Baltimore ? Johns Hopkins University surgeons performed three simultaneous kidney transplants in a complex piece of medical choreography that had nurses rushing organs in labeled coolers among six operating rooms.

The six synchronized operations — three to remove the kidneys, three to implant them — became possible after an extraordinarily lucky, six-way organ match among the patients, their friends and their families.

All six patients were doing well after Monday’s surgery. Each recipient met his or her donor for the first time Friday.

“We each have a piece of each other inside us,” recipient Germaine Allum said through tears at a hospital news conference.

The surgery lasted 11 hours, with two doctors, two nurses and two anesthesiologists in each operating room.

“It was truly a marathon,” Dr. Robert Montgomery said.

The six operations were performed simultaneously, in part, “to avoid any possibility of anyone backing out, someone getting in a car accident, whatever,” Montgomery said. “If all the operations start at the same time, it removes those variables.”

Montgomery called the coordinated operations “logistically a monumental experience,” and described the matching of each of the three transplant patients with a healthy stranger as a “Eureka-type moment.”

Julia Tower, right, discusses the three-way kidney transplant in which she was a donor. Joining her Friday at Johns Hopkins Hospital in Baltimore are, from left, donor Paul Boissiere, recipient Germaine Allum, recipient Tracy Stahl, donor Connie Dick, and Linda Warschoff and Ellen Weiser, parents of recipient Jeremy Weiser-Warschoff, 13.

The process began last October, when Connie Dick offered to donate a kidney to her sister, Tracy Stahl.

Dick’s kidney was not a good match, but during tests, nurses found that Julia Tower, who had originally wanted to donate her kidney to the teenage son of some friends, had a rare tissue type that was compatible with Stahl’s.

The bond between Stahl and Tower “became the centerpiece of the whole exchange,” Montgomery said. It also made a triple swap necessary, he said, because neither Dick nor Tower was a good match for 13-year-old Jeremy Weiser-Warschoff.

In Jeremy’s case, a transplant kidney he received as a baby had begun to fail this year, Montgomery said.

Meanwhile, Paul Boissiere’s blood was incompatible with his fiancee, Allum, but his tissue and blood matched Jeremy’s, so he became the teen’s donor. Dick had the same blood type as Allum and became her donor.

Montgomery said the patients had cleared the most dangerous time for transplant patients — the first few days after an operation.

“It was really possible because these three donors desperately wanted to see their loved ones receive a kidney and were open to any possibility to make that happen,” Montgomery said.