The shock for life: early defibrillation in first aid and by the professional paramedic]

The Automated External Defibrillation is the key link of the chain of survival for patients in cardiac arrest. A lot of case series and trials have shown the effectiveness of early defibrillation by first rescuers and trained lay persons. The earlier the defibrillation is performed, the better is the rate of survival to hospital discharge. To increase the survival rate healthcare providers, first rescuer citizens at worksites and trained lay rescuers should be authorized, equipped and encouraged to perform early defibrillation combined with effective cardiopulmonary resuscitation (CPR). The new generation of Automated External Defibrillators (AED) are sophisticated, computerized devices that are reliable and simple to operate, enabling also lay rescuers to administer this lifesaving intervention to victims of cardiac arrest. For the concept of recurrent adequate and qualified training in the use of the AED integrated in effective DPR is recommended.     

The Chemotherapy of Cardiac Arrest

Direct-air ventilation, external cardiac compression, and external defibrillation are established techniques for patients who unexpectedly develop cardiac arrest. The proper use of drugs can increase the incidence of successful resuscitation. Intracardiac adrenaline (epinephrine) acts as a powerful stimulant during cardiac standstill and, in addition, converts fine ventricular fibrillation to a coarser type, more responsive to electrical defibrillation. Routine use of intravenous sodium bicarbonate is recommended to combat the severe metabolic acidosis accompanying cardiac arrest. Lidocaine is particularly useful when ventricular fibrillation or ventricular tachycardia tends to recur. Analeptics are contraindicated, since they invariably increase oxygen requirements of already hypoxic cerebral tissues. The following acrostic is a useful mnemonic for recalling the details of the management of cardiac arrest in their proper order: A (Airway), B (Breathing), C (Circulation), D (Diagnosis of underlying cause), E (Epinephrine), F (Fibrillation), G (Glucose intravenously), pH (Sodium bicarbonate), I (Intensive care).     

The future of electrical defibrillators for the heart]

The aim of electric defibrillation of the heart is to salvage a greater percentage of victims of cardiac arrest in the future. An initial decisive pathway towards this goal is to get a defibrillator to the victim as quickly as possible and apply an electric shock. This has now been implemented on a large scale--by means of the widespread propagation of (semi-)automatic external defibrillators (AED) and their PAD (Public Access Defibrillator) variant for use by laypersons. This is an initial necessary prerequisite which, however, is not sufficient to have a real impact on saving lives. For experience has shown that, despite the early use of AEDs, an appreciable proportion of the victims cannot be saved. The intention is to improve this situation by increasing the efficacy and reducing the harmful downside of the defibrillation waveforms applied. The solution is optimally dimensioned biphasic waveforms with high efficacy at low energy levels. In this connection, it is shown that the efficacy of high-energy defibrillation shocks is exceeded by their injurious effects, thus thwarting life-saving defibrillation. Examples of new waveforms of particularly high efficacy are presented. It is shown how such impulses should be physiologically dimensioned, and clinical results of cardioversion (atrial defibrillation) and initial out-of-hospital results of emergency defibrillation are discussed. In addition, new approaches for future waveforms enabling pulsed pulse-pause-modulated biphasic shocks are described. In this way, waveforms with a physiologically optimal effect on the heart can be produced which were previously impossible with portable defibrillators. Waveforms that have already been tested or are still in the research stage, justify hopes that improved survival of cardiac arrest victims may be expected. These new waveforms may also be of benefit in other types of defibrillators (e.g. cardioversion or implanted defibrillators).     

CARDIAC RESUSCITATION THROUGH THE INTACT CHEST

External cardiac compression and external defibrillation were successful in resuscitating 27 consecutive dogs after the production of ventricular fibrillation. Twelve patients survived following circulatory arrest treated with closed chest cardiac compression and, when indicated, defibrillation. Five additional patients were successfully resuscitated but died in the hospital. In fifteen cases, resuscitation was not successful.     

Acute cardiovascular failure and its treatment--value of defibrillation in preclinical management]

Ventricular fibrillation is the most common cause of cardiac arrest. The only scientifically proved therapy that guarantees a long time survival is the early electrical defibrillation. As early as 200 years ago electricity was employed in trying to regain circulation in cases of unexpected death. In the field of emergency medicine almost all rescue services are equipped with defibrillators nowadays and the personnel is trained in using them. Since the application of electricity on the myocardium can lead to damage, there are devices with a varied defibrillation pulse available since recently. The advantage of the biphasic defibrillation is a less harmful impact on the myocardium at lower shock intensity. A further novelty which enables the application by groups other than the rescue services, is the automatic external defibrillator (AED). Extending the availability of defibrillators can contribute to an increase in the presently low success rates of resuscitation.     

Emergency Cardiopulmonary Resuscitation—A Fifteen-Month Experience in a General Hospital

Results under a resuscitation program in a general hospital in which the entire house staff is capable of functioning as a team in emergency, bear out the effectiveness of prompt action in cardiopulmonary or other life-threatening emergencies. Such a program remains important in spite of the salutary trend toward coronary care units. Both emergency and definitive therapy must be accomplished without delay. A house staff is necessary for an effective emergency resuscitation program. Paramedical personnel must be instructed to recognize an emergency and immediately institute life-sustaining therapy. Definitive therapy must be applied as soon as possible.The entire house staff, rather than a specially organized team, should be trained in the techniques of definitive therapy.Consideration should be given to immediate defibrillation following diagnosis of cardiac arrest as an early step in definitive therapy.     

Sudden cardiac arrest on the field of play: turning tragedy into a survivable event

Sudden cardiac arrest remains the leading cause of death in exercising athletes, and recent studies have shown that it occurs more frequently than historical estimates. While out-of-hospital cardiac arrest often proves fatal, advance preparation can improve outcomes and the chance of survival. First responders to a collapsed athlete on the field of play may include team medical personnel, coaches, other athletes, officials, venue staff, emergency medical services personnel, or lay bystanders. Prompt and accurate recognition of sudden cardiac arrest, a comprehensive and rehearsed emergency action plan, early cardiopulmonary resuscitation, and immediate access to and use of an automated external defibrillator are each pivotal links in the chain of survival. This review summarises the components of an effective emergency action plan, highlights the critical role of automated external defibrillators, and reviews the diagnosis and management of sudden cardiac arrest on the field of play.     

Contribution of cardiogenic oscillations to gas exchange in constant-flow ventilation

The contribution of cardiogenic oscillations to gas exchange during constant-flow ventilation was examined in 11 dogs. With the use of two variations of cardiopulmonary bypass to maintain the systemic and pulmonary circulation, the influence of cardiogenic oscillations was removed by arresting the heart. Cardiac arrest by ventricular fibrillation was associated with a mean decrease in alveolar ventilation of 43% in five dogs on right and left heart bypass. However, successful defibrillation and return of the prearrest level of alveolar ventilation could not be achieved; thus we studied six dogs on left heart bypass. Alveolar ventilation decreased an average of 37% with cardiac arrest, and defibrillation resulted in a return of alveolar ventilation to 81% of the prearrest value. These results are consistent with previous predictions that cardiogenic oscillations are an important mechanism of gas transport during constant-flow ventilation.     

Defibrillators in general practice.

After a successful pilot scheme introduced in 1975, when six portable defibrillators were provided for health centres, an additional 50 defibrillators were provided in February 1982 for general practitioners to use. Between December 1975 and February 1984 defibrillation was attempted in 54 patients who collapsed with clinical cardiac arrest in the presence of general practitioners or less than five minutes before their arrival. A cardiac output was achieved in 32 patients, 28 survived to reach hospital via a mobile coronary care unit, and 22 were discharged alive. Of the 28 admitted to hospital, 24 were found to have myocardial infarction. If all general practitioners carried defibrillators they might make an important dent in the early mortality from myocardial infarction in addition to that achieved by a mobile coronary care unit.     

Estimation of current density distribution under electrodes for external defibrillation

Background  

Transthoracic defibrillation is the most common life-saving technique for the restoration of the heart rhythm of cardiac arrest victims. The procedure requires adequate application of large electrodes on the patient chest, to ensure low-resistance electrical contact. The current density distribution under the electrodes is non-uniform, leading to muscle contraction and pain, or risks of burning. The recent introduction of automatic external defibrillators and even wearable defibrillators, presents new demanding requirements for the structure of electrodes.     

New approaches in first aid for cardiovascular patients]

Sudden cardiac arrest is a major problem of our society. Ventricular fibrillation strikes without any warning. It leads to unconsciousness and death occurs within minutes. Every year at least 100,000 people die from sudden cardiac arrest in Germany alone. The following article is concerned with how todays rescue system can be improved in order to increase survival rates. The time which passes between occurrence of the ventricular fibrillation and the therapeutic defibrillation plays a major role. It is being observed that decentralizing the rescue system is of great advantage. The idea of the "first responder", involving laymen, family members, and company paramedics, reduces the rescue time extraordinarily. The introduction of a digital emergency health record which provides the doctor with all the important data on the patient briefly seems to be of equal importance. Hereby, delays based on false information can be reduced to a minimum. Optimizing the equipment by means of implementing automatic procedures which enable the application by laymen is just as important. But the key to medical success appears to be educating and repeatedly training as many people as possible.     

Home Care Providers to the Rescue: A Novel First-Responder Programme

AimTo describe the implementation of a novel first-responder programme in which home care providers equipped with automated external defibrillators (AEDs) were dispatched in parallel with existing emergency medical services in the event of a suspected out-of-hospital cardiac arrest (OHCA).MethodsWe evaluated a one-year prospective study that trained home care providers in performing cardiopulmonary resuscitation (CPR) and using an AED in cases of suspected OHCA. Data were collected from cardiac arrest case files, case files from each provider dispatch and a survey among dispatched providers. The study was conducted in a rural district in Denmark.ResultsHome care providers were dispatched to 28 of the 60 OHCAs that occurred in the study period. In ten cases the providers arrived before the ambulance service and subsequently performed CPR. AED analysis was executed in three cases and shock was delivered in one case. For 26 of the 28 cases, the cardiac arrest occurred in a private home. Ninety-five per cent of the providers who had been dispatched to a cardiac arrest reported feeling prepared for managing the initial resuscitation, including use of AED.ConclusionHome care providers are suited to act as first-responders in predominantly rural and residential districts. Future follow-up will allow further evaluation of home care provider arrivals and patient survival.     

Integration of Attributes from Non-Linear Characterization of Cardiovascular Time-Series for Prediction of Defibrillation Outcomes

Objective

The timing of defibrillation is mostly at arbitrary intervals during cardio-pulmonary resuscitation (CPR), rather than during intervals when the out-of-hospital cardiac arrest (OOH-CA) patient is physiologically primed for successful countershock. Interruptions to CPR may negatively impact defibrillation success. Multiple defibrillations can be associated with decreased post-resuscitation myocardial function. We hypothesize that a more complete picture of the cardiovascular system can be gained through non-linear dynamics and integration of multiple physiologic measures from biomedical signals.

Materials and Methods

Retrospective analysis of 153 anonymized OOH-CA patients who received at least one defibrillation for ventricular fibrillation (VF) was undertaken. A machine learning model, termed Multiple Domain Integrative (MDI) model, was developed to predict defibrillation success. We explore the rationale for non-linear dynamics and statistically validate heuristics involved in feature extraction for model development. Performance of MDI is then compared to the amplitude spectrum area (AMSA) technique.

Results

358 defibrillations were evaluated (218 unsuccessful and 140 successful). Non-linear properties (Lyapunov exponent > 0) of the ECG signals indicate a chaotic nature and validate the use of novel non-linear dynamic methods for feature extraction. Classification using MDI yielded ROC-AUC of 83.2% and accuracy of 78.8%, for the model built with ECG data only. Utilizing 10-fold cross-validation, at 80% specificity level, MDI (74% sensitivity) outperformed AMSA (53.6% sensitivity). At 90% specificity level, MDI had 68.4% sensitivity while AMSA had 43.3% sensitivity. Integrating available end-tidal carbon dioxide features into MDI, for the available 48 defibrillations, boosted ROC-AUC to 93.8% and accuracy to 83.3% at 80% sensitivity.

Conclusion

At clinically relevant sensitivity thresholds, the MDI provides improved performance as compared to AMSA, yielding fewer unsuccessful defibrillations. Addition of partial end-tidal carbon dioxide (PetCO₂) signal improves accuracy and sensitivity of the MDI prediction model.     

High survival rate of 43% in out-of-hospital cardiac arrest patients in an optimised chain of survival

Aims

Survival to hospital discharge after out-of-hospital cardiac arrest (OHCA) varies widely. This study describes short-term survival after OHCA in a region with an extensive care path and a follow-up of 1 year.

Methods

Consecutive patients ≥16 years admitted to the emergency department between April 2011 and December 2012 were included. In July 2014 a follow-up took place. Socio-demographic data, characteristics of the OHCA and interventions were described and associations with survival were determined.

Results

Two hundred forty-two patients were included (73 % male, median age 65 years). In 76 % the cardiac arrest was of cardiac origin and 52 % had a shockable rhythm. In 74 % the cardiac arrest was witnessed, 76 % received bystander cardiopulmonary resuscitation and in 39 % an automatic external defibrillator (AED) was used. Of the 168 hospitalised patients, 144 underwent therapeutic procedures. A total of 105 patients survived until hospital discharge. Younger age, cardiac arrest in public area, witnessed cardiac arrest, cardiac origin with a shockable rhythm, the use of an AED, shorter time until return of spontaneous circulation, Glasgow Coma Scale (GCS) ≥13 during transport and longer length of hospital stay were associated with survival. Of the 105 survivors 72 survived for at least 1 year after cardiac arrest and 6 patients died.

Conclusion

A survival rate of 43 % after OHCA is achievable. Witnessed cardiac arrest, cardiac cause of arrest, initial cardiac rhythm and GCS ≥13 were associated with higher survival.     

Impact of Rescue-Thrombolysis during Cardiopulmonary Resuscitation in Patients with Pulmonary Embolism

Background

Cardiac arrest in patients with pulmonary embolism (PE) is associated with high morbidity and mortality. Thrombolysis is expected to improve the outcome in these patients. However studies evaluating rescue-thrombolysis in patients with PE are missing, mainly due to the difficulties of clinical diagnosis of PE. We aimed to determine the success influencing factors of thrombolysis during resuscitation in patients with PE.

Methodology/Principal Findings

We analyzed retrospectively the outcome of 104 consecutive patients with confirmed (n = 63) or highly suspected (n = 41) PE and monitored cardiac arrest. In all patients rtPA was administrated for thrombolysis during cardiopulmonary resuscitation. In 40 of the 104 patients (38.5%) a return of spontaneous circulation (ROSC) could be achieved successfully. Patients with ROSC received thrombolysis significantly earlier after CPR onset compared to patients without ROSC (13.6±1.2 min versus 24.6±0.8 min; p<0.001). 19 patients (47.5%) out of the 40 patients with initially successful resuscitation survived to hospital discharge. In patients with hospital discharge thrombolysis therapy was begun with a significantly shorter delay after cardiac arrest compared to all other patients (11.0±1.3 vs. 22.5±0.9 min; p<0.001).

Conclusion

Rescue-thrombolysis should be considered and started in patients with PE and cardiac arrest, as soon as possible after cardiac arrest onset.     

Attitudes and Long-term Adjustment of Patients Surviving Cardiac Arrest

Twenty patients surviving cardiac resuscitation following myocardial infarction were seen at least six months after the cardiac arrest. The patient and spouse were interviewed separately. Though they had not usually been informed by the medical staff, 16 of the 20 patients were aware that a cardiac arrest had occurred and had a good understanding of what this meant. Six patients remembered the start or end of the cardiac arrest and five specifically remembered external cardiac massage. Their feelings and their attitudes to the cardiac arrest are described.Initial anxiety was experienced by all the patients and their spouses, particularly after hospital discharge, but in the long term only five patients failed to make a reasonably satisfactory adjustment. Poor rehabilitation seemed to be mainly associated with persisting physical disability and personality factors and not with features associated with the cardiac arrest, such as the duration of external cardiac massage. The spouses often found it difficult to know exactly how to treat the patients after hospital discharge and most patients and spouses felt that more explanation and discussion with the medical staff would have helped to alleviate anxiety.     

Appraisal of pediatric cardiopulmonary resuscitation.

Sixty-six patients more than 30 days and less thant 16 years of age suffering an unexpected cardiac arrest in an 18-month period were included in a study of resuscitative measures in children. Six children survived to be discharged from hospital. Respiratory disease accounted for most (29%) of the cardiac arrests, but it also had the most favourable prognosis, 21% of the 19 patients surviving. None of the patients survived whose cardiac arrest was secondary to sepsis or trauma, even when the resuscitative efforts were initially successful. Only 1 of the 41 patients who had a cardiac arrest outside of hospital survived, and only 1 of the 34 patients who presented with asystole survived, and then with considerable damage to the central nervous system. The interval between cardiac arrest and application of basic life support was substantially shorter among the survivors. Also, most of the survivors did not present with asystole. The results of this study suggest that survival among resuscitated children is no better than that among adults but can be improved with early recognition and monitoring of children at risk. earlier application of basic and advanced life support, improved education of medical and lay personnel, and further research into pediatric resuscitative techniques.     

Methods of ambulatory detection and treatment of cardiac arrhythmias using implantable cardioverter-defibrillators

The use of the implantable cardioverter-defibrillator (ICD) for the treatment of ventricular fibrillation, a condition that can lead to sudden cardiac death, is examined. Topics relevant to the development and implementation of ICD technology, such as defibrillation threshold optimization, battery design, lead configuration, arrhythmia-detection algorithms, and pacemakers-ICD interactions, are described. Clinical situations involving the surgical implantation procedures and the quality of life after implantation are also considered. Cost-benefit analysis of ICD treatment as well as an overview of cardiac arrhythmias and emerging technologies are also included. A survey of ICD recipients was conducted and its results are discussed.     

Out-of-hospital cardiac arrest in high-rise buildings: delays to patient care and effect on survival

Background:

The increasing number of people living in high-rise buildings presents unique challenges to care and may cause delays for 911-initiated first responders (including paramedics and fire department personnel) responding to calls for out-of-hospital cardiac arrest. We examined the relation between floor of patient contact and survival after cardiac arrest in residential buildings.

Methods:

We conducted a retrospective observational study using data from the Toronto Regional RescuNet Epistry database for the period January 2007 to December 2012. We included all adult patients (≥ 18 yr) with out-of-hospital cardiac arrest of no obvious cause who were treated in private residences. We excluded cardiac arrests witnessed by 911-initiated first responders and those with an obvious cause. We used multivariable logistic regression to determine the effect on survival of the floor of patient contact, with adjustment for standard Utstein variables.

Results:

During the study period, 7842 cases of out-of-hospital cardiac arrest met the inclusion criteria, of which 5998 (76.5%) occurred below the third floor and 1844 (23.5%) occurred on the third floor or higher. Survival was greater on the lower floors (4.2% v. 2.6%, p = 0.002). Lower adjusted survival to hospital discharge was independently associated with higher floor of patient contact, older age, male sex and longer 911 response time. In an analysis by floor, survival was 0.9% above floor 16 (i.e., below the 1% threshold for futility), and there were no survivors above the 25th floor.

Interpretation:

In high-rise buildings, the survival rate after out-of-hospital cardiac arrest was lower for patients residing on higher floors. Interventions aimed at shortening response times to treatment of cardiac arrest in high-rise buildings may increase survival.More than 400 000 out-of-hospital cardiac arrests occur annually in North America.^1,2 Despite considerable effort to improve resuscitation care, survival to hospital discharge in most communities remains below 10%.² Rapid defibrillation and high-quality cardiopulmonary resuscitation (CPR) are essential for survival, with an absolute decrease in survival of 7% to 10% for each 1-minute delay to defibrillation.^3–5Recently, there has been a dramatic increase in the number of people living in high-rise buildings (e.g., a 13% relative increase in Toronto from 2006 to 2011^6,7). As more high-rise buildings are constructed in urban centres across Canada, the number of 911 calls for emergency medical services in high-rise buildings will also continue to increase. Furthermore, over 40% of homeowners over the age of 65 years reside in high-rise buildings.⁸ These older residents have higher risks for a number of serious medical conditions, including cardiac arrest. Cardiac arrests that occur in high-rise buildings pose unique challenges for 911- initiated first responders. Building access issues, elevator delays and extended distance from the location of the responding vehicle on scene to the patient can all contribute to longer times to patient contact and, ultimately, longer times to initiation of resuscitation. Previous research has shown that longer 911 response times result in decreased patient survival after cardiac arrest,^9,10 but response times are traditionally measured from the time a call is received by the 911 dispatch centre to when the response vehicle arrives on scene. This measure fails to take into account the time required for 911-initiated first responders to make patient contact once they arrive on scene. This interval can contribute substantial delays to patient treatment, in some cases more than 4 minutes, and can account for up to 28% of the total time from the 911 call to arrival of the first responders at the patient’s side.^11–14There is a lack of literature describing the delay to patient contact during out-of-hospital cardiac arrests in high-rise buildings, where time-sensitive, life-saving interventions matter most. Furthermore, the effect on survival of vertical delay to patient contact is unknown. As the number of high-rise buildings continues to increase and as population density rises in major urban centres, is important to determine the effect of delays to patient care in high-rise buildings on survival after cardiac arrest and to examine potential barriers to patient care in this setting.The primary objective of this study was to compare the rate of survival to hospital discharge after out-of-hospital cardiac arrest at different vertical heights in residential buildings, specifically higher floors (≥ 3 floors) relative to lower floors (< 3 floors), with adjustment for standard Utstein variables.¹⁵The secondary objectives were to determine the delay to patient contact by 911-initiated first responders for cardiac arrests occurring on higher floors and to examine the use of automated external defibrillators by bystanders in private residences.