Despite an 11th-hour plea from the St. John’s Medical Center board of trustees, the Wyoming Senate voted late Thursday afternoon against expanding Medicaid coverage to many of the state’s poorest residents.

The hospital board unanimously passed a resolution at the beginning of its Thursday meeting urging lawmakers to increase coverage of the government insurance plan as called for under the Patient Protection and Affordable Care Act. The board then had a staff member email it to Sen. Leland Christensen, R-Alta.

Christensen, who received the message just before the Senate voted, sided with the hospital, but much of the rest of the Senate did not. The bill failed 22-8.

It may have been the last gasp for statewide Medicaid expansion this legislative session.

Under the Affordable Care Act, commonly called Obamacare, states have the option of increasing coverage to include single, low-income adults. In Wyoming, that works out to about 17,600 more people.

The federal government has said it will pick up nearly all of the additional costs of an expansion.

During the Senate discussion, officials said they were concerned about the federal government’s ability to pay.

The last-minute push from the hospital board came after impassioned speeches from several members during the meeting.

“Teton County has a huge reserve of uninsured individuals — individuals who cannot afford insurance under the current system,” St. John’s board member Dr. Bruce Hayse, a longtime Jackson physician, said before the board voted on the resolution.

Forty-eight percent of Teton County residents within 138 percent of the poverty line did not have coverage in 2010, according to the most recent data from the U.S. Census Bureau. That is the highest rate of uninsured residents of any county in the state. The next closest were Sublette and Crook counties, where 39 percent of poor residents went without coverage.

“I see these people every day in my office,” Hayse said. “This will allow these people to actually have insurance.”

Board vice chairwoman Barbara Herz said Friday she was “horrified” and “disgusted” by the Legislature’s decision. She pointed out that increasing coverage would benefit many of Jackson Hole’s poorest while also saving money for the hospital, the public and the state.

A Wyoming Department of Health study late last year found that the state would save $47 million over six years because it wouldn’t have to spend as much on other health care programs aimed at helping the poor.

“It would encourage more efficient use of health care,” Herz said. “People would come in sooner for problems, instead of ending up with a hugely expensive trip to the [emergency room], which may not even cure you.”

Such costs are often passed down to insured patients or absorbed by the hospital, she said.

Still, Wyoming could opt to expand at a later date. Gov. Matt Mead wants to work with the Legislature over the next year to create an expansion option tailored to Wyoming that could then be proposed to the federal government, Mead spokesman Renny MacKay said.