For example, last year, Jeffrey Layten pulled a gun and started shooting at Creighton University Medical Center in Omaha and was killed by police return fire.

Hospitals are wide open places featuring life-and-death drama and intense emotion, and in rare instances those factors lead to violence. A study of gun violence statistics shows that trauma centers are more often a place of violence as compared to other hospital areas. Connie Potter, president of the New Mexico-based Trauma Center Association of America, notes some commonalities. More people are carrying guns, some hold anger toward government and institutions such as hospitals, and some believe modern medicine can cure every illness, she says.

People have “unrealistic expectations of the medical community, that we can save everybody,” says Potter, a registered nurse who was a trauma center administrator in Santa Ana, Calif., and El Paso, Texas. “And we are living in an increasingly violent, vitriolic, payback type of society.”

The Joint Commission, which accredits hospitals, wrote in a June report that there have been 256 documented cases of homicide, assault and rape against patients and visitors in American health care facilities since 1995. And 110, or 43 percent, took place from 2007 through 2009. The commission wrote: “Once considered safe havens, healthcare institutions today are confronting steadily increasing rates of crime.''