MountainGoat

I played around with the settings some more last night (at altitude at the moment). I dropped the max pressure to 12 and increased the min pressure to 8, without EPR and with Ramp turned off. I turned off the EPR as that is what the pulmonologist recommended. I also found that the machine ramped too slowly and it felt that I wasn't getting enough air when trying to fall asleep. This may have a lot to do with the oxygen content of the air on the mountain. With those settings, it was uncomfortable to sleep and, because of the back pressure on expiration, woke up with a dry mouth a few times, as I was trying to breathe out through my mouth.

In those few hours, I had 22 clear airway and 4 hypopnea events, resulting in an AHI of 12.13. When I woke up again, I gave up and then set the min to 6 and the max to 10, with an EPR of 3 and left Ramp turned off. This ended up being pretty close to the magic settings. The heated hose and humidifier was set to auto. The resulting AHI for the rest of the night (~3 hours) was 2.89, with most of the events occurring within the first 15 minutes of changing the settings. For the rest of the time I had only two CA events and no obstructive or hypopnea events.

I'm going to leave these settings as is for a few days and see what happens.

The altitude issue is going to be challenging. At the altitude I'm at, the relative oxygen content is about 16% compared to sea level at 21%, so quite a big difference.

I was also considering buying a second machine to leave at home and if a good deal comes up, I will probably do that. I'll keep the settings the same initially and see what happens. This could tell us if the machines do compensate for altitude, which is what the lab tech told me.

I agree with Biguglygremlin that no machine might still be the best option and hope that when I reach my target BMI of 25, I will be able to go without.

As far as real world benefits is concerned, I use a FB Versa and found that my resting heart rate reduced by 5 bpm since starting to use the machine. This is great news as my heart rate normally goes up by up to 10 bpm when I'm at altitude.

The Fitbit app now rates my 'cardio fitness level' as 'average to good', where it used to be 'fair to average'. Don't tell anyone but this machine is a fitness machine too, hehe!

Good to get some real-world feedback. I was also told CPAP will cure T2DM and also laughed it off. The biggest driver for me starting to use CPAP is the polycythaemia, as this is apparently quite dangerous and can cause heart attacks and strokes due to the increased viscosity of the blood.

I couldn't tolerate metformin due to severe gastric symptoms so switched to dapagliflozin. The endo then added liraglutide, which dropped HbA1C it to just above the 'very good control' level. The great side effect of the liraglutide is assisting weight loss and it also appears to have a positive effect on cholesterol and triglycerides, as well as blood pressure. My total cholesterol and LDL is well within limits, despite the elevated triglycerides.

Although I've only used the machine for one night at sea level and two nights at altitude, there is about a threefold increase in CA events at altitude. There's quite a bit of literature on high altitude CA, so I suppose it isn't too unexpected.

I'll post some SleepyHead shots when there is a bit more history. I read your very good explanation on your journey and will probably reduce the pressures to see if the CA events reduce, but altitude may be the enemy here.

Hi All,

A longer introduction below, but I'm interested to know how many people have seen real-world health benefits from CPAP, other than reduced fatigue, that can be objectively measured with blood tests etc.

I was referred for a sleep study as I suffer from type 2 diabetes, hypothyroidism, hypertension, obesity (31 BMI), polycythaemia and elevated haematocrit, high triglycerides and low HDL cholesterol as well as low testosterone. The doctor who referred me felt that the only way all of these can come together is due to OSA and that treating this will resolve a lot of these issues. Therefore my question on how many people have actually seen a positive change in blood test results after 90 plus days of use.

During the sleep study done in May 2017, I was diagnosed with severe obstructive sleep apnea, AHI 31.5. Due to the quality of the sleep study, which by the looks of it from other's comments here are pretty standard, I wasn't convinced that CPAP was really indicated. My reason for this was that the study found only 2.9 events per hour of obstructive apnea when on my back (NREM) and zero for other positions, including during REM sleep, for an average of 1.1 NREM and 0 REM. The hypopnea events though was a lot higher at 31.9 NREM and 26.7 REM. The thing is, I don't sleep on my back and the NREM OA events of 2.9/hr was actually while I was awake, waiting for day to break.

After subsequent visits to an ENT and a pulmonologist, both recommending CPAP, I decided to take the plunge. Interestingly enough, and admittedly after only three nights of use, the machine reflects similar findings to the sleep study with an average of 0.43 obstructive and 0.73 hypopnea events. However, the clear airway events are 4.57 average, pushing the AHI up to 5.73. The sleep study didn't recognise any of the hypopnea events as central apnea but again understand that often happens with sleep studies.

I started using a ResMed AirSense 10 Autoset with N30i nasal mask three nights ago, but have done a lot of reading on machines, masks, OSA etc. before the time and found this forum to be a fantastic resource. We're currently still fine tuning the settings on the machine, so hopefully the central apnea events can be reduced while maintaining the obstructive and hypopnea events at a low level.

What makes life more complicated for me is that I work at an altitude of 2,200 meter (~7,200 foot) above sea level for up to 16 days at a time, with a break of 7 to 10 days at sea level. This also has an effect on my polycythaemia and elevated haematocrit, as the wonderfully adaptable body adjust for the lower level of oxygen by creating more red blood cells.