Clinical diagnosis of acute bacterial rhinosinusitis, typical of experts

Background  Clinical diagnosis of acute bacterial sinusitis (ABS) is a concern when a patient presents with nasal discharge of recent onset together with facial pain or pressure. Given this presentation, the doctor would benefit from having access to software that specifies, first, what diagnostic indicators experts typically use in that diagnosis and then, upon entry of those facts, what experts' typical probability of ABS is in such a case.
Methods  We specified a set of 23 hypothetical presentations of this type by patients 20–75 years of age, involving a comprehensive set of clinical-diagnostic indicators. Members of an international expert panel independently set the probability of ABS in each of these cases. A logistic function of the diagnostic indicators was fitted to the medians of the probabilities.
Results  The fitting led to an expression of the experts' median probability of ABS as a joint function of the duration of the patient's facial pain/pressure, and indicators of the location(s) of this; indicators of exacerbation of the pain/pressure on bending forward, nasal obstruction, maxillary and/or frontal tenderness, pus from middle meatus, purulent postnasal drip, and fever; and indicators of recent upper respiratory tract infection, nasal polyposis and status post sinus surgery. This probability function is accessible at http://www.evimed.ch/ABS .
Interpretation  That probability function, made readily accessible, provides for expertly probability setting in clinical diagnosis of ABS, relevant for decisions about further diagnostics or treatment without further tests.     

Surgical blood ordering schedule for better inventory management: An experience from a tertiary care transfusion center

BackgroundOverordering of blood has been a challenge faced by the blood bank staff. The present study addresses the role of maximum surgical blood ordering schedule (MSBOS) in optimizing the blood inventory management.MethodsThe blood requests for elective surgical procedures from various surgical departments were reviewed to constitute MSBOS. Transfusion profile was assessed using crossmatch to transfused units (C/T) ratio, transfusion probability (TP), and transfusion index (TI). A cutoff of 0.3 and 5% value of TI and TP, respectively, was considered to decide on the type of crossmatch. The efficacy of MSBOS implementation has been determined prospectively by unpaired t test using SPSS software, version 20 (IBM, USA).ResultsA total of 2674 patients were studied. Overall red cell usage rate was 15%. The comprehensive C/T ratio was 4.57. The C/T ratios for the various departments ranged from 1 to 8.5 (adjusted C/T ratio). Highest C/T ratio was observed for surgical procedures performed in the specialties of otorhinolaryngology and urology. A C/T ratio greater than 5 was noted in 30.4% of different types of surgical procedures. Of the 176 different types of elective surgical procedures studied, type and screen protocol was applicable for 75.5% (133) of the procedures. After implementation of MSBOS, the number of crossmatches reduced by 2152 and total working time saved in our laboratory is close to 75,320 man hours.ConclusionMSBOS helps in identifying the common surgical procedures with low TP and is one of the efficient tools in preventing the overordering of the blood.     

Comparing simulation and threshold approaches when analysing data with probabilities of categories

Objective Constructing categories based on probabilities is not unusual in defining the outcome or the exposure. We compare the threshold approach and the simulation approach in making inferences. Method We used a simple structured example as well as published data to illustrate the difference between the simulation and the threshold approaches. Results We demonstrated that simulation results were different from the threshold approach in estimating the effect of a high‐deductible health plan. For repeat visits, we estimated a statistically significant ratio of incident rate ratio (IRR) 0.78 (95% CI: 0.64, 0.93) for non‐preventable emergency department visits using the simulation approach while the high‐severity category showed no statistical significance with the ratio of IRR 0.98 (95% CI: 0.64, 1.49) using a threshold of 75%. We also demonstrated that none of the threshold values could achieve the results of the simulation approach. Conclusions The simulation approach is preferred over the threshold one when analysing data with probability‐based outcome, exposure and/or other covariates if the size of the data permits.     

野战卫生装备战场抢修性研究

目的：研究野战卫生装备战场枪修性指标和战场损伤概率计算模型，为野战卫生装备战场维修保障提供决策依据。方法：结合卫生装备的战场枪修性特点，着重对战场枪修性的枪修度和平均枪修时间2个衡量指标进行分析．通过假设推导出卫生装备战场损伤的概率计算模型。结果：得出了降低枪修时间、提高枪修效果的策略。结论：战场损伤分析过程为卫生装备损伤分析提供了系统的思路和方法，是获取损伤评估信息的有效途径，为合理配置战场维修力量奠定理论基础。     

熵指数对异丙酚麻醉中体动反应的预测

目的:研究异丙酚麻醉中熵指数对于体动反应的预测并与双频谱指数比较.方法:ASA Ⅱ级择期腹部手术患者20例,按对切皮有无体动反应分为体动组(8例)和非体动组(12例).入室后常规监测,然后异丙酚、琥珀胆碱、芬太尼静脉注射快诱导气管插管,持续泵入异丙酚 20 mg·kg-1·h-1, 15 min 后开始手术,如果患者发生切皮体动,则按10%提高下一个患者异丙酚输注速度,如果不动则按10%降低下一个患者异丙酚输注速度.每例患者同时行两种脑电监测,于以下时点记录指数:基础值、切皮前60s、切皮前30s、切皮后45s、 120s.结果:熵指数值在两组之间有显著性差异(P＜0.05),双频谱指数值在两组之间无显著性差异(P＞0.05);熵指数可以预测切皮体动,其Pk值分别为0.8935和0.8872,BIS不能预测切皮体动,预测概率是0.5719,两种监测方法的预测概率之间有统计学差异(P＜0.05);预测概率与熵指数的Logistic回归方程分别为ln Pk/(1-Pk)= 26.505-0.394x和ln Pk/(1-Pk)= 28.553-0.435x,熵指数的ED50是67,ED95是64.结论:熵指数能够预测异丙酚麻醉中的体动反应,能够反映麻醉的镇痛深度.     

The “Critical volume tolerance method” for estimating the limits of dose escalation during three-dimensional conformal radiotherapy for prostate cancer

: To describe the “Critical Volume Tolerance” (CVT) method for defining normal tissue tolerance during 3D-based dose escalation studies for prostate cancer.

: The CVT method predicts the tolerance to radiation for “in series”-type functional units based on the assumption that tolerance depends on a critical threshold “low-volume high-dose region.” The data used for describing this model were generated from 3D analysis of randomly selected patients with prostate cancer. Commonly used coplanar frou- and six-field conformal (SFC) techniques were chosen as the comparison techniques. For purposes of comparison, rectal tolerance was assumed to be reached following whole pelvic irradiation using a four-field box technique to 50 Gy, followed by a conedown boost to 70 Gy using bilateral 9 × 9 cm 120 degree arcs as popularized by investigators from Stanford University (SUH).

: Based on the average dose volume histograms for the patients studied, the maximum safe increase in dose for the SFC technique compared to the SUH technique, would be 10% if 30% of the rectal volume was the critical dose limiting volume (CVT = 30%), 5%if the CVT = 10%, or greater than 20% if the CVT = 40%. Commonly used four-field conformal techniques would not be expected to allow significant escalation of the dose without increasing the risk of complications.

: The CVT method is relatively simple, and data general based on it can be used to support normal tissue complication probability equations. The CVT method can be verified or modified as partial tolerance data become available. Based on the CVT model, sophisticated treatment techniques should allow a modest increase in the total dose of radiation delivered to the prostate without an increase in late complications.     

Dimensional measures of psychopathology. The probability of being classified with a psychiatric disorder using empirically derived symptom scales

Objectives: We sought to develop a ranking scheme that assigns a probability of having one of four psychiatric disorders to children based on their scores on a symptom scale. We then estimated the impact of each scale symptom on the prevalence of the disorder in the population. Method: Logistic regressions were specified for ADHD, ODD, depressive, and conduct disorders using all the individual symptoms in the pertinent scale as predictors. Individual fitted values from the regression function then served as a probability scale measure. We combined the prevalence and influence of each scale symptom to calculate its overall impact on the prevalence of the disorder. Results: Probability distributions had a wide range of values and discriminated between cases and non-cases. Those having a disorder were consistently associated with higher probabilities in the scale. The estimated probability corresponds to the empiric prevalence of the diagnosis in a group of persons sharing the same estimated probabilities. Symptoms varied on their impact on the prevalence of the disorder. Conclusions: We recommend the estimated probability of the disorder based on the empirically defined scales as dimensional measures that complement prevalence of the disorder. Different symptoms are identified as targets for screening when selection is based on their impact on the prevalence of the disorder than when selection is based on the strength of the association with the disorder. We recommend using a common nosology with different classification schemes; the categorical definition of the disorder, the probability of having the disorder, and the impact of each symptom in the prevalence. Different measures serve different purposes. Accepted: 5 April 2002 Correspondence to Maritza Rubio-Stipec     

Inclusion of geometric uncertainties in treatment plan evaluation

: To correctly evaluate realistic treatment plans in terms of absorbed dose to the clinical target volume (CTV), equivalent uniform dose (EUD), and tumor control probability (TCP) in the presence of execution (random) and preparation (systematic) geometric errors.

: The dose matrix is blurred with all execution errors to estimate the total dose distribution of all fractions. To include preparation errors, the CTV is randomly displaced (and optionally rotated) many times with respect to its planned position while computing the dose, EUD, and TCP for the CTV using the blurred dose matrix. Probability distributions of these parameters are computed by combining the results with the probability of each particular preparation error. We verified the method by comparing it with an analytic solution. Next, idealized and realistic prostate plans were tested with varying margins and varying execution and preparation error levels.

: Probability levels for the minimum dose, computed with the new method, are within 1% of the analytic solution. The impact of rotations depends strongly on the CTV shape. A margin of 10 mm between the CTV and planning target volume is adequate for three-field prostate treatments given the accuracy level in our department; i.e., the TCP in a population of patients, TCP_pop, is reduced by less than 1% due to geometric errors. When reducing the margin to 6 mm, the dose must be increased from 80 to 87 Gy to maintain the same TCP_pop. Only in regions with a high-dose gradient does such a margin reduction lead to a decrease in normal tissue dose for the same TCP_pop. Based on a rough correspondence of 84% minimum dose with 98% EUD, a margin recipe was defined. To give 90% of patients at least 98% EUD, the planning target volume margin must be approximately 2.5 Σ + 0.7 σ − 3 mm, where Σ and σ are the combined standard deviations of the preparation and execution errors. This recipe corresponds accurately with 1% TCP_pop loss for prostate plans with clinically reasonable values of Σ and σ.

: The new method computes in a few minutes the influence of geometric errors on the statistics of target dose and TCP_pop in clinical treatment plans. Too small margins lead to a significant loss of TCP_pop that is difficult to compensate for by dose escalation.     

Visual extinction with double simultaneous stimulation: what is simultaneous?

Patients with unilateral lesions to the parietal lobe leading to extinction were tested with stimuli presented in both hemifields. In addition to simultaneous presentation of two stimuli, trials were given with the contralesional or ipsilesional side having an onset slightly before the other. In the first experiment, subjects were asked to identify the stimuli. In agreement with di Pellegrino et al. [Neuropsychologia 35(1997)1215], all patients showed maximal extinction when the stimuli were physically simultaneous. In the second experiment, the same patients were requested to report whether the left or right item had been presented first. In accordance with Rorden et al. [Neuropsychologia 35(1997)421], all three patients required the contralesional item to have a significant lead in order to in order to be judged as occurring first. Taken together, these findings appear to present a paradoxical picture of extinction: the first task implies that items compete maximally when they are physically simultaneous, while the second study suggests that the physical simultaneity is not phenomenally special to the patients. Attempts to reconcile these findings with popular models of extinction are discussed.     

GCRM模型的精细大偏差

目的 研究GCRM风险模型的大偏差破产概率。方法 在索赔量分布属于ERV重尾类时，讨论索赔盈余过程尾概率的渐近行为。结果 得到GCRM模型索赔盈余过程{S（t）}的精细大偏差。结论 GCRM模型在索赔量分布属于ERV重尾类时，{S（t）}的尾概率与索赔量尾分布及索赔强度存在渐近关系。