At 6:45 a.m. Thursday, the surgeon in Maryland called Eugenia Steffens with an anxious question: How's the weather out there in Minnesota?

Don't worry, said Steffens, a transplant coordinator at Hennepin County Medical Center: The airport won't close.

With four surgeries and two lives in the balance, it's no wonder the two of them were watching the forecast.

At 1 p.m., a Northwest Airlines flight took off from the Twin Cities with precious cargo: Kathie Blomstrand's kidney, destined for a transplant patient in Baltimore. Meanwhile, a flight was leaving Baltimore for Minneapolis carrying a kidney that would be transplanted Thursday night into Blomstrand's husband, Floyd Johnson.

The two-way kidney swap between HCMC and the University of Maryland Medical Center this week was a dramatic example of the next best idea in transplant medicine: A highly choreographed computer exchange that matches living donors with people in kidney failure across the country. It promises to save millions of dollars in medical costs and end the ordeal facing many of the 80,000 kidney patients on the nation's transplant list, who face a wait of five years or more to get an organ from a deceased donor.

"If this paired exchange hadn't taken place, I don't think I would ever have gotten a kidney," a grateful Johnson, 73, said before he went into surgery on Thursday. "I'm too old."

Nor would the transplant patient in Maryland have gotten a kidney, said Dr. Matt Cooper, director of kidney transplantation at the Maryland medical center. Very few people in the general population would have been a match for his patient, he said.

Only a large, computerized data base of potential donors could find her that "needle in a haystack," he said.

That rare donor turned out to be Blomstrand, a 60-year-old registered nurse from Duluth. By sending her kidney to the patient in Maryland, she gave her husband the gift of a kidney sent back in exchange. She jumped at the chance to help her husband get off dialysis and return to the life of hunting and fishing that he loves.

"He was able to do less and less of that," she said. "I really wanted him to get a kidney."

These sophisticated national organ exchanges are still in their infancy, and Minnesota hospitals are only now beginning to participate. In November the Mayo Clinic did a four-way swap among three kidney patients at the Rochester clinic and one at its Arizona clinic. In the last two years, transplant centers in other states have done several hundred such paired exchanges. Late last year, the organization that manages the national transplant system for the federal government launched a pilot program that could eventually create a nationwide matching system.

Growing waiting list

With the rapid spread of kidney disease in the past two decades and an ever-longer waiting list for organs from deceased donors, "the wait times are becoming unpalatable," said Dr. Mark Odland, Johnson's transplant surgeon at HCMC. "You have to start looking for alternatives."

Minnesota, which has four transplant centers, could quickly become a national leader in such exchanges because it is by far a leader in the number of kidney transplants using living donors.

"For people with kidney disease, this is the best deal," said Dr. Mikel Prieto, head of Mayo's kidney and pancreas transplant program.

Johnson went on the transplant list two years ago. He had had high blood pressure most of his life, and didn't take care of it soon enough, he said.

When his kidneys failed, he refused to ask either of his two children to be a donor -- it didn't feel right to him, Blomstrand said.

She was willing, but she had the wrong blood type to be a match for her husband.

Then she heard about the kidney exchange program.

Steffens had started a data base of local kidney patients and donors in 2008. But it was only when HCMC merged its pool with a larger list managed by Johns Hopkins University in Baltimore that Blomstrand and Johnson were matched with a pair at the University of Maryland Medical Center.

"The bigger the pool, the bigger the chance of a match," said Prieto.

Johnson was matched with donor Nancy Miller, a 44-year-old crew leader for an electric company. Blomstrand was deemed a match to give a kidney to Miller's partner in the exchange, Cindy Wickesser.

In an interview this week, Miller said she decided to be an altruistic donor -- meaning she would give her kidney to anyone who needed it -- when she found out that Wickesser, the wife of a coworker, was in kidney failure. Cooper, the surgeon, suggested that she pair up with Wickesser in the exchange program.

"I think it's wonderful," Miller said. "Instead of one person getting a kidney, two people get a kidney."

The logistics of such exchanges are daunting. Only now are transplant centers figuring out systems that work.

Until recently, for example, donors often had to have surgery at the same hospital as the recipient, which could mean traveling across the country. That cost, which donors must pay, and the inconvenience, has been a major barrier.

But increasingly the kidneys do the travel -- rather than the donors -- just as they do in the case of transplants using organs from deceased donors.

LifeSource, the organization that manages the deceased donor system in Minnesota, arranged the shipping for Blomstrand's and Miller's kidneys.

As the transplant team at HCMC waited on Thursday, the plane from Baltimore carrying Miller's kidney was only a half hour late.

"This went much smoother and better than I imagined," Odland said. "As soon as the kidney hit the door, everyone was ready to hit the OR."

Of course, transplant centers and surgeons also have to trust that those on the other end will do their jobs.

"We have great faith,'' said Cooper, the surgeon in Maryland. "But we don't know what's going to arrive in the box when it gets here.''

Josephine Marcotty • 612-673-7394