Survival And Outcome From Prehospital Cardiac Arrest

摘要

Early observational studies commented on the likelihood of survival associated with EMS sites and providers, while the efficacy of both EMTs and paramedics is still hotly debated. Demographic profiles of the prehospital arrest population find those who are younger, present with ventricular dysrhythmia or with shorter response times optimize the "prehospital chain of survival" have better outcome. Specific arrest outcome predictors that are standardized help to clarify outcome including arrest time, location of arrest, bystander CPR, and early defibrillation. Predictors of long term survival focus on the presence of return of spontaneous circulation (ROSC), as well as intervals until resuscitation intervention that preclude functional recovery. Overall survival to hospital discharge was 3.8% (1.7-13%) of a 3,220 pooled patient group. Analysis of their functional recovery found good outcome in 86.7% (44-89%), moderate impairment in 10.2% (8.5-44%) and severe impairment in 3.1% (2-36%) of survivors from a cohort of 1679 pooled patients. Although, survival from prehospital arrest is diminished in geriatric groups, those who survive often have good functional recovery. Introduction A description of early ambulance systems that were utilized for evacuation of battlefield casualties were described by military surgeon, Dominque-Jean Larrey (1766-1842) during the Napoleonic Wars.1 They were then adapted for clinic use in large American cities such as Cleveland and New York prior to 1865.2 Skeptics questioned the necessity of an ambulance transport service suggesting “what difference would that make, the case must come to the hospital anyway.”3 One of the earliest EMS outcome studies was reported by Pantridge in 1967 citing the Belfast experience.4 The mobile intensive care unit was summoned in 338 cases with 312 admissions for myocardial infarction with a 50% “rule in” rate an exceptionally high acuity patient population. The prehospital arrest incidence was 3.4% (10) with 50% (5) of this group surviving to discharge, a surprising survival statistic in this critically ill population.The US experience was reported by Crampton in 1975, noting a 26% decline in prehospital and 62% in-hospital mortality involving those who have undergone ambulance transport. These patients were younger than 70 years, and were found to have a 66% success rate in prehospital CPR, measured as long term survival.5 Iseri et al reported the early American experience with 26 patients and rapid response paramedic units defining the ventricular fibrillation group, which was amenable to successful countershock therapy in 86% (12), where they demonstrated survival in 43%.6 They defined a brady-systolic cardiac arrest group, which was found to be associated with autopsy proven complete coronary artery occlusion in 50% (7) of patients, with a universally fatal result. Interestingly, they conclude that a more aggressive approach to prehospital management of brady-systolic arrests is warranted.Eisenberg et al report the results of an evaluation of prehospital care by Emergency Medical Technicians (EMT) compared to that after the addition of paramedic skills such as defibrillation, endotracheal intubation and drug administration to the resuscitation armaterium.7 They report an improved rate of survival (19 to 34%) to the coronary care unit (CCU) as well as rate of hospital discharge from 7 to 17%, which they related to a decrease in time to advanced care delivery that was shortened from 27.5 to 7.7 minutes. In a separate report they analyzed 487 prehospital arrest patients cared for by EMTs or paramedics in specific regions where the annual arrest incidence was 5.6-6.0/10,000. Proportionally more lives were saved in paramedic than EMT provider areas with 8.4% and 1.3% mortality reduction respectively, a six fold improvement.8 EMS The use of prehospital health care providers to intervene in acute cardiac emergencies has historically been a focus of emergency care. However,