Hypothermia and the Approximate Entropy of the Electroencephalogram

Background: The electroencephalogram is commonly used to monitor the brain during hypothermic cardiopulmonary bypass and circulatory arrest. No quantitative relationship between the electroencephalogram and temperature has been elucidated, even though the qualitative changes are well known. This study was undertaken to define a dose-response relationship for hypothermia and the approximate entropy of the electroencephalogram.

Methods: The electroencephalogram was recorded during cooling and rewarming in 14 patients undergoing hypothermic cardiopulmonary bypass and circulatory arrest. Data were digitized at 128 Hz, and approximate entropy was calculated from 8-s intervals. The dose-response relationship was derived using sigmoidal curve-fitting techniques, and statistical analysis was performed using analysis of variance techniques.

Results: The approximate entropy of the electroencephalogram changed in a sigmoidal fashion during cooling and rewarming. The midpoint of the curve averaged 24.7[degrees]C during cooling and 28[degrees]C (not significant) during rewarming. The temperature corresponding to 5% entropy (T0.05) was 18.7[degrees]C. The temperature corresponding to 95% entropy (T0.95) was 31.3[degrees]C during cooling and 38.2[degrees]C during rewarming (P < 0.02).     

Familias Unidas: The Efficacy of an Intervention to Promote Parental Investment in Hispanic Immigrant Families

This paper reports a test of the efficacy of Familias Unidas, a Hispanic-specific, ecologically focused, parent-centered preventive intervention, in promoting protection against and reducing risk for adolescent behavior problems. Specifically, the intervention was designed to foster parental investment, reduce adolescent behavior problems, and promote adolescent school bonding/academic achievement, all protective factors against drug abuse and delinquency. One-hundred sixty seven Hispanic families of 6th and 7th grade students from three South Florida public schools were stratified by grade within school and randomly assigned to intervention and no-intervention control conditions. Results indicated that Familias Unidas was efficacious in increasing parental investment and decreasing adolescent behavior problems, but that it did not significantly impact adolescent school bonding/academic achievement. Summer-vacation rates of adolescent behavior problems were six times higher in the control condition than in the intervention condition. Furthermore, change in parental investment during the intervention was predictive of subsequent levels of adolescent behavior problems. The findings suggest that Familias Unidas is efficacious in promoting protection and reducing risk for adolescent problem behaviors in poor immigrant Hispanic families.     

Lipoprotein macroaggregates in bronchoalveolar lavage fluid from patients with diffuse interstitial lung disease: comparison with idiopathic alveolar lipoproteinosis.

Lipoprotein macroaggregates were present in cytocentrifuge preparations of bronchoalveolar lavage fluid from four patients with diffuse lung diseases other than idiopathic alveolar lipoproteinosis. In three patients the primary diagnosis was cryptogenic fibrosing alveolitis and in one sarcoidosis. We confirmed the presence of large multilamellar aggregates of lipoprotein by ultrastructural examination in patients with both interstitial lung disease and idiopathic alveolar lipoproteinosis. The small lamellar bodies and amorphous debris found in idiopathic alveolar lipoproteinosis were rare in the patients with interstitial lung disease. The lavage fluid from patient with interstitial lung disease did not show the substantial alterations in phospholipid composition that were seen in lavage fluid in idiopathic alveolar lipoproteinosis. These ultrastructural and biochemical features may help to distinguish idiopathic from other causes of alveolar lipoproteinosis, particularly at an early stage, when differential diagnosis may be difficult.     

The role of chest radiography in patients presenting with anterior chest pain to the Accident & Emergency Department.

The chest radiological findings and outcomes of 120 consecutive patients attending the Accident & Emergency Department with anterior chest pain were recorded prospectively to investigate the value of routine chest radiography in their management. Twenty-one patients (17.5%) were excluded because of incomplete information. Thirty-seven radiological abnormalities were identified in 33 (33%) of the remaining 99 chest X-rays. Seventeen of the abnormalities identified in 14 (14%) of the chest X-rays were clinically significant. The casualty officer's interpretation of 70 (70%) of the chest X-rays was correct, but 36 errors were made interpreting the other 29 chest X-rays. Of these errors, 19 were false negative errors, resulting in the mismanagement of two patients and 17 false positive errors, resulting in the mismanagement of four patients. It appears that a routine chest X-ray provides little information of practical value in the management of patients with anterior chest pain attending an Accident & Emergency Department, unless the training of medical students and junior doctors in the interpretation of chest X-rays is improved.     

Development of OASYS-2: a system for the analysis of serial measurement of peak expiratory flow in workers with suspected occupational asthma.

BACKGROUND: Serial peak expiratory flow (PEF) measurement is usually the most appropriate first step in the confirmation of occupational asthma. Visual assessment of the plotted record is more sensitive and specific than statistical methods so far reported. The use of visual analysis is limited by lack of widespread expertise in the methods. A computer assisted diagnostic aid (OASYS-2) has been developed which is based on a scoring system developed from visual analysis. This removes the requirement for an experienced interpreter and should lead to the more widespread use of the technique. METHODS: PEF records were collected from workers attending an occupational lung disease clinic for investigation of suspected occupational asthma and from workers participating in a study of respiratory symptoms in a postal sorting office. PEF records were divided into two development sets and two gold standard sets. The latter consisted of records from workers in which a final diagnosis had been reached by a method other than PEF recording. An experienced observer scored individual work and rest periods for the two development set PEF records; linear discriminant analysis was used to compare measurements taken from development set 1 records with visual scores. Two equations were produced which allowed prediction of scores for individual work or rest periods. The development set 2 was used to determine how these scores should be used to produce a whole record score. The first gold standard set was used to determine the whole record score which best separated those with and without occupational asthma. The second set determined the sensitivity and specificity of the chosen score. RESULTS: Two hundred and sixty eight PEF records were collected from 169 workers and divided into two development sets (81 and 60 records) and two gold standard sets (60 and 67 records). Linear discriminant analysis produced equations predicting the score for work periods incorporating five indices of PEF change and one for rest periods using seven indices. These equations correctly predicted the score for development set 1 work and rest periods on 61% of occasions (kappa = 0.47). The whole record score for development set 2 records, after weighting for definite or definitely no occupational effect, correlated with the visual score (correlation coefficient 0.86). Comparison with gold standard set 1 identified a cut off which proved to have a sensitivity of 75% and a specificity of 94% for an independent diagnosis of occupational asthma when applied to gold standard set 2. CONCLUSIONS: These results suggest that the sensitivity and specificity of analysing PEF records for occupational asthma using OASYS-2 approaches that of visual analysis, but it should be absolutely reproducible. The performance of OASYS-2 is more specific and approaches the sensitivity of other statistical methods of analysis. The evaluation of a large number of PEF records from workers exposed to different sensitising agents suggests that these results should be robust and should be repeatable in clinical practice.     

Addressing Methodologic Challenges and Minimizing Threats to Validity in Synthesizing Findings from Individual-Level Data Across Longitudinal Randomized Trials

Integrative Data Analysis (IDA) encompasses a collection of methods for data synthesis that pools participant-level data across multiple studies. Compared with single-study analyses, IDA provides larger sample sizes, better representation of participant characteristics, and often increased statistical power. Many of the methods currently available for IDA have focused on examining developmental changes using longitudinal observational studies employing different measures across time and study. However, IDA can also be useful in synthesizing across multiple randomized clinical trials to improve our understanding of the comprehensive effectiveness of interventions, as well as mediators and moderators of those effects. The pooling of data from randomized clinical trials presents a number of methodological challenges, and we discuss ways to examine potential threats to internal and external validity. Using as an illustration a synthesis of 19 randomized clinical trials on the prevention of adolescent depression, we articulate IDA methods that can be used to minimize threats to internal validity, including (1) heterogeneity in the outcome measures across trials, (2) heterogeneity in the follow-up assessments across trials, (3) heterogeneity in the sample characteristics across trials, (4) heterogeneity in the comparison conditions across trials, and (5) heterogeneity in the impact trajectories. We also demonstrate a technique for minimizing threats to external validity in synthesis analysis that may result from non-availability of some trial datasets. The proposed methods rely heavily on latent variable modeling extensions of the latent growth curve model, as well as missing data procedures. The goal is to provide strategies for researchers considering IDA.

     

A randomized controlled trial of a parent-centered intervention in preventing substance use and HIV risk behaviors in Hispanic adolescents

The present study evaluated the efficacy of Familias Unidas + Parent-Preadolescent Training for HIV Prevention (PATH), a Hispanic-specific, parent-centered intervention, in preventing adolescent substance use and unsafe sexual behavior. Two hundred sixty-six 8th-grade Hispanic adolescents and their primary caregivers were randomly assigned to 1 of 3 conditions: Familias Unidas + PATH, English for Speakers of Other Languages (ESOL) + PATH, and ESOL + HeartPower! for Hispanics (HEART). Participants were assessed at baseline and at 6, 12, 24, and 36 months postbaseline. Results showed that (a) Familias Unidas + PATH was efficacious in preventing and reducing cigarette use relative to both control conditions; (b) Familias Unidas + PATH was efficacious, relative to ESOL + HEART, in reducing illicit drug use; and (c) Familias Unidas + PATH was efficacious, relative to ESOL + PATH, in reducing unsafe sexual behavior. The effects of Familias Unidas + PATH on these distal outcomes were partially mediated by improvements in family functioning. These findings suggest that strengthening the family system, rather than targeting specific health behaviors, may be most efficacious in preventing and/or reducing cigarette smoking, illicit drug use, and unsafe sex in Hispanic adolescents.     

Programs for Preventing Depression in Adolescence: Who Benefits and Who Does Not? An Introduction to the Supplemental Issue

We introduce this supplemental issue of Prevention Science, which brings together a set of papers from leading investigators who have conducted trials testing whether intervention programs prevent adolescent depression. Using data from these trials, these papers explore a series of factors that might account for variation in intervention benefit, employing several novel methods for assessing effect heterogeneity. These studies follow two general paradigms: three papers report findings from single randomized preventive intervention trials, while the remaining papers develop and apply new methods for combining data from multiple studies to evaluate effect heterogeneity more broadly. Colleagues from NIMH and SAMHSA also provide commentaries on these studies. They conclude that synthesis of findings from multiple trials holds great promise for advancing the field, and progress will be accelerated if collaborative data sharing becomes the norm rather than the exception.     

Ecodevelopmental HIV prevention programs for Hispanic adolescents

The purpose of this article is to illustrate how an ecodevelopmental perspective on risk and protection can be applied to the study and prevention of unsafe sexual behavior in Hispanic immigrant adolescents. Special attention is given to culturally based ecodevelopmental risk and protective processes that may influence unsafe sexual behavior among Hispanic adolescents. Principles for designing prevention programs to offset these risks are offered on the basis of an ecodevelopmental HIV prevention program that has been developed and is currently being tested.