The Challenge of Predicting Demand for Emergency Department Services

Objectives:  The objective was to develop methodology for predicting demand for emergency department (ED) services by characterizing ED arrivals.
Methods:  One year of ED arrival data from an academic ED were merged with local climate data. ED arrival patterns were described; Poisson regression was selected to represent the count of hourly ED arrivals as a function of temporal, climatic, and patient factors. The authors evaluated the appropriateness of prediction models by whether the data met key Poisson assumptions, including variance proportional to the mean, positive skewness, and absence of autocorrelation among hours. Model accuracy was assessed by comparing predicted and observed histograms of arrival counts and by how frequently the observed hourly count fell within the 50 and 90% prediction intervals.
Results:  Hourly ED arrivals were obtained for 8,760 study hours. Separate models were fit for high- versus low-acuity patients because of significant arrival pattern differences. The variance was approximately equal to the mean in the high- and low-acuity models. There was no residual autocorrelation ( r  = 0) present after controlling for temporal, climatic, and patient factors that influenced the arrival rate. The observed hourly count fell within the 50 and 90% prediction intervals 50 and 90% of the time, respectively. The observed histogram of arrival counts was nearly identical to the histogram predicted by a Poisson process.
Conclusions:  At this facility, demand for ED services was well approximated by a Poisson regression model. The expected arrival rate is characterized by a small number of factors and does not depend on recent numbers of arrivals.     

Emmetropic eye growth in East Asians and non-East Asians

Purpose

To compare axial length (AL) growth curves in East Asian (EA) and non-EA emmetropes.

Methods

A meta-regression of 28 studies with emmetrope-specific AL data (measured with optical biometry) was performed. Emmetropia was defined as spherical equivalent refraction (SER) between −0.50 and +1.25 D, determined under cycloplegia if the mean age was ≤20 years. The AL growth curve (mean AL vs. mean age) was first fitted to the full dataset using a weighted nonlinear mixed-effects model, before refitting the model with ethnicity as a two-level grouping variable (EA vs. non-EA). Ethnic differences in growth curve parameters were tested using the Wald test.

Results

A total of 3331 EA and 1071 non-EA emmetropes (mean age: 6.5–23.1 years) were included. There was no evidence of an ethnic difference in either final AL (difference: 0.15 mm, 95% CI: −0.04 to 0.35 mm, p = 0.15) or initial AL, as represented by the amount that the final AL needed to be offset to obtain the y-intercept (difference: −2.77 mm, 95% CI: −10.97 to 5.44, p = 0.51). Likewise, AL growth rate (curve steepness) did not differ between ethnic groups (difference: 0.09, 95% CI: −0.13 to 0.31, p = 0.43). Collectively, AL growth rate decreased from 0.24 mm/year at 6 years of age to around 0.05 mm/year at 11 years of age, after which it dipped below the repeatability of optical biometry (±0.04 mm) and practically plateaued around 16 years of age (final AL: 23.60 mm).

Conclusions

EA and non-EA emmetropes have comparable AL growth curves.     

Coronary heart disease and depression in the elderly--a population- based study

BACKGROUND: Growing interest is nowadays focused on the quality of life of elderly people who survive with chronic diseases. Coronary heart disease (CHD) is one of the most common diseases among the elderly and may have an unfavourable impact on the patient's emotional well-being. OBJECTIVES: We aimed to describe the prevalence of depression and the occurrence of depressive symptoms among elderly CHD patients, with a special emphasis on the relations between depression and the severity of CHD, and to find out the possible association between CHD and depression. METHODS: The study was carried out at the health centre of the municipality of Lieto, in south-west Finland. The study population consisted of 488 community-dwelling men and 708 women, over 64 years old, from among whom the participants with CHD (89 men and 73 women) were selected, and for whom 178 male and 146 female sex- and age- matched controls (free of CHD) were drawn from the population. CHD patients were selected on the basis of the presence of angina pectoris or a past myocardial infarction. Depressive symptoms were measured with the Zung Self-rating Depression Scale. Depression was described in relation to the severity of dyspnoea and chest pain among patients. The associations between depression and age, health, health behaviour, drugs, functional ability and social, psychosocial and environmental factors were analysed by logistic regression analyses. RESULTS: The prevalence of depression was 29% among male patients and 20% among female patients. Depression was significantly more common among male CHD patients than among male controls (P = 0.011). Among women, depression was not associated with CHD. Earlier, depression had gone undiagnosed among many CHD patients and controls, especially male patients. Among male CHD patients, depression was associated with more severe dyspnoea, but no similar association was found among female CHD patients. Among men the occurrence of CHD, physical disability, widowhood or divorce, and among women previous clinical depression, physical disability and the use of angiotensin-converting enzyme (ACE) inhibitors, were associated with depression. CONCLUSION: Depression is common among patients with CHD. It seems that CHD is not an independent factor in the aetiology of depression among the elderly. The association of CHD with depression among men is explained by the acute or chronic psychic stress caused by CHD. It may be that the more complicated the patient's CHD, the more probable is the presence of depression.      

Heterogeneity of Age-Related Neural Hyperactivity along the CA3 Transverse Axis

Age-related memory deficits are correlated with neural hyperactivity in the CA3 region of the hippocampus. Abnormal CA3 hyperactivity in aged rats has been proposed to contribute to an imbalance between pattern separation and pattern completion, resulting in overly rigid representations. Recent evidence of functional heterogeneity along the CA3 transverse axis suggests that proximal CA3 supports pattern separation while distal CA3 supports pattern completion. It is not known whether age-related CA3 hyperactivity is uniformly represented along the CA3 transverse axis. We examined the firing rates of CA3 neurons from young and aged, male, Long–Evans rats along the CA3 transverse axis. Consistent with prior studies, young CA3 cells showed an increasing gradient in mean firing rate from proximal to distal CA3. However, aged CA3 cells showed an opposite, decreasing trend, in that CA3 cells in aged rats were hyperactive in proximal CA3, but possibly hypoactive in distal CA3, compared with young (Y) rats. We suggest that, in combination with altered inputs from the entorhinal cortex and dentate gyrus (DG), the proximal CA3 region of aged rats may switch from its normal function that reflects the pattern separation output of the DG and instead performs a computation that reflects an abnormal bias toward pattern completion. In parallel, distal CA3 of aged rats may create weaker attractor basins that promote abnormal, bistable representations under certain conditions.SIGNIFICANCE STATEMENT Prior work suggested that age-related CA3 hyperactivity enhances pattern completion, resulting in rigid representations. Implicit in prior studies is the notion that hyperactivity is present throughout a functionally homogeneous CA3 network. However, more recent work has demonstrated functional heterogeneity along the CA3 transverse axis, in that proximal CA3 is involved in pattern separation and distal CA3 is involved in pattern completion. Here, we show that age-related hyperactivity is present only in proximal CA3, with potential hypoactivity in distal CA3. This result provides new insight in the role of CA3 in age-related memory impairments, suggesting that the rigid representations in aging result primarily from dysfunction of computational circuits involving the dentate gyrus (DG) and proximal CA3.     

Harvesting-resistant estimates of air pollution effects on mortality

A number of studies have recently shown an association between particle concentrations in outdoor air and daily mortality counts in urban locations. In the public health interpretation of this evidence, a key issue is whether the increased mortality associated with higher pollution levels is restricted to very frail persons for whom life expectancy is short in the absence of pollution. This possibility has been termed the "harvesting hypothesis." We present an approach to estimating the association between pollution and mortality from times series data that is resistant to short-term harvesting. The method is based in the concept that harvesting alone creates associations only at shorter time scales. We use frequency domain log-linear regression to decompose the information about the pollution-mortality association into distinct time scales, and we then create harvesting-resistant estimates by excluding the short-term information that is affected by harvesting. We illustrate the methods with total suspended particles and mortality counts from Philadelphia for 1974-1988. The total suspended particles-mortality association in Philadelphia is inconsistent with the harvesting-only hypothesis, and the harvesting-resistant estimates of the total suspended particles relative risk are actually larger-not smaller-than the ordinary estimates.     

The inter‐rater reliability between nurse‐assessors clinically assessing infection of chronic wounds using the WUWHS criteria

The aim of this study was to determine the inter‐rater reliability between one expert‐nurse and four clinical‐nurses who were asked to clinically assess infection of chronic wounds by using the World Union of Wound Healing Societies (WUWHS) criteria. A quasi‐experimental design was used to collect the data. In comparison to phase 1 in which ‘open questions’ were asked, in phase 2 a pre‐printed form (checklist) was introduced. In both phases, 55 chronic wounds were clinically assessed. For each WUWHS criterion the inter‐rater reliability of signs and symptoms was expressed by Cohens Kappa (κ). A substantial agreement (κ ≥ 0·6) was considered as adequate. In both phases pocketing (p < 0·02), and erythema (p < 0·004) scored statistically significant results. Phase 2 showed higher inter‐rater agreements compared with phase 1 (three substantial agreements (easily bleeding/friable granulation tissue, delayed healing, increasing exudate), an almost perfect‐ and a perfect agreement for malodour and pain, respectively. According to the results it can be concluded that the clinical assessment of infection of chronic wounds may be better supported by a pre‐printed form than making use of an ‘open questions’ form. To provide this with a higher level of evidence, there is need for more well conducted studies.     

高效液相色谱法测定消痰咳片的含量

目的：采用反相色谱法同时测定消痰咳片中两种主要成分甲氧苄啶和磺胺体的含量。方法：以乙腈：0.1%H3PO4(15:85)为流动相，检测波长254nm，HPLC法测定含量。结果：试验表明，甲氧苄啶和磺胺林在0.8-8ug范围内呈良好的线性关系，回归方程分别为Y＝－1127.1＋110.2x(r=0.9994),Y=-1852.3 256.2x(r=0.9996),相对标准偏差分别为2.1%和0.8%。结论：该方法简便、准确、可靠。     

5种注射剂的细菌内毒素检查法初步考察

目的：考察５种注射剂盐酸林可霉素注射液，盐酸精氨酸注射液，注射用玻璃酸酶，肝素钠注射液和顺铂注射液的细菌内毒素检查法可行性。方法：中国药典细菌内毒素检查法。结果；除ｄ外，其余原液及稀释液均于有干扰作用。结论：ｄ的原液及ａ的２０倍以上稀释液可用灵敏度为０．５ＥＵ／ｍｌ的鲎试剂作细菌内毒素检查，而ｂ，ｃ和ｅ尚需进一步探讨。