Study indicates improvement in EMS responders' ability to identify unsuccessful resuscitation

TORONTO, ON - Prehospital care experts at Sunnybrook Health Sciences Centre have validated a guideline that emergency medical service (EMS) responders trained in the use of automatic defibrillation can use to identify patients who will not survive after suffering a cardiac arrest. The study, which examined over 1200 adult patients suffering an out-of-hospital cardiac arrest, appears in the New England Journal of Medicine's August 3rd issue.

For many years termination of resuscitation (TOR) protocols have existed for paramedics trained in advanced cardiac life support care including defibrillation, intravenous drugs and advanced airway management. However, for EMS responders trained solely in defibrillation, all patients required transport to the nearest emergency department for ongoing resuscitation efforts, which were almost always unsuccessful. As a result, large numbers of patients with little or no potential for survival are regularly transported to emergency departments. The continued resuscitation effort and emergency transfer negatively impacts the patient's family, the receiving emergency department and the EMS system.

"The family is forced to begin the grieving process in a busy emergency department often lacking privacy and dignity rather than in the comfort of their own home," says Dr. Laurie Morrison, lead investigator on the study and director of the Prehospital and Transport Medicine Research Program. "Many studies have shown that families' long term grief adjustment is as good or better with in-the-home termination of resuscitation. In addition transporting patients by speeding ambulance can cause motor vehicle injuries resulting in
injury to other drivers, pedestrians and EMS personnel."

The Termination of Resuscitation guideline determines that resuscitation can be stopped if all of the following are true: (1) no return of pulse is achieved; (2) no shock to the heart was given; and (3) the cardiac arrest was not directly witnessed by EMS responders. During the study's trial, current procedures for cardiac resuscitation did not change. Patients who fit the criteria were documented and followed-up over a six month period.

The main results of the study showed there was a 99.5 per cent probability that patients who fit all three criteria would not survive if transported to the nearest emergency department. Implementation of the guideline would result in only 37 per cent of patients requiring transport to the emergency department rather than the current practice of 100 per cent.

"We did not expect to find that the guideline would show a 100 per cent probability of not surviving since there are so many unique factors associated with each cardiac arrest," says Dr. Richard Verbeek, a co-author of the study and medical director for the Sunnybrook-Osler Centre for Prehospital Care. "That is why emergency medical responders must contact an emergency physician to discuss each individual call when the guideline is used. The emergency physician will take into account other clinical aspects of the call before any final decision to terminate resuscitation is made. This guideline helps to determine when ongoing resuscitation will not be successful, but also does not deny potentially viable patients full resuscitation and the best chance for survival."

Past research has demonstrated that over 96 per cent of out-of-hospital cardiac arrest patients do not survive and are pronounced dead upon arrival at the hospital. This low survival rate is primarily due to the fact that very few bystanders in Canada provide CPR in the initial stages of cardiac arrest. In many cases, when CPR is performed the patient's heart is more likely to attain a recoverable rhythm, which makes it easier to resuscitate the patient.

"I see the results of this study, not only as a way to focus our resources more effectively, but also as a strong indication of how vital it is for members of the public to receive training in CPR and to overcome their fear to provide CPR to a stranger or a loved one who suffers a cardiac arrest," says Dr. Morrison. "It's no myth, CPR could mean the difference between life and death."

The trial involved 24 regional EMS systems across Ontario. The TOR guideline is currently going through an implementation trial. Eight communities are involved in this stage, and will be looking at the guideline's impact on the system, providers and various stakeholders.