More people can survive a heart attack if emergency medical workers use a new CPR method that starts with chest compressions before a defibrillator shock, finds a new study.
Rescue teams in Arizona who tried the new approach for a study that appears in the Journal of the American Medical Association tripled the survival rate of people who were in cardiac arrest compared to the standard approach.
Often when people go into cardiac arrest, they develop a type of heart rhythm known as ventricular fibrillation, in which the heart quivers but does not pump blood. If no defibrillator shock is delivered in the first four minutes of this deadly rhythm, the heart stops altogether and it becomes much harder to get it restarted.
Traditionally, when rescue workers arrive on the scene, they are told to defibrillate right away. But the patient often dies with that method.
The new resuscitation approach calls for a round of 200 chest compressions given in the first two minutes of cardiac arrest, followed by a shock and then another 200 chest compressions.
After that, rescue workers should do a rhythm re-analysis and decide whether to administer epinephrine (adrenaline, used to stimulate the heart), and to intubate (place a flexible plastic tube into the trachea to ventilate the lungs).
The new approach is called minimally interrupted cardiac resuscitation (MICR), because it is designed to limit interruption of chest compressions to keep blood flowing to the heart and brain.
It's meant to be used only by emergency medical workers, not bystanders. Bystanders should offer chest compressions and breaths for as long as it takes for emergency workers to arrive.
Few patients who go into out-of-hospital cardiac arrest survive, even if emergency workers arrive quickly. In fact, in 2004, the average survival of patients with out-of-hospital cardiac arrest was just three per cent in the state of Arizona.
The JAMA study looked at the survival data of 886 patients with cardiac arrest in two Arizona cities, before and after emergency workers in the cities' fire departments were trained in the new method.
They found that the rate of people who lived long enough to be taken to hospital and then sent home again rose from just 1.8 per cent before the training to 5.4 per cent after the new protocol was introduced.
The benefit was greatest for those who had ventricular fibrillation with a shockable rhythm. Survival in those patients rose from 4.7 per cent to 17.6 per cent.
B.J. Chute, the director of public education for the Ambulance Paramedics of British Columbia, tells CTV.ca that the technique is not altogether new.
He says paramedics in his province and many other parts of Canada have been advised for at least the last year to provide two minutes of chest compressions to patients in cardiac arrest before defibrillating, as a way of "priming the pump" and preparing the heart for the shock.
Dr. Mary Ann Peberdy of Virginia Commonwealth University in Richmond said the findings suggest the need for a back-to-basics approach to cardiopulmonary resuscitation.
"We are learning more and more that we can't get sloppy on how we do CPR," Peberdy writes in a commentary in JAMA.
