Lifesaving doctors at Yale New Haven Hospital say they've completed the largest kidney transplant chain in state history.

Eighteen patients exchanged nine kidneys, according to the hospital's organ transplant team.

In a kidney chain, a humanitarian donor sets off a series of transplants in which family or friends of recipients give a kidney to another person in need -- basically paying donations forward on behalf of a loved one.

The Yale New Haven chain took place over two months, and most of the patients are from Connecticut, including a mother-and-son pair from Bridgeport, a husband and wife from Sandy Hook and another couple from Bethel.

The Bridgeport pair, Cheryl Murphy and her son Cory, were not a match, and he could not donate to treat her stage-four kidney failure. So they entered the organ swap program and Cory matched up with Michael Murphy -- who shares a surname but no relation. Cheryl got a kidney from another patient's loved one.