Francis C. Dane

Success changes the problem: Why ventricular fibrillation is declining, why pulseless electrical activity is emerging, and what to do about it

BACKGROUND Programs for research and practice in resuscitation have focused on identification and reversal of ventricular fibrillation (VF). While substantial progress has been achieved, evidence is accumulating that clinical death is less likely to be caused by fibrillation now than in the 1960s and 1970s. Pulseless electrical activity (PEA) has emerged as the most common rhythm found in arrests in the hospital and is rapidly rising in pre-hospital reports. PURPOSE To identify the magnitude of changes occurring, search for potential explanations from population and clinical epidemiology and present the data available regarding etiology and treatment of PEA. DATA SOURCES Synthesis of material from population epidemiology, clinical epidemiology, animal and human research on VF and PEA. CONCLUSIONS VF is a manifestation of severe, undiagnosed coronary artery disease (CAD). Rates of death from CAD increased from rare in 1930 to become the most common cause of death in the US. CAD death rates peaked in the early 1960s and had declined over 50% by the late 1990s. Primary and secondary prevention, early diagnosis and aggressive, successful treatment have contributed to this decline. PEA is a brief phase in clinical death that occurs after losses in consciousness, ventilatory drive and circulation but before decay to asystole; survival rates are poor. PEA is a common stage in clinical death from any of a variety of tissue hypoxic/anoxic insults. Research on PEA is needed; 50 years of attention to CAD and VF have resulted in improved survival and changed the disease spectrum. Similar attention to animal and clinical research on PEA may have the potential to improve survival.

Resuscitation in the hospital: Differential relationships between age and survival across rhythms

OBJECTIVE Assess the frequency and outcome of inhospital resuscitation and determine the relationship between patient age and survival and whether it is affected by initial rhythm. DESIGN Retrospective, single-institution, registry study of inhospital resuscitation. SETTING A 550-bed, tertiary-care, teaching hospital in Macon, GA. PATIENTS All admissions for which a resuscitation was attempted in the Medical Center of Central Georgia during the period of January 1, 1987 through December 31, 1993. The registry sample included 2,394 admissions, for which 2,813 resuscitation attempts were made; only the first resuscitation attempt during an admission was analyzed. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Rates of survival to discharge steadily increased from 24.4% in 1987 to 38.6% in 1993; the overall survival rate was 26.8%. Age, used as a continuous variable, was strongly related to survival (odds ratio = 0.984; p < .0001). Categorically, overall survival rates for pediatric, adult, and geriatric patients were 56.4%, 29.0%, and 24.0%, respectively. Survival rates also varied significantly (odds ratio = 0.469; p < .0001) among initial rhythms, i.e., supraventricular tachycardia (60.7%), ventricular tachycardia (57.6%), perfusing rhythms (49.84%), ventricular fibrillation (32.0%), pulseless electrical activity (14.6%), and asystole (9.1%). The relationship between age and survival did not change across the years included in the study, but did vary as a function of initial rhythm (p < .0001). Age was positively related to survival when initial rhythm was supraventricular tachycardia (p = .04), negatively related to survival when the initial rhythm was perfusing (p < .0001) or pulseless electrical activity (p = .0002), and not related to survival when the initial rhythm was ventricular tachycardia (p = .98), ventricular fibrillation (p = .14), or asystole (p = .21). CONCLUSIONS The relationship between patient age and a successful resuscitation attempt is not as simple as reported earlier. Whether age is related to increased or decreased survival, or is unrelated to survival, depends on the rhythm extant when resuscitation attempts begin. Survival rates were higher than most reported elsewhere and improved significantly over time. Multicentered studies are needed to determine whether these results are unique to the institution studied.

Resuscitation in the hospital: relationship of year and rhythm to outcome

OBJECTIVE determine the frequency of initial rhythms in in-hospital resuscitation and examine its relationship to survival. Assess changes in outcome over time. METHODS retrospective cohort (registry) including all admissions to the Medical Center of Central Georgia in which a resuscitation was attempted between 1 January, 1987 and 31 December, 1996. RESULTS the registry includes 3327 admissions in which 3926 resuscitations were attempted. Only the first event is reported. There were 961 hospital survivors. Survival increased from 24.2% in 1987 to 33.4% in 1996 (chi(2)=39.0, df=1, P<0.0001). Survival was affected strongly by initial rhythm (chi(2)=420.0, df=1, P<0.0001) and decreased from 63.2% for supraventricular tachycardia (SVT) to 55.3% for ventricular tachycardia (VT), 51.0% for perfusing rhythms (PER), 34.8% for ventricular fibrillation (VF), 14.3% for pulseless electrical activity (PEA) and 10.0% for asystole (ASYS). PEA was the most frequent rhythm (1180 cases) followed by perfusing (963), asystole (580), VF (459), VT (94) and SVT (38). DISCUSSION the powerful effect of initial rhythm on survival has been reported in pre-hospital and in-hospital resuscitation. VF is considered the dominant rhythm and generally accounts for the most survivors. We report good outcome for each; however, VF represents only 13.8% of events and 16.7% of survivors. PEA accounts for more survivors (169) than does VF (160). Our improved outcome is partially explained by changes in rhythms, but other institutional variables need to be identified to fully explain the results. Further studies are needed to see if our findings can be sustained or replicated.

Fatigue in Medical Residents Leads to Reactivation of Herpes Virus Latency

The main objective of this study was to detect fatigue-induced clinical symptoms of immune suppression in medical residents. Samples were collected from the subjects at rest, following the first night (low-stress), and the last night (high-stress) of night float. Computerized reaction tests, Epworth Sleepiness Scale, and Wellness Profile questionnaires were used to quantify fatigue level. DNA of human herpes viruses HSV-1, VZV, EBV, as well as cortisol and melatonin concentrations, were measured in saliva. Residents at the high-stress interval reported being sleepier compared to the rest interval. EBV DNA level increased significantly at both stress intervals, while VZV DNA level increased only at low-stress. DNA levels of HSV-1 decreased at low-stress but increased at high-stress. Combined assessment of the viral DNA showed significant effect of stress on herpes virus reactivation at both stress intervals. Cortisol concentrations at both stress intervals were significantly higher than those at rest.

Mechanism of death: there’s more to it than sudden cardiac arrest

The dying process begins with the loss of function of one or more of the three classic vital organs: heart, brain, lungs. Failure to resuscitate the function of the affected primary organ results in cessation of function of the others.

Mastery Learning of ACLS among Internal MedicineResidents

Mastery Learning of ACLS among Internal Medicine Residents Mastery learning has been employed to overcome poor retention of skills, but it is unclear what level of technological fidelity is necessary to achieve skill enhancement.The use of widely available technical-fidelity simulation can overcome declines in resuscitation skills when utilized in a mastery-learning program that emphasizes psychological fidelity.

Survival patterns with in-hospital cardiac arrest.

To the Editor: In their study of in-hospital cardiac arrests, Dr Peberdy and colleagues found lower survival rates during nights and weekends. Similarly, patients admitted on weekends for acute myocardial infarction have been found to have a significantly higher mortality compared with patients admitted on weekdays. Nights and weekends share several potentially harmful factors, such as lower surveillance levels; less availability of trained medical staffing, ancillary personnel, important medical services, and common urgent procedures; and reduced psychophysical performance. This plausible interpretation is mainly focused on the health care workers or structures. However, circadian or weekly oscillations of endogenous biological rhythms related to the patient or the disease itself may also play a role. Medical emergencies, especially cardiovascular and respiratory, exhibit a circadian variation characterized by a progressive increase in frequency rate during nighttime and a peak soon after awakening, with a temporal pattern similar to the hourly rate of survival to discharge reported in the study by Peberdy et al. This temporal window includes peaks of many underlying risk factors, including sympathetic activity, arterial blood pressure, heart rate, basal vascular tone, platelet aggregability, plasma viscosity, and hematocrit. It also includes the nadir of others factors such as blood flow, oxygen availability, and endogenous fibrinolytic activity. This combination may contribute to the increased frequency and severity of cardiovascular events. Such a constellation of physiological and biological rhythms may determine different patterns in the clinical presentation features of a disease. In one study, weekends and nights were found to have a lower rate of admissions of acute coronary syndromes than expected but a significantly higher proportion of cases presenting with ST-segment elevation myocardial infarctions (relative increase, 64% for weekends compared with weekdays; P .001; 30.9% for nights compared with days; P=.02). As a consequence, weekends and nights were characterized by an increased proportion of acute coronary syndromes with acute STelevation myocardial infarctions (relative increase, 9.7% for weekends compared with weekdays; P=.006; 7.1% for nights compared with days; P=.03), independent of the conventional risk factors. It is therefore possible that the lower survival rates of patients with in-hospital cardiac arrest during nights and weekends may reflect in part different levels of disease severity due to endogenous biological rhythms. A deeper knowledge of environmental and physiological factors, particularly rhythmic patterns of biological functions potentially responsible for increased night and weekend cardiovascular mortality, may have practical implications in reducing mortality.