Lane101 wrote: ↑Sat Jun 26, 2021 1:26 pmJust found this on the ResMed web site. Relevant to this discussion thread. Link at https://www.resmed.com/en-us/other-manu ... call-2021/ .
Have been researching to figure out the safest option in place of my Dream Station APAPs. Looking at all the details below and experience with foam degradation in other manufacturers units (my old GoodKnight unit's foam disintegrated) noted above there is a strong possibility that there is risk with many of the machines out there regardless of manufacturer. Phillips may be the first to "come clean" about these risks because they can more easily absorb the recall costs since they have much higher corporate sales from a broad range of products. Other manufacturers that are more dependent on sleep therapy sales may be more resistant to a recall that could be more damaging to their bottom line.
Per ResMed under Frequently Asked Questions:
"ResMed devices use two foam materials that are different than the foam material Philips says are in its recalled machines. ResMed devices use polyETHER-urethane or silicone foams for sound abatement; Philips has said it uses PolyESTER-based polyurethane for sound abatement. The foams used by ResMed in its devices are safe for patients when following the device’s instructions for use. ResMed devices are not subject to Philips’ recall."
"ResMed’s AirSense 10 device contains foam located within the device airpath to minimize noise produced by the device during therapy. Based on the AirSense 10 device design, air can safely pass around or through the foam during therapy, with the majority of air passing around the foam. We have not observed the issues that Philips is reporting with its devices;"
Note that ResMed states that the foams used are only safe when "following device's instruction for use" - guessing that could imply they are unsafe if an ozone cleaner, that now voids the warranty, is used. Per above post ozone cleaners caused ResMed machines to generate particles. Second statement by ResMed is somewhat contradicted by posts from ResMed users who found particles and ResMeds action of voiding warranties when ozone cleaners are used.
From the Polymer Properties Database at https://polymerdatabase.com/Elastomers/PUR.html :
AU (PolyESTER) & EU (PolyETHER)– polyurethane
"Properties
Cast polyurethanes can be divided into two main classes; polyester (AU) and polyether urethanes (EU). Many polyurethane elastomers are based on diphenylmethane diisocyanate (MDI). These elastomers have outstanding tensile strength, tear and abrasion resistance. They also have good resistance to oxidation, ozone, aliphatic solvents, and petroleum based fuels and oils. The electrical properties, the compression set and the creep properties are only fair and the heat resistance is poor.
The physical properties of polyester urethanes (AU) are somewhat better than those of polyether urethanes (EU); whereas EU elastomers have better chemical resistance and better low temperature flexibility but are more expensive and are sensitive to ultraviolet light. For example, polyesters can be affected by hot water, high humidity and their resistance to acids and alkalis is rather poor. They are also prone to microbiological attack. EU elastomers, on the other hand, have poor resistance to oxidation and heat."
Per this summary it appears that there are material differences between the two foams and one can draw the following possible conclusions:
1) Both have similar resistance to ozone (resistance for both noted as "good") per the above but per user reports and CPAP manufacturer recommendations not enough resistance to prevent problems when ozone cleaners are used
2) The AU used by Phillips is more susceptible to degradation from high humidity, a risk factor noted in the Phillips recall.
3) The EU, that is the type of foam used by ResMed, is noted as having "poor resistance to heat and oxidation". If Phillips, using the more heat resistant AU, notes that heat is a risk factor for foam degradation couldn't machines with the EU foam have an even higher risk of heat induced foam degradation?
4) ResMed appears to be dancing around the fact that it may have some issues in this area.
If anyone has a technical background on the above please chime in. A quick look at silicone foam indicates that it may be much more resilient/safer than polyurethane per foam manufacturers web sites.
Bottom line the above details imply to me that there are risks with air flow going through either of these polyurethane foams. It seems that most of the major manufacturers designed air flow paths that run through some type of foam. Phillips, ResMed, ApexMedical/ZZZPap, old Puritan Bennett GoodKnight 420 units. Devilbiss Intellipap also does this. Perhaps an independent third party needs to further evaluate machine safety in this area and future machine designs should at least isolate any foam behind a more resilient/solid air flow path material?
In my case I happen to also own a 2 year old fixed pressure Intellipap CPAP purchased 6 months before my doctor moved me to APAP. Since either CPAP or APAP works for me I've switched back to the Intellipap until Phillips can repair or replace my Dream Stations based on my doctors advice. Don't plan to buy a Dream Station replacement from another manufacturer given that my Intellipap works and I suspect that the eventual Phillips recall repair/replacement could be safer than any replacement machine I could buy today given the above information. Realize that calculus will be different for others given personal needs/situation.
P.S. I called the Phillips 1-877 number yesterday. Pending regulatory approval they can't provide any additional information on recall next steps and timing beyond registration of our affected machines.
Could it be that Resmed's lawyers decided their statements about Ozone and cleaners is enough to cover any liabilities and Philips' lawyers decided it best to come out on the matter and do the recall? My first Sleep Dr. told me they were dishonest.
