Knocking Noise

General Discussion on any topic relating to CPAP and/or Sleep Apnea.

Knocking Noise

Post by roxieatheart » Sun Jun 14, 2009 3:47 am

Tonight I woke up with a knocking noise coming from my mask. I've not had this before. Has anyone else experienced this? It's now 2:42 am and I can't get back to sleep without wearing it.

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Re: Knocking Noise

Post by hummer3d » Sun Jun 14, 2009 5:59 am

What mask are you using? I had my mask pulsate a few times due to leaks .

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Re: Knocking Noise

Post by plr66 » Sun Jun 14, 2009 7:39 am

Hmm. Not sure of a "knocking noise," but if it sounds like a rattle, it is probably what we call rainout. This is condensation in your hose or mask, and can/should be eliminated by a variety of methods. Try lowering or even turning your humidity setting to zero if you use a heated humidifier. And depending upon what mask you use and how the hose is routed, you can either keep the hose under the covers or use a hose cover (made of fleece or old socks or sleeves from old flannel shirts, etc) to prevent cooler night air from hitting the warmer air you're breathing through the hose--which is what causes the condensation. Some people use hose hangers above the headboard or side of the bed. There are hundreds of posts on this subject that you can find by typing "rainout" into the Search box at the top left of this page.
DeVilbiss IntelliPap Std Plus with Smartflex; Transcend miniCPAP & Everest2 w/humidifier & batt for travel. UltraMirage FFM; PadACheeks; PaPillow. Using straight CPAP at 13.0/passover humidifier. AHI consistently < 1.5. Began CPAP 9/4/08.


Re: Knocking Noise

Post by roxieatheart » Sun Jun 14, 2009 8:15 am

Yes, the "rainout" makes sense as when I came back to bed my mask had alot of water in it. I cleaned it up and it wasn't there anymore. You've given me good ideas, thanks.

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Re: Knocking Noise

Post by El Pap » Sun Jun 14, 2009 10:28 am

I've only had "knocking" after experiencing ridiculous amounts of rainout - at a hotel where un-pointable A/C vents were dousing the hose with cold air. The "knocking" was actually cause by water pooling at the low point of the hose, which literally blocked the airflow.