FRIDAY, May 24 (HealthDay News) -- The number of U.S. patients admitted to hospitals' intensive care units after spending time in an emergency room has increased by nearly 50 percent, according to new research.

The study, conducted by researchers at the George Washington University School of Public Health and Health Services in Washington, D.C., found that patients wait five hours in the emergency room on average before being admitted to the ICU. The researchers said improved coordination between ER and ICU staff could prevent complications and help critically ill patients more quickly receive the care they need.

"These findings suggest that emergency physicians are sending more patients on to the ICU," lead author Peter Mullins said in a university news release. "The increase might be the result of an older, sicker population that needs more care."

After analyzing data from the National Hospital Ambulatory Care Survey, a survey of U.S. hospital-based emergency departments during a seven-year span, the researchers found that ICU admissions increased nearly 50 percent, from 2.79 million in 2002 to 4.14 million in 2008. Meanwhile, emergency room admissions increased by just 5.8 percent.

The study also showed that ICU admissions involving patients aged 85 and older grew the most, increasing 25 percent every two years during the study period. Tests and services provided to ER patients heading to the ICU also increased: CT and MRI scans jumped from 16.8 percent in 2002 to 37.4 percent in 2008.

Chest pain and shortness of breath were most often the reason people were admitted to the ICU. The researchers said these symptoms often are a red flag for life-threatening conditions such as heart attacks.

Dr. Jesse Pines, an emergency physician and associate professor of emergency medicine and health policy at the university, said more research is needed to figure out how to reduce the amount of time critically ill patients spend waiting in the emergency room before being admitted to the ICU.

"Studies have shown that the longer ICU patients stay in the emergency department, the more likely they are to die in the hospital," Pines said in the news release. "Better coordination between the emergency department and ICU staff might help speed transfers and prevent complications caused by long emergency department waits."

The study was published in the May issue of the journal Academic Emergency Medicine.

More information

The Society of Critical Care Medicine provides more statistics on ICU admissions.