NEW YORK (WCBS 880)  -- A top heart surgeon from Montefiore Hospital in the Bronx may have made medical history when he took a break from heart-valve replacement surgery to donate his own blood to save a boy.

Dr. Samuel Weinstein is part of a Heart Care International, a group of medical professionals who travel the world to perform heart surgery for people who couldn't otherwise afford it.

But when he was replacing a valve in the heart of eight-year-old Francisco Hernandez in El Salvador, the boy started bleeding uncontrollably.

"When we heard he was B-negative, I mentioned that was my blood type. We decided that I would scrub out, donate blood, and then scrub back in," Weinstein said.

Weinstein's  colleague, Dr. Robert Michler --  who founded Heart Care International -- kept operating while Weinstein gave blood, had a Pop-Tart, and then wathced as his blood was pumped into the patient

"Everybody on the heart team made a contribution to this child," Weinstein said. "I believe it was among our finest moments."

The boy is now doing fine.

Doctors say this may be the first time a surgeon has donated blood at the operating table.

For more on this story, click on the audio link on the right.

Photo: Dr. Samuel Weinstein and Dr. Robert Michler (Montefiore Hospital)