In the first week, both sides were operating without the other: Sierra without access to the local hospital chain for its patients, and Sunrise without 600,000 patients insured by the area's largest health insurer.

Some seriously sick children with heart problems will be sent out of state because access to Sunrise Children's Hospital has been cut off for Sierra customers. But the issue was no more urgent after the contract ended than it was in December, when the sides could not reach a last-minute agreement.

In fact, Sunrise Health still considers side negotiations for access to Children's cardiac program open. This was based on correspondence with Sierra at the end of December, hospital spokeswoman Amy Stevens said.

As for the rest of the hospitals - including Sunrise, Sunrise Children's, Southern Hills and MountainView - officials reported a 25 percent to 30 percent daily reduction in Sierra patients in December.

"And yet our hospitals as a whole are above their average number of patients in hospitals at this time of year," she said. "The other patients, and physicians in particular, have quickly brought their patients to fill these spots."

The trend seems to prove what Sunrise leaders suspected: The hospitals took care of so many Sierra patients, it was hard for doctors to bring in patients insured by other companies.

Sierra has maintained that it has the support of employers and insurance brokers for keeping costs low.

The impasse was over money; generally, Sunrise wanted higher reimbursement rates and Sierra did not want to give them. The companies have had a nearly two-decade contract that sends most of Sierra's patients to Sunrise.

Sunrise Chief Executive Tony Marlon said in Sierra's third-quarter earnings conference call that the company has the support of its clients.

"Could you find a single employer that would be upset with us? Absolutely," Marlon said. "But the majority of employers and brokers are telling us to please hold the line and keep medical costs reasonable around here."

Sierra has been mailing flyers to its patients, explaining that they can visit any of the valley's hospitals except for those owned by Sunrise Health, a subsidiary of Tennessee-based Hospital Corporation of America.

Sierra still covers emergency care at Sunrise hospitals, but it will not pay for non-emergencies like surgeries and births.

There is hope that the issue will be resolved in coming months. After all, HCA hospitals in Florida and Denver earlier this year underwent a similar impasse with insurer UnitedHealthcare.

Two months later, a five-year contract was announced.

"Most doctors I know think this will be worked out in the relatively near future," said Dr. Don Havins, an ophthalmologist and executive director of the Clark County Medical Society.

He added: "There are some who are glad that the contract is going away from Sunrise because they have trouble getting patients into the hospital, it's so crowded with Health Plan of Nevada (Sierra's HMO) patients."

Dr. Ron Kline, a pediatric oncologist, said young patients who he treated at Sunrise Children's will have to make do at some of the valley's other hospitals.

"I think that Sunrise is the best place to take care of really sick children," he said. "Other places like UMC and St. Rose are coming up to speed, but they're not there yet."

Kline is rearranging treatment for some children, but said, "We'll do fine."

He predicted that the contract impasse would continue until one side felt economic pressure, or if the valley's other hospitals could not handle the shift in patients.

So far, it seems too soon to tell.

"The Valley Health System has seen an increase, but it's too early to determine overall volume," said Gretchen Papez, spokeswoman for local hospital chain Valley Health System, which owns four hospitals.