A portable chest compressor does CPR better than paramedics:

"We're probably not compressing hard enough," said Dr. Paul Pepe, chair of Emergency medicine at the University of Texas Southwestern Medical Center. "We're probably not compressing fast enough, and we're probably interrupting to give breaths too often to be effective, or as effective as we could be."

The solution, say some paramedics, is a new portable chest compressor.

Once the victim has been strapped in, the machine calculates the person's shape and size to deliver the optimal chest compression -- just the right pressure and frequency for that particular patient.

Unlike manual CPR, the machine can compress the chest without stopping.

I was taught that if you didn't break any ribs, then your chest compressions weren't hard enough. ("CPR Machine Proves More Effective Than Paramedics", ABC News, Jul.19)