Scheduling admissions and reducing variability in bed demand

Variability in admissions and lengths of stay inherently leads to variability in bed occupancy. The aim of this paper is to analyse the impact of these sources of variability on the required amount of capacity and to determine admission quota for scheduled admissions to regulate the occupancy pattern. For the impact of variability on the required number of beds, we use a heavy-traffic limit theorem for the G/G/∞ queue yielding an intuitively appealing approximation in case the arrival process is not Poisson. Also, given a structural weekly admission pattern, we apply a time-dependent analysis to determine the mean offered load per day. This time-dependent analysis is combined with a Quadratic Programming model to determine the optimal number of elective admissions per day, such that an average desired daily occupancy is achieved. From the mathematical results, practical scenarios and guidelines are derived that can be used by hospital managers and support the method of quota scheduling. In practice, the results can be implemented by providing admission quota prescribing the target number of admissions for each patient group.     

The demand for elective surgery in a public system: time and money prices in the UK National Health Service

We construct a model of the admission process for patients from general practices for elective surgery in the UK National Health Service. Public patients face a positive waiting time, but a zero money price. Fundholding practices faced a positive money price for each patient admitted. The model is tested with data on general practice admission rates for cataract procedures in an English Health Authority. Admission rates are negatively related to waiting times and distance to hospital. Practices respond to financial incentives as predicted by the model: fundholding practices have lower admission rates than non-fundholders and respond differently to changes in waiting times and patient characteristics.     

住院服务中心模式流程再造的探索与实践

通过推进电子化预约登记,整合＂预约登记、安排入院、入院检查、出院随访＂服务流程,以信息化统筹全院床位,再造了入院流程。住院服务中心模式的实施,缩短了患者入院前等候时间,简化了入院手续办理和入院后检查检验流程,缩短了患者平均住院日,提高了床位使用率。     

Estimating the intensity of ward admission and its effect on emergency department access block

Emergency department access block is an urgent problem faced by many public hospitals today. When access block occurs, patients in need of acute care cannot access inpatient wards within an optimal time frame. A widely held belief is that access block is the end product of a long causal chain, which involves poor discharge planning, insufficient bed capacity, and inadequate admission intensity to the wards. This paper studies the last link of the causal chain—the effect of admission intensity on access block, using data from a metropolitan hospital in Australia. We applied several modern statistical methods to analyze the data. First, we modeled the admission events as a nonhomogeneous Poisson process and estimated time‐varying admission intensity with penalized regression splines. Next, we established a functional linear model to investigate the effect of the time‐varying admission intensity on emergency department access block. Finally, we used functional principal component analysis to explore the variation in the daily time‐varying admission intensities. The analyses suggest that improving admission practice during off‐peak hours may have most impact on reducing the number of ED access blocks. Copyright © 2012 John Wiley & Sons, Ltd.     

An integer programming model to limit hospital selection in studies with repeated sampling.

OBJECTIVE: We describe an integer programming model that, for studies requiring repeated sampling from hospitals, can aid in selecting a limited set of hospitals from which medical records are reviewed. STUDY SETTING: The model is illustrated in the context of two studies: (1) an analysis of the relationship between variations in hospital admission rates across geographic areas and rates of inappropriate admissions; and (2) a validation of computerized algorithms that screen for complications of hospital care. STUDY DESIGN: Common characteristics of the two studies: (1) hospitals are classified into categories, e.g., high, medium, and low; (2) the classification process is repeated several times, e.g., for different medical conditions; (3) medical records are selected separately for each iteration of the classification; and (4) for budgetary and logistical reasons, reviews must be concentrated in a relatively small subset of hospitals. DATA COLLECTION/EXTRACTION METHODS. In each study, hospitals are ranked based on analysis of hospital discharge abstract data. CONCLUSIONS: The model is useful for identifying a subset of hospitals at which more intensive reviews will be conducted.     

Statistical epidemic modeling with hospital outbreak data

The analysis of epidemic data has one special feature: individuals are highly dependent, i.e. infected cases are the cause of further infected cases (cross-infection). The main epidemiological parameter of interest is the transmission rate: the rate with which an infectious individual has close contacts with other patients in the hospital unit resulting in colonization or infection. In order to estimate this parameter, the statistical analysis should be based on an appropriate compartmental model that describes the transmission dynamics of an epidemic process. Nonparametric methodology is available for closed populations without migration, but especially in hospitals, admission and discharge have to be taken into account in addition. Transmission and discharge have to be considered as competing events. Martingale-based methodology takes the time-dependent feature of the rates adequately into account and yields useful estimates. These methods are applied to an outbreak of the specific hospital pathogen vancomycin-resistant enterococci (VRE) in an onco-haematological unit at the University Medical Center Freiburg in Germany.     

Generalisability of a composite student selection programme

Objectives The reliability of individual non‐cognitive admission criteria in medical education is controversial. Nonetheless, non‐cognitive admission criteria appear to be widely used in selection to medicine to supplement the grades of qualifying examinations. However, very few studies have examined the overall test generalisability of composites of non‐cognitive admission variables in medical education. We examined the generalisability of a composite process for selection to medicine, consisting of four variables: qualifications (application form information); written motivation (in essay format); general knowledge (multiple‐choice test), and a semi‐structured admission interview. The aim of this study was to estimate the generalisability of a composite selection. Methods Data from 307 applicants who participated in the admission to medicine in 2007 were available for analysis. Each admission parameter was double‐scored using two random, blinded and independent raters. Variance components for applicant, rater and residual effects were estimated for a mixed model with the restricted maximum likelihood (REML) method. The reliability of obtained applicant ranks (G coefficients) was calculated for individual admission criteria and for composite admission procedures. Results A pre‐selection procedure combining qualification and motivation scores showed insufficient generalisability (G = 0.45). The written motivation in particular, displayed low generalisability (G = 0.10). Good generalisability was found for the admission interview (G = 0.86), and for the final composite selection procedure (G = 0.82). Conclusions This study revealed good generalisability of a composite selection, but indicated that the application, composition and weighting of individual admission variables should not be random. Knowledge of variance components and generalisability of individual admission variables permits evidence‐based decisions on optimal selection strategies.     

Self‐admission to inpatient treatment for patients with anorexia nervosa: The patient's perspective

The aim of the present study was to explore patients’ experiences of participating in a self‐admission program at a specialist eating disorders clinic. Sixteen adult program participants with a diagnosis of anorexia nervosa were interviewed at 6 months about their experiences in the self‐admission program. A qualitative content analysis approach was applied to identify recurring themes. Four themes were identified: Agency and Flexibility, Functions, Barriers, and Applicability. Participants used self‐admission to boost healthy behaviors, to prevent deterioration, to forestall the need for longer periods of hospitalizations, and to get a break from overwhelming demands. Quick access to brief admissions provides a safety net that can increase feelings of security in everyday life, even for patients who do not actually make use of the opportunity to self‐admit. It also provided relief to participants' relatives. Furthermore, participants experienced that self‐admission may foster agency and motivation. However, the model also requires a certain level of maturity and an encouraging environment to overcome barriers that could otherwise hinder optimal use, such as ambivalence in asking for help. Informants experienced that self‐admission could allow them to gain greater insight into their disease process, take greater responsibility for their recovery, and transform their health care from crisis‐driven to proactive. By offering a shift in perspective on help‐seeking and participation, self‐admission may potentially strengthen participants’ internal responsibility for their treatment and promote partnership in treatment.     

Modeling the impact of changing patient transportation systems on peri-operative process performance in a large hospital: insights from a computer simulation study

Transportation of patients is a key hospital operational activity. During a large construction project, our patient admission and prep area will relocate from immediately adjacent to the operating room suite to another floor of a different building. Transportation will require extra distance and elevator trips to deliver patients and recycle transporters (specifically: personnel who transport patients). Management intuition suggested that starting all 52 first cases simultaneously would require many of the 18 available elevators. To test this, we developed a data-driven simulation tool to allow decision makers to simultaneously address planning and evaluation questions about patient transportation. We coded a stochastic simulation tool for a generalized model treating all factors contributing to the process as JAVA objects. The model includes elevator steps, explicitly accounting for transporter speed and distance to be covered. We used the model for sensitivity analyses of the number of dedicated elevators, dedicated transporters, transporter speed and the planned process start time on lateness of OR starts and the number of cases with serious delays (i.e., more than 15 min). Allocating two of the 18 elevators and 7 transporters reduced lateness and the number of cases with serious delays. Additional elevators and/or transporters yielded little additional benefit. If the admission process produced ready-for-transport patients 20 min earlier, almost all delays would be eliminated. Modeling results contradicted clinical managers’ intuition that starting all first cases on time requires many dedicated elevators. This is explained by the principle of decreasing marginal returns for increasing capacity when there are other limiting constraints in the system.     

基于人工神经网络模型的胆石病参保患者住院费用分析

目的分析天津市胆石病患者住院费用的变化趋势及影响因素,评价神经网络模型对医保费用的预测和分析效果。方法从天津市2003-2007年住院患者医保数据库中抽取4 205名患者,对住院总费用和药费等各项费用的影响因素进行单因素分析,并建立BP神经网络模型对影响因素进行敏感度分析。结果 2003-2007年胆石病患者的住院费用呈现增长趋势（F=11.818,P=0.001）;单因素分析显示年龄、住院天数、医院等级、结石部位、是否手术等对住院费用均有影响（P〈0.01）;BP神经网络敏感度分析显示,影响因素的敏感度最大的为住院天数（0.492）,敏感度最小的为是否有合并症（0.023）。结论天津市胆石病参保患者的住院费用呈增长趋势,影响住院费用的主要因素为住院天数、是否手术、住院次数、结石部位、年龄、医院等级、是否有合并症和炎症部位。BP神经网络模型可应用到胆石病患者住院费用的识别、评价、预测和控制中。     

信息化下入院服务全流程再造

目的 优化入院服务流程,提高医疗服务质效,提升就医体验.方法 运用系统理论和流程管理理论,基于信息化支撑再造入院服务全流程.结果 信息化入院服务全流程再造实现一站式入院服务,缩短患者及家属时间,减少患者折返,提升床位使用率和患者满意度.结论 基于信息化支撑的入院服务全流程为优化、改善医疗服务提供借鉴.     

Selection of medical students: the Beer-Sheva perspective

Summary: Summary. In many Western medical schools with a low attrition rate the selection of medical students represents the key hurdle for admission to the practice of medicine. The process therefore deserves careful attention. Described herein are impressions and conclusions from almost two decades' experience in selecting medical students at the Ben-Gurion University in Beer-Sheva, Israel.
Emphasis is placed on personal qualities as determined by an interview process of those students who pass a relatively lenient academic threshold. Interviewing is carried out by teams of two, one of whom is a doctor, and each candidate who is accepted is interviewed by four members of the admission committee. Emphasis is placed on clear goals for the interview process, carefully selected and trained interviewers and continual review of the process. In spite of the inherent limitations of a subjective interview process we feel that it offers considerable advantage over other approaches in student selection.     

Comparison of the results of Cox proportional hazards model and parametric models in the study of length of stay in a tertiary teaching hospital in Tehran, Iran

Survival analysis is a set of methods used for analysis of the data which exist until the occurrence of an event. This study aimed to compare the results of the use of the semi-parametric Cox model with parametric models to determine the factors influencing the length of stay of patients in the inpatient units of Women Hospital in Tehran, Iran. In this historical cohort study all 3421 charts of the patients admitted to Obstetrics, Surgery and Oncology units in 2008 were reviewed and the required patient data such as medical insurance coverage types, admission months, days and times, inpatient units, final diagnoses, the number of diagnostic tests, admission types were collected. The patient length of stay in hospital 'leading to recovery' was considered as a survival variable. To compare the semi-parametric Cox model and parametric (including exponential, Weibull, Gompertz, log-normal, log-logistic and gamma) models and find the best model fitted to studied data, Akaike's Information Criterion (AIC) and Cox-Snell residual were used. P<0.05 was considered as statistically significant. AIC and Cox-Snell residual graph showed that the gamma model had the lowest AIC (4288.598) and the closest graph to the bisector. The results of the gamma model showed that factors affecting the patient length of stay were admission day, inpatient unit, related physician specialty, emergent admission, final diagnosis and the number of laboratory tests, radiographies and sonographies (P<0.05). The results showed that the gamma model provided a better fit to the studied data than the Cox proportional hazards model. Therefore, it is better for researchers of healthcare field to consider this model in their researches about the patient length of stay (LOS) if the assumption of proportional hazards is not fulfilled.     

Variations in practice admission rates: the policy relevance of regression standardisation

OBJECTIVES: To explore variations in general practice admission rates, comparing standardisation by regression with direct standardisation of the data to identify explained and unexplained variation. METHODS: Data from hospital episode statistics and the attribution dataset on 8048 cataract admissions from 109 practices in an English health district (North Yorkshire) between 1995 and 1998. Multiple regression was used to estimate the effect of practice characteristics, socio-economic factors, waiting times and distance on practice admission rates. Rankings of practices by the residuals from the regression were compared with rankings by directly standardised admission rates. RESULTS: The regression model yielded intuitively plausible results and explained 35% of the cross-practice variation in directly standardised admission rates. Standardisation by regression, compared with direct standardisation, made as least as much difference to the ranking of practices as direct standardisation compared with crude admission rates. Regression standardisation suggested that 10 practices not identified as 'unusual' by comparison of their rates to the district mean were in fact 'unusual', and that six practices identified as unusual by comparison with the district mean were not unusual once allowing for the explanatory factors used in the regression model. CONCLUSIONS: Given the increasing importance of systematic performance assessment to support quality improvement, care must be taken when interpreting variations in health care activity even after conventional standardisation of the data. If significant variations are detected, regression analysis can assist in explaining some of it, which is the starting point in informing discussions about whether variations are justified or unjustified.     

应用系统动力学模型对SARS疫情传播及主要防控措施效果的计算机模拟仿真研究

目的　(1)应用系统动力学方法建立数学模型,宏观地模拟严重急性呼吸综合征(SARS)疫情在自然人群和医院内传播的过程,以及患者通过就诊和社区隔离措施移出传播链的过程。(2)通过计算机对该模型的仿真模拟,分析在突发 SARS疫情的情况下,代表主要防控措施的变量对疫情曲线的影响模式和相对强度。(3)重点分析发热监测措施对疫情的影响,根据分析结果对今后SARS防控工作提出政策建议。方法　采用面访、问卷调查、文献检索、个案分析等方式,获取SARS传播的重要参数。应用系统动力学理论及计算机仿真系统建立数学模型,并进行 What if仿真分析。结果　建立了能够反映SARS自然传播、患者就诊及医院内传播、社区隔离措施、发热监测过程的计算机仿真模型,通过宏观模拟SARS患者从发病到被移出传播链的过程得出下列结果:(1)患者从发病到就诊的时间、患者每日平均接触人数、就诊时医院内接触人数等是对 SARS的院内、院外传播过程影响最大的几个变量;(2)隔离强度、接诊医生对 SARS的警惕性、医院通风消毒、医院优化患者流动路线、医生防护强度是影响疫情控制的主要变量;(3)医院入口的体温筛查措施对疫情控制的作用不大。结论　按照目前制定的SARS防治预案,卫生系统能够快速控制突发的SARS疫情。     

Secondary school and admission test grades as predictors of performance of medical students

The performance of three consecutive classes of students admitted to the Colleges of Medicine and Medical Sciences at King Faisal University was studied. All students took the high school graduation examination and sat the college admission test. It was found that performance on the admission test was a better predictor than high school grades in the first two levels of the medical curriculum. However, performance in a combination of certain high school and admission test subjects was a more powerful predictor of students' achievement at all levels. This study indicates that the college admission test is a useful additional tool in the process of medical student selection at this college. Further studies are needed, however, for the formulation of general recommendations.     

Utilization patterns of cohorts of elderly clients: a structural equation model.

OBJECTIVE. To identify a model that takes into account the interrelationship of health services utilization variables, and that allows examination of the utilization patterns of health services for a cohort of elderly clients. DATA SOURCES AND STUDY SETTING. The data of each client in the study were taken from three computer databases maintained for administrative purposes by the Ministry of Health in British Columbia. Time frame for the utilization variables is one year before and one year after admission to the long-term care program in BC which occurred in 1981-1982. STUDY DESIGN. A basic model was fitted to the utilization data for the year before admission and patterns of utilization were assessed for each gender-age group for the year before admission and for the two periods, using LISREL. Fifteen utilization variables were included: number of GP and specialist visits in different settings (office, home, etc.) and number of other services such as lab tests, hospital stay, etc. DATA COLLECTION. The three files were linked to produce one record per client. PRINCIPAL FINDINGS. A model was identified that fits the data well. The total effect of GP emergency room visits on hospital stay is 0.30 compared to 0.19 direct effect. The additional impact is produced via the effect of specialist consultations on hospital stay. This and similar findings by age, gender, and period are consistent with the joint dependency of utilization variables. CONCLUSIONS. The analysis shows that males and females have different utilization patterns, while age has no effect on utilization of health services by male clients and only a small effect on utilization patterns by female clients. Admission to LTC causes more specialist contacts resulting from contact with a GP and generally a more intensive use of diagnostic and surgical procedures. However, there is significantly less acute care hospital services utilization.     

Sustaining critical care: using evidence-based simulation to evaluate ICU management policies

Intensive Care Units (ICU) are costly yet critical hospital departments that should be available to care for patients needing highly specialized critical care. Shortage of ICU beds in many regions of the world and the constant fire-fighting to make these beds available through various ICU management policies motivated this study. The paper discusses the application of a generic system dynamics model of emergency patient flow in a typical hospital, populated with empirical evidence found in the medical and hospital administration literature, to explore the dynamics of intended and unintended consequences of such ICU management policies under a natural disaster crisis scenario. ICU management policies that can be implemented by a single hospital on short notice, namely premature transfer from ICU, boarding in ward, and general ward admission control, along with their possible combinations, are modeled and their impact on managerial and health outcome measures are investigated. The main insight out of the study is that the general ward admission control policy outperforms the rest of ICU management policies under such crisis scenarios with regards to reducing total mortality, which is counter intuitive for hospital administrators as this policy is not very effective at alleviating the symptoms of the problem, namely high ED and ICU occupancy rates that are closely monitored by hospital management particularly in times of crisis. A multivariate sensitivity analysis on parameters with diverse range of values in the literature found the superiority of the general ward admission control to hold true in every scenario.