Advanced Statistics: Developing a Formal Model of Emergency Department Census and Defining Operational Efficiency

Background: Emergency department (ED) crowding has been a frequent topic of investigation, but it is a concept without an objective definition. This has limited the scope of research and progress toward the development of consistent and meaningful operational responses.
Objectives: To develop a straightforward model of ED census that incorporates concepts of ED crowding, daily patient surge, throughput time, and operational efficiency.
Methods: Using 2005–2006 patient encounter data at a Level 1 urban trauma center, a set of three stylized facts describing daily patterns of ED census was observed. These facts guided the development of a formal, mathematical model of ED census. Using this model, a metric of ED operational efficiency and a forecast of ED census were developed.
Results: The three stylized facts of daily ED census were 1) ED census is cyclical, 2) ED census exhibits an input-output relationship, and 3) unexpected shocks have long-lasting effects. These were represented by a three-equation system. This system was solved for the following expression, Censust = A(·) + B(·) cos(vT +ε) + a(et), that captured the time path of ED census. Using nonlinear estimation, the parameters of this expression were estimated and a forecasting tool was developed.
Conclusions: The basic pattern of ED census can be represented by a straightforward expression. This expression can be quickly adapted to a variety of inquiries regarding ED crowding, daily surge, and operational efficiency.     

A Comprehensive Set of Coded Chief Complaints for the Emergency Department

OBJECTIVE: To develop a generally applicable set of coded chief complaints for the computerized patient records of emergency departments (EDs). METHODS: At an urban teaching ED the chief complaints of more than 50,000 patients were analyzed retrospectively during a 29-month period (June 1995-October 1997). Applying continuous quality improvement methods, a multidisciplinary team examined the current process documenting the patient's chief complaint. During two prospective periods (November 1997-December 1998; January 1999-June 1999), more than 34,000 chief complaints were analyzed. To reduce free-text charting practices, a variety of interventions on individual and team level were applied. Quantitative analysis was performed with statistical process control charts, and a qualitative evaluation was performed with a questionnaire. RESULTS: The charting of chief complaint in free-text format decreased from 23% to 1%. The range among individual ED staff members narrowed from 45% to 9%. During the refinement of the set of coded chief complaints, six infrequently charted items were removed. Five new chief complaints identified by analysis of free-text entries during the second study period were added. The current set of chief complaints consists of 54 codable and the three original free-text items. The ED staff members perceived all the interventions beneficial. A poster displaying all available terms as a visual aid, however, had the largest impact on charting the patient's chief complaint in coded format. CONCLUSIONS: Applying continuous quality improvement methods, the authors created a clinically developed and applicable set of codable chief complaints that can be easily integrated into a computerized patient record of an ED.     

Classroom Injuries in Utah Public Schools

OBJECTIVES: School injuries are a serious public health problem, yet classroom injuries have received little attention. The purpose of this study was to describe the epidemiology of classroom injuries in Utah public schools. METHODS: Utah statewide school injury data on kindergarten through 12th grade students for 1996 through 1998 were used. The data were generated from a standardized Student Injury Report (SIR) form completed by school personnel for injuries that (1) caused loss of at least one half of a day of school or (2) warranted medical attention and treatment. Injuries occurring in laboratories, shop, and physical education classes were excluded. To determine the medical outcome and charges associated with classroom injuries, the authors probabilistically linked the SIR database to Utah statewide emergency department (ED) records and Utah statewide hospital inpatients discharge records for 1996 through 1998. RESULTS: During the period 1996 through 1998, there were 1,366 classroom injuries. Nearly two thirds of the injuries occurred to male students. More than half the classroom injuries were related to equipment use. Weapon use was rare. Twenty percent of students injured in the classroom obtained treatment in an ED, where 71% of these injuries were determined to involve the head, neck, and upper extremity. Two incidents, one involving carbon monoxide and the other tear gas, accounted for 11% of the ED admissions. CONCLUSIONS: Classroom injuries are not sufficiently frequent, severe, or costly to justify special studies focused solely on acute injuries in standard classrooms. This does not negate the need for continued surveillance of classroom injuries along with other school injuries.     

Association Between Postoperative Complications and Clinical Cancer Outcomes

Introduction

The treatment for a majority of solid organ tumors is surgical resection; 10–20 % of patients suffer a perioperative complication. Perioperative complications may contribute to cancer recurrence. This study examined the relationship between postoperative complications and risk-adjusted patient overall survival.

Methods

Data from 2003 to 2009 were linked from our clinical cancer registry, the National Surgery Quality Improvement Project (NSQIP), and medical records. Patients who had tumor extirpation for cure were included. The NSQIP was used to identify complications. Patients with a complication were matched to patients without a complication. χ ² tests and Cox proportional hazard regression models were used.

Results

A total of 415 patients were included for survival analysis. The hazard ratio (HR) for mortality associated with having a complication was 2.17. The HR for mortality after 200 days postoperatively was 2.47. Infectious complications were associated with the highest association with increased mortality (HR = 3.56). Noninfectious complications were not associated with an increased risk of mortality.

Conclusions

This study investigated the relationship of surgical infectious complications in cancer patients with long-term survival for patients who had a number of different types of cancer. After taking into account the site, histology, and stage of the cancer, we found that patients with infectious complications had earlier death.     

A Food Frequency Questionnaire can Detect Pregnancy-Related Changes in Diet

Objective To determine whether a food frequency questionnaire (FFQ) can detect changes in dietary intake before pregnancy to mid-pregnancy relative to a 4-day food record.Design FFQs and 4-day, weighed food records (4DRs) were completed during similar time intervals before pregnancy and again near mid-pregnancy by women served by a large health maintenance organization in the Minneapolis-St Paul, Minn, area. The outcome of interest was change in the intake of energy and 16 nutrients. Participants were members of the Diana Project, a prospective study of relationships among prepregnancy and pregnancy nutritional and other exposures and reproductive outcomes. Fifty-six (51%) of the eligible women completed the study.Subjects Well-educated, healthy, white women.Statistical analyses performed Spearman rank order correlations.Results Mean energy and nutrient intake levels estimated using the 4DR were generally higher than those estimated using the FFQ. Correlations between change in energy and nutrient intakes measured by the 4DR and FFQ ranged from 0.75 for vitamin C to 0.02 for cholesterol and averaged 0.48.Applications Comparisons with 4DRs indicate that the FFQ used in this study is appropriate for obtaining reliable estimates of prepregnancy to mid-pregnancy changes in intake of energy and a number of nutrients in similar groups of women. J Am Diet Assoc. 1996; 96:262-266.