Summary of the Methodology for the Validation Study for a Termination of Resuscitation Clinical Prediction Rule

Abstract

Basic life support (BLS) providers are the most common type of emergency responder in the world. Thus, many patients experiencing out-of-hospital cardiac arrest in North America receive only BLS care (cardiopulmonary resuscitation and automated external defibrillation) from emergency medical technicians (EMTs). Current practice is for every cardiac arrest patient receiving only BLS care to be transported to the emergency department (ED) with lights and sirens. The survival rate from out-of-hospital cardiac arrest is approximately 5%; therefore, most patients are pronounced dead in the field or in the ED. Emergency ambulance transport to the ED and futile resuscitation of patients experiencing cardiac arrest is potentially hazardous to paramedics and the public. Accordingly, care of these patients is not an efficient use of ED resources because these patients generally do not survive. Patients experiencing cardiac arrest demand the immediate attention of the physician and ED staff and may divert care from potentially more salvageable patients. More importantly, the time spent with grieving families is often compromised by the competing time-sensitive needs of other ED patients. The literature demonstrates that most family members are satisfied with the experience of out-ofhospital termination of resuscitation and the manner used for breaking bad news. American Heart Association guidelines for cardiopulmonary resuscitation acknowledged that there is a need to develop Termination of Resuscitation (TOR) protocols for EMTs in situations in which advanced cardiac life support (ACLS) is not rapidly available. To date, research supporting TOR guidelines has been limited to patients who received full prehospital ACLS care, inhospital patients experiencing cardiac arrest, prehospital cardiac arrests treated by EMT-Ps, all patients experiencing cardiac arrest resuscitated by EMTs, and a subset of patients presenting in asystole. None are validated in the prehospital setting. The implementation of a Basic Life Support Termination of Resuscitation (BLS TOR) clinical prediction rule for patients who fail to respond to BLS care would decrease the number of futile resuscitations directed to the ED by EMTs. We recently derived a clinical prediction rule through retrospective case review for the termination of BLS resuscitative efforts by EMTs who had been trained in the use of automated external defibrillation. This rule suggests that continued BLS cardiac resuscitation is futile and can be terminated in the field if the following 3 conditions are met: 1) no return of spontaneous circulation, 2) no shock given before transport, and 3) cardiac arrest not witnessed by EMS personnel (Fig. 1). The decision rule was 100% sensitive (95% confidence interval CI 99.3–100) and the negative predictive value was 100% (95% CI 99.3–100) in determining which patients survived to discharge when applied retrospectively to the study population.