"When you get an opportunity to participate in these types of relief efforts, you reconnect with the purity of medicine, as well as your reasons for entering the field."

De Marchena arrived in Haiti as a volunteer for the UM Global Institute for Community Health and Development on January 16, four days after the earthquake. He was placed in charge of a makeshift hospital created in a United Nations open-air warehouse on the grounds of Port-au-Prince's international airport.

There was a steady flow of patients suffering from compound fractures, crush injuries and severe dehydration. The warehouse reeked of decaying flesh, human excrement and even rotting food. With the exception of one or two patients who'd sustained chest trauma, de Marchena had few opportunities to put his skills as an interventional-cardiologist to use.

Still, there were plenty of critical tasks for de Marchena, who participated in and helped organize Mississippi relief efforts associated with Hurricane Katrina.

He set to work stabilizing and triaging patients, creating an inventory of the needed medical equipment, and coordinating relief efforts with personnel at an Israeli field hospital and other medical units. De Marchena also threw himself into improving infection management, helping to set up a provisional operating room and mobilizing volunteers to improve the site's hygiene.

"During my first day, I probably slept an hour," de Marchena recalls. "You're driven by adrenaline so you don't even feel all that tired, which is kind of weird. The second night I probably got about six hours. You get to the point where you become a little dysfunctional if you don't rest."

All told, de Marchena spent a week in Haiti, before returning to Miami. The transition was jarring.

"Almost all the medical personnel I talked to in Haiti had the same feeling -- they did not want to leave," de Marchena says. "And it wasn't because they weren't uncomfortable or they weren't tired -- they just saw so much need.

"You actually feel a sense of withdrawal from those chaotic conditions," de Marchena continued. "I mean, I experienced withdrawal for a good five to six days where I was seeking that hectic, nonstop pace."

The Miller School's medical relief mission in Haiti "is the activity that the school has done that I'm the proudest of," de Marchena says. "It was something that was a fantastic humanitarian initiative and completely selfless. All my colleagues who went down there were just astonishing. They were working day and night. Definitely, as an alumnus, it makes you very proud."