Philips Respironics provided the latest results and conclusions on the comprehensive test and research program to assess potential health risks related to the polyester-based polyurethane (PE-PUR) sound abatement foam in specific sleep therapy and ventilator devices under the voluntary June 2021 recall notification/field safety notice.
Philips completed the analyses for System One and DreamStation Go sleep therapy devices related to the impact of ozone cleaning on the foam in these devices. The analyses indicate that the volatile organic compounds (VOCs) and particulate matter (PM) emissions related to foam degradation in these devices are within the applicable safety limits and are unlikely to result in appreciable harm to the health of patients.
Additional visual assessments have been performed for used/returned first-generation DreamStation devices that confirmed the previously established low prevalence of significant visual foam degradation/volume reduction in these devices.
The risk assessments had already been completed for the first-generation DreamStation, System One, and DreamStation Go sleep therapy devices (representing approximately 95% of the registered devices globally) that had not been exposed to ozone cleaning in line with the instructions for use. Additionally, tests and analyses had been completed for first-generation DreamStation devices that have been deliberately exposed to multiple cycles of ozone cleaning.
Philips has provided the summary of the PE-PUR test results and analyses available to date to the US Food and Drug Administration (FDA) and other competent authorities. The FDA is still considering the data and analyses that Philips has provided and may reach a different conclusion.
Healthcare providers, patients, and other stakeholders should use the complete July 24 update (including information on the limitations of the testing) for any informed decision-making. Guidance for health care providers and patients using devices that have not been remediated yet remains unchanged.
To date, more than 4.5 million devices have been remediated globally, of which approximately 2.4 million devices are in the US. Patients with any remaining sleep therapy device currently in use that has not been remediated yet and not registered yet are requested to register their product to facilitate the remediation of their devices.
The Impact of Ozone Cleaning on Foam Degradation
Philips Respironics completed testing and analyses on System One sleep therapy devices that have been exposed to ozone cleaning and found:
- Exposure to VOC emissions from the assessed devices treated with ozone cleaning is unlikely to result in appreciable harm to health in patients. ISO 18562-3 VOC testing was conducted after up to 500 ozone cleaning cycles with each cycle simulating one night of use and then ozone cleaning. The VOC toxicological risk of this ozone-induced degradation determined that exposure to VOC emissions from the assessed System One devices exposed to ozone cleaning suggests no appreciable risk to health for patients.
- Exposure to PM emissions from the assessed devices treated with ozone cleaning is unlikely to result in appreciable harm to health in patients. Regarding risks associated with respirable and non-respirable particulates, testing to date has been performed on devices with known ozone exposure. The third-party collective analysis concluded that exposure to particulate matter from ozone-induced degraded foam in System One devices is unlikely to result in appreciable harm to health in patients.
A third-party review concluded that the testing results on the first-generation DreamStation devices and System One devices are applicable to DreamStation Go devices to determine health risks for patients from ozone treatment and foam degradation, based on multiple lines of evidence including, but not limited to, the same intended use, the same operating parameters, the same type of foam, the same foam degradation products, less foam contained within DreamStation Go, and the conservative, protective nature of the testing and risk assessments performed.
Additional visual inspection of the foam in used first-generation DreamStation devices confirms the low prevalence of significant visual foam degradation/volume reduction.
In the US and Canada, an additional analysis using an algorithm to assess collected images of foam within a representative random sample of 100,000 used devices from the US and Canada (devices were selected to represent different manufacture dates) showed that 2,011 devices (approximately 2%) were identified as having significant visual degradation/volume reduction.
A comparison of ozone use among these devices found that devices for which the user self-reported ozone use were approximately 17 times more likely to have significant visual foam degradation/volume reduction (1,368 out of 14,971 or 9.1%) than those where the user reported no ozone use (357 out of 68,702 or 0.5%).
In Europe and Japan, an additional analysis of images from a representative random sample of 152,000 devices from Europe and 241,000 devices from Japan were analyzed by an algorithm to identify significant visual degradation/volume reduction.
A subset of devices from Europe and Japan were identified by the algorithm as potentially having significant visual degradation/volume reduction, and this subset was manually inspected. It was observed that 17 devices of the 152,000 devices (approximately 0.01 %) from Europe and three devices of the 241,000 devices (0.001%) from Japan had significant visual degradation/volume reduction.
Summary of Ongoing Tests
Philips is in the process of completing various remaining tests and analyses. For the Trilogy 100/200 and OmniLab Advanced Plus ventilator devices, VOC and PM testing continues, as well as chemical evaluation and toxicological risk assessment. These devices contain a different type of PE-PUR foam than the first-generation DreamStation devices. Philips expects to provide an update on this in Q3 2023.
Guidance for Healthcare Providers and Patients
Patients currently using an affected sleep therapy device that has not been remediated and not registered yet are requested to register their devices to facilitate the remediation.
Philips continues to advise patients using affected sleep therapy devices that have not been remediated yet to contact their physician or care provider to decide on a suitable treatment for their condition, which may include stopping use of their device, continuing to use their affected device, using another similar device that is not part of the recall, or using alternative treatments for sleep apnea. Moreover, patients are advised to follow Philips’ instructions and recommended cleaning and replacement guidelines for their sleep therapy device and accessories. Ozone and UV light cleaning products are not currently approved cleaning methods for sleep therapy devices or masks and should not be used.
