Resmed airfit p10 nasal pillow recurrently becomes obstructed under rain out conditions especially if used long enough to develop sufficient dust deposits within the interstices of the webbed vents that, when combined with condensation within the tubing can lead to complete obstruction of the vents, leading to significantly elevated levels of inhaled co2.Since being diagnosed with obstructive sleep apnea i have used, perhaps 30 different apparatus from nasal pillows to full face masks.I settled on resmed airfit p10 for its comfort, resistance to leakage and quiet venting.But, in 2016 i woke with the abrupt onset of dyspnea and suspected the vents were obstructed and resulted in hypercapnia.I could clearly determine the vents were closed with direct sensory feedback as there was virtually no airflow from the vents.This was during the colder weather and there was observable rain out in the p10 tube.I went on the apnea board forum and found that others were reporting similar concerns.However, the feedback from other forum members tended to question the possibility of this occurring.They didn't believe a high tech medical device company, with large r&d resources would market a product with such a risk due to liability concerns.I decided that the only way to definitively settle this controversy would be to directly measure the intraluminal co2.I acquired the equipment to make a simple capnograph, but unfortunately the software for the co2 sensor was locking up my computer.After six months of being promised it would be fixed, i finally lost interest and moved on to other things.But in the winter of 2018, i decided to renew my efforts as it was the time when condensation was more probable and also a review of the apnea board forum revealed another thread that also was expressing concern about obstructed airfit p10s and the risk for re-breathing and hypercarbia.I proceeded to make capnographs of these events since i could still actually log the co2 vs time data, i just had to close the program manually since it would lock up windows 10 os.My data revealed not only were the vents obstructed, but co2 levels were rising from baseline of around 750ppm (near ambient room levels) to about 40,000 - 45,000ppm.This was of great concern as it made me feel quite sick during and for some time after these events occurred.I have not gotten authoritative input regarding the extent of health risks these levels expose one to.But, i suspect that individuals with co-morbid medical problems such as copd, chf, arrhythmias, obesity, use of respiratory depressant medications or even alcohol, etc., could be at considerably more risk than i am currently.I have included some of the threads from two sleep apnea forums that indicate this problem has been noted by a number of other users over the last several years.I have included the following items to corroborate these concerns: pictures that show the built up of microscopic deposits of dust deep within the mesh of the vents.Multiple graphs that demonstrate how high levels of co2 accumulate within the hose and pillows of the p10.See scanned pages.
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