YouTube may be a great place to watch a dog play the accordion, but a new study suggests it's not the most reliable source for learning CPR (cardiopulmonary resuscitation).

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.

Another gap in the videos was that only a handful of them dealt with "hands-only" CPR, where bystanders skip the traditional mouth-to-mouth breathing and perform chest compressions only.

That's important because the AHA and other medical groups now recommend that whenever an adult suddenly collapses and is unresponsive, bystanders perform hands-only CPR -- unless they are confident in their ability to do traditional CPR.

"I would say although there is very accurate information out there on YouTube," Murugiah said, "it is difficult for the lay person to wade through all the content and watch the right videos. And there is a risk of dissemination of incorrect information."

He said the findings, reported in the journal Resuscitation, suggest that guideline-making groups, like the AHA and Red Cross, should get more CPR information onto online "platforms" like YouTube.

Of course, the content on YouTube changes by the moment. And since the time of this study -- February 2010 -- the AHA has added a couple CPR-teaching videos to its YouTube channel (http://www.youtube.com/user/americanheartassoc).

The Red Cross also has a video demonstrating hands-only CPR on its channel (http://www.youtube.com/user/AmRedCross).

Both groups' YouTube channels, Murugiah said, "are certainly good, reliable sources of information on CPR." But even their CPR videos, he added, are somewhat short on detail and show "room for improvement."

Since sites like YouTube have such a huge reach, Murugiah said, professional groups could make more use of them to boost public awareness of when and how to perform CPR.

The AHA and Red Cross both have more CPR information on their own Web sites, at www.americanheart.org and www.redcross.org.