Brandon Littlejohn was shot just after 11 P.M. on Saturday, April 23, 2011. The day had started out cold and rainy, but by evening the temperature hinted at the summer to come. Littlejohn was playing basketball on a court at a corner of Harlem Square Park, in West Baltimore, when his girlfriend drove by to pick him up. He jogged over to her car, said he’d be back in a minute, and returned to the basketball court to tell his friends that he was leaving.

“She heard the gunshots,” Littlejohn’s aunt Roxanne Cunningham told me. “She looked, and he was falling.” One of Littlejohn’s friends helped his girlfriend get him into the car, and she drove him to the hospital. He had been shot multiple times in the chest and lower body, but he was still alive when he reached the emergency room, ten minutes away. “He told her to tell his family that he was sorry,” Cunningham said.

The hospital was the University of Maryland’s R Adams Cowley Shock Trauma Center (universally known as Shock Trauma), the oldest and probably the leading trauma unit in the country. Baltimore has one of the nation’s highest rates of gun violence, and Shock Trauma admits at least two or three shooting victims each week—often, like Brandon Littlejohn, young black men. Frequently, it sees that many cases in a single night. As it happens, Cunningham—a stylish, soft-voiced fifty-seven-year-old, born and brought up in West Baltimore—works at Shock Trauma, managing paperwork for the operating rooms. She was not on duty that night, however, so she didn’t have to watch as surgeons and nurses struggled to save her nephew’s life.

The Trauma Resuscitation Unit, or T.R.U., consists of twelve bays divided by curtains and arranged in a horseshoe configuration around three banks of workstations. Electrocardiographs, infusion pumps, and ventilators hum and beep incessantly, punctuated every few minutes by a ringing phone, followed by a nurse’s voice repeating the cryptic snippets of information relayed by emergency services—GSW face, arrest in the field, blood levels at thirty-nine—as colleagues take notes and ready the next bay.

That April evening, as Littlejohn was rolled into an open bay, a cluster of nurses, an anesthesiologist, a resident, and the attending surgeon descended on him and began performing dozens of complicated procedures at once. They worked with the efficiency and furious intensity of people who have tried to save many, many lives in exactly the same way. As the anesthesiologist took her position at the head of the bed to insert a breathing tube into Littlejohn’s windpipe, a nurse cut off what remained of his blood-soaked clothes, another attached electrocardiogram sensors to his chest, and others performed chest compressions, took samples, passed the X-ray machine over his abdomen, and attached an I.V. line to his arm to begin delivering blood. And then Brandon Littlejohn’s heart stopped.

Statistically speaking, Littlejohn’s chances of survival were now less than one in twenty. For most people who sustain traumatic injuries, whether from bullets or car crashes, death occurs within the hour. The primary cause is exsanguination cardiac arrest, the technical term for losing so much blood that too little is left for the heart to continue to circulate. Even as nurses pumped fresh blood into Littlejohn, it flowed straight back out of his bullet wounds, pooling in his abdominal cavity and soaking the bed on which he lay.

“There’s not a whole lot you can do at this point,” Deborah Stein, the attending surgeon that night, told me. “All you can try to do is get their heart re-started, but while they’re still actively bleeding . . .” She trailed off, gesturing to indicate the hopelessness of the situation. “They basically never make it.” Nonetheless, as soon as Stein lost Littlejohn’s pulse she used a scalpel to make a long, smile-shaped incision below his left nipple, then wedged a stainless-steel rack-and-pinion into the slit, cranking its lever to spread his ribs apart and expose his heart. By clamping the aorta in such a way as to cut off circulation to the lower body, she forced what little blood remained in Littlejohn’s body up to his brain, then cradled his heart between both hands to massage it.

Around her, a tight knot of nurses and residents in pink scrubs continued to work, putting in stitches, administering drugs, hanging fresh blood, suctioning out Littlejohn’s chest cavity. So much was being done to Littlejohn’s body with each fateful minute that the passage of time seemed to slow. “I got him back once or twice, but he kept arresting,” Stein said. Each time Littlejohn flatlined, Stein stopped operating on his bullet wounds in order to palpate his heart again, and each time she revived him his battered body became even weaker. “Everything was out of whack—his electrolytes, his pH, his platelets,” she said. “You’re trying to do two things at once, but you can’t. I just needed more time to fix what was bleeding.”

The third or fourth time his heart stopped beating—Stein lost count—it couldn’t be re-started. Just after midnight, Stein pronounced Brandon Littlejohn dead. He was twenty years old.

Losing a patient is always painful, but losing one like Littlejohn is also exasperating. Even though everyone at Shock Trauma knew that the odds were against him, they also knew that every injury he’d sustained was fixable. He hadn’t been shot in the head or in a vital organ. The holes in his body could have been sewn up—they just couldn’t be sewn up in less than the five or six minutes it takes for the brain to die from lack of oxygen. “It is the most frustrating thing, and it happens all the time,” Tom Scalea, Shock Trauma’s physician-in-chief, told me. “Some kid comes in with cardiac arrest from a fixable injury—an easily fixable injury—and you open them up in the T.R.U. and they kind of come back, and then they die. And then you get to go tell their mom that they are not coming home, when all we needed was a few more minutes.”

The R Adams Cowley Shock Trauma Center is named in memory of the pioneering surgeon who founded it, in the nineteen-sixties, and who is generally considered the father of trauma medicine. Today, Cowley is remembered for developing the concept of “the golden hour”: the idea that the sooner critically injured patients are treated the better their chances of survival. To get patients to properly equipped hospitals as quickly as possible, he developed the country’s first statewide E.M.S. system, including helicopter ambulances.

Earlier this year, the center announced that it was conducting a trial of a procedure that may revolutionize trauma care by buying patients and their doctors even more time. Known as E.P.R., for “emergency preservation and resuscitation,” it is the result of nearly thirty years of work. The procedure has long been proved successful in animal experiments, but overcoming the institutional, logistical, and ethical obstacles to performing it on a human being has taken more than a decade.

The director of the E.P.R. trial is Sam Tisherman, a professor of surgery at the University of Maryland, who works at Shock Trauma. He is fifty-seven, bespectacled, mild-mannered, and quick to blush, and he has an understated sense of humor. He trained as a trauma surgeon more than twenty years ago, but the memory of his first experience of running out of time while trying to resuscitate someone remains indelible. The patient was a twenty-three-year-old man. “We almost saved him,” Tisherman said. “We actually got him in the operating room, and then we just couldn’t keep his heart going.” He had been stabbed in an argument over bowling shoes.