AT 7:45 ON A FRIDAY MORNING, four young doctors are pawing through a bag of bagels in a staff lounge at the Veterans Administration Hospital down the street from Stanford University in Palo Alto, California. As on any typical workday, they are dressed in their blue hospital scrubs. They swap department gossip while they slurp coffee and juice.

But details suggest the hours ahead will not be routine. The physicians have switched off their pagers. The quiet lounge lies in the basement, far from the hospital bustle. And on the table sits a stack of papers to be signed, each labeled “Confidentiality Agreement.”

One of the group, Stephen Ternlund, is bigger and taller than the rest, with thick arms and oversized palms. He looks more like a football player than a man who spends his days probing people’s airways.

Ternlund and his colleagues are medical residents in a three-year anesthesiology training program at Stanford University Medical Center, where they learn to numb bodies against the surgeon’s knife, put patients to sleep, and most important, keep them breathing. Split-second decisions can determine life or death. Throughout residency, the trainees are under the supervision of senior attending physicians who take over if things go wrong. But today, the young doctors will have a chance to fly solo.

Two instructors, also in operating room garb, enter the lounge. Steve Howard, a man in his mid-forties wearing his scrubs inside-out, is a professor and attending anesthesiologist. Kyle Harrison, a postdoctoral fellow, unwraps his own breakfast of a sweet scone and strong Peet’s coffee.

The other doctors delicately dip their plastic knives into a tub of cream cheese and slather it onto sesame bagels. They banter and chat, but their fidgets and nervous laughter betray tension. The group teases Howard, who sports a thin blond beard. “What’s with the new facial hair?” they ask. Howard is only mildly defensive. “And just how easy do you want me to be on you today?” he retorts.

The new doctors will face their worst medical nightmares over the next eight hours. They will scramble to care for a special patient named Sam: a 5-foot-8-inch plastic dummy who breathes, twitches, blinks, talks — and even bleeds. Sam’s vital signs will crash, and the trainees will battle crisis after crisis to save this fully computerized patient, as their teachers watch closely and direct the unfolding drama.

These doctors practice in an elaborate reproduction of a modern operating theater. The props are real medicine and equipment, and the supporting cast are actual hospital staff. But the starring actors — the trainees — don’t know the script: They take turns sitting in the “hot seat” in the operating room, where each must navigate through an unrelenting torrent of medical emergencies.

The teachers hope to take these residents to a medical hell and back — and return them to the hospital as better doctors. Ternlund and his peers are participating in a pioneering training program started by Stanford anesthesiologist David Gaba. What’s important in medicine, Gaba believes, is not just how much doctors know; it’s also how well they perform under the gun in a crisis that can tip the balance between life and death.

Doctors need to rehearse these emergencies in a safe place, Gaba says, where they are free to make mistakes. The faked crises they face must be as realistic as possible. “It’s equal parts medicine and theater,” Gaba says of his program. “It’s all about recreating realities.”

In medical schools around the world, educators agree with Gaba’s philosophy. From Stockholm to Salt Lake City, hospitals are setting up crisis simulation centers modeled after Stanford’s. Other disciplines, such as intensive care and emergency medicine, are joining in too. Critics of such programs point to hefty price tags and ask for proof that the programs improve patient care. But Gaba and others say the benefits go beyond what can be pegged down with numbers. One thing is certain, though: Simulation programs such as Stanford’s are starting to change the face of modern medical education.

The idea of the Stanford program took root in 1985, when Gaba, then a young anesthesiology professor, began asking hard questions: Why do things go wrong in the operating room? How do doctors make mistakes? Gaba, who studied biomedical engineering at Northwestern University, in Evanston, Illinois, before medical school, became interested in the psychology and sociology of crises — and the fuzzy behavioral skills that doctors were never explicitly taught.

He and colleague Kevin Fish wanted to observe anesthesiologists’ behavior in action. To do this in an experimental setting without risk to patients, they needed a lifelike dummy. “We realized that, between us, we really could build one,” he says. “So we did. By hand.” After nine months of tinkering, Gaba’s first patient simulator — Sam’s grandfather — was born in 1986. This version was only a head and neck attached to a computer. The third generation simulator, manufactured in 1995 by CAE Electronics, Inc., was a completely automated full body. Technically Sam’s cousin, this dummy patient achieved notoriety with a cameo role in 2003 in the television show ER.

Gaba, a big NASA fan growing up, saw that beyond allowing researchers to watch how doctors handle emergencies, the patient simulator could also help physicians practice their skills under stress, just as pilots or astronauts do. Gaba and his colleagues turned to the air and space sciences field to adapt pilot training into a set of good-practice principles for doctors, called Anesthesia Crisis Resource Management. At least 70 percent of anesthesia mistakes stem from human error, they say, such as when doctors become fixated on a small part of the problem at hand and ignore a snowballing emergency. Gaba's crisis training emphasizes planning, communication, and perspective.

In 1990, Gaba and his colleague Steve Howard began a full crisis-management course at Stanford. They taught on weekends in empty operating rooms until 1995, when the Stanford VA Hospital opened a state-of-the-art simulation center.

Educators at other top schools quickly took notice. In 1993, Harvard anesthesia departments set up their own simulation center modeled after Stanford’s, says Jeff Cooper, director of the Harvard University-affiliated Center for Medical Simulation in Boston. “We’ve been going strong ever since, building on what we learned from Gaba and Howard.” Now major crisis simulation programs are found in at least 15 hospitals in countries around the world.

Back in the hospital lounge, Howard explains the rules of today’s exercise. He stresses the simultaneous safety and brutality of the session that the young doctors are about to experience. “You need a friendly environment to try out these things.” As the residents sign confidentiality agreements in illegible scrawls, Howard tells them that no one outside the room will be informed about their individual performances today. “I don’t discuss this with your attendings.” (Indeed, media stories such as this one are allowed only under special permission and if certain details are changed or omitted.) But he warns, “Today will be very, very intense. You will be stressed. Adrenaline will flow.”

AT 9:30 A.M., TERNLUND and the other residents follow Howard and Harrison into the operating theater. In the center of the room the patient lies on the operating table, tucked modestly beneath a sheet.

The doctors circle the bed, and Howard introduces them to Sam. His eyelids can flutter, and his pupils will react to light. A pulse throbs in his neck, ankle, wrist and groin. The passage to his lungs is ready for a breathing tube or advanced airway surgery. And if Sam doesn’t get enough oxygen, his heart will stop beating.

The residents watch Sam’s chest rise and fall. Ternlund leans forward with a stethoscope to listen to the patient’s breathing and heartbeat. Sam’s left arm jumps occasionally. His thumb twitches. Right now, he is in “healthy sleep” mode.

The doctors are ready to begin the session. Three of them disperse to a nearby room to watch the events on closed-circuit television. Ternlund, the first in the hot seat, goes back to the lounge to await his cue.

To set the scene for an emergency C-section, a long-haired brunette wig is tossed onto Sam’s head. Harrison begins to prep for his role as an obstetrics surgeon, because Sam is now Sammie, a pregnant woman in distress. Her baby’s heart rate is fading fast. Both Sammie and her child are in critical danger.

Howard retreats to the control booth adjoining the operating theater. From there he will direct the drama and watch the scene through a one-way mirror. He can talk to Harrison through a headset, urging him at pivotal moments to turn up the heat on Ternlund. Howard also has the power to tweak nearly every aspect of Sammie’s existence, from breathing to bleeding to death.

The action begins.

“The baby is not doing well,” Harrison announces gravely from Sammie’s side. A nurse is dispatched to find Ternlund, the designated anesthesiologist on call. The surgeon needs to deliver the baby immediately.

In the control booth, Howard flips through a copy of today’s simulation script. Instead of stage directions, the pages are filled with computer instructions. A technician at a nearby computer sets Sammie’s heart rate and other vital signs. Howard tells her to get the blood ready, and she fiddles with equipment under the desk.

Ternlund hurries into the operating theater and takes his place. His 6-foot-4-inch frame fills the small work space behind Sammie’s head. “The baby is not doing well,” Harrison tells him urgently. “We need a stat C-section.”

The pressure is on. Ternlund must work with an impatient surgeon who wants to operate immediately. Nonetheless, the young doctor takes a moment to call in another resident for help.

Ternlund confers with Harrison and decides to use general anesthesia, putting Sammie completely to sleep. Since the medicine will paralyze Sammie’s lungs along with the rest of her body, Ternlund will need to make sure a machine keeps her breathing steadily.

On cue, the technician checks a box on her computer screen next to the “Airway Swelling Program.” Hormones coursing through pregnant women’s bodies often swell up tissues in their throats. This makes it hard for an anesthesiologist to get a breathing tube in fast enough. Deep in Sammie’s throat, small balloons inflate to constrict the airway.

Ideally, Ternlund would put the breathing tube into Sammie now, before he allows the surgeon to begin cutting, to make sure she gets enough oxygen throughout the operation. But Harrison is impatient. “We need to go, go, go, go,” he tells Ternlund bluntly. “This baby has got to come out.”

Ternlund bangs loudly through the drawers of a metal cabinet, looking for a vial of medicine. In the operating room, now crowded with four doctors and a nurse, the well-choreographed dance quickens, with one person ducking just as another dives.

Ternlund hooks up an intravenous bag with the anesthesia drugs to Sammie’s arm. She starts to fall asleep. Ternlund tells Harrison to start the operation.

The meds will soon paralyze her lungs. Ternlund needs to put a breathing tube down her throat, fast. He should have done this first, before Harrison began cutting. Ternlund has assumed that the intubation will be easy.

Howard tells Harrison to start the surgery. The technician begins the blood flow. Beneath Sammie’s bed, red liquid streams up out of a vat and gushes out of an opening in her inner thigh. A vacuum hose sucks up the fake blood and pumps it to transparent canisters below.

Most of a pregnant woman’s blood circulates around her baby in the womb, so bleeding from a C-section can be profuse. The anesthesiologist needs to keep a close eye on the blood loss. Ternlund can see the canisters of blood as he tries to insert the breathing tube into Sammie’s windpipe. He checks a machine to see if the carbon dioxide she exhales is flowing out of the tube. It isn’t. He must have missed the trachea and put the tube in the esophagus instead.

He tries again. Still no carbon dioxide.

Howard tells Harrison to slowly start bringing the baby — also made of plastic — out of the dummy.

Harrison reaches in and tugs the baby quickly from Sammie’s uterus. “It’s out,” he announces to the room.

Howard laughs. “No, no! That was too fast,” he says. Through the headset, Harrison protests in a low mutter. “But that’s real life,” he says. “Sometimes you don’t get much time.” Meanwhile, the technician turns up the bleeding.

Ignoring for now the blood in the canisters, Ternlund again tries to position the breathing tube. Again he misses. Without enough oxygen flowing through her blood, Sammie’s heart could stop within seconds. The danger is even greater with a pregnant woman, who needs extra oxygen to share with her unborn baby.

Compounding the crisis, two of the blood canisters have already filled. If the lack of oxygen doesn’t kill her, the hemorrhaging will, in about 15 minutes. Ternlund realizes he can’t afford to neglect the bleeding any longer. He asks the nurse for more transfusion blood and the resident for another IV. His voice is sharp. The choreography of the operating room dance has turned fast and furious.

Howard notices. He sees how well Ternlund has been communicating with the O.R. staff and delegating tasks. He shows mercy. “All right, drop the swelling,” he tells the technician. The unseen balloons deflate.

Desperate, Ternlund tries the breathing tube a fourth time. Any more unsuccessful attempts could damage Sammie’s throat. But this time, the tube slips in just right.

Sammie is now breathing. The first danger is gone. Ternlund lets out a small sigh.

Howard tells the technician to slowly back off on the blood. He improves Sammie’s vitals on the computer.

Ternlund and the resident debate how to stop the bleeding. Then they notice the steady flow into the canisters is slowing down. The blood transfusions that Ternlund ordered must have worked. He relaxes. Danger number two is also gone.

Thirty stressful minutes after walking through the door, Ternlund has brought the situation under control. Harrison jokes with Ternlund about Sammie. “Is she all right now?” he asks. “Because she’s an attorney, you know.”

Ternlund is still immersed in the theater, though. “Yeah, but right now,” he says, “she’s just a mommy.” He smiles.

Howard flips his microphone on. “All right, very nice,” he says. “That’s a wrap.”

AFTERWARD, TERNLUND, HOWARD and Harrison join the other residents in the debriefing room. They analyze Ternlund’s actions, discussing what he did well and where he went wrong. A common mistake, the instructors note, is to become fixated on delivering the endangered baby and not to first ensure that the mother can breathe properly. It’s good to call for help early and not get rattled by the surgeon’s pressure.

“That was not fun,” Ternlund says of his turn in the hot seat. He swivels his chair around in anxious circles.

Harrison nods. “It’s no fun because you see how real it is,” he says.

“I didn’t realize how lonely you can feel,” Ternlund says, “how isolated.”

What Ternlund just went through was a moderately difficult exercise. Howard and Gaba have also concocted even tougher scripts. Particularly harrowing is the “Death Scenario,” in which nothing doctors do can save Sam from dying of an unforeseen drug allergy. The real challenge comes when the trainees must deliver the bad news to the patient’s family — played by actors — in a session that often turns highly emotional.

Realism is, of course, crucial for the success of crisis simulation programs. Gaba and his colleagues go to extraordinary lengths to create convincing dilemmas. But that’s not always enough, according to physician Ashish Jha, of Harvard Medical School in Boston, who studies patient safety. A scenario’s believability is also limited by the simulator’s technology. “It is much more difficult to ‘re-create’ a human being than to do so for, say, an airplane,” Jha says, writing in the book Making Health Care Safer: A Critical Analysis of Patient Safety Practices. As a result, he adds, “Participants may be unable to ‘suspend disbelief,’ may treat the simulation only as a game, or act in a cavalier fashion, knowing that the simulator is not a real patient.”

But supporters say simulation programs are realistic for those who throw themselves into the role. Teachers try to discourage residents from taking the training sessions lightly. “If they’re not serious,” Howard says, “we raise the stakes. If they’re stressed, well, they’re just as stressed as they would be in reality.”

Even if physicians embrace the simulation experience, can the program save patients’ lives? It's an obvious question with financial implications. The training is expensive, so gimlet-eyed accountants of the medical world are likely to pay for it only if they’re confident it will truly improve doctors' ability to rescue patients.

No one knows the answer. “Serious medical crises are extremely rare,” Gaba says, so it’s difficult to collect data on them to measure how physicians perform. And complicating medical factors, such as surgery difficulties, make it tough to study the influence of simulation training on patients’ health. When it comes to judging the effectiveness of programs like his, Gaba acknowledges, “we may never have the level of definitive proof.”

Proof may be missing, but satisfied participants are not. Of the thousands of doctors and nurses who have gone through crisis simulation training, Gaba says, “most believe it contributes to their safe practice of anesthesia.” One anesthesiologist who did the Stanford program later successfully treated a passenger on an airplane who had a heart attack. “She wrote about it and gave us credit for that,” Gaba recalls. At Harvard’s simulation center, Jeff Cooper reports similar results. “The program is powerful,” Cooper says. “The participants believe that it works. So do we.”

Anecdotal evidence doesn’t satisfy accountants, though. “Critics say it’s not that this is a bad idea,” Gaba says. “It’s just expensive.” A simulation center costs between $500,000 to $1 million to set up. Costs for the training may range from $800 to $2,000 per participant, per day. And in the Stanford program, its six anesthesiologist instructors could be earning more money for the hospital by working in a real O.R. rather than in a fake one.

But Gaba and others say the benefits can’t be fully captured in numbers or dollars. “No industry in which human lives depend on skilled performance has waited for unequivocal proof of the benefits of simulation before embracing it,” he says. “Aviation doesn’t have definitive proof, but they still use simulations. Why should medicine be any different?”

Medical education has been slow to require the equivalent of flight simulation training for physicians, Gaba says. Although patient simulators are popping up in more and more hospitals in a variety of departments, only 1 percent of all health care professionals have undergone the training. Traditionally, new doctors have been expected to learn through osmosis — by watching senior physicians, Gaba says. “Good clinicians have always done the things we teach. We didn’t invent the principles. We just codified them. Before, you couldn’t learn them systematically. What we hope is that in medical education simulations will become something embedded, not extra.”

Change is coming, however haltingly. Recently, anesthesiologists in Harvard-affiliated hospitals were offered reduced rates on malpractice insurance if they went through yearly crisis simulation training. But Gaba would like to see the training become a requirement in this country, as it is in some others, not just an incentive. “In Denmark, simulation is mandatory for all medical students. In Germany, it’s in all the med schools,” he says. He thinks it’s easier to make these changes in smaller countries. “The U.S. with its 50 states has a history of opposing regulations. We’re going to be the last to do it on a widespread basis.”

Gaba also hopes to push the technology of his simulations into new areas, such as virtual surgery training that lets physicians practice their operating techniques on the computer screen. (See “Getting a Feel for Surgery” by Shawne Neeper.) “Right now there’s simulated laparoscopic surgery, and there’s better and better virtual reality,” says Gaba. “We’re hoping to have a business between our two fields.” Eventually, he says, programs will marry virtual surgery with patient simulation.

A FEW MONTHS AFTER his training session with Sam, Ternlund takes stock of the lessons he learned. Recently, during a late-night emergency at the hospital, he was part of a team of about 10 nurses and doctors of different specialties who responded when a patient started to crash. “The people I was with that night really could have used the course,” he says. Since they hadn’t trained in crisis-management principles, they didn’t work together to handle the emergency as smoothly as they might have, Ternlund says.

But it was a different experience entirely when, in another case, he worked on a patient emergency with some of the residents who had trained with him on Sam, he says. “We had gone through the ropes together with the simulator, and it helped. The more you go through something like that and practice communication, the better it gets.”

That’s what the Stanford simulation center offers Ternlund and his colleagues: a guided tour through the inner depths of medicine — and, upon emerging wiser but unscathed, the chance to share the lessons of their journey to hell and back.