Help interpreting low AHI after reducing CPAP pressure?
In 2022, I was diagnosed via in-lab study with OSA with an AHI of 14.8, all hypopneas, with mild hypoxemia (a two-second nadir at 88% and a mean of 93%), and no snoring.
Since then, I've been using CPAP (Resmed Airsense 11 with Dreamwear mask) with a minimum pressure of 5 and a maximum pressure of 20, EPR set at 1. My CPAP has always reported a low AHI, generally between 1-2. My mask fit is excellent; no reported leaks.
During that time, my GP and a cardiologist (I got routine checkups from both) expressed doubts about my diagnosis; it took three studies to find a diagnosable AHI (an at-home test and a prior in-lab both returned AHI of 1.3), I don't snore, my BMI is 21, my symptoms are mild, and as far as they can tell I'm in excellent physical health. I harbored doubts, too; after several months of exemplary compliance, CPAP was having no significant effect on my symptoms (fatigue, eyelid twitches, brain fog, low mood).
Last month, I learned I could adjust my own pressure settings via my CPAP's clinical menu, and I decided to experiment with lowering my max pressure. This was in part to reduce awakenings from air blasts and in part to see whether my AHI would climb as my CPAP pressure dropped.
For the last week, I've been using a minimum pressure of 5 and a maximum pressure of 7, and my AHI has been very low, generally between 0.0 and 0.5. The clinical menu reports no obstructive or central apneas, which I assume means my few events are hypopneas, which aligns with my in-lab studies. My symptoms continue to wax and wane with no apparent correlation to what happens between me and my CPAP.
Is this drop in AHI during my low-pressure experiment significant? Is it a glitch? Is it actionable information, or should I put it out of mind? I'll be grateful for any guidance.
As a side note: I'm a lifelong sufferer of major-depression and major-anxiety disorders. This feels relevant but might not be.
Since then, I've been using CPAP (Resmed Airsense 11 with Dreamwear mask) with a minimum pressure of 5 and a maximum pressure of 20, EPR set at 1. My CPAP has always reported a low AHI, generally between 1-2. My mask fit is excellent; no reported leaks.
During that time, my GP and a cardiologist (I got routine checkups from both) expressed doubts about my diagnosis; it took three studies to find a diagnosable AHI (an at-home test and a prior in-lab both returned AHI of 1.3), I don't snore, my BMI is 21, my symptoms are mild, and as far as they can tell I'm in excellent physical health. I harbored doubts, too; after several months of exemplary compliance, CPAP was having no significant effect on my symptoms (fatigue, eyelid twitches, brain fog, low mood).
Last month, I learned I could adjust my own pressure settings via my CPAP's clinical menu, and I decided to experiment with lowering my max pressure. This was in part to reduce awakenings from air blasts and in part to see whether my AHI would climb as my CPAP pressure dropped.
For the last week, I've been using a minimum pressure of 5 and a maximum pressure of 7, and my AHI has been very low, generally between 0.0 and 0.5. The clinical menu reports no obstructive or central apneas, which I assume means my few events are hypopneas, which aligns with my in-lab studies. My symptoms continue to wax and wane with no apparent correlation to what happens between me and my CPAP.
Is this drop in AHI during my low-pressure experiment significant? Is it a glitch? Is it actionable information, or should I put it out of mind? I'll be grateful for any guidance.
As a side note: I'm a lifelong sufferer of major-depression and major-anxiety disorders. This feels relevant but might not be.
