When Dr. Charles Willey walks into treatment rooms, his laptop computer is as prominent as his stethoscope. After his examination and his diagnosis, he types information into the laptop. If the patient wants to watch, that's OK.

The computer screen kicks back a list of the latest studies and information about the diagnosis he's made - treatments, changes in treatments and the list of medicines that are available to treat the condition.

After he and the patient agree on treatments and medicines, he can hit a button to print out prescriptions or fax the information to a pharmacy.

Willey practices with Esse Health in south St. Louis County. The company has been working with a spinoff company, Purkinje, also of South County, to create a computer program that helps doctors decide on treatments for patients.

Instead of Willey having to rely strictly on his experience and memory, the computer kicks out the latest information that he can use for his patients.

What Willey is practicing is called evidence-based medicine.

What is evidence-based medicine?

No one makes more monumental decisions about your life than your doctors. Evidence-based medicine is a means to help doctors base those decisions on science rather than experience and opinion.

"The operative words here are 'good science,'" said Dr. Michael LeFevre, medical director for the Department of Family and Community Medicine at the University of Missouri at Columbia. "Decisions are based on evidence that includes consistent results from a number of studies ... carried out on a large number of patients in a variety of settings.

"Evidence-based medicine is the right care, and only the right care, for the right patient at the right time."

Ross Bronson, an epidemiologist with the St. Louis University School of Public Health, says, "We spend close to $30 billion a year in research that ends up in scientific journals, but don't always get read by practicing (physicians). So we want to take all of this and put it into practice; that involves clinical care and how you impact the whole community."

Since the first healers of ancient times, doctors have relied on education, experience, hunches, habits, anecdotal evidence and their own observations. Modern times have added reimbursement by insurance companies and defense against the threat of malpractice suits to their decision-making.

The result is that separate doctors could see the same patient with the same illness and diagnose and treat it differently depending on how their years of experience shaped their opinions.

The challenge

Conflicting studies have brought about situations such as the one involving the painkiller Vioxx. One day it was a revolutionary painkiller; the next day it was linked to heart disease.

And let's not forget when a variety of hormonal treatments to relieve menopause later were linked to certain cancers.

"Science is a moving target," said Kathryn McDonald, director of the Evidence-Based Medicine Center at Stanford University in California. "Often, studies have not been critically evaluated in the context of previous evidence."

And, Bronson said, "There's a lot of efficient information, but there's also a lot of information overload."

The opening for doctors wanting to use evidence-based medicine has been the Internet. Scads of information is available on the Web, mainly through physicians' organizations and Web sites that specialize in providing up-to-date information on medical treatments.

The age of technology

"The problem is to get it out of academia and to the patients," said Dr. Thomas Doerr, chief medical officer of Purkinje, which has created a computerized system that supports evidence-based medicine.

The wall of time constraints and accessibility between doctors and burgeoning information appears to be the greatest impediment to evidence-based medicine, say experts. The physician in the trenches faces demands that tell him to keep moving and work from the knowledge in his head.

In addition, the shrinking number of front-line physicians - family practitioners, internists, pediatricians and geriatricians - is pushing up the number of patients that a doctor sees. Will evidence-based medicine slow him or her down too much?

Hundreds of businesses sponsored by physicians, physician organizations and medical-records companies are trying to find a way to get up-to-date information on-the-fly, so doctors can use it in real time in their practices.

In the St. Louis area, Purkinje is attempting to lead the country in generating computer-based medical research that can travel around a doctor's office. That's the system Willey uses in his practice.

How it works

At Esse Health, as doctors examine a patient, they type information into a laptop computer. It works this way:

The doctor still makes a diagnosis, but the computer brings back information on tests that work, tests that don't work, remedies that work, remedies that are used but don't work, and even remedies that many doctors didn't know would work.

For example, Willey showed the computer's reply to a diagnosis of an ear infection that was caused by antibiotic-resistant bacteria. Conventional medicine says the most common antibiotic, amoxicillin, doesn't work on resistant bacteria. But the information in the computer said studies had shown that doubling the dosage of amoxicillin would cure the infection and was safe.

In another instance, a patient with arthritis needed a pain reliever. The computer brought back several choices. This time, though, a colored bar appeared on the screen that said Cox-2 inhibitors, which are expensive and are suspected of causing heart problems, are no more effective against the pain than over-the-counter pain relievers.

The information is fed to the computer by a staff of medical professionals, including pharmacists and physicians, said Doerr. The first manual for the program started out at a few hundred pages and now is several thousand. However, computers hold that much information with little problem.

Since Esse physicians started using this program a few years ago, they've found that their use of generic drug prescriptions has jumped to 69 percent from 52 percent. Also, they say they've cut medical costs for patients by more than $1,200 per doctor per month by increasing the use of generic drugs and cutting down on tests and procedures that the science says generally don't work or aren't necessary.

The patient's job

Patients need to be informed and assertive in their dealings with doctors, experts say. They also should know that this new technology and method helps the doctor; it doesn't replace him, experts say. Doctors still do the examinations, order the tests and work out treatments, and patients still have the final say on what happens.

"Consumers may benefit from understanding that there is a fair bit of uncertainty and limited information for a number of medical situations," McDonald said. "One study usually doesn't represent the variation in patients and clinical practices."

That's important, because so many studies fall short in examination of differences in gender, race, even national origin. A treatment that science says works for white males between 25 and 50 may not have been tested on a black woman over 50.

"The consumer's job is to trust, but question - to ask questions, and when in doubt, get a second opinion," said LeFevre of the University of Missouri. What has changed is consumer access to much of the same information that physicians have upon which decisions are made.

"Motivated patients (should) attempt to educate themselves about issues, and use this education to ask appropriate questions and make appropriate challenges when necessary," he said. "Physicians will understand that they are no longer the sole 'keeper' of the knowledge.

"Decision-making will more often be shared. Frankly, the educated patient will be very skeptical about the latest headline about the latest study."