Philips testing finds minimal risk of patient harm in some recalled CPAP and BiPAP machines

Nearly two years after Philips first publicly raised concerns about the potential breakdown of the polyester-based polyurethane foam found in many of its CPAP and BiPAP machines and other respiratory devices, the company has wrapped up safety tests of some of its machines.

The results, which Philips published (PDF) Wednesday—and which focused only on the first generation of its DreamStation devices, making up about two-thirds of the 5.5 million recalled products—suggest that the disintegrating foam is linked to minimal health risks, the company said. The FDA recently tallied over 250 deaths among people affected by the recall but has not linked them directly to the devices.

“We now have a better understanding of the potential health risks compared to the limited insights that we had in early 2021,” CEO Roy Jakobs said in the release. “I would like to stress that we are very sorry that it has taken this much time, but the testing involved long throughput times and needed to be done thoroughly.”

Jakobs added, “We deeply regret the concern and uncertainty felt by patients, their physicians and customers, and continue to work hard to address their needs.”

Philips conducted the research alongside five independent testing labs—with the results reviewed by Philips, experts from outside the company and a panel of external medical experts. It focused on DreamStation devices that hadn’t been exposed to ozone-based cleaners, which Philips has suggested may speed up the foam’s disintegration.

One set of tests looked at the particulate matter emissions that came from degraded foam in the devices. It examined a total of 181 DreamStation devices, spanning a range of degradation levels—including new, used and lab-aged machines.

All of the tested devices were found to be compliant with maximum emissions levels set by the International Organization for Standardization (ISO). The testing also concluded that the particulate matter emissions from degraded foam “were not statistically different” than those from foam inserts that had yet to break down, according to Philips. Finally, in biocompatibility testing, the particles that came from degraded foam were found to be “unlikely to result in an appreciable harm to health in patients”—even if a user was exposed to a maximum amount of the degraded foam in their device.

The testing program also looked at the volatile organic compounds (VOCs) emitted as the foam breaks down. In toxicological risk assessments of a similar combination of new, used and lab-aged devices, the scientists concluded that the detected VOCs showed “no appreciable harm to health.” Exposure to the compounds is, therefore, “not anticipated to result in long-term health consequences for patients,” Philips reported.

Though the study results are promising for Philips, Steve Klink, a company VP and head of its global press office, said during a call with reporters on Wednesday that both testing and the recall program will continue.

“We have still established that the foam can degrade,” he said. “If foam degradation occurs, then there is no appreciable harm to patients. Nevertheless, the foam can degrade, so we will continue with the remediation program. We will continue to repair and replace each of the 5.5 million devices that are out there.”

The company has submitted the findings to the FDA and other relevant authorities for final sign-off. In the meantime, it’s conducting similar testing on other devices affected by the recall, including the SystemOne and DreamStation Go machines—which use the same polyurethane foam at the first-gen DreamStation devices—and the Trilogy 100/200 and OmniLab Advanced Plus ventilators, which contain a different type of polyester-based polyurethane foam.

According to Philips, while the Trilogy ventilators have so far passed several biocompatibility tests, they failed genotoxicity testing, “and therefore a weight of evidence assessment is ongoing to confirm or exclude potential risks for patients under the expected usage of these devices.”

The findings that the particle emissions in the bulk of the recalled devices pose no serious risk to patients come not long after the FDA updated its tally of recall-related complaints to reach more than 90,000 between April 2021 and October of this year, including 260 reports of patient deaths—though the count comprises reports that haven’t been verified as directly linked to use of the devices.

Philips has yet to find “a direct or indirect correlation” between the complaints and the foam degradation, Jan Kimpen, Philips’ chief medical officer, said during the call Wednesday.

“We do not have any more information on that, but so far, we could not connect any of the complaints to the use of these devices,” he said. “But we take every complaint seriously, and we also are in communication with the FDA and with all the competent authorities on that.”

Kimpen pointed to a pair of studies conducted in Canada and France that found that using Philips’ CPAP and BiPAP devices for obstructive sleep apnea didn’t increase a user’s risk of developing cancer when compared to those who used other companies’ devices or none at all.

Additionally, as Klink added, “We have inspected quite a few devices, and in the subset of 400 devices that were linked to a complaint of alleged degradation, we found that only in 4% of those devices there was in fact degraded foam inside.”

He continued, “So there is quite a bit of work to be done, going through all the various complaints and getting to the bottom of this.”

Skeptical of those findings, however, is the legal team representing the far-reaching class-action case over the recall. In a joint statement from multiple law firms sent to Fierce Medtech, the attorneys labeled the test results “PR spin masquerading as research.”

“Despite their previous acknowledgments to the FDA of how detrimental the foam degradation is, Philips continues to desperately try to downplay the issue and the health risks consumers face as a result,” they said.

“Philips knew as far back as 2015 that the foam it used in the recalled devices would degrade, creating an unreasonable health hazard to patients, but waited until June 2021 to issue a recall or notify health regulators. Today, thousands of patients who put their trust in Philips are suffering from cancer and respiratory illnesses, while millions more are forced to rely on the company’s dangerously defective devices while waiting for a replacement,” the statement concluded. “We look forward to holding Philips fully accountable for its misconduct.”

Alongside the new study results, Philips once again shared the results of its previous examinations of more than 40,000 returned devices. In visual inspections, they were able to spot “significant” visible foam degradation in just 164 of the 36,341 devices returned from the U.S. and Canada, in only one of 2,469 that came in from Europe and in zero of the 1,964 devices returned from Japan.

The company also reiterated the results of ongoing tests of devices that were cleaned with ozone cleaners. So far, the tests suggest that “ozone cleaning exacerbates foam degradation,” according to Philips, but the FDA has previously warned the company against blaming the entire recall—and the many reports of adverse events that it has sparked—on the cleaners.

“Although the use of ozone cleaners by device users may have exacerbated degradation of the PE-PUR foam, evidence indicates that the unreasonable risk associated with the products was not caused by the use of ozone cleaning agents, nor did the use of ozone to clean the products constitute a failure to exercise due care,” the agency wrote in a May letter to Philips.