A significant increase in ED utilization is also occurring for patients with mental health and chemical use presentations. The NHAMCS report is finding an increased number of patients seen for mental health reasons, and their disposition is often difficult and time consuming. An examination of the NHAMCS database reveals that about half of patient transfers from EDs are for mental health treatment. This is a significant burden on emergency physicians and the organizations that must move these patients safely between sites.

Matching the increase in acuity is the need for further hospital-based service at the end of ED visits. A growing percentage of hospital admissions are funneled through the ED. The EDBA data indicate that 68 percent of all hospital inpatients are processed through the ED. In many hospitals, especially those in community settings, the number is 80 percent or greater. Clearly, the ED is the front door to the hospital!

The growing volume of patients also reflects the position of the ED as the diagnostic center for the American medical community. The need for precision in defining patient needs has resulted in increased use of diagnostic tools in the ED, especially diagnostic imaging. The use of diagnostic testing has changed dramatically over the last 20 years, according to surveys on ED practice. Some diagnostic tests have almost completely disappeared. Arterial blood gases were used in many patients in 1992 and now have completely disappeared due to low utilization.

The use of other diagnostic tests has increased. CT scans increased in usage from about 2.4 percent of visits in 1992 to about 16 percent in 2010. The EDBA uses a different collection and reporting methodology and found that CT use, as measured by the number of CT procedures performed per 100 patients, plateaued in 2008 at about 23 procedures per 100 patients and has now decreased to about 20 CT procedures per 100 patients. Plain diagnostic X-rays, of which about 50 percent are chest X-rays, were performed on about 42 percent of patients in 1992 and have since decreased to about 35 percent in 2010.

ECG utilization has increased from a rate of 13 uses per 100 patients in 1992 to about 26 in 2010.

The most common medicine used in the ED was promethazine prior to about 2007, when it was replaced by ondansetron, which came off patent protection in 2006, dropping the cost to hospitals significantly. Both drugs were used about 12 times per 100 patients. The changeover was also boosted due to the unusual black box warning on promethazine in 2009.