As Philips' subsidiary Philips Respironics continues a sprawling repair and replacement program for 5.5 million breathing machines in the wake of a June 2021 recall mainly due to potential health risks from polyester-based polyurethane (PE-PUR) sound abatement foam, new issues are plaguing some of the repaired devices.
In mid-November, the FDA to the recall that affected certain continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BiPAP) machines and mechanical ventilators, stating that Philips had informed the agency that reworked Philips Respironics Trilogy ventilators have two new potential issues.
First, the silicone sound abatement foam installed in the devices to replace the PE-PUR foam has the potential to separate from plastic backing and could impact the performance of the device by possibly blocking the air inlet, thus lowering inspiratory pressure. If the air pressure is significantly impacted, the device could issue a ventilator alarm, such as the low inspiratory pressure alarm.
Furthermore, trace amounts of particulate matter have been found in the air pathway of some of the reworked ventilators. Preliminary lab results from a third party identified PE-PUR and environmental debris in some samples, and only environmental debris in others.
For Philips, which also last week, the new issues mark a setback for its ongoing repair efforts. As Philips Respironics investigates the issues, it has temporarily suspended the repair of Trilogy 100/200 devices, according to the update.
A spokesperson for Philips provided additional context on the new issues in an email to Ƶ, writing in part that, "It is important to note that this only affects Trilogy 100/200 ventilators (approximately 3% of the registered affected devices globally), which have already been repaired. These problems do not affect any of the CPAP or BiPAP sleep apnea devices that have been remediated."
In its update, Philips said the repair of Trilogy 100/200 ventilators has begun in recent months, and that Philips Respironics detected the two problems with the corrected ventilators "following a limited number of complaints from the U.S. and Japan."
Elaborating on the issue of silicone foam separation, Philips said that, as of November 1, the observed occurrence rate of reportable events was less than 0.015% of corrected Trilogy 100 devices. Based on the latest available information, the root cause was linked to an assembly step in inserting the silicone foam, the company noted.
Additionally, pending an investigation into both of the new issues, Philips Respironics plans to take appropriate action if required.
When it comes to the CPAP and BiPAP machines included in the June 2021 recall, Philips stated in its update that they comprise approximately 95% of the affected devices, adding that the repair and replacement of those devices is "well underway globally."
Specifically, the spokesperson told Ƶ that "more than 4 million replacement devices and repair kits have been produced, of which approximately 2 million have been shipped to the U.S."
Shannon Sullivan, MD, a pediatric sleep medicine specialist at Stanford Medicine and chair of the American Academy of Sleep Medicine's public safety committee, told Ƶ that it's difficult to know where there may still be trouble spots across the U.S. in terms of patients waiting on repaired or replaced sleep apnea devices. However, at her practice, the majority of cases have been mitigated in one way or another, she said.
Many patients' CPAP or BiPAP machines have been repaired or replaced at this point, while other patients have transitioned to a different brand or therapy, she added.
Still, there is the occasional patient who comes into the clinic believing their device isn't affected when it is, she said, noting that she also worries about patients who don't have or haven't been in contact with a sleep medicine physician to discuss mitigation measures.
Last week, the FDA issued another update that included received from August 1 to October 31 that are reportedly associated with the breakdown or suspected breakdown of PE-PUR foam used in the breathing devices included in the recall.
During the most recent period, there were more than 21,000 MDRs received, including 91 reports of deaths.