Massachusetts Gov. Deval Patrick approved a record $9.6 billion last July for the state?s health insurance program for the poor ? sufficient, he assumed, to last a year. But the program?s costs quickly outpaced expectations, forcing the governor to approve an additional $329 million in October and then seek $258 million more, which lawmakers approved last week. And even that may not last, with six months remaining in the budget year. The ballooning cost of Medicaid is one of the biggest challenges facing Massachusetts and other states, which have seen demand for the program jump during the recession as increasing numbers of unemployed residents enroll in the subsidized insurance plan.