Shields, like millions of Americans, has sleep apnea, which causes short pauses in breathing, raising the risk of heart disease, stroke, high blood pressure and an irregular heartbeat. Devices called continuous positive airway pressure, or CPAP, machines are the recommended treatment. The small bedside units pump a steady stream of air through a hose and face mask to ensure uninterrupted breathing during sleep.

Today, those machines are at the heart of one of the biggest medical device debacles in decades. In June 2021, the Dutch health-care conglomerate Royal Philips announced that millions of CPAP machines and mechanical ventilators had a hidden flaw: The foam used to reduce the noise of the motor could disintegrate, releasing debris and chemicals into the air hoses.

If inhaled or swallowed, the emissions could cause headaches, asthma, lung problems and even cancer, the company warned in launching a massive recall. The Food and Drug Administration classified the recall as the most serious type, saying “use of these devices may cause serious injuries or deaths.”

But as the voluntary recall enters its second year, the pace is excruciatingly slow. Philips says it has repaired or replaced about 1.7 million of 2.8 million affected devices in the United States and about half of 5.5 million machines around the world. The recall, originally scheduled to be completed this fall, will stretch into next year.

That leaves millions of patients in the lurch, many of whom are railing against Philips on social media and flooding the inboxes of FDA officials with complaints. Attorneys are trolling for clients on television and Twitter, with lawsuits against the company proliferating.

“This is dangerous, you stop breathing, that’s why you are using it,” said Christine Hinckley, who lives in Prospect, Conn. “Someone needs to do something. Months go by and you hear nothing. Nothing.”

The FDA, usually tight-lipped about companies, has taken an aggressive stance with Philips, accusing the company of being too slow in notifying consumers about machines that the agency suggests were defective from the outset.

In May, the FDA announced it had received 21,000 reports, including 124 deaths, concerning the breakdown of the polyester-based polyurethane foam in sleep apnea machines and ventilators during the past year — a sharp increase from 30 the previous decade. The agency said the reports, by Philips and others, do not prove that foam deterioration caused injuries. The FDA also said there was evidence some company officials knew about problems as early as 2015 — six years before the FDA was notified.

Now, the agency is threatening to take the unprecedented step of requiring Philips to submit a detailed plan to repair or replace the devices or refund the cost so consumers can buy their own or be reimbursed if they have already done so.

Philips, in a statement to The Washington Post, denied dragging its feet in notifying the FDA and consumers. Spokesman Steve Klink acknowledged that Philips Respironics, the subsidiary that made the machines, handled occasional foam problems on a “case-by-case” basis in years past but said that when Philips’s executive committee became aware of the issue in early 2021, “we took adequate actions leading to the voluntary recall notification.”

Today, patients who have not received replacement machines face difficult decisions. Some continue to use the recalled devices, most of which are DreamStation 1 CPAPs, saying it is the only way to avoid pounding headaches or nodding off during the day. Others have stopped treatment altogether, raising the risk of health problems. Still others have bought new machines, which can cost $1,000 or more, or tried changing sleeping positions or losing weight to deal with their sleep apnea.

“Patients are stuck between a rock and a hard place,” said Vinay Rathi, an otolaryngologist and health policy researcher at Massachusetts Eye and Ear.

Josh Alba, a 32-year-old utility worker and stand-up comedian, was desperate when his doctor told him to stop using the Philips CPAP machine.

“Hello, I can’t breathe when I sleep, can you help me?” he said he told operators at the Philips call center. When the Brooklyn resident received a replacement machine, key parts were missing. He was finally bailed out by a “kind man in Queens” who gave him an old device made by a different company, he said.

To medical device experts, the problems with the Philips recall partly reflect weaknesses in the FDA’s oversight of the sprawling industry.

The episode “is unfortunately a sterling example of a lot of the problems with medical device safety,” said Sanket Dhruva, assistant clinical professor at the University of California at San Francisco. “There are lots of safety concerns that are being missed or being identified too late. This has been a saga for a period of years. And it shows that even knowing about a recall and having a fix in place is not always a solution.”

Philips acknowledges it has faced supply chain and other production challenges in trying to handle the recall. Usually, the company makes 1 million sleep apnea machines and ventilators a year; now, it is trying to crank out many more than that.

“The supply and logistics environment is going to remain a daily battle because the world is so unpredictable, and we see covid rising again, unfortunately,” Roy Jakobs, chief business leader for Philips’s Connected Care unit, told the trade publication MedTech Dive.

Nearly 30 million U.S. adults endure sleep apnea, with many remaining undiagnosed, according to the American Academy of Sleep Medicine, whose members are sleep specialists. The most common type, obstructive sleep apnea, occurs when muscles in the back of the throat relax, closing or narrowing the airway and causing snoring, gasping and choking, according to the Mayo Clinic.

Lower oxygen levels in the blood increase the risk of high blood pressure, recurrent heart attacks and strokes. People who are overweight or older than 50 are more likely to have sleep apnea.

Three years ago, Deb Miller, a retired schoolteacher, was driving past a Marietta, Ga., landmark — a 56-foot-tall metal bird called the Big Chicken — when she passed out and crashed into oncoming cars. She woke to the screams of her 4-year-old granddaughter in the back seat.

During a subsequent sleep study, a technician rushed in saying, “You have the worst sleep apnea we have ever seen. How do you even function?”

“Diet Coke, I guess,” Miller replied.

When Miller began using a Philips DreamStation, she immediately felt more energetic: “It was life-changing.” When she heard about the recall, she stopped using the device and became achy and exhausted. After months of waiting for a replacement, she finally paid $900 for a device made by another company, she said.

But many people cannot afford a new machine or find one. Many insurers, including Medicare, cover new devices every five years — their expected life span. But they typically don’t pay to replace newer machines, even if they have been recalled.

‘Why can’t Philips find me?’

After Shields heard about the CPAP recall, the Wilmington, Del., resident stopped using the Philips machine, and the black spots in her phlegm disappeared.

But she soon developed other problems: bouts of dizziness and sometimes feeling that her heart was racing. She was worried her atrial fibrillation — an abnormal heart beat that can be triggered by sleep apnea — had recurred. While her doctor said that wasn’t the case, Shields was unnerved enough to get a machine from another manufacturer.

Shields said she was infuriated by a lack of information from Philips. “If Honda … can track me down and tell me to replace my air bags, why can’t Philips find me?” she said.

When Philips announced the recall, it urged consumers to register so they could be sent replacement machines with different foam. But after the FDA complained that the notification efforts were insufficient, Philips began to run ads about the recall online, in newspapers and in doctor offices.

In the last several months, Philips has walked back its earlier draconian assessment of health problems linked to the machines, saying the devices passed new safety tests by independent laboratories. The machines showed “a very low prevalence of visible foam degradation” and passed testing on the release of gases and particulates, Frans van Houten, chief executive of Royal Philips, said in June. “This is very encouraging.”

The original, alarming notice was based on an “initial, limited data set … and assumed a worst-case scenario for the possible health risks,” the company said. Philips also has pointed to an independent study that did not find a higher risk of cancer among people with sleep apnea who used the firm’s CPAP device compared with those who used other companies’ machines or did not receive treatment.

The FDA has expressed skepticism about Philips’s test results, saying in May that certain data were “not persuasive” and rejecting the company’s argument that use of unapproved ozone cleaners is a main culprit. The agency has suggested the machines were not made properly in the first place. The FDA told The Post that many tests “are still outstanding” and that recommendations by the agency and Philips about the devices have not changed.

The sweeping recall has spurred calls for improved FDA safety surveillance, which the agency itself has sought. Last year, the FDA proposed spending millions of dollars in industry medical device user fees to improve oversight of an array of medical machines on the market.

Industry representatives balked, arguing the FDA should use the fees to speed up approvals slowed down by the pandemic — not to check on devices already on the market, according to meetings between the FDA and industry officials posted on the agency website.

The FDA dropped the plan, saying it was “disappointed.”

Scott Whitaker, president of AdvaMed, a trade group for medical technology companies, said the user-fee program was designed to help pay for FDA work involving device approval, not monitoring their safety afterward. If the agency wants to beef up post-approval surveillance, it should use its funding from Congress, he said.

Dhruva, of UCSF, sees parallels between the infant formula crisis and the Philips problem. In both cases, he said, the FDA lacks the staff and resources needed to monitor companies to ensure “the successful and timely resolution of safety concerns.”

Tom Wilson, a retired corporate executive, began using a Philips CPAP device in spring 2018 after being diagnosed with sleep apnea. By that fall, he started coughing excessively and vomiting. In June 2021, when the recall was announced, he stopped using his machine and bought one from ResMed, another big manufacturer. Wilson now runs a Facebook support group on the Philips recall with more than 4,000 members who post about their frustration.

At Wilson’s suggestion, several members have emailed Jeffrey Shuren, director of the FDA’s device center, to complain about the difficulty of getting replacement machines. Wilson said Shuren asked him for permission to forward some of the complaints to Royal Philips’s CEO.

“Many patients and caregivers have reached out to share their concern over Philips Respironics’ response and we share their frustration,” the FDA said, adding it is “engaging with Philips leadership on a regular basis.”

The recall has sparked a tsunami of class action and personal injury lawsuits against Philips. In addition, the Justice Department is investigating Philips Respironics, its parent company announced this year. Royal Philips has set aside more than $900 million to handle expenses related to the recall, a figure that does not include the potential cost of legal action.

Susan Halpin recently posted on the Facebook group that after waiting a year for a replacement machine, she sent an email to Jakobs, the Philips executive, saying: “Shame on you. It is absolutely absurd that I’ve been waiting for a year now for a new machine. When an individual calls your customer service they just say they don’t know. I can’t sleep at night, I’m short of breath.”

She said she got a quick response, asking for more information and soon her replacement was on the way. “Wish I’d been more persistent earlier,” she said.