New CPAP user

[Ron AKA]

My sleep pulmonologist wants me to continue using CPAP at 4cm cpap mode until I can easily sleep with the machine.  Its day 10 and I am still having difficulty going to sleep, waking up and having a hard time getting back to sleep.  Tonight I am going to change the settings to 4-7 apap with 3 epr.   

If your issue is going to sleep at bedtime or when you wake up I think your problem is letting the machine take pressure down to 4 cm. For most people that is too low a pressure to be comfortable, relax, and go to sleep. I would suggest a slightly different setting. It might also help bring your O2 levels up. 

Stay in the CPAP fixed pressure mode, and try some fixed pressure settings in the range of 4 cm, 6 cm, 7 cm, while you are awake. Leave the EPR at 3 cm. Try to determine what is comfortable to you. It should feel virtually effortless to breath in and out, like the mask is not there. I am guessing it will be around 6 cm, but it depends on the mask and the person. So, try for yourself.

Assuming 6 cm is the comfort setting, then I would suggest staying in the CPAP fixed pressure mode for now. Set the pressure at 7 cm. Turn on the Auto Ramp feature. This will allow you to set a Ramp Start pressure. Set that at your comfort setting of 6 cm. Leave EPR on and set at 3 cm. 

This combination of settings should provide you with the most comfort while you are awake, and 1 cm higher pressure while you are asleep and similar comfort. There could be some small increases in O2 levels. This should help you sleep easily with the machine compared to where it is set now.

[Ron AKA]

Oh, I should have mentioned that if you change the machine to 4-7 APAP with EPR at 3 cm, it probably is not going to change how it operates one bit. Based on your lack of events I suspect it would still sit at the uncomfortable 4 cm level all night. EPR will not do anything as it cannot reduce pressure below 4 cm.

[Walla Walla]

Ron, Good catch. What the settings should be is 7cm minimum pressure with 3cm EPR. This will give more air pressure on the inhale and make it easier to exhale. Since the minimum pressure is 4cm you can't get 3cm EPR without setting the minimum pressure to 7cm.

[mountainbird]

Good morning,

Last night I raised the cpap pressure to 5 and set the epr to 1.  I found it less comfortable than at 4 cm.  My AHI was the highest I have had at 0.91 but still quite low.  The CAs and REs all occurred as I was transitioning in and out of short bouts of REM sleep.  My leak rate was much higher but still under 24.

My overnight oximetry was slightly worse than the previous night but probably not significantly worse.  

Events/hour went from 3.3 to 6.9,  basal oxygen 90.7 to 89.9, % time under 90% 11.7 to 34.3%.  

My diagnosis from the sleep study is mild OSA, severe during REM sleep.  I think the diagnosis is an artifact of taking Benadryl to sleep and experiencing respiratory depression from the Benadryl.  I think hypoventilation is the problem.  My sleep pulmonologist keeps saying to get used to sleeping with cpap.

Should I increase the pressure more?

Thanks

[Sleeprider]

As you can see, your tidal volume is unchanged from previous results at 260 mL, as well as minute vent at 3.6 L/min. The increase in AHI is not significant at .91 vs .71. Your comfort is important, and a good bit of the challenge is to maintain that while improving your respiration. For hypoventilation, we really want to see higher end expiratory pressure and better tidal volume which can be achieve through a larger difference between the inhale and exhale pressure. However, since you are pressure sensitive, I think the best solution for you may be supplemental oxygen added to a bleed port on the CPAP tube. This would resolve your apparent hypoxemia, and could be done at the minimum pressure you find more comfortable. The low pressure apparently resolves your obstructive apnea and hypopnea issues very well, but you continue to have fairly low SpO2.

I think the best approach in this case is not for us on the forum to attempt to modify your therapy through pressure, but to refer you back to your physician for consideration for supplemental oxygen. Using CPAP to resolve obstruction, and oxygen for hypoxemia appears to be the most comfortable and viable solution for you. I think if we attempt to achieve better ventilation and oxygenation through pressure, you would find that uncomfortable; and frankly the forum is not the best place to get that kind of advise. Please talk to your doctor about supplemental oxygen to go with your CPAP.

[Ron AKA]

I think sleeprider has given you good advice. About the only thing I would add is that the main component of your apnea is central events. CPAP can actually increase the frequency of them in the initial treatment. Statistics show that in about 6% of those who start CPAP will experience an increase in the frequency of CA events. After about 6-8 weeks the frequency will reduce in about 75% of those cases. What I am saying is that if you continue with CPAP use, the CA component most likely will go down slowly over time.

[mountainbird]

After being on CPAP for 2.5 weeks at 4 cm pressure and experiencing severe sleep deprivation (lost 7 lbs as I was often unable to eat or drink from nausea).  I have had insomnia since birth and the CPAP  worsened my insomnia.    I finally controlled the small leaks enough to sleep for 6 hours on two nights.  I saw my GP and she said to stop using CPAP as my overnight oximetry readings and my daytime peak flow measures were worsening.  I was loathe to stop as I had made a lot of progress, but I did.  

I had a second in lab sleep study done and today, the office administrator called to say my AHI was 1 and my apnea score during REM sleep was normal.  I have not seen the sleep study yet.  In September I had a sleep study done with an AHI of 9.7 and a score of 99+ during 12 minutes of REM sleep.  I took the standard dose of Benadryl for  the first test and did not take any sleep aid for the second test.  I may have had the rare false positive test.  Both my sister and I have extreme reactions to anesthesia and sedation.  I have been advised to never have any procedures done that require anesthesia or sedation and had to have an unmedicated high forceps delivery when my second child became stuck during delivery.  I did not realize that this warning extended to antihistamines.  I had pharmocogenetic testing done and I am wild type for the enzymes that metabolize the sedatives I have had problems with.  So it is not a mutation in liver enzymes.  

 My GP is concerned I have chronic nocturnal hypoventilation as my oximetry baseline SpO2 values range from 89 to 91% each night while daytime readings are 96%.  A daytime ABG showed normal oxygen and CO2 levels but metabolic alkalosis.  I will be having an early morning ABG this week.   My chest xray is normal.  I will be having an exercise stress test next week.  I will also be seeing the local sleep physician in two weeks. 

The sleep pulmonologist  who strongly recommended CPAP based on my first sleep study finally returned my calls after 3 weeks of daily messages to him.  He said he had not looked at any of my data and advised me to keep trying to sleep with the CPAP.   I'd rather work with my GP to figure out what is going on.  

I may be returning to pap therapy to treat hypoventilation but I don't think CPAP is the appropriate machine for that.

[Walla Walla]

It sounds like your GP has a better grasp of whats going on than your pulmonologist. Or should I say Ex-pulmonologist?