that when rescuers pushed at a rate above 145 compressions per minute, the depth of those compressions dropped to less than four cm.
Recommendations from Europe and the United States now both call for compressions to be at least five cm deep (about two inches), at a rate of 100/min or faster.
For the new study, Dr Koenraad Monsieurs from Antwerp University Hospital in Belgium and his colleagues used an accelerometer to measure chest compression rate and depth during CPR performed by healthcare professionals on 133 patients.
They found very fast compressions were often shallower than ones closer to a rate of 100/min. And at about 145/min, the depth got "unacceptably low," the researchers reported in Resuscitation.
That was according to 2005 European guidelines calling any compressions four cm or more deep enough. Since then, the standard has been raised.
"From my experience doing CPR - I had the impression that some rescuers would think, the faster the better," Dr Monsieurs said. "It turns that for most rescuers, when they really go too fast the compression depth becomes insufficient."
Healthcare professionals can get speed and depth feedback from compression-measuring devices like accelerometers - but for bystanders the most important thing is just to do CPR in the first place, said Dr Benjamin Abella, an emergency physician at the Hospital of the University of Pennsylvania in Philadelphia, who wasn't involved in the new study.
For bystanders who aren't professionally trained in CPR, one option is to try to push along to the Bee Gees 1977 disco song "Stayin' Alive," which happens to have a rhythm of 100 beats per minute.
(Reuters Health, July 2012)
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