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Population Values (population + value)

Distribution by Scientific Domains

Medical Sciences	50%
Mathematics and Statistics	33%

Selected Abstracts

Variation in the Type, Rate, and Selection of Patients for Out-of-hospital Airway Procedures Among Injured Children and Adults

ACADEMIC EMERGENCY MEDICINE, Issue 12 2009
Craig D. Newgard MD
Abstract Objectives:, The objective was to compare the type, rate, and selection of injured patients for out-of-hospital airway procedures among emergency medical services (EMS) agencies in 10 sites across North America. Methods:, The authors analyzed a consecutive patient, prospective cohort registry of injured adults and children with an out-of-hospital advanced airway attempt, collected from December 1, 2005, through February 28, 2007, by 181 EMS agencies in 10 sites across the United States and Canada. Advanced airway procedures were defined as orotracheal intubation, nasotracheal intubation, supraglottic airway, or cricothyrotomy. Airway procedure rates were calculated based on age-specific population values for the 10 sites and the number of injured patients with field physiologic abnormality (systolic blood pressure of ,90 mm Hg, respiratory rate of <10 or >29 breaths/min, Glasgow Coma Scale [GCS] score of ,12). Descriptive measures were used to compare patients between sites. Results:, A total 1,738 patients had at least one advanced airway attempt and were included in the analysis. There was wide variation between sites in the types of airway procedures performed, including orotracheal intubation (63% to 99%), supraglottic airways (0 to 27%), nasotracheal intubation (0 to 21%), and cricothyrotomy (0 to 2%). Use of rapid sequence intubation (RSI) varied from 0% to 65%. The population-adjusted rates of field airway intervention (by site) ranged from 1.2 to 22.8 per 100,000 adults and 0.2 to 4.0 per 100,000 children. Among trauma patients with physiologic abnormality, some sites performed airway procedures in almost 50% of patients, while other sites used these procedures in fewer than 10%. There was also large variation in demographic characteristics, physiologic measures, mechanism of injury, mode of transport, field cardiopulmonary resuscitation, and unadjusted mortality among airway patients. Conclusions:, Among 10 sites across North America, there was wide variation in the types of out-of-hospital airway procedures performed, population-based rates of airway intervention, and the selection of injured patients for such procedures. [source]

Upper susceptibility threshold limits with confidence intervals: a method to identify normal and abnormal population values for laboratory toxicological parameters, based on acetylcholinesterase activities in sea lice

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 3 2006
Anders Fallang
Abstract The interpretation and importance of comparing field values of susceptibility to pesticides with a laboratory reference strain that might bear little resemblance to the actual situation in the field are problematic and a continuing subject of debate. In this paper a procedure for defining a ,normal sensitive' population from a field study of 383 individuals to provide a basis for analysing and interpreting in vitro results is described and examined. Instead of using only the 95th percentile, the upper and lower confidence limits for the 95th percentile were also compared to select the best estimation of the limit for the normal material. A field population constrained by the upper confidence limit for the 95th percentile provides appropriate descriptions of the normal material in this study. This approach should prove useful in studies of pesticide resistance in field populations. Copyright © 2006 Society of Chemical Industry [source]

Evaluating Normal Approximation Confidence Intervals for Measures of 2 × 2 Association with Applications to Twin Data

BIOMETRICAL JOURNAL, Issue 1 2003
M.M. Shoukri
Abstract Twin data are of interest to genetic epidemiologists for exploring the underlying genetic basis of disease development. When the outcome is binary, several indices of 2 × 2 association can be used to measure the degree of within twin similarity. All such measures share a common feature, in that they can be expressed as a monotonic increasing function of the within twin correlation. The sampling distributions of their estimates are influenced by the sample size, the correlation and the marginal distribution of the binary response. In this paper we use Monte-Carlo simulations to estimate the empirical coverage probabilities and evaluate the adequacy of the classical normal confidence intervals on the population values of these measures. [source]

Bayesian Quantile Regression for Longitudinal Studies with Nonignorable Missing Data

BIOMETRICS, Issue 1 2010
Ying Yuan
Summary We study quantile regression (QR) for longitudinal measurements with nonignorable intermittent missing data and dropout. Compared to conventional mean regression, quantile regression can characterize the entire conditional distribution of the outcome variable, and is more robust to outliers and misspecification of the error distribution. We account for the within-subject correlation by introducing a,,2,penalty in the usual QR check function to shrink the subject-specific intercepts and slopes toward the common population values. The informative missing data are assumed to be related to the longitudinal outcome process through the shared latent random effects. We assess the performance of the proposed method using simulation studies, and illustrate it with data from a pediatric AIDS clinical trial. [source]

High levels and gender difference of exhaled nitric oxide in Chinese schoolchildren

CLINICAL & EXPERIMENTAL ALLERGY, Issue 7 2005
G. W. K. Wong
Summary Background Exhaled nitric oxide (eNO) may represent a useful noninvasive marker of airway inflammation, but data on the reference population values in schoolchildren are limited. No reference eNO study in Asian children has been published. Methods Levels of eNO in a sample of 531 schoolchildren aged 11,18 years recruited from five schools (three international schools) in Hong Kong were measured online by a chemiluminescence analyser according to ERS/ATS standard. Each student also completed an International Study of Asthma and Allergic disease in Childhood questionnaire. Results Among the children without a physician's diagnosis of asthma or symptoms of wheeze, rhinitis and eczema, there were 258 Chinese and 33 Caucasians. In control Chinese children, the eNO level (median: interquantile range) was significantly higher (P<0.001) in males (17.0 parts per billion (p.p.b.); 10.7,36.6) than in females (10.8 p.p.b.; 7.8,17.6). When compared with Caucasian control males (11.6 p.p.b.; 8.2,19.3) and females (9.1 p.p.b.; 7.5,11.9), the Chinese children had significantly higher eNO levels for both males (P=0.011) and females (P=0.037). For Chinese asthmatic males, the median eNO (interquartile range) was 39.8 p.p.b. (12.5,73.8), and for asthmatic females, 18.0 (9.6,56.3). After controlling for sex in Chinese controls, eNO did not have any significant correlation with height, weight and body mass index or body surface area. Conclusions This study demonstrates a gender difference of eNO level in healthy Chinese schoolchildren. When compared with Caucasians, Chinese children have significantly higher eNO levels. [source]

Growth hormone (GH) replacement in hypopituitary adults with GH deficiency evaluated by a utility-weighted quality of life index: a precursor to cost,utility analysis

CLINICAL ENDOCRINOLOGY, Issue 1 2008
Maria Ko, towska-Häggström
Summary Objectives To examine quality of life (QoL) measured by a utility-weighted index in GH-deficient adults on GH replacement and analyse the impact of demographic and clinical characteristics on changes in utilities during treatment. Design Utilities for items in the QoL-Assessment of Growth Hormone Deficiency in Adults (QoL-AGHDAutility) were estimated based on data obtained from the general population in England and Wales (E&W). These estimates were used to calculate QoL changes in GH-treated patients and compare these with normative population values. Patients A total of 894 KIMS patients (53% women) from E&W were followed for 1 to 6 years. Measurements QoL-AGHDAutility at baseline and at the last reported visit, total QoL-AGHDAutility gain and QoL-AGHDAutility gain per year of follow-up. Results QoL-AGHDAutility in patients before GH treatment differed from the expected population values [0·67 (SD 0·174) vs. 0·85 (SD 0·038), P < 0·0001], constituting a mean deficit of ,0·19 (SD 0·168). There was a difference in the mean QoL-AGHDAutility deficit for men [,0·16 (SD 0·170)] and women [,0·21 (SD 0·162)] (P < 0·001). The main improvement occurred during the first year of treatment [reduction of a deficit to ,0·07 (SD 0·163) (P < 0·001) in the total cohort]; however, patients' utilities remained lower than those recorded for the general population during subsequent follow-up (P < 0·001). Despite an observed impact of age, primary aetiology, disease onset and comorbidities on QoL-AGHDAutility, all patients showed a similar beneficial response to treatment. Conclusions QoL-AGHDAutility efficiently monitors treatment effects in patients with GHD. The study confirmed the QoL-AGHDAutility deficit before treatment and a similar QoL-AGHDAutility gain observed after commencement of GH replacement in all patients. [source]