EVIDENCE OF AIRFIT P10 VENT OBSTRUCTION CAUSING HYPERCAPNIA

[mdmarmd]

Mine's Oil Free

[mdmarmd]

Sorry, I meant to add that I never actually recommended that anyone try to use their air compressor to clean their P10, only that was one of the early attempts I made to try and dislodge the deeper, residual dust that remained after the warm, soapy wash.

[AlanE]

I can concur that this happens in the P10. I've been using it for years and never had rainout or saturated vents. Enter a new DME. They "mistakenly" gave me a climateline hose instead of the standard. It was shipped to my house so I wasn't going to return it. I figured I'll try it. What the hey, I'm a team player, right? With the A10 set to comfort control auto I had constant rainout and vent saturation. After a couple of weeks of trying to make it work it was "outta here-uh".  Much like the photo that DaveResmedP10 posted.

Still using the P10 but I'm back to selecting my own temperature and using a standard hose again. Not so much as a drop in the mask/hose now. Defective A10? Maybe... the climate algorithms should have adjusted for a temperature swing but didn't.

[vroomvroom]

I can concur that this happens in the P10. I've been using it for years and never had rainout or saturated vents. Enter a new DME. They "mistakenly" gave me a climateline hose instead of the standard. It was shipped to my house so I wasn't going to return it. I figured I'll try it. What the hey, I'm a team player, right? With the A10 set to comfort control auto I had constant rainout and vent saturation. After a couple of weeks of trying to make it work it was "outta here-uh".  Much like the photo that DaveResmedP10 posted.

Still using the P10 but I'm back to selecting my own temperature and using a standard hose again. Not so much as a drop in the mask/hose now. Defective A10? Maybe... the climate algorithms should have adjusted for a temperature swing but didn't.

Pardon my ignorance, but isn't the Climateline their "better" hose with more features? Wouldn't one want that over the standard hose? Worst case, you can always disable whatever features the Climateline hose comes with and use it as the normal one, no?

[Crimson Nape]

Pardon my ignorance, but isn't the Climateline their "better" hose with more features? Wouldn't one want that over the standard hose? Worst case, you can always disable whatever features the Climateline hose comes with and use it as the normal one, no?

You could turn off the humidifier or even remove the tub, but then your are left with a heavy hose for no good reason. A regular slimline hose would achieve the same purpose while being lighter and less expensive.

[vroomvroom]

Pardon my ignorance, but isn't the Climateline their "better" hose with more features? Wouldn't one want that over the standard hose? Worst case, you can always disable whatever features the Climateline hose comes with and use it as the normal one, no?

You could turn off the humidifier or even remove the tub, but then your are left with a heavy hose for no good reason.  A regular slimline hose would achieve the same purpose while being lighter and less expensive.

Understood, thanks! Having never used a non-Climateline hose (I think that's what they gave me during my CPAP 5 night test), I don't know if I could get a non-CLimateline hose from the DME if my RX says otherwise.

[Sleeprider]

Slimeline tubing on Amazon ranges from $$.24 for generic with Prime shipping to $13.20 with shipping for Resmed brand tubing. I wouldn't lose much sleep worrying about what a DME will do for you given the cost of entry is less than $15.

[mdmarmd]

Note Bene: This post is really only for those that have a greater interest in what these levels of 
CO2 exposure might mean clinically.  Skip it if this stuff is too "granular" for your interest.

I found this commentary by Robert Thomas MD in the Journal of Clinical Sleep Medicine: Carbon Dioxide in Sleep Medicine: The Next Frontier for Measurement, Manipulation, and Research

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4046364/pdf/jcsm.10.5.523.pdf

Some of the points made:

Carbon dioxide (CO2) is the most important regulator of respiration and blood pH. Papers are published with scant new information every so often that largely focus on clinical descriptions of hypercapnic individuals, often obese. While there is intense basic science interest in CO2 sensitive neurons in the brainstem…the science and industry of sleep-breathing medicine has generally neglected CO2. Much of the information on chronic exposure to elevated but low levels of CO2 comes from submarine research, targeting sustained ambient concentrations in the low single digits.4–8 Acute exposure to high concentrations of CO2 results in extreme dyspnea and death

…the data strongly suggest an adverse and partially reversible impact of hypercapnia on brain function in the context of sleep disordered breathing…

…Do we have a relatively silent “hypercapnic dementia” epidemic coming, just a large number of individuals at second gear? Even if CO2 is normal in the day, can we assume that moderate hypercapnic during sleep is harmless? We are largely blind to the degree and severity of hypercapnia in laboratory and home sleep testing. Hypoxia has always taken center stage in “sleep apnea medicine,” and the study of hypoxia biology is highly mature and constantly progressing. CO2 has not lit the same exploratory fires under clinicians and scientists. Why is that so?...

…Is hypercapnia on treatment as acceptable as hypercapnia before treatment? Do we call this treatment-emergent hypercapnia? The majority of sleep laboratories do not have the technology (and thus not even the technical expertise) to manipulate CO2. How do bilevel ventilators and the new volume target ventilators specifically designed for hypoventilation receive FDA approval with no need to measure or track CO2 during use? We would never use supplemental O2 without oximetry assessments. The business practice of sleep medicine is a further barrier, with no additional reimbursement for CO2-tracking and manipulation, which surely requires greater expertise, training, and perhaps certification than standard continuous positive airway pressure titrations…

…There is currently little incentive to integrate cheap and accurate CO2 monitoring into routine clinical sleep medicine practice, including follow-up of treatment effects. Transcutaneous and end-tidal measurements should be an integrated part of polysomnography and even perhaps cardiopulmonary monitoring equipment, which will surely drive down the current high costs. Measuring end-tidal CO2 accurately during positive pressure titration is challenging but feasible. An oximeter which can also measure capillary CO2 could cause a paradigm shift in medical practice by exposing this largely hidden pathology. For now, clinical and research sleep teams should consider biting the bullet and absorbing the cost of routine CO2 measurements…

Since he clearly had expertese and an interest in the role of CO2 in sleep disorders, I decided to send my capnographic data to him to see if he would give some input, Like many academic professors, his responses were very short and succinct:
 
Me:                  My crude CO2 sensor recorded sustained hypercapnia over 45,000 ppm in the distal CPAP tube.
                        Anyway, if you are so inclined.  I'd love to get any input you might give me in terms of the clinical 
                        relevance of this data.
 
Dr. Thomas:    Thank you for sharing. If the CPAP mask vents are blocked, CO2 can rise quickly. We routinely block
                        vents and add a WhisperSwivel valve to various masks to introduce dead space in those with central
                        apnea. If the valve is smothered by a blanket, CO2 rises immediately.
 
                        I did read the blog.
                        It is not clear why TcCO2 units are so expensive. Probably just market forces.
 
Me:                  Can you tell me how clinically significant exposure to CO2 at 40,000 ppm for 20-30 minutes is? I just 
                        can't seem to find input on how to put these finding in clinical perspective.
 
Dr. Thomas:     4% CO2?  Uncomfortable, dyspnea, not tolerable for more than several minutes.               
                        We can handle and adapt to 1-2%, but not 4 over short term (long-term, yes, but that is not relevant
                        here)
 
Me:                 Thanks, that give me some perspective. It suggests this is probably not a good process to have
                        recurring night after night.
 
Dr. Thomas      Not good. Maybe the idea if poking some holes is not so outlandish.
 
Me:                  What would you say to a patient using this?
 
Dr. Thomas     A mask with too little venting? Change the mask


It was interesting that he seems to lament that the high cost of CO2 monitoring devices erects an additional barrier to greater CO2 monitoring.  My capnograph cost all of $255.  Of course it wouldn't pass FDA muster, but is it better to have something that works or nothing at all? In-line CO2 monitoring units for anesthesia run around $2000-6000.
 

DIVISION OF SLEEP MEDICINE

HARVARD MEDICAL SCHOOL

Robert J. Thomas, MD

Assistant Professor of Medicine, Harvard Medical School
Physician, Assistant Professor, Pulmonary, Critical Care & Sleep, Department of Medicine, Beth Israel Deaconess Medical Center
Visiting Scientist, Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital

Administrative Title(s)
Sleep Medicine Fellowship Director, Beth Israel Deaconess Medical Center

Research Interests
The central theme of my research is integration of data obtained from diverse physiological measurement tools to better understand sleep and sleepiness. Functional neuroimaging has demonstrated the neurocircuitry vulnerable in sleep apnea, narcolepsy, and following sleep deprivation and fragmentation. Assessment of hypoxia effects relatively free from sleep fragmentation is ongoing. There are strong suggestions that residual symptoms in highly treatment compliant patients with sleep apnea are due to ongoing sleep fragmentation from "complex disease" - chemoreflex mediated or modulated upper airway obstruction. We are developing methods to modulate CO2 to improve management of chemoreflex-driven sleep apnea syndromes.

The development of a ECG-based sleep spectrographic technique has provided profound insights into the nature of sleep that challenges the conventional characterization of sleep (staging, utility of delta power as an assay of sleep homeostatic drive, arousal scoring, respiratory event scoring). Sleep spectrograms are now being applied to rodent models of heart failure to understand the temporal relationships between sleep fragmentation and heart failure. The hereditability of spectrographic phenotyping characteristics is being evaluated.

[ghce]

After reading this thread I couldn't wait to clean my P10 vents, I had noted a reduction in air flow from them in the last month (or more) this was the second time in the last year I have cleaned them, they were really black with dust!

After they dried out i used them that night and it was immediately apparent how much greater the resultant airflow was.
Though it's only been one night the leakage rate was more than double the last few months leakage rates so I would say the CO2 I have been experiencing night after night for the last few months would be very elevated. Pretty scary, it's the things that you don't know that can kill you!

Thank you very much for this independent research, it's a shame that Resmed was not cooperative and it just highlights what their true customer is, dollars.

[mdmarmd]

they were really black with dust!

ghce,

i curious to know the conditions that led to your vents being so dirty?

Usually, they just begin to look a little grey/brown to the naked eye compared to new P10 vents.

Did you use it a really long time? It sounds like you've used them at least for a years time.

Do you change your CPAP filter with some regularity?

Do you live in a very dusty environment?

Anyway, just curious to know what would lead to such visually prominent dust deposits.