A related study in the same issue of the journal showed that many Americans living in rural areas lack good access to trauma care. Researchers at the University of California, San Francisco, used data on maps and zip codes to find that while only 12 percent of urban residents had "difficult access" to a trauma center, defined as 60 minutes or more of driving time, 31 percent of rural residents faced the same travel obstacles to trauma care.

"Vulnerable populations," including blacks, foreign-born people and people with low incomes, were most likely to have "difficult access" to trauma care, according to the study.

Other barriers to such health care included language and cultural differences that sometimes inhibit those needing medical attention from seeking it, according to the research.

More information

For more on the essentials of trauma care, go to World Health Organization.

SOURCES: Marie Griffin, M.D., professor, preventive medicine and medicine, Department of Preventive Medicine, Vanderbilt University Medical Center, Nashville, Tenn.; Pratik Doshi, M.D., director, emergency critical care, Memorial Hermann Texas Medical Center, and assistant professor, emergency medicine and internal medicine, UT Health, Houston; Jan. 17, 2011, Archives of Surgery