When it comes to treating the elderly, not all emergency rooms are created equal, according to a recent study conducted on Medicare beneficiaries.

The study, conducted by health care research company, HealthGrades, concluded that people admitted to one of the country's 236 top-performing emergency departments experienced a 40 percent reduction in their risk of death.

This figure is particularly pertinent to caregivers of the elderly as the study also found that the majority of seniors (61 percent) enter a hospital through the doors of the emergency department.

To discover the best emergency programs, researchers analyzed the records of over seven million Medicare beneficiaries admitted to the hospital by way of the emergency room between the years 2008 and 2010. A variety of ailments afflicted the seniors in the study, including: heart failure, sepsis, pneumonia, pancreatitis, and stroke, among others.

Where you live could make the difference between life and death

According to researchers, nearly 171,000 lives could have been saved between 2008 and 2010 if every emergency department exhibited the quality of care found in the top five percent of hospitals in the study.

Unfortunately, like real estate, the value of emergency room care appears to depend on location, location, location. Ninety-four of the 263 top hospitals are clustered around eight major cities: Baltimore, Detroit, Cincinnati, St. Louis, Los Angeles, Phoenix-Prescott, Chicago, and Cleveland.

Seniors who live outside the reasonable range of these cities may not be able to get to a top-tier hospital in a life-or-death emergency situation.

Knowledge could save their life

When your elderly loved one requires emergency care, you may or may not be able to choose which ER they go to. If you call an ambulance, the EMT may solicit your opinion as to where you want a senior to go, but more often they will make a decision on which hospital is most appropriate based on the senior's ailment and the current state of patient traffic in the nearest ERs.

However, knowing how your local hospitals rank may help in the event of a lesser emergency.

Caregivers should do their homework in advance—researching the hospitals in their area in order to find the best one. In a company press release, study author, Arshad Rahim, M.D., director of accelerated clinical excellence at HealthGrades, urges people to "educate themselves about the quality of emergency medical providers in their area and to choose a top performing hospital whenever there is a choice."