Investigating a Work System Approach to Implement an Emergency Department Surge Management System: Case Study.

BACKGROUND: Emergency department (ED) crowding is a global health care issue. eHealth systems have the potential to reduce crowding; however, the true benefits are seldom realized because the systems are not integrated into clinicians' work. We sought a deep understanding of how an eHealth system implementation can be structured to truly integrate the system into the workflow. OBJECTIVE: The specific objectives of this study were to examine whether work system theory (WST) is a good approach to structure the implementation of an eHealth system by incorporating the entire work system, and not just the eHealth system, in the implementation framework; identify the role that specific elements of WST's static framework and dynamic work system life cycle model play in the implementation; and demonstrate how WST can be applied in the health care setting to guide the implementation of an eHealth system. METHODS: Through a case study of an ED in a rural hospital, we used a mixed methods approach to examine the implementation of a surge management system through the lens of WST. We conducted 14 hours of observation in the ED; 20 interviews with clinicians, management, and members of the implementation team; and a survey of 23 clinicians; reviewed related documentation; and analyzed ED data to measure wait times. We used template analysis based on WST to structure our analysis of qualitative data and descriptive statistics for quantitative data. RESULTS: The surge management system helped to reduce crowding in the ED, staff was satisfied with the implementation, and wait time improvements have been maintained for several years. Although study participants indicated changes to their workflow, 72% (13/18) of survey participants were satisfied with their use of the system, and 82% (14/17) indicated that it was integrated with their workflow. Examining the implementation through the lens of WST enabled us to identify the aspects of the implementation that made it so successful. By applying the WST static framework, we saw how the implementation team incorporated the elements of the ED work system, assessed their alignment, and designed interventions to address areas of misalignment. The dynamic work system life cycle model captured how planned and unplanned changes were managed throughout the iterative implementation cycle-83% (15/18) of participants indicated that there was sufficient management support for the changes and 80% (16/20) indicated the change served an important purpose. CONCLUSIONS: The broad scope and holistic approach of WST is well suited to guide eHealth system implementations as it focuses efforts on the entire work system and not just the IT artifact. We broaden the focus of WST by applying it to the implementation of an ED surge management system. These findings will guide further studies and implementations of eHealth systems using WST.

Visual recognition of social signals by a tectothalamic neural circuit.

Social affiliation emerges from individual-level behavioural rules that are driven by conspecific signals1-5. Long-distance attraction and short-distance repulsion, for example, are rules that jointly set a preferred interanimal distance in swarms6-8. However, little is known about their perceptual mechanisms and executive neural circuits3. Here we trace the neuronal response to self-like biological motion9,10, a visual trigger for affiliation in developing zebrafish2,11. Unbiased activity mapping and targeted volumetric two-photon calcium imaging revealed 21 activity hotspots distributed throughout the brain as well as clustered biological-motion-tuned neurons in a multimodal, socially activated nucleus of the dorsal thalamus. Individual dorsal thalamus neurons encode local acceleration of visual stimuli mimicking typical fish kinetics but are insensitive to global or continuous motion. Electron microscopic reconstruction of dorsal thalamus neurons revealed synaptic input from the optic tectum and projections into hypothalamic areas with conserved social function12-14. Ablation of the optic tectum or dorsal thalamus selectively disrupted social attraction without affecting short-distance repulsion. This tectothalamic pathway thus serves visual recognition of conspecifics, and dissociates neuronal control of attraction from repulsion during social affiliation, revealing a circuit underpinning collective behaviour.

Analysis of an Alternative Model of Definitive Care For Low-Acuity Emergency Calls: A Natural Experiment.

BACKGROUND: Emergency medical services (EMS) diversion strategies attempt to limit the impact of low-acuity care on emergency department (ED) crowding, but evidence supporting these strategies is scarce. OBJECTIVE: This study aims to measure the effect of a treat-in-place and alternative destination program on ED transports and EMS utilization. METHODS: We used a natural experiment study design to measure effects of a pilot prehospital diversion program on ED transport, number of EMS vehicles dispatched, and EMS time on task for low-acuity emergency calls in a midsized urban setting characterized by a high prevalence of health disparities, concentrated poverty, and limited access to primary care between October 2018 and January 2020. We also used direct variable cost to estimate the return on investment attributable to avoided ED visits. RESULTS: Of 3725 calls that met eligibility criteria, the program responded to 1084 (29.1%), with 56.7% of those resulting in an ED visit, compared with 64.6% of the 492 control calls that were eligible but were dispatched when program services were unavailable. Of 1084 calls receiving response, 213 (19.6%) were enrolled in the program, and 8.5% of those were transported by EMS to the ED. Adjusted results show EMS time on task was 23.4 min less for enrolled calls vs. controls. The program can achieve a positive return on investment by enrolling 2.9 patients/day. CONCLUSIONS: A prehospital diversion program reduced ED visits and EMS transport times. Improved targeting of patients for enrollment would further increase the intervention's efficacy and cost savings.

The Efficacy of Lavender Aromatherapy in Reducing the Overcrowding-Related Anxiety in Health Care Workers.

In general, emergency departments (EDs) are stressful workplaces with excessive workloads and time pressures. Crowding, which is an important problem worldwide disrupting ED functions, leads further increases in the stressors which health care workers are exposed to. Long-term exposure to stressors can lead to anxiety in health care workers. The aim of this study was to determine the effect of aromatherapy on crowding-related anxiety in ED health care workers. Crowding was measured simultaneously with the National Emergency Department Overcrowding Scale objectively and the Health Care Workers' Crowding Perception Evaluation Form subjectively. The state-trait anxiety level was measured at each crowding level according to the health care workers' perception. When perceived crowding was at severely overcrowding level, lavender oil aromatherapy was applied. Anxiety level was measured before and after aromatherapy. Aromatherapy was repeated 3 times on different days. A significant positive correlation was found between state anxiety level and perceived crowding (r = 0.415, p < 0.001). Aromatherapy was found to have a significant correlation in reducing the overcrowding-related anxiety in health care workers (p < 0.05). This study showed that there is a significant correlation between anxiety level and perceived crowding, and aromatherapy is related to a decrease in overcrowding-related anxiety. In EDs, lavender oil aromatherapy can be used as a complementary method in reducing the overcrowding-related anxiety. But further researches are needed to verify that aromatherapy has a causative effect on reducing overcrowding-related anxiety.

Psychosocial Crowding Stress-Induced Changes in Synaptic Transmission and Glutamate Receptor Expression in the Rat Frontal Cortex.

This study demonstrates how exposure to psychosocial crowding stress (CS) for 3, 7, and 14 days affects glutamate synapse functioning and signal transduction in the frontal cortex (FC) of rats. CS effects on synaptic activity were evaluated in FC slices of the primary motor cortex (M1) by measuring field potential (FP) amplitude, paired-pulse ratio (PPR), and long-term potentiation (LTP). Protein expression of GluA1, GluN2B mGluR1a/5, VGLUT1, and VGLUT2 was assessed in FC by western blot. The body's response to CS was evaluated by measuring body weight and the plasma level of plasma corticosterone (CORT), adrenocorticotropic hormone (ACTH), and interleukin 1 beta (IL1B). CS 3 14d increased FP and attenuated LTP in M1, while PPR was augmented in CS 14d. The expression of GluA1, GluN2B, and mGluR1a/5 was up-regulated in CS 3d and downregulated in CS 14d. VGLUTs expression tended to increase in CS 7d. The failure to blunt the effects of chronic CS on FP and LTP in M1 suggests the impairment of habituation mechanisms by psychosocial stressors. PPR augmented by chronic CS with increased VGLUTs level in the CS 7d indicates that prolonged CS exposure changed presynaptic signaling within the FC. The CS bidirectional profile of changes in glutamate receptors' expression seems to be a common mechanism evoked by stress in the FC.

Characteristic time in highly motivated movements of children and adults through bottlenecks.

Current codes for fire protection of buildings are mainly based on the movement of adults and neglect the movement characteristic of pre-school children. Having a profound comprehension of the difference between children and adults passing bottlenecks is of great help to improve the safety levels of preschool children. This paper presents an experimental study on the bottleneck flow of pre-school children in a room. The movement characteristics of children's and adults' bottleneck flow are investigated with two macroscopic properties: density and speed profiles as well as microscopic characteristic time: motion activation time, relaxation time, exit travel time and time gap. Arch-like density distributions are observed both for highly motivated children and adults, while the distance between the peak density region and the exit location is shorter for children and longer for adults. Children's movement is less flexible manifested as longer motion activation time and longer relaxation time compared to that of adults. The findings from this study could enhance the understanding of crowd dynamics among the children population and provide supports for the scientific building design for children's facilities.

Multiple criteria decision analysis approach to consider therapeutic innovations in the emergency department: The methoxyflurane organizational impact in acute trauma pain.

BACKGROUND: Acute trauma pain is poorly managed in the emergency department (ED). The reasons are partly organizational: ED crowding and rare trauma care pathways contribute to oligoanalgesia. Anticipating the organizational impact of an innovative care procedure might facilitate the decision-making process and help to optimize pain management. METHODS: We used a multiple criteria decision analysis (MCDA) approach to consider the organizational impact of methoxyflurane (self-administered) in the ED, introduced alone or supported by a trauma care pathway. A MCDA experiment was designed for this specific context, 8 experts in emergency trauma care pathways (leading physicians and pharmacists working in French urban tertiary hospitals) were recruited. The study involved four steps: (i) Selection of organizational criteria for evaluating the innovation's impact; (ii) assessment of the relative weight of each criterion; (iii) choice of appropriate scenarios for exploring the organizational impact of MEOX under various contexts; and (iv) software-assisted simulation based on pairwise comparisons of the scenarios. The final outcome measure was the expected overall organizational impact of methoxyflurane on a 0-to-100 scale (score >50: positive impact). RESULTS: Nine organizational criteria were selected. "Mean length of stay in the ED" was the most weighted. Methoxyflurane alone obtained 59 as a total score, with a putative positive impact for eight criteria, and a neutral effect on one. When a trauma care pathway was introduced concomitantly, the impact of methoxyflurane was greater overall (score: 75) and for each individual criterion. CONCLUSIONS: Our model highlighted the putative positive organizational impact of methoxyflurane in the ED-particularly when supported by a trauma care pathway-and the relevance of expert consensus in this particular pharmacoeconomic context. The MCDA approach could be extended to other research fields and healthcare challenges in emergency medicine.

Safety and Efficacy of an On-Site Intensive Treatment Protocol for Mild and Moderate Sympathomimetic Toxicity at Australian Music Festivals.

INTRODUCTION: Serotonin and sympathomimetic toxicity (SST) after ingestion of amphetamine-based drugs can lead to severe morbidity and death. There have been evaluations of the safety and efficacy of on-site treatment protocols for SST at music festivals. PROBLEM: The study aimed to examine the safety and efficacy of treating patients with SST on-site at a music festival using a protocol adapted from hospital-based treatment of SST. METHODS: The study is an audit of presentations with SST over a one-year period. The primary outcome was need for ambulance transport to hospital. The threshold for safety was prospectively defined as less than 10% of patients requiring ambulance transport to hospital.The protocol suggested patients be treated with a combination of benzodiazepines; cold intravenous (IV) fluid; specific therapies (cyproheptadine, chlorpromazine, and clonidine); rapid sequence intubation; and cooling with ice, misted water, and convection techniques. RESULTS: One patient of 13 (7.7%) patients with mild or moderate SST required ambulance transport to hospital. Two of seven further patients with severe SST required transport to hospital. CONCLUSIONS: On-site treatment may be a safe, efficacious, and efficient alternative to urgent transport to hospital for patients with mild and moderate SST. The keys to success of the protocol tested included inclusive and clear education of staff at all levels of the organization, robust referral pathways to senior clinical staff, and the rapid delivery of therapies aimed at rapidly lowering body temperature. Further collaborative research is required to define the optimal approach to patients with SST at music festivals.

Effects of long-term crowding stress on neuro-endocrine-immune network of rainbow trout (Oncorhynchus mykiss).

Low levels of stresses cause eustress while high stressful situations result in distress. Female rainbow trout (Oncorhynchus mykiss) was reared under crowded conditions to mimic the stressful environment of intensive fishery production. Trout was stocked for 300 days with initial densities of 4.6 ±â€¯0.02 (final: 31.1 ±â€¯0.62), 6.6 ±â€¯0.03 (final: 40.6 ±â€¯0.77), and 8.6 ±â€¯0.04 (final: 49.3 ±â€¯1.09) kg/m3 as SD1, SD2 and SD3. We assessed molecular, cellular and organismal parameters to understand the flexibility of neuro-endocrine-immune network during stress. Trout with higher initial density (SD3) displayed the slightly activated hypothalamus-pituitary-interrenal (HPI) axis with positively increased antioxidant enzyme activities and anti-inflammatory cytokine transcriptions on day 60 or 120. These results indicated that low level of stress was capable of exerting eustress by activating neuro-endocrine-immune network with beneficial adaptation. Transition from eustress to distress was induced by the increased intensity and duration of crowding stress on day 240 and 300. The prolonged activation of HPI axis resulted in suppressed growth hormone-insulin-like growth factor (GH-IGF) axis, up-regulated cytokine transcriptions and severe reactive oxygen species stress. Stress means reset of neuro-endocrine-immune network with energy expenditure and redistribution. Digestive ability of trout with distress was also inhibited on day 240 and 300, indicating a decreased total energy supplement and energy distribution for functions are not necessary for surviving such as growth and reproduction. Consequently, we observed the dyshomeostasis of energy balance and neuro-endocrine-immune network of trout during long-term crowding conditions.

Effects of Myofunctional Appliance in Children with Sleep-Disordered Breathing: Two Case Reports / 대한소아치과학회지

Sleep-disordered breathing (SDB) induces dysfunction of the orofacial muscles, leading to morphologic alteration of the face and dental malalignment. Early diagnosis and treatment of SDB is required in pediatric patients to ensure normal facial growth. Myofunctional therapy (MFT) is a modality for the treatment of SDB and prefabricated appliances can be used. Herein 2 cases of malocclusion with SDB, in which MFT with a prefabricated appliance was used for orthodontic treatment, have been described. SDB was diagnosed based on clinical symptoms taken by interview and home respiratory polygraphy. In both cases, SDB was improved using prefabricated appliance for MFT. However, resolution of crowding depended on the degree of crowding.

Effects of dietary 1,8-cineole supplementation on physiological, immunological and antioxidant responses to crowding stress in rainbow trout (Oncorhynchus mykiss).

The aim of the present study was to investigate beneficial effects of dietary 1,8-cineole (cineole) supplementation on physiological, immunological and antioxidant responses of rainbow trout (Oncorhynchus mykiss) to crowding stress. The fish were fed for 50 days with diets containing 0 (control), 0.05, 0.1, 0.25, 0.5 and 1% cineole prior to exposure to a 14-day crowding stress. Serum stress markers (cortisol, glucose, lactate, T4 and T3), antioxidant responses [catalase (CAT) and superoxide dismutase (SOD) activities and total antioxidant capacity (TAC) and malondyaldehyde (MDA) levels] and immune responses [lysozyme and alternative complement (ACH50) activity, and total immunoglobulin (Ig) levels], and blood leukocyte (WBC) and differential counts were measured before and after crowding stress. Results showed that 1% cineole was capable to reduce the basal and stress-induced cortisol elevation and increase the serum T3 levels after stress. Increase in dietary cineole levels significantly decreased serum cortisol, glucose and lactate levels. Increase in dietary cineole levels significantly increased serum CAT, SOD, lysozyme and ACH50 activities, and TAC and eosinophil levels, and decreased MDA and monocyte levels. After the stress, there was no significant difference in the control group CAT and SOD activities compared to the basal values; however, CAT activities decreased and SOD activities increased in the cineole-treated groups compared to the basal values. Nevertheless, the control group had significantly lower CAT and SOD activities compared to the fish treated with 0.1-1% cineole. Cineole significantly increased blood WBC and serum lysozyme, ACH50 and total Ig. Moreover, cineole administration significantly mitigated the stress-induced decrease in total Ig levels as well as increase in leukocyte count. The cineole-treated fish had higher survival and growth performance compared to the control group. Although all levels of cineole (0.05-1%) showed beneficial effects on different tested factors, 0.5 and 1% levels had beneficial effects on most of the tested factors; thus, are recommended for dietary inclusion to suppress adverse effects of stress in trout.

Effect of yeast (Xanthophyllomyces dendrorhous) and plant (Saint John's wort, lemon balm, and rosemary) extract based functional diets on antioxidant and immune status of Atlantic salmon (Salmo salar) subjected to crowding stress.

Salmon farming may face stress due to the intensive culture conditions with negative impacts on overall performance. In this aspect, functional feed improves not only the basic nutritional requirements but also the health status and fish growth. However, to date no studies have been carried out to evaluate the effect of functional diets in salmon subjected to crowding stress. Thus, the aim of this study was to evaluate the effect of yeast extract (Xanthophyllomyces dendrorhous; diet A) and the combination of plant extracts (common Saint John's wort, lemon balm, and rosemary; diet B) on the antioxidant and immune status of Atlantic salmon grown under normal cultured conditions and then subjected to crowding stress. Fish were fed with functional diets during 30 days (12 kg/m3) and then subjected to crowding stress (20 kg/m3) for 10 days. The lipid peroxidation in gut showed that both diets induced a marked decrease on oxidative damage when fish were subjected to crowding stress. The protein carbonylation in muscle displayed at day 30 a marked decrease in both functional diets that was more marked on the stress condition. The expression of immune markers (IFNγ, CD4, IL-10, TGF-ß, IgMmb, IgMsec, T-Bet, and GATA-3) indicated the upregulation of those associated to humoral-like response (CD4, IL-10, GATA-3) when fish were subjected to crowding stress. These results were confirmed with the expression of secreted IgM. Altogether, these functional diets improved the antioxidant status and increased the expression of genes related to Th2-like response suggesting a protective role on fish subjected to crowding stress.

Effects of l-tryptophan on the growth, intestinal enzyme activities and non-specific immune response of sea cucumber (Apostichopus japonicus Selenka) exposed to crowding stress.

In order to reveal the effects of l-tryptophan (Trp) on the physiology and immune response of sea cucumber (Apostichopus japonicus Selenka) exposed to crowding stress, four density groups of sea cucumbers (i.e. 4, 8, 16 and 32 individuals per 40 L water, represented as L, ML, MH and H) were fed with diets containing 0, 1, 3 and 5% l-tryptophan respectively for 75 days. The results showed that the specific growth rates (SGR) of the sea cucumber fed with diet with 3% Trp (L, 2.1; ML, 1.76; MH, 1.2; H, 0.7) were significantly higher than those fed with basal diet without Trp supplementation (P < .05). Peak amylase activity occurred at H stress density at 3% dietary Trp. Trypsin activity was higher in diet 3% in ML and MH densities than the controls, which increased by 66.4% and 53.8%. However, the lipase activity first increased and then decreased from the stocking density L to H, with highest values of 3% Trp group showed the highest value than other groups. Compared to those fed with the basal diet, sea cucumber fed diets with Trp (3%) had significantly higher phagocytic activities (0.28 OD540/106 cells, H) in coelomic fluid and respiratory burst activities (0.105 OD630/106 cells, MH) (P < .05). The results suggested that Trp cannot improve superoxide dismutase (SOD) activity at L, ML and MH densities. The alkaline phosphatase activity (AKP) significantly decreased at H stress density. Under the experimental conditions, the present results confirmed that a diet supplemented with 3% Trp was able to enhance intestinal enzyme activities, non-specific immune response and higher growth performance of A. japonicus.

Effects of a blend of essential oils and overcrowding stress on the growth performance, meat quality and heat shock protein gene expression of broilers.

Overcrowding stress is common in the poultry industry. Chickens exposed to long-term stressful situations are characterised by welfare impairment and immunosuppression. 1. The present study evaluated the effects of a blend of essential oils (EOB; cinnamaldehyde and thymol) and stocking density on the performance, gut microflora, meat quality and physiological stress markers of broilers. 2. One-day-old Ross 308 male broiler chickens (n = 360) were allocated to 4 experimental groups from d 22 to 42. Each treatment had 6 replicates of 15 chicks. Two groups were subjected to a high stocking density (HSD) of 20 birds/m2 and the other two groups were kept at a low stocking density (LSD) of 10 birds/m2. 3. The results of this study indicate that overcrowding stress decreased growth performance parameters, blood immunoglobulin (Ig)G and heterophil:lymphocyte (H:L) ratio but increased IgA and IgM levels. HSD reduced water-loss rate and pH decline at 45 min post mortem in the breast muscle. 4. Essential oils supplementation elevated H:L ratio but decreased breast meat redness and pH24. 5. Significant interactions between EOB and stocking density were observed for corticosterone (CS) level and mRNA levels of heat shock protein 70 (HSP70) in brain and heart. Although HSD increased CS and HSP70 when compared to LSD, the effects of the former were inconsistent with EOB supplemented diets. 6. In conclusion, dietary EOB supplementation could improve some of the biomarkers associated with overcrowding stress in broiler chickens.

Unraveling vasotocinergic, isotocinergic and stress pathways after food deprivation and high stocking density in the gilthead sea bream.

The influence of chronic stress, induced by food deprivation (FD) and/or high stocking density (HSD), was assessed on stress, vasotocinergic and isotocinergic pathways of the gilthead sea bream (Sparus aurata). Fish were randomly assigned to one of the following treatments: (1) fed at low stocking density (LSD-F; 5kg·m-3); (2) fed at high stocking density (HSD-F, 40kg·m-3); (3) food-deprived at LSD (LSD-FD); and (4) food-deprived at HSD (HSD-FD). After 21days, samples from plasma, liver, hypothalamus, pituitary and head-kidney were collected. Both stressors (FD and HSD) induced a chronic stress situation, as indicated by the elevated cortisol levels, the enhancement in corticotrophin releasing hormone (crh) expression and the down-regulation in corticotrophin releasing hormone binding protein (crhbp) expression. Changes in plasma and liver metabolites confirmed a metabolic adjustment to cope with energy demand imposed by stressors. Changes in avt and it gene expression, as well as in their specific receptors (avtrv1a, avtrv2 and itr) at central (hypothalamus and pituitary) and peripheral (liver and head-kidney) levels, showed that vasotocinergic and isotocinergic pathways are involved in physiological changes induced by FD or HSD, suggesting that different stressors are handled through different stress pathways in S. aurata.

Seasonality and selective trends in viral acute respiratory tract infections.

Influenza A and B, and many unrelated viruses including rhinovirus, RSV, adenovirus, metapneumovirus and coronavirus share the same seasonality, since these viral acute respiratory tract infections (vARIs) are much more common in winter than summer. Unfortunately, early investigations that used recycled "pedigree" virus strains seem to have led microbiologists to dismiss the common folk belief that vARIs often follow chilling. Today, incontrovertible evidence shows that ambient temperature dips and host chilling increase the incidence and severity of vARIs. This review considers four possible mechanisms, M1 - 4, that can explain this link: (M1) increased crowding in winter may enhance viral transmission; (M2) lower temperatures may increase the stability of virions outside the body; (M3) chilling may increase host susceptibility; (M4) lower temperatures or host chilling may activate dormant virions. There is little evidence for M1 or M2, which are incompatible with tropical observations. Epidemiological anomalies such as the repeated simultaneous arrival of vARIs over wide geographical areas, the rapid cessation of influenza epidemics, and the low attack rate of influenza within families are compatible with M4, but not M3 (in its simple form). M4 seems to be the main driver of seasonality, but M3 may also play an important role.

Understanding the Role of Social Factors in Farmworker Housing and Health.

Differences in social advantage significantly influence health conditions and life expectancy within any population. Such factors reproduce historic class, race, and ethnic disparities in community success. Few populations in the United States face more social and economic disadvantage than farmworkers, and farmworker housing has significant potential to ameliorate or amplify the health impact of those disadvantages. Drawing on the limited direct research on farmworkers, and on additional research about poor, isolated, and immigrant societies, we propose four mechanisms through which housing can be expected to affect farmworker health: quality of social capital within farmworker communities, stress effects of poor housing situations, effects of housing on social support for healthy behaviors, and interactions among these factors, especially effects on children that can last for generations. Policy and planning definitions of "adequate" farmworker housing should take a more holistic view of housing needs to support specific social and community benefits in design decisions.

Emergency Department Crowding and Outcomes After Emergency Department Discharge.

STUDY OBJECTIVE: We assess whether a panel of emergency department (ED) crowding measures, including 2 reported by the Centers for Medicare & Medicaid Services (CMS), is associated with inpatient admission and death within 7 days of ED discharge. METHODS: We conducted a retrospective cohort study of ED discharges, using data from an integrated health system for 2008 to 2010. We assessed patient transit-level (n=3) and ED system-level (n=6) measures of crowding, using multivariable logistic regression models. The outcome measures were inpatient admission or death within 7 days of ED discharge. We defined a clinically important association by assessing the relative risk ratio and 95% confidence interval (CI) difference and also compared risks at the 99th percentile and median value of each measure. RESULTS: The study cohort contained a total of 625,096 visits to 12 EDs. There were 16,957 (2.7%) admissions and 328 (0.05%) deaths within 7 days. Only 2 measures, both of which were patient transit measures, were associated with the outcome. Compared with a median evaluation time of 2.2 hours, the evaluation time of 10.8 hours (99th percentile) was associated with a relative risk of 3.9 (95% CI 3.7 to 4.1) of an admission. Compared with a median ED length of stay (a CMS measure) of 2.8 hours, the 99th percentile ED length of stay of 11.6 hours was associated with a relative risk of 3.5 (95% CI 3.3 to 3.7) of admission. No system measure of ED crowding was associated with outcomes. CONCLUSION: Our findings suggest that ED length of stay is a proxy for unmeasured differences in case mix and challenge the validity of the CMS metric as a safety measure for discharged patients.