While civilians and police officers depend on trained medics and medical professionals to be able to take over CPR in a crisis situation, two recent studies found that many doctors, paramedics, and nurses don’t perform the procedure properly.

Both studies found the steps of the Cardio-Pulmonary Resuscitation procedure most often done incorrectly were chest compressions and breathing techniques. According to the research, rescuers often did not push hard enough or frequently enough on the victim’s chest to restart the heart, and breathed air into the lungs too often.

In analyzing the results, researchers say that failure to follow all of the CPR guidelines can result from forgetting them in the chaotic environment of a crisis situation and from fatigue. Chest compressions necessary to restart a heart sometimes must be strong enough to break ribs, which can be difficult to keep up for long periods of time.

A new combination heart monitor and defibrillator used in the studies includes a small sensor that attaches to the patient’s chest and evaluates depth of chest compressions and other aspects of CPR. An automated voice that notifies rescuers if techniques need to be changed as the process is taking place was not used in the studies.

The studies appeared in yesterday’s Journal of the American Medical Association.