(CNN) When Donna Hernandez had the flu last year, she went to her local emergency room in New Mexico, where she received two IV bags of saline, a dose of antiviral medication and a drug to help with her nausea.

She says after about two and a half hours, she was on her way.

Hernandez recovered from the flu, but still hasn't recovered from the shock of the bill she received afterward. It was for more than $6,000.

She works as a hotel manager, and that's more than 10% of her annual income of $52,000, before taxes.

She knew that if she didn't pay her bill, Carlsbad Medical Center might sue her. And then, as part of the lawsuit, they might garnish her wages or put a lien on her house.

Donna Hernandez, manager of the Trinity Hotel in Carlsbad, New Mexico, was sued by Carlsbad Medical Center after she couldn't pay her hospital bill.

The hospital says it sues less than 1% of its patients. But Hernandez knows other patients at the hospital who've had it happen to them.

She knows Victoria Piña, a teacher's aide in nearby Loving, who had her wages garnished and a lien put on her home because of emergency room visits to fix her dislocated shoulder -- and she has insurance.

She knows Misti Price. Her three children have had visits to the emergency room to treat asthma attacks and injuries. Carlsbad Medical Center has sued her five times -- and she also has insurance.

Hernandez hears their stories, and she's terrified.

"It's really scary," she said. "Are they going to do this to me next?"

Hernandez doesn't have insurance, but even Americans with insurance are finding that an ER visit can turn into a financial nightmare.

That's because of two trends happening at the same time: Hospital prices are on the rise, and so is the use of high-deductible insurance policies. Some insurance plans have deductibles as high as $7,900, according to HealthPocket , a plan comparison website. That means patients have to pay that amount before insurance kicks in.

Dr. Marty Makary, a surgeon at Johns Hopkins Medicine, wrote a new book, " The Price We Pay ." It has a whole chapter about Carlsbad Medical Center.

Carlsbad Medical Center, in the Pecos Valley in southeastern New Mexico, is the only hospital in town. The next closest hospital is about a 40-minute drive away.

Makary says patients in Carlsbad suffer from those two national trends and then an extra double whammy.

First, Carlsbad Medical Center is the only hospital within about a 40-minute radius, so in an emergency, patients don't have a choice about where to go.

"They've got a very cornered market," said Misti's husband, AJ Price, who was also sued by Carlsbad Medical Center four years ago after receiving treatment in the emergency room for a dislocated shoulder. "They are going to get every case, every injury, every accident [and] I think they prey on that -- you're going to pay our price and sorry about your bad luck, you can't do anything about it."

Second, when patients don't pay, Carlsbad Medical Center is particularly aggressive about collecting those debts in comparison to other hospitals in its area, suing thousands of people over the past decade.

The hospital says it only sues people as a "last resort."

"Doctors and hospitals should be paid fairly. I firmly believe that," said Makary, a surgical oncologist and professor at Johns Hopkins University School of Medicine and the Johns Hopkins Bloomberg School of Public Health. "But oftentimes these patients are being shaken down with the most aggressive and predatory practices we've ever seen in the history of medicine."

Carlsbad Medical Center is owned by a large national hospital chain, Community Health Systems Inc., headquartered in Franklin, Tennessee. Officials there declined to speak on the record with CNN for this story. The hospital sent CNN a written statement from its CEO, Cathy Hibbs.

"Absolutely no patient pays the full price of our services. We provide charity care for anyone who qualifies and substantial discounts for everyone else," Hibbs wrote. "[For] those who struggle to pay their hospital bills, we offer additional discounts and reasonable, extremely low payment plans."

She also noted that "high deductible insurance plans have created a seismic shift in the healthcare industry" where "patients are left to pay a much greater portion of their hospital bill."

'Mystery prices'

As Hernandez, the hotel manager, has struggled to pay her hospital bills, she asks herself: How could less than three hours in the emergency room cost more than $6,000? There were no surgical procedures, no fancy, expensive drugs. What exactly was she charged for?

She said she's repeatedly asked the hospital for an itemized bill and never received one. Several other patients interviewed by CNN said the same thing happened to them.

"These are mystery prices," Hernandez said. "I have no way of knowing what they're charging me for."

Hibbs, the hospital CEO, said in her statement that the hospital provides itemized bills "when requested."

"In 2018, we received and fulfilled approximately 120 patient requests for itemized bills," she wrote. "Because hospital bills can be complex and difficult to understand, we are always happy to explain charges directly to our patients."

More than 3,000 lawsuits in 10 years

A CNN review of court records shows the hospital has sued more than 3,000 people to collect debts over the past 10 years.

Hibbs, the hospital CEO, declined to say how many patients the hospital has sued over the past decade but said the hospital sues less than 1% of its patients. She also declined to say how often the hospital garnishes patients' wages or put liens on their homes.

Several other area hospitals don't sue patients when they owe money, according to CNN's review of New Mexico court records.

In the past 10 years, three area hospitals -- Artesia General Hospital, Nor-Lea Hospital District in Lovington, and Lincoln County Medical Center in Ruidoso -- have not sued patients to collect debts.

"We sue less than one percent of the patients who receive care at our hospital," Hibbs, the Carlsbad CEO wrote in her statement to CNN. "Litigation is always the last resort when our hospital attempts to collect what it is owed for the services we provide. Before initiating a collection suit against anyone, we make multiple attempts -- usually trying to contact our patients ten to twelve times -- to offer manageable payment plans and additional discounts off of already discounted charges. In many cases, patients do not respond to our calls or letters."

New policies at Carlsbad Medical Center

Carlsbad Medical Center said it would no longer sue some patients, including those who earn less than 150% of the federal poverty level.

After CNN and The New York Times reached out to Carlsbad Medical Center, the hospital announced a new policy.

The hospital will no longer sue patients who earn below 150% of the federal poverty level, Hibbs wrote to CNN. That means, for example, it won't sue an individual who makes less than about $19,000, or a family of four with a household income of less than $39,000.

The hospital will also release current court judgments against patients who can prove their income is below these levels, Hibbs added.

If a patient is uninsured, the hospital will reduce bills to "roughly the equivalent of the reimbursement the hospital receives for Medicaid patients," Hibbs wrote.

These policy changes are "part of our continuing efforts to make healthcare more affordable in our community," according to her statement. "Through these efforts, we reaffirm our desire to be a part of a larger solution -- and we call on others to join us in efforts to make healthcare more affordable and accessible."

Melissa Suggs, a hospital spokeswoman, said the hospital was "already in the process of evaluating our charity care policies at the hospital relative to our low-income patients" when CNN made its inquiry.

'These are baby steps'

Makary, the author of "The Price We Pay," said while he welcomed the hospital's new policies, they seemed more like PR moves than substantial changes.

"These are baby steps in the direction of how they should respond, which is to stop suing patients," he said.

He said most of the patients he's met in Carlsbad who've been sued by the hospital do have jobs and make more than the income levels set by the hospital. But their incomes aren't high -- they're nurses, teachers, hotel managers, waitresses -- and a bill of a few thousand dollars can be devastating.

He added that garnishing wages is not particularly lucrative for hospitals. His Virginia study found that the mean amount garnished per hospital in 2017 was $722,342, or on average just 0.1% of a hospital's gross revenue.

Hospitals that don't garnish wages have found much more effective ways to make money, Makary said, such as managing the hospital well so there's as little waste as possible.

He said he hopes Carlsbad Medical Center will eventually come to the same conclusion as Mary Washington Hospital in Virginia.

Soon after the media articles appeared, Mary Washington Healthcare , announced it had "reflected on our payment processes" and would "suspend the practice of pursuing legal action for unpaid bills."

The response on social media was swift and bitter.

"How many lives and families did you ruin before you were shamed into this?" one user wrote on Twitter.

"You did irreparable damage to my credit when I was 22 years old and had a miscarriage," a woman wrote on Facebook.

A spokesperson for Mary Washington Healthcare said the hospital "pursued legal action on a couple thousand patients per year," which represents less than half of 1% of the 500,000 patients cared for each year at the hospital. He added that the hospital works hard to get in touch with patients who owe them money to try to make payment arrangements or arrange for free care if the patient qualifies.

"Before we get to the point of litigation, the patient has ignored eight to ten attempts at contacting them to work out some kind of payment arrangement or qualify them for charity care," said the spokesperson, Eric Fletcher. "Not for profit hospitals have a responsibility first and foremost to care for people without regard to their ability to pay, and we do that. We also have a responsibility to be a sustainable institution for our community, and to do that we have to be able to collect from patients who can pay."

Hernandez, the hotel manager in New Mexico, understands the anger of the patients in Virginia.

Carlsbad Medical Center has filed a lawsuit against her, and she's been desperately talking to their lawyers, hoping to convince them not to garnish her wages or put a lien on her house.

She was relieved when they cut the debt in half to a little over $3,000.

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Hernandez relived her fear and anger all over again when she received a legal notice at work a few months ago ordering her to garnish the wages of a waitress at the hotel who owed money to Carlsbad Medical Center.

"There was nothing I could do to stop it or help her, and she's a single mother with three little boys," Hernandez said. "What they're doing to her is terrible."

She worries that if one of those little boys needs to go to the emergency room, the waitress might hesitate to take them.

"It makes me mad. It angers me that [the hospital] would take advantage of people that are in a situation where they need medical care," she said. "Do you forego medical care because you can't afford the bill? What do you choose first? Your health, or a medical bill that you may not be able to pay down the road?"