Hey All,

I'm reaching out regarding some data I've collected via OSCAR since starting treatment with CPAP. As a fair warning, I'm giving a fair amount of detail in hopes that it may promote a greater understanding of my situation:

Relevant Background

My AHI is Very Mild at 6.3 

• I had a PSG on March 27th and it showed hypopnea-dominant events, with more events in occurring during REM.
• While at face value 6.3 is quite mild, I'm not sure it is totally representative of the overall picture. I've tried to illustrate my rationale below.

Overnight Pulse-oximeter Data Aligns with PSG Data

• I collected data prior to my formal PSG using an overnight pulse-oximeter (per second measurement frequency), and this is ultimately what led me to seeking out a formal PSG.
• While the accuracy of the pulse-ox can be debated, the internal accuracy (meaning the device's variability) is probably trustworthy measurement-to-measurement. The pulse-ox generates a report from overnight data that I use to correlate O2 desaturations with an increase in HR and determine likely O2-related arousals.
• It's worth noting that I used the pulse-ox again a few days after my sleep study and found the data it reported mirrored the PSG O2 desats quite closely . While this doesn't prove anything specifically, it does give me more confidence that the pulse-ox is reliable from an oxygen desaturation standpoint.

 

Weight is a Factor (Empirically)

• By the time I had my PSG, I had lost ten pounds from when I had originally collected my own pulse-ox data. My BMI was hovering around 27 in late February, and was just under 26 going into my sleep study.

 

Night-to-night Variability

• All of this information is to help corroborate the idea that there is significant night-to-night variability to consider as well as the role of weight in the process for my case. 
• To provide some concrete numbers, my pulse-ox data in early March showed ODI 4% ranging from 22-28/hr per night over multiple nights. Following my PSG (and weight loss) the same pulse-ox showed ODI 4% ranging from 2.4-9.7/hr per night over multiple nights.

Data Conclusions and Limitations of ODI

The only conclusion I can draw from the data I have is that the night-to-night variability is driven by another factor other than weight, and this is what has led me to this forum. 

I understand ODI is not a replacement for PSG data, but due to limitations from insurance and as a human who wouldn't want to sleep with the PSG equipment nightly, it's not possible to collect all PSG datapoints each night.

CPAP Data

I am using a ResMed AirSense 11 with ResMed F40 full face mask. My pressure is currently set to 10.0 with EPR 2. To date, I've collected 29 days' worth of data using CPAP, with 21 of those days using the machine for >4 hours. The timeline may seem off and that's becuase I purchased a machine off Craigslist because I wanted to start the process of diagnostic exclusion as quickly as possible since my sleep study was originally scheduled at the end of May and my issues had been ongoing for over 1.5 years. For the sake of simplicity, I'll summarize that my first few weeks were a train wreck where I had myriad issues trying to adjust to the mask and in controlling leaks. 

I ultimately determined that I sleep too sensitively for APAP; although, perhaps now that I'm more adapted it's possible my sensitivity would be reduced. I eventually have determined that I need a full face mask due to mouth-breathing (thanks to a deviated septum and jaw-drop during REM). I eventually discontinued using the CPAP prior to my PSG and decided that I would await my results before continuing.

Since restarting the CPAP about a week ago, I've had a much-improved nightly AHI compared to my initial foray with CPAP a couple months back. 

• However, I still can't seem to dial in my exact settings. I've pored through my OSCAR data and conducted numerous searches in this forum to try and find the solution, but I've had little success.

I tried using a nasal mask, but couldn't control the leaks during REM, so I switched back to my full face mask, ResMed F40. 

• I have had zero issues adapting to the F40 mask in the last five days. I put it on and have been falling asleep right away. My numbers for the five days since have ranged from 2.49-9.56 AHI.

I've tried to increase the pressure in small increments to normalize inspiration patterns (flow rate) and find the sweet spot for CA events, but it seems adjustments up always lead to more CA events and no change on the inspiration patterns.

I tried 11.6 one night to see if I could reel in my inspiratory irregularities that I suspect are occurring during a specific sleeps stage, based on the timing and frequency. That night yielded a 9.56 so I quickly reverted back to 10.4 the next night.

These irregularities occur throughout the night and are not limited to the screenshot example given. 

By and large, most of the night seems to have relatively regular (slightly skewed right) inspiratory waves, but I've noticed that the events I have seem to fall around the inspiratory waves becoming irregular.

Lastly, it's worth noting that when I would wear the CPAP during the day (as I began adjusting to it), my inspiratory waves were nearly perfectly sinusoidal, so it's clear something is happening during sleep to my airflow.

Advice Needed

While I have been feeling a positive response to CPAP already, which is genuinely surprising for me to say after such a short time, so I don't want to get too lost in the weeds with the inspiratory flow if I'm improving. I will admit that I went into this expecting no response, so I think we can safely rule out placebo effect for me. However, I don't want to ignore what might be precipitating events since my reported AHI is still hanging around 5, and most of my events seem staged around the irregular inspiratory flow rates observed in the data. Thanks to anyone for your time reading and any advice you have.