Many caregivers perform CPR incorrectly and fail to restart stopped hearts by not adhering to strict guidelines governing the frequency and force of chest compressions, a pair of studies said on Tuesday.

Poor and outdated training or overly complicated instructions in Cardiopulmonary resuscitation (CPR) for paramedics, nurses and doctors may be to blame.

One solution may be mechanical monitors to aid caregivers to adjust their technique, one researcher suggested.

One study of cardiac arrest victims in Stockholm, London and Akershus, Norway, found that paramedics and other caregivers failed to begin CPR quickly enough in nearly half the cases, which occurred outside the hospital.

When CPR was performed, the number of compressions were often applied too quickly - the number should be between 100 and 120 per minute - and less than one-third of the compressions were done with the requisite force. Also, breaths were often applied too frequently, said study author Lars Wik of Ulleval University Hospital, Oslo.

Sixty-one of the 176 patients, or 35 percent, had their heartbeats restarted and circulation resume, which must occur within a few minutes to avoid brain damage. The other 65 percent of the patients could not be revived and died.

Lives are lost when CPR is applied incorrectly in terms of the number and force of chest compressions and breaths into the victim’s mouth, researchers writing in the Journal of the American Medical Association said.

“Current resuscitation guidelines are not being followed,” wrote Arthur Sanders and Gordon Ewy, doctors at the University of Arizona College of Medicine, in Tucson.

“In the past such inadequacies have been dismissed as an education (or) training problem. But perhaps it is not a question of how well rescuers are being taught and learn the material. In reality, the training courses for health care professionals get more complex with each revision of the guidelines. Some of the skills taught, such as two breaths in five seconds, are impossible to deliver,” said their editorial commenting on the two studies.

In the other study of 67 patients at the University of Chicago Hospitals, 27 patients were revived. But university researcher Benjamin Abella said 28 percent of the time the compressions were applied too slowly, 37 percent of the compressions were not deep enough, and 61 percent of the breaths were given too frequently.