When medical simulators were featured in Proto’s inaugural issue five years ago (“All Too Human,” Fall 2005), they were still a sideshow in medical education. Even at elite medical schools, students might train just a few times a year on simulators—lifelike mannequins implanted with sensors that can raise or lower blood pressure and pulse, monitor breathing, even groan in pain or “die.”

Yet the story concluded with a confident prediction from Jeffrey B. Cooper, a senior biomedical engineer at Massachusetts General Hospital: “A generation ago people questioned whether computers would ever have a place in medicine. Now, they’re so common you don’t even think about them—you just realize the benefits. That’s where simulators are headed.”

His prediction is already coming to pass. There are about 1,000 simulation centers in the United States today, compared with perhaps 100 five years ago, says Mary Patterson, medical director of the Center for Simulation and Research at Cincinnati Children’s Hospital Medical Center. “Now, it would be unusual for a student to get through medical school without experience on simulators,” she says.

Moreover, the technology is becoming more advanced. Computer graphics and mannequins are coming together in simulators that re-create such procedures as endoscopies, in which physicians thread their instruments into a bodily orifice, after which sensors detect the path of the instruments and create realistic images displayed on monitors. Eventually, some researchers predict, mannequins might themselves be phased out while virtual environments give trainees, clad in virtual-reality goggles and gloves, the look and feel of cutting into a patient.

Meanwhile, existing technologies are being used to train a much larger field of clinicians. Five years ago, simulation centers were concentrated in large medical schools and research hospitals. Today they are also found in nursing schools, regional hospitals and technical colleges that train physician’s assistants and emergency medical technicians.

Perhaps the most important advance is the ability of simulation training to reduce medical errors. Several studies on simulation-based training have shown that central line catheter infections (a major health and cost issue for hospitals) occur less frequently in patients treated by clinicians who had first practiced inserting catheters into mannequins.

“Five years ago, we all thought simulation was a good idea,” says Patterson. “We have evidence now that simulation really does make a difference.”