EFFECTS OF ADDING LINKS TO THE CHAIN OF SURVIVAL FOR PREHOSPITAL CARDIAC-ARREST - A CONTRAST IN OUTCOMES IN 1975 AND 1995 AT A SINGLE INSTITUTION

Study objective: The concept of a ''chain of survival'' to improve out come from prehospital cardiac arrest has been defined and promulgated over the last two decades. The purpose of this study was to compare ou tcomes of prehospital cardiac arrest in 1975 and 1995 at a single inst itution. Methods: This longitudinal, before-after study compares publi shed data collected at our municipal, tertiary care in 1974-1975 with data collected prospectively in 1995. The 1975 study group served as c ontrol subjects (n=120). We enrolled an equal number of consecutive pa tients who met inclusion criteria in the 1995 cohort (consecutive pati ents who experienced prehospital arrest and who received prehospital A dvanced Cardiac Life Support (ACLS) measures during the two study peri ods). Patients younger than 18 years or with posttraumatic arrest were excluded. Between 1975 and 1995 the following ''links'' in the ''chai n of survival'' were added to the prehospital care system: (1)911 acce ss and dispatch, (2) paramedic endotracheal intubation, (3) EMT automa ted defibrillation, (4) standing out-of-hospital orders before hospita l radiotelemetry contact, and (5) introduction of American Heart Assoc iation ACLS algorithms. Results: The following significant differences (chi(2)) were observed between the study periods: prevalence of ventr icular fibrillation or tachycardia (42% in 1975 versus 28% in 1995, P= .021), prevalence of asystole or pulseless electrical activity as the first documented rhythm (58% versus 72%, P=.021), survival to hospital discharge (22% versus 9%, P=.007), and percent of survivors of ventri cular fibrillation or tachycardia (30% versus 0%, P=.004). Eighty-six percent of the 1995 cohort had advanced chronic disease and 29% experi enced cardiopulmonary arrest in a nursing home. Conclusion: Survival d ecreased dramatically during the 20-year study period. This may be bec ause of the high incidence of chronic disease, the greater frequency o f asystole and pulseless electrical activity, and the inclusion of pat ients with ''end-of-life'' arrests in which ACLS protocol was initiate d in the 1995 cohort. The patient population in which ACLS is initiate d is the weakest link in the ''chain of survival.''