The Automatic External Cardioverter-Defibrillator--论文代写范文精选

在发达国家(例如美国),几乎一半的死亡是意想不到的。虽然多数突然心脏死亡发生在医院外存活率十分低。因此，在医院内治疗心脏骤停仍然是一个主要问题。下面的paper代写范文进行详述。

Abstract
In-hospital cardiac arrest remains a major problem but new technologies allowing fully automatic external defibrillation are available. These technologies allow the concept of “external therapeutic monitoring” of lethal arrhythmias. Since early defibrillation improves outcome by decreasing morbidity and mortality, the use of this device should improve the outcome of inhospital cardiac arrest victims. Furthermore, the use of these devices could allow safe monitoring and treatment of patients at risk of cardiac arrest who not necessarily must be in conventional monitoring units (Intensive or Coronary Care Units) saving costs with a more meaningful use of resources. The capability to provide early defibrillation within any patient-care areas should be considered as an obligation (“standard of care”) of the modern hospital. 
Key words: cardiac arrest, cost-effective, defibrillation, ventricular arrhythmias, ventricular fibrillation and ventricular tachycardia.

Introduction 
Cardiovascular disease is the major cause of death in the majority of countries1,2 . In developed countries (e.g. United States), nearly the half of these deaths are unexpected and sudden3,4 . Although the broad majority of sudden cardiac deaths occur outside the hospital and very poor survival rates have been reported, in-hospital cardiac arrest remains a major problem. The aim of this article is to review the actual knowledge of the utility of “fully automatic” external defibrillators for treatment of in-hospital cardiac arrest. The name “automated” external defibrillator (AED) must be distinguished from fully “automatic” external defibrillator. The automatic device is able to deliver a shock without intervention from an operator whereas the automated device only “advises” by a voice or a text to deliver the energy. Thus, the automated device requires operator intervention.

The classical reality 
Sustained ventricular tachycardia (VT) and VF, even in hospitalized patients, are major causes of morbidity and mortality 28,35,36,37 . In the best setting (monitoring wards), continuous ECG monitoring allows identification of lethal arrhythmias and alarm systems alert nursing and medical staff. However, a time delay between the arrhythmic event and human intervention obviously exists. This time delay may be prolonged in certain circumstances even in monitoring wards. In addition, response time intervals for in-hospital resuscitation events are often inaccurate and must be corrected before documented times to defibrillation can be considered reliable 34 . Although major evidence exists supporting the need for rapid defibrillation and important advances in out-of-hospital cardiac arrest treatment have been achieved (e.g. out-of hospital cardiac arrest quick response programs), in-hospital cardiac arrest is still a major problem without significant advances (e.g. changing strategies) during the last 30 years. This leads to important mortality, morbidity and social as well as economic costs28,35,36,37 . The scarcity of data 28,44 related to deployment of AEDs in hospitals and its impact on patient outcome reflects the very limited existence of in-hospital early defibrillation programs. However, as stated in major guidelines, early defibrillation is a high-priority goal in outof hospital as well as in-hospital cardiac arrest 31,32,33,34 . Clearly the earlier defibrillation occurs, the better the prognosis in adults and children. 

The capability to provide early defibrillation within any patient-care areas should be considered as an obligation (“standard of care”) of the modern hospital. Furthermore, cardiac arrests often occur outside monitored areas. Recently, Herlitz et al.28 reported that out of 557 patients suffering in-hospital cardiac arrest, only 292 patients (53%) were in monitored wards and from those only 43.2% of the patients could be discharged alive. 

They reported that the median interval between collapse and first defibrillation was 1 minute in monitored wards and 5 minutes in non-monitored wards. Only 31% of patients from non-monitored wards could be discharged alive and with a cerebral performance inferior to that of survivors of monitored wards. Other authors48 present similar data showing better in-hospital survival for witnessed arrest (25%) than for non-witnessed arrest (7%) but, in addition, they report a disproportionately high incidence of non-witnessed arrests during the night (12AM to 6 AM) resulting in a very poor survival rate (0%). Cardiac arrest occurs in 4.8% of hospitalized patients because of acute myocardial infarction49 . The survival rate to hospital discharge for these individuals was 29.4% 49 . Although ventricular tachycardia or fibrillation was documented in 34.7% of patients, only 47.5% of those survived to discharge 49 . Thus, the use of “automatic” defibrillators had probably improved outcome of those patients presenting in-hospital cardiac arrest. Furthermore, although survival to hospital discharge offers an objective evaluation point and is used in the broad majority of reports, several patients who survive a cardiac arrest present neurological damage, which is highly dependent of the response time to cardiac arrest18,28,29 . Therefore, the neurological status should also be considered when reporting results of resuscitation procedures30 .

The performance of the device in detecting shockable and non-shockable rhythms was confirmed by review of the simultaneously recorded Holter data and the programmed parameters. A total of 1,240 hours of monitoring and 1,988 episodes of rhythm changes were documented. The device detected ventricular arrhythmias with a sensitivity of 100% and specificity of 97.6%. The mean response time to shock was 14.4 seconds [evaluated in those episodes (sustained) that were associated with a full capacitor charge cycle]. All false positives were caused by T-wave oversensing during ventricular pacing. There were no complications or adverse events. There were a total of 35 sustained arrhythmic episodes treated by the device (12 in the EP lab and 23 in monitoring wards). All 35 episodes were successfully (100% efficacy) converted to normal sinus rhythm with a first shock success of 94.3% (Figure 1). 

This European study 50 confirms the initial experience presented by Mattioni et al 51 in a multicenter American trail. These authors reported a sensitivity and specificity of 100% and 99.4%, respectively, and a response time of 22 seconds 51 . Although some differences exist (e.g. sample size, hours of monitoring, software version, etc.) both studies50,51 lead to the same conclusions. Thus, both groups (European and American) of investigators agree that the device is safe and highly effective in monitoring, detecting and treating spontaneous rhythms. Therefore, with its wide use a significant improvement in the treatment of in-hospital cardiac arrest should be expected. In addition, the now available version of the described automated external cardioverter-defibrillator has important improvements (compatibility to commercially available patient monitoring systems, biphasic wave forms, etc.)(paper代写)

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