Researchers found that of the 52 videos teaching CPR they discovered on YouTube, half were uploaded by individuals with no apparent health credentials.
Of the rest, most were posted either by a private group (not a government agency or medical group with official CPR guidelines) or by people who claimed they were a certified CPR instructor, a doctor or a paramedic.
As for content, there were many videos that gave accurate information on how to perform CPR, lead researcher Dr. Karthik Murugiah told Reuters Health in an e-mail.
However, there were also many that painted an incorrect or incomplete picture, according to Murugiah, an assistant professor at the Medical College of Wisconsin in Milwaukee.
Close to two-thirds, for example, either incorrectly described the rate of CPR chest compressions or did not cover that detail at all. And 57 percent fell short on showing viewers how deep the chest compressions should be.
According to the American Heart Association (AHA), the ideal rate is at least 100 compressions per minute -- coincidentally, about the same beat as the Bee Gees 1977 disco hit "Stayin' Alive."
Each compression should be about two inches (five centimeters) deep in adults and children, and about one and a half inches in infants. It's important to let the chest return to its starting position, so rescuers shouldn't lean on the chest between compressions.