Waveform analysis-guided treatment versus a standard shock-first protocol for the treatment of out-of-hospital cardiac arrest presenting in ventricular fibrillation: results of an international randomized, controlled trial.

BACKGROUND: Ventricular fibrillation (VF) waveform properties have been shown to predict defibrillation success and outcomes among patients treated with immediate defibrillation. We postulated that a waveform analysis algorithm could be used to identify VF unlikely to respond to immediate defibrillation, allowing selective initial treatment with cardiopulmonary resuscitation in an effort to improve overall survival. METHODS AND RESULTS: In a multicenter, double-blind, randomized study, out-of-hospital cardiac arrest patients in 2 urban emergency medical services systems were treated with automated external defibrillators using either a VF waveform analysis algorithm or the standard shock-first protocol. The VF waveform analysis used a predefined threshold value below which return of spontaneous circulation (ROSC) was unlikely with immediate defibrillation, allowing selective treatment with a 2-minute interval of cardiopulmonary resuscitation before initial defibrillation. The primary end point was survival to hospital discharge. Secondary end points included ROSC, sustained ROSC, and survival to hospital admission. Of 6738 patients enrolled, 987 patients with VF of primary cardiac origin were included in the primary analysis. No immediate or long-term survival benefit was noted for either treatment algorithm (ROSC, 42.5% versus 41.2%, P=0.70; sustained ROSC, 32.4% versus 33.4%, P=0.79; survival to admission, 34.1% versus 36.4%, P=0.46; survival to hospital discharge, 15.6% versus 17.2%, P=0.55, respectively). CONCLUSIONS: Use of a waveform analysis algorithm to guide the initial treatment of out-of-hospital cardiac arrest patients presenting in VF did not improve overall survival compared with a standard shock-first protocol. Further study is recommended to examine the role of waveform analysis for the guided management of VF.

CPR with chest compression alone or with rescue breathing.

BACKGROUND: The role of rescue breathing in cardiopulmonary resuscitation (CPR) performed by a layperson is uncertain. We hypothesized that the dispatcher instructions to bystanders to provide chest compression alone would result in improved survival as compared with instructions to provide chest compression plus rescue breathing. METHODS: We conducted a multicenter, randomized trial of dispatcher instructions to bystanders for performing CPR. The patients were persons 18 years of age or older with out-of-hospital cardiac arrest for whom dispatchers initiated CPR instruction to bystanders. Patients were randomly assigned to receive chest compression alone or chest compression plus rescue breathing. The primary outcome was survival to hospital discharge. Secondary outcomes included a favorable neurologic outcome at discharge. RESULTS: Of the 1941 patients who met the inclusion criteria, 981 were randomly assigned to receive chest compression alone and 960 to receive chest compression plus rescue breathing. We observed no significant difference between the two groups in the proportion of patients who survived to hospital discharge (12.5% with chest compression alone and 11.0% with chest compression plus rescue breathing, P=0.31) or in the proportion who survived with a favorable neurologic outcome in the two sites that assessed this secondary outcome (14.4% and 11.5%, respectively; P=0.13). Prespecified subgroup analyses showed a trend toward a higher proportion of patients surviving to hospital discharge with chest compression alone as compared with chest compression plus rescue breathing for patients with a cardiac cause of arrest (15.5% vs. 12.3%, P=0.09) and for those with shockable rhythms (31.9% vs. 25.7%, P=0.09). CONCLUSIONS: Dispatcher instruction consisting of chest compression alone did not increase the survival rate overall, although there was a trend toward better outcomes in key clinical subgroups. The results support a strategy for CPR performed by laypersons that emphasizes chest compression and minimizes the role of rescue breathing. (Funded in part by the Laerdal Foundation for Acute Medicine and the Medic One Foundation; ClinicalTrials.gov number, NCT00219687.)

Public perceptions and experiences of myocardial infarction, cardiac arrest and CPR in London.

INTRODUCTION: The lay public have limited knowledge of the symptoms of myocardial infarction ("heart attack"), and inaccurate perceptions of cardiac arrest survival rates. Levels of CPR training and willingness to intervene in cardiac emergencies are also low. AIMS: To explore public perceptions of myocardial infarction and cardiac arrest; investigate perceptions of cardiac arrest survival rates; assess levels of training and attitudes towards CPR, and explore the types of interventions considered useful for increasing rates of bystander CPR among Greater London residents. METHODS: A quantitative interview survey was conducted with 1011 Greater London residents. Eight focus groups were also conducted to explore a range of issues in greater depth and validate trends that emerged in the initial survey. RESULTS: Chest pain was the most commonly recognised symptom of "heart attack". Around half of the respondents were aware that a myocardial infarction differs from a cardiac arrest, although their ability to explain this difference was limited. The majority overestimated that at least a quarter of cardiac arrest patients in London survive to hospital discharge. Few participants had received CPR training, and most were hesitant about performing the procedure on a stranger. CONCLUSIONS: Awareness and knowledge of CPR, and reactions to cardiac emergencies, reflect relatively low levels of CPR training in London. Publicising cardiac arrest survival figures may be instrumental in prompting members of the public to train in CPR and motivating those who have been trained to intervene in a cardiac emergency.

The influence on cognition of the interactions between lecithin, carnitine and carbohydrate.

It is accepted that acetylcholine-mediated neurones modulate memory. As lecithin, carnitine and glucose all influence acetylcholine metabolism, the possibility of synergistic interactions was considered. Four hundred young adult females randomly, and under a double-blind procedure, received capsules for 3 days that contained a placebo, lecithin (1.6 g/day), carnitine (500 mg/day) or carnitine plus lecithin. A battery of cognitive tests was administered prior to taking the capsules, after 3 days of taking the supplements, and for a third time after consuming either a glucose drink or a placebo. Reaction times were more rapid when carnitine and a glucose drink were taken together. Memory was enhanced in those taking a glucose rather than placebo drink. Neither mood nor the ability to sustain attention were influenced by these procedures. The hypothesis that memory would be facilitated by offering supplements of lecithin, carnitine and glucose was not supported.

Out-of-hospital cardiac arrest in patients aged 35 years and under: a 4-year study of frequency and survival in London.

BACKGROUND: The aim of this study was to describe the frequency and characteristics of cardiac arrest patients of 35 years and under attended by the London Ambulance Service NHS Trust between April 2003 and March 2007. Few large studies have described the occurrence, mechanism, resuscitation viability and outcome of this substantial subset of the cardiac arrest population. By documenting over 3000 cardiac arrests in young people we sought to improve understanding, awareness and ultimately survival of a condition notorious for high mortality rates. METHODS AND RESULTS: Data were analysed for 3084 young cardiac arrest patients and reported retrospectively. Patients were categorised by age, gender, aetiology and whether or not resuscitation attempts were made. Over 75% of patients were aged 18-35 years. There were significantly more males in this age group (p<0.001) compared to those aged 17 years or less. The most common cause of cardiac arrest was an underlying cardiac cause (44.9%). Overdoses, hanging and other suicides were found to be major causes of cardiac arrests of non-cardiac origin in young adult males. Sudden Infant Death Syndrome (SIDS) was the most common known cause of death in infants aged less than 1 year. This age group received bystander CPR most often. 5.6% of young cardiac arrest patients who were taken to hospital survived to hospital discharge. CONCLUSIONS: Mortality in young cardiac arrest patients remains high. Focus should be placed on tackling social and psychological causes of cardiac arrest as well as cardiac aetiologies.