Demand on ED resources during periods of widespread influenza activity

doi:10.1016/j.ajem.2003.08.011

The American Journal of Emergency Medicine

Volume 21, Issue 7, November 2003, Pages 534-539

Presented at the Society for Academic Emergency Medicine Regional Meeting, Portland, OR, April 2000.

https://doi.org/10.1016/j.ajem.2003.08.011 Get rights and content

Abstract

The purpose of this study was to investigate ED resource demand during periods of Centers for Disease Control and Prevention (CDC)-declared widespread influenza activity (WIA). An observational analysis of secondary data describing ED resource demand was performed using computerized ED patient data over a 130-week period. Measures of ED resource utilization were compared during WIA and non-WIA periods. These measures included weekly census; percentage of patients triaged as having fever, infection, or respiratory (flu index) chief complaints; admission rate, ED LOS (length of stay), total bed time (TBT), the number of patients who left the ED without being seen by a physician (LWBS), and ED saturation time. The study included 34 weeks of CDC-designated WIA occurring over 3 distinct periods. During WIA, the flu index was elevated, 23% (95% confidence interval [CI], 20–25) versus 17% (95% CI, 16–17). There was increased resource utilization during WIA periods compared with the non-WIA periods for the following parameters: admission rate (24% [95% CI, 24–25%] versus 23% [23–23%]), ED LOS admitted (296 [95% CI, 280–313] versus 271 [95% CI, 265–277]), ED LOS discharged (162 [95% CI, 156–168] versus 152 [95% CI, 150–154]), ED saturation time (1292 [95% CI, 689–1894] versus 409 [95% CI, 209–609]) and LWBS (31 [95% CI, 19–42] versus 14 [95% CI, 12–15]). Although each WIA period was marked by an initial spike in patient volume, weekly census did not increase (1365 [95% CI, 1297–1433] during WIA versus 1297 [95% CI, 1275–1320] during non-WIA). An association between WIA and greater ED resource demand was observed. A spike in census was observed at the onset of each WIA period. In addition, the flu index increased during WIA, suggesting the use of the ED as a site for syndromic surveillance of WIA onset.

Section snippets

Study design

An observational analysis of secondary data was obtained from a computerized ED patient log over a 130-week period.

Study setting

We studied an urban level-one trauma center with a 32-bed ED and an annual patient census of approximately 68,000 during the study period. The institution is a private, 877-bed, not-for-profit teaching hospital located in western Los Angeles County. The catchment area for the hospital has a lower- to upper-income population of approximately 550,000. The major ethnic groups

Results

The study period, from October 1997 through March 2000, included 34 weeks of CDC designated WIA occurring in 3 distinct time periods (Fig. 1). Period I spanned 12 weeks, beginning week 51 of 1997 and ending week 10 of 1998.3 Period II spanned 14 weeks beginning week 1 of 1999 and ending week 14 of 1999.4 Period III spanned 8 weeks, beginning week 50 of 1999 and ending week 5 of 2000.5

Overall, the ED’s census increased throughout the entire study period independent of WIA. There was no

Discussion

Influenza annually affects thousands of individuals from all segments of the population.2, 5, 6, 7, 8, 9, 10, 11, 12 The primary objective of this study was to investigate the relationship between periods of WIA and ED resource demand. We found WIA to be associated with recurrent and predictable changes in markers of resource utilization in our ED, with the most significant changes occurring during the initial weeks of each episode. Increases were seen in the time patients spent in the ED, the

Conclusions

We found an association between WIA and increased ED resource demand. Several markers we used to measure this demand were elevated during periods of WIA, including increases in time patients spent in the ED, the number of inpatient admissions, the number of LWBS patients, and the amount of time the ED was closed as a result of saturation.

A spike in ED patient census was found at the start of each period of WIA. We also discovered an association between periods of WIA and the flu index. This

Acknowledgements

The authors thank Cindy Balin, RN, for her help with data collection and Mendel Roth for his help with manuscript preparation.

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Original contributionDemand on ED resources during periods of widespread influenza activity

Abstract

Section snippets

Study design

Study setting

Results

Discussion

Conclusions

Acknowledgements

Ann Emerg Med

Am J Emerg Med

Ann Emerg Med

Am J Emerg Med

Ann Emerg Med

Ann Emerg Med

InfluenzaED considerations for the 1997–98 season

Ann Emerg Med

Influenza-associated morbidity and mortality in young and middle-aged women

JAMA

Updateinfluenza activity—United States and worldwide, 1997–1998 season, and composition of the 1998–99 influenza vaccine

MMWR Morb Mortal Wkly Rep

Updateinfluenza activity—United States and worldwide, 1998–1999 season, and composition of the 2000–01 influenza vaccine

MMWR

Updateinfluenza activity—United States and worldwide, 1999–2000 season, and composition of the 2000–01 influenza vaccine

MMWR Morb Mortal Wkly Rep

The impact of influenza epidemics on mortalityintroducing a severity index

Am J Public Health

Original contribution
Demand on ED resources during periods of widespread influenza activity