Appropriate Utilization of EMS Services

Abstract & Commentary

By John P. DiMarco, MD, PhD, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville; Dr. DiMarco is a consultant for Novartis, and does research for Medtronic and Guidant.

Source: Sasson C, et al. Prehospital termination of resuscitation in cases of refractory out-of-hospital cardiac arrest. JAMA. 2008;300:1432-1438.

The cardiac arrest registry to enhance survival (CARES) is a registry designed to help local emergency medical system officials monitor outcomes of out-of-hospital resuscitation. In this paper, data from eight cities in the United States are analyzed to determine if termination of resuscitation rules can be successfully applied in routine practice. The two proposed sets of guidelines were classified as the basic life support (BLS) and the advanced life support (ALS) rules. The BLS rule had three components. The event could not be witnessed by emergency medical services personnel; no automated external defibrillator was used or any manual shock applied in the out-of-hospital setting, and there was no return of spontaneous circulation. The ALS rule added two additional criteria. The arrest could not be witnessed by a bystander, and no bystander-administered cardiopulmonary resuscitation had been attempted. This current paper tests the ability of these rules in classifying patients who are unlikely to survive to hospital discharge after an out-of-hospital cardiac arrest.

The CARES registry collects data from 911 call centers, EMS personnel, and the receiving hospitals. To protect privacy, individual identifiers are removed from the data. Characteristics of the arrest are then correlated with short- and long-term survival. In this paper, the data set was used to calculate the sensitivity, specificity, and positive and negative predictive values of the BLS and ALS rules for identifying patients likely to not survive to hospital discharge. The goal of the study was to develop accurate indicators for termination of resuscitation that would prevent unnecessary emergency transports to the hospital, yet now compromise potential for meaningful survival.

The CARES registry data covered in this report included 7,235 cases collected from 19 EMS agencies and 111 hospitals in eight United States cities. To this group, standard exclusion criteria were applied, so that 5,505 cardiac arrest cases comprised the final study group. The overall group was 60% male with a mean age of 64.4 years. Sixty-five percent of the arrests occurred at home, 14.5% in nursing homes or assisted-living facilities, and 21% in public settings. The initial rhythm recorded was ventricular fibrillation or ventricular tachycardia in 18.3%, and unknown shockable rhythm in 5.3%, and either an unknown shockable rhythm, asystole, or pulseless electrical activity in the remainder. The arrest was witnessed by a bystander in 37% of the patients and by EMS personnel in 12%. Using local protocols, 947 patients were pronounced dead in the out-of-hospital setting and were not transported emergently with on-going resuscitation attempts to the hospital. Return of spontaneous circulation in the out-of-hospital setting was achieved in 30.7% of the patients. Survival to hospital admission was noted in 21.9% of the patients, with 7.1% surviving to hospital discharge. Overall, 3.5% of the cases survived to discharge and had a normal, or nearly normal, functional status. If the BLS termination rule had been applied, 2,592 patients would have had resuscitation attempts terminated in the out-of-hospital setting. Of these patients who met BLS criteria for termination, only 70 could be resuscitated in the emergency department and admitted to the hospital but, of these, only five (0.2% of the entire group) survived to hospital discharge. Use of the BLS rule would have resulted in an out-of-hospital pronouncement of death of 47%. If the more conservative ALS rule had been applied, then 1,192 patients would have had termination of resuscitation out-of-hospital. Of these, 24 patients were resuscitated in the emergency department but none survived to hospital discharge.

Sasson et al conclude that the BLS rule for termination of resuscitation identifies with a high specificity and a high positive predictive value, patients with out-of-hospital cardiac arrest who have a very low likelihood of survival to hospital discharge. Implementation of this rule could substantially reduce the risks and costs associated with high-speed transports of patients in the setting of ongoing resuscitation attempts. This, in turn, would decrease pressure on overburdened EMS systems and allow emergency department staff to focus on patients with a greater probability of survival.

Commentary

Each year, there are approximately 175,000 out-of-hospital sudden cardiac arrests in the United States. In patients with ventricular fibrillation and ventricular tachycardia, early defibrillation (or cardioversion) is the key to survival. Bystander CPR can widen the window of opportunity for successful defibrillation in some cases. Despite widespread efforts over many years to decrease EMS response times and put defibrillators in the hands of first responders and lay rescuers, overall survival after an out-of-hospital cardiac arrest remains low. Many cardiac arrest victims with virtually no hope for survival are transported as emergencies to the nearest hospital. This places rescuers and others at risk of injury during the transport and increase costs within the EMS system with little or no return. In this paper, simple rules are evaluated that would permit EMS responders to discontinue resuscitation effects in the field. The BLS guideline used here is simple and, if adopted, would eliminate a large number of futile transports and emergency room resuscitation attempts. If we can make our EMS systems more efficient, they will be able to focus their limited resources on patients with a realistic chance for survival.