National Growth in Intensive Care Unit Admissions From Emergency Departments in the United States from 2002 to 2009

Abstract

The authors describe national trends in use, reasons for visit, most common diagnoses, and resource utilization in patients admitted to intensive care units (ICUs) from hospital-based emergency departments (EDs) in the United States. This was an observational study using data from the National Hospital Ambulatory Care Survey, a nationally representative, weighted sample of U.S. hospital-based EDs from 2002 through 2009. The sample comprised a total of 4,267 patients aged 18 years or older admitted to the ICU from the ED, which represent over 14.5 million ED encounters from 2002 through 2009. Over the study period, ICU admissions from EDs increased from 2.79 million in 2002/2003, to 4.14 million in 2008/2009, an absolute increase of 48.8% and a mean biennial increase of 14.2%. By comparison, overall ED visits increased a mean of 5.8% per biennial period. The three most common diagnoses for ICU admissions were unspecified chest pain, congestive heart failure, and pneumonia. Utilization rates of most tests and services delivered to patients admitted to the ICU from the ED increased, with the largest increase occurring in computed tomography (CT) and magnetic resonance imaging (MRI), which increased from 16.8% in 2002/2003 to 37.4% in 2008/2009, a 6.9% mean biennial increase. Across all years, mean ED length of stay (LOS) for ICU admissions was 304 minutes (95% confidence interval [CI] = 286 to 323 minutes), and mean hospital LOS was 6.6 days (95% CI = 6.2 to 7.0 days). There was no significant change in either mean ED or hospital LOS over the study period. Intensive care unit admissions from EDs are increasing at a greater rate than both population growth and overall ED visits. ED resource use, specifically advanced diagnostic imaging, has increased markedly among ICU admissions. While mean ED and hospital LOS have not changed significantly, the mean ICU admission spends over 5 hours in the ED prior to transfer to an ICU bed. A greater emphasis on the ED-ICU interface and critical care delivered in the ED may be warranted.