When Sienna D'Andrea was just two months old, her mother Raquel got the shock of her life.
"The cardiologist said, 'Go home, pack your bags, your daughter needs surgery today.'"
Fortunately, Sienna's emergency heart surgery at a New York hospital was a success. But after the procedure was completed, the family faced another emergency: the medical bills.
"I mean, we couldn't afford this — we knew that there was months and months and months of bills still coming," Raquel recalled in an interview with NBC News correspondent Olivia Sterns.
In total, more than $100,000 in bills were sent to the D'Andreas' home. Many of these bills were total surprises, because the family thought their hospital was in their insurance network.
The family had insurance, but was told it didn't cover everything in the emergency department, and the family had to pay for hospital supplies, assistant surgeons, and X-ray technicians.
"I think it's just deeply unfair to consumers," said Dr. Ashish Jha, a professor of international health at the Harvard School of Public Health. "Hospitals just have to function differently. I think ultimately they should be responsible for making sure everybody's on the same insurance and that customers get one, simple bill."
Consumer advocates point out that this is an all-too-common problem. According to Consumer Reports, nearly one third of Americans who have visited a hospital in the last year have received a surprise medical bill. In Texas, more than 20 percent of hospitals considered in-network by the top 3 insurers had no in-network emergency room doctors on staff.
"Quite honestly, it's better if the providers and the insurance company take it out in the hallway and work it out without putting us in the middle," said Chuck Bell, program director for Consumer's Union, an advocacy group.
Legislation has been passed in New York and Florida that excludes the consumer from surprise medical bills, and requires the insurance company and healthcare provider to work it out when the consumer's surprise out-of-network payment exceeds the deductible covered by the insurance company.
"This new law protects consumers by holding them harmless in times of both emergency situations when choosing a provider is not an option, and in non-emergency situations," says Jeff Atwater, the state of Florida's chief financial officer.
The hospital industry says that insurers should bear the responsibility when it comes to covering enough doctors and clearly identifying who they are. And the insurance industry points its finger at doctors who don't accept enough plans.
"These state-based solutions are helping provide consumers with needed relief, as well as offering an outlet to amicably settle out-of-network bills," said Rick Pollack, president and chief executive of the American Hospital Association.
"Any proposals to address balance billing should address the core issues at hand — lack of transparency and excessive charges billed by certain specialists and doctors who choose to forego participation in health plans' networks," a representative from America's Health Insurance Plans, a trade association that represents health insurance companies, told NBC News.
"Health plans will continue to work with policymakers and providers to advance solutions that protect patients."
In the case of baby Sienna, her mother and grandmother stepped in to help shoulder the hefty bills. Sienna's grandmother quit her job to work on negotiating the medical bills directly with the hospital, and was able to talk them down from $100,000 to just $10,000.
As for Sienna, she's now a thriving three-year-old, and her mother has a very different set of worries.
"I worry about her getting hurt because she's so active!" her mom said.